fix(plugins): add base64 handling for []byte and remove raw=true (#5121)

* fix(plugins): add base64 handling for []byte and remove raw=true

Go's json.Marshal automatically base64-encodes []byte fields, but Rust's
serde_json serializes Vec<u8> as a JSON array and Python's json.dumps
raises TypeError on bytes. This fixes both directions of plugin
communication by adding proper base64 encoding/decoding in generated
client code.

For Rust templates (client and capability): adds a base64_bytes serde
helper module with #[serde(with = "base64_bytes")] on all Vec<u8> fields,
and adds base64 as a dependency. For Python templates: wraps bytes params
with base64.b64encode() and responses with base64.b64decode().

Also removes the raw=true binary framing protocol from all templates,
the parser, and the Method type. The raw mechanism added complexity that
is no longer needed once []byte works properly over JSON.

* fix(plugins): update production code and tests for base64 migration

Remove raw=true annotation from SubsonicAPI.CallRaw, delete all raw
test fixtures, remove raw-related test cases from parser, generator, and
integration tests, and add new test cases validating base64 handling
for Rust and Python templates.

* fix(plugins): update golden files and regenerate production code

Update golden test fixtures for codec and comprehensive services to
include base64 handling for []byte fields. Regenerate all production
PDK code (Go, Rust, Python) and host wrappers to use standard JSON
with base64-encoded byte fields instead of binary framing protocol.

* refactor: remove base64 helper duplication from rust template

Signed-off-by: Deluan <deluan@navidrome.org>

* fix(plugins): add base64 dependency to capabilities' Cargo.toml

Signed-off-by: Deluan <deluan@navidrome.org>

---------

Signed-off-by: Deluan <deluan@navidrome.org>

plugins/cmd/ndpgen/integration_test.go

@@ -282,9 +282,6 @@ type ServiceB interface {
 
 			Entry("option pattern (value, exists bool)",
 				"config_service.go.txt", "config_client_expected.go.txt", "config_client_expected.py", "config_client_expected.rs"),
-
-			Entry("raw=true binary response",
-				"raw_service.go.txt", "raw_client_expected.go.txt", "raw_client_expected.py", "raw_client_expected.rs"),
 		)
 
 		It("generates compilable client code for comprehensive service", func() {

plugins/cmd/ndpgen/internal/generator.go

@@ -256,6 +256,15 @@ func GenerateClientRust(svc Service) ([]byte, error) {
 		return nil, fmt.Errorf("parsing template: %w", err)
 	}
 
+	partialContent, err := templatesFS.ReadFile("templates/base64_bytes.rs.tmpl")
+	if err != nil {
+		return nil, fmt.Errorf("reading base64_bytes partial: %w", err)
+	}
+	tmpl, err = tmpl.Parse(string(partialContent))
+	if err != nil {
+		return nil, fmt.Errorf("parsing base64_bytes partial: %w", err)
+	}
+
 	data := templateData{
 		Service: svc,
 	}
@@ -622,6 +631,15 @@ func GenerateCapabilityRust(cap Capability) ([]byte, error) {
 		return nil, fmt.Errorf("parsing template: %w", err)
 	}
 
+	partialContent, err := templatesFS.ReadFile("templates/base64_bytes.rs.tmpl")
+	if err != nil {
+		return nil, fmt.Errorf("reading base64_bytes partial: %w", err)
+	}
+	tmpl, err = tmpl.Parse(string(partialContent))
+	if err != nil {
+		return nil, fmt.Errorf("parsing base64_bytes partial: %w", err)
+	}
+
 	data := capabilityTemplateData{
 		Package:    cap.Name,
 		Capability: cap,

plugins/cmd/ndpgen/internal/generator_test.go

@@ -264,96 +264,6 @@ var _ = Describe("Generator", func() {
 			Expect(codeStr).To(ContainSubstring(`extism "github.com/extism/go-sdk"`))
 		})
 
-		It("should generate binary framing for raw=true methods", func() {
-			svc := Service{
-				Name:       "Stream",
-				Permission: "stream",
-				Interface:  "StreamService",
-				Methods: []Method{
-					{
-						Name:     "GetStream",
-						HasError: true,
-						Raw:      true,
-						Params:   []Param{NewParam("uri", "string")},
-						Returns: []Param{
-							NewParam("contentType", "string"),
-							NewParam("data", "[]byte"),
-						},
-					},
-				},
-			}
-
-			code, err := GenerateHost(svc, "host")
-			Expect(err).NotTo(HaveOccurred())
-
-			_, err = format.Source(code)
-			Expect(err).NotTo(HaveOccurred())
-
-			codeStr := string(code)
-
-			// Should include encoding/binary import for raw methods
-			Expect(codeStr).To(ContainSubstring(`"encoding/binary"`))
-
-			// Should NOT generate a response type for raw methods
-			Expect(codeStr).NotTo(ContainSubstring("type StreamGetStreamResponse struct"))
-
-			// Should generate request type (request is still JSON)
-			Expect(codeStr).To(ContainSubstring("type StreamGetStreamRequest struct"))
-
-			// Should build binary frame [0x00][4-byte CT len][CT][data]
-			Expect(codeStr).To(ContainSubstring("frame[0] = 0x00"))
-			Expect(codeStr).To(ContainSubstring("binary.BigEndian.PutUint32"))
-
-			// Should have writeRawError helper
-			Expect(codeStr).To(ContainSubstring("streamWriteRawError"))
-
-			// Should use writeRawError instead of writeError for raw methods
-			Expect(codeStr).To(ContainSubstring("streamWriteRawError(p, stack"))
-		})
-
-		It("should generate both writeError and writeRawError for mixed services", func() {
-			svc := Service{
-				Name:       "API",
-				Permission: "api",
-				Interface:  "APIService",
-				Methods: []Method{
-					{
-						Name:     "Call",
-						HasError: true,
-						Params:   []Param{NewParam("uri", "string")},
-						Returns:  []Param{NewParam("response", "string")},
-					},
-					{
-						Name:     "CallRaw",
-						HasError: true,
-						Raw:      true,
-						Params:   []Param{NewParam("uri", "string")},
-						Returns: []Param{
-							NewParam("contentType", "string"),
-							NewParam("data", "[]byte"),
-						},
-					},
-				},
-			}
-
-			code, err := GenerateHost(svc, "host")
-			Expect(err).NotTo(HaveOccurred())
-
-			_, err = format.Source(code)
-			Expect(err).NotTo(HaveOccurred())
-
-			codeStr := string(code)
-
-			// Should have both helpers
-			Expect(codeStr).To(ContainSubstring("apiWriteResponse"))
-			Expect(codeStr).To(ContainSubstring("apiWriteError"))
-			Expect(codeStr).To(ContainSubstring("apiWriteRawError"))
-
-			// Should generate response type for non-raw method only
-			Expect(codeStr).To(ContainSubstring("type APICallResponse struct"))
-			Expect(codeStr).NotTo(ContainSubstring("type APICallRawResponse struct"))
-		})
-
 		It("should always include json import for JSON protocol", func() {
 			// All services use JSON protocol, so json import is always needed
 			svc := Service{
@@ -717,49 +627,7 @@ var _ = Describe("Generator", func() {
 			Expect(codeStr).To(ContainSubstring(`response.get("boolVal", False)`))
 		})
 
-		It("should generate binary frame parsing for raw methods", func() {
+		It("should not import base64 for non-byte services", func() {
-			svc := Service{
-				Name:       "Stream",
-				Permission: "stream",
-				Interface:  "StreamService",
-				Methods: []Method{
-					{
-						Name:     "GetStream",
-						HasError: true,
-						Raw:      true,
-						Params:   []Param{NewParam("uri", "string")},
-						Returns: []Param{
-							NewParam("contentType", "string"),
-							NewParam("data", "[]byte"),
-						},
-						Doc: "GetStream returns raw binary stream data.",
-					},
-				},
-			}
-
-			code, err := GenerateClientPython(svc)
-			Expect(err).NotTo(HaveOccurred())
-
-			codeStr := string(code)
-
-			// Should import Tuple and struct for raw methods
-			Expect(codeStr).To(ContainSubstring("from typing import Any, Tuple"))
-			Expect(codeStr).To(ContainSubstring("import struct"))
-
-			// Should return Tuple[str, bytes]
-			Expect(codeStr).To(ContainSubstring("-> Tuple[str, bytes]:"))
-
-			// Should parse binary frame instead of JSON
-			Expect(codeStr).To(ContainSubstring("response_bytes = response_mem.bytes()"))
-			Expect(codeStr).To(ContainSubstring("response_bytes[0] == 0x01"))
-			Expect(codeStr).To(ContainSubstring("struct.unpack"))
-			Expect(codeStr).To(ContainSubstring("return content_type, data"))
-
-			// Should NOT use json.loads for response
-			Expect(codeStr).NotTo(ContainSubstring("json.loads(extism.memory.string(response_mem))"))
-		})
-
-		It("should not import Tuple or struct for non-raw services", func() {
 			svc := Service{
 				Name:       "Test",
 				Permission: "test",
@@ -779,8 +647,37 @@ var _ = Describe("Generator", func() {
 
 			codeStr := string(code)
 
-			Expect(codeStr).NotTo(ContainSubstring("Tuple"))
+			Expect(codeStr).NotTo(ContainSubstring("import base64"))
-			Expect(codeStr).NotTo(ContainSubstring("import struct"))
+		})
+
+		It("should generate base64 encoding/decoding for byte fields", func() {
+			svc := Service{
+				Name:       "Codec",
+				Permission: "codec",
+				Interface:  "CodecService",
+				Methods: []Method{
+					{
+						Name:     "Encode",
+						HasError: true,
+						Params:   []Param{NewParam("data", "[]byte")},
+						Returns:  []Param{NewParam("result", "[]byte")},
+					},
+				},
+			}
+
+			code, err := GenerateClientPython(svc)
+			Expect(err).NotTo(HaveOccurred())
+
+			codeStr := string(code)
+
+			// Should import base64
+			Expect(codeStr).To(ContainSubstring("import base64"))
+
+			// Should base64-encode byte params in request
+			Expect(codeStr).To(ContainSubstring(`base64.b64encode(data).decode("ascii")`))
+
+			// Should base64-decode byte returns in response
+			Expect(codeStr).To(ContainSubstring(`base64.b64decode(response.get("result", ""))`))
 		})
 	})
 
@@ -939,46 +836,6 @@ var _ = Describe("Generator", func() {
 			Expect(codeStr).To(ContainSubstring("github.com/navidrome/navidrome/plugins/pdk/go/pdk"))
 		})
 
-		It("should include encoding/binary import for raw methods", func() {
-			svc := Service{
-				Name:       "Stream",
-				Permission: "stream",
-				Interface:  "StreamService",
-				Methods: []Method{
-					{
-						Name:     "GetStream",
-						HasError: true,
-						Raw:      true,
-						Params:   []Param{NewParam("uri", "string")},
-						Returns: []Param{
-							NewParam("contentType", "string"),
-							NewParam("data", "[]byte"),
-						},
-					},
-				},
-			}
-
-			code, err := GenerateClientGo(svc, "host")
-			Expect(err).NotTo(HaveOccurred())
-
-			codeStr := string(code)
-
-			// Should include encoding/binary for raw binary frame parsing
-			Expect(codeStr).To(ContainSubstring(`"encoding/binary"`))
-
-			// Should NOT generate response type struct for raw methods
-			Expect(codeStr).NotTo(ContainSubstring("streamGetStreamResponse struct"))
-
-			// Should still generate request type
-			Expect(codeStr).To(ContainSubstring("streamGetStreamRequest struct"))
-
-			// Should parse binary frame
-			Expect(codeStr).To(ContainSubstring("responseBytes[0] == 0x01"))
-			Expect(codeStr).To(ContainSubstring("binary.BigEndian.Uint32"))
-
-			// Should return (string, []byte, error)
-			Expect(codeStr).To(ContainSubstring("func StreamGetStream(uri string) (string, []byte, error)"))
-		})
 	})
 
 	Describe("GenerateClientGoStub", func() {
@@ -1748,22 +1605,17 @@ var _ = Describe("Rust Generation", func() {
 			Expect(codeStr).NotTo(ContainSubstring("Option<bool>"))
 		})
 
-		It("should generate raw extern C import and binary frame parsing for raw methods", func() {
+		It("should generate base64 serde for Vec<u8> fields", func() {
 			svc := Service{
-				Name:       "Stream",
+				Name:       "Codec",
-				Permission: "stream",
+				Permission: "codec",
-				Interface:  "StreamService",
+				Interface:  "CodecService",
 				Methods: []Method{
 					{
-						Name:     "GetStream",
+						Name:     "Encode",
 						HasError: true,
-						Raw:      true,
+						Params:   []Param{NewParam("data", "[]byte")},
-						Params:   []Param{NewParam("uri", "string")},
+						Returns:  []Param{NewParam("result", "[]byte")},
-						Returns: []Param{
-							NewParam("contentType", "string"),
-							NewParam("data", "[]byte"),
-						},
-						Doc: "GetStream returns raw binary stream data.",
 					},
 				},
 			}
@@ -1773,24 +1625,36 @@ var _ = Describe("Rust Generation", func() {
 
 			codeStr := string(code)
 
-			// Should use extern "C" with wasm_import_module for raw methods, not #[host_fn] extern "ExtismHost"
+			// Should generate base64_bytes serde module
-			Expect(codeStr).To(ContainSubstring(`#[link(wasm_import_module = "extism:host/user")]`))
+			Expect(codeStr).To(ContainSubstring("mod base64_bytes"))
-			Expect(codeStr).To(ContainSubstring(`extern "C"`))
+			Expect(codeStr).To(ContainSubstring("use base64::Engine as _"))
-			Expect(codeStr).To(ContainSubstring("fn stream_getstream(offset: u64) -> u64"))
 
-			// Should NOT generate response type for raw methods
+			// Should add serde(with = "base64_bytes") on Vec<u8> fields
-			Expect(codeStr).NotTo(ContainSubstring("StreamGetStreamResponse"))
+			Expect(codeStr).To(ContainSubstring(`#[serde(with = "base64_bytes")]`))
+		})
 
-			// Should generate request type (request is still JSON)
+		It("should not generate base64 module when no byte fields", func() {
-			Expect(codeStr).To(ContainSubstring("struct StreamGetStreamRequest"))
+			svc := Service{
+				Name:       "Test",
+				Permission: "test",
+				Interface:  "TestService",
+				Methods: []Method{
+					{
+						Name:     "Call",
+						HasError: true,
+						Params:   []Param{NewParam("uri", "string")},
+						Returns:  []Param{NewParam("response", "string")},
+					},
+				},
+			}
 
-			// Should return Result<(String, Vec<u8>), Error>
+			code, err := GenerateClientRust(svc)
-			Expect(codeStr).To(ContainSubstring("Result<(String, Vec<u8>), Error>"))
+			Expect(err).NotTo(HaveOccurred())
 
-			// Should parse binary frame
+			codeStr := string(code)
-			Expect(codeStr).To(ContainSubstring("response_bytes[0] == 0x01"))
+
-			Expect(codeStr).To(ContainSubstring("u32::from_be_bytes"))
+			Expect(codeStr).NotTo(ContainSubstring("mod base64_bytes"))
-			Expect(codeStr).To(ContainSubstring("String::from_utf8_lossy"))
+			Expect(codeStr).NotTo(ContainSubstring("use base64"))
 		})
 	})
 })

plugins/cmd/ndpgen/internal/parser.go

@@ -761,7 +761,6 @@ func parseMethod(name string, funcType *ast.FuncType, annotation map[string]stri
 	m := Method{
 		Name:       name,
 		ExportName: annotation["name"],
-		Raw:        annotation["raw"] == "true",
 		Doc:        doc,
 	}
 
@@ -800,13 +799,6 @@ func parseMethod(name string, funcType *ast.FuncType, annotation map[string]stri
 		}
 	}
 
-	// Validate raw=true methods: must return exactly (string, []byte, error)
-	if m.Raw {
-		if !m.HasError || len(m.Returns) != 2 || m.Returns[0].Type != "string" || m.Returns[1].Type != "[]byte" {
-			return m, fmt.Errorf("raw=true method %s must return (string, []byte, error) — content-type, data, error", name)
-		}
-	}
-
 	return m, nil
 }
 

plugins/cmd/ndpgen/internal/parser_test.go

@@ -122,119 +122,6 @@ type TestService interface {
 			Expect(services[0].Methods[0].Name).To(Equal("Exported"))
 		})
 
-		It("should parse raw=true annotation", func() {
-			src := `package host
-
-import "context"
-
-//nd:hostservice name=Stream permission=stream
-type StreamService interface {
-	//nd:hostfunc raw=true
-	GetStream(ctx context.Context, uri string) (contentType string, data []byte, err error)
-}
-`
-			err := os.WriteFile(filepath.Join(tmpDir, "stream.go"), []byte(src), 0600)
-			Expect(err).NotTo(HaveOccurred())
-
-			services, err := ParseDirectory(tmpDir)
-			Expect(err).NotTo(HaveOccurred())
-			Expect(services).To(HaveLen(1))
-
-			m := services[0].Methods[0]
-			Expect(m.Name).To(Equal("GetStream"))
-			Expect(m.Raw).To(BeTrue())
-			Expect(m.HasError).To(BeTrue())
-			Expect(m.Returns).To(HaveLen(2))
-			Expect(m.Returns[0].Name).To(Equal("contentType"))
-			Expect(m.Returns[0].Type).To(Equal("string"))
-			Expect(m.Returns[1].Name).To(Equal("data"))
-			Expect(m.Returns[1].Type).To(Equal("[]byte"))
-		})
-
-		It("should set Raw=false when raw annotation is absent", func() {
-			src := `package host
-
-import "context"
-
-//nd:hostservice name=Test permission=test
-type TestService interface {
-	//nd:hostfunc
-	Call(ctx context.Context, uri string) (response string, err error)
-}
-`
-			err := os.WriteFile(filepath.Join(tmpDir, "test.go"), []byte(src), 0600)
-			Expect(err).NotTo(HaveOccurred())
-
-			services, err := ParseDirectory(tmpDir)
-			Expect(err).NotTo(HaveOccurred())
-			Expect(services[0].Methods[0].Raw).To(BeFalse())
-		})
-
-		It("should reject raw=true with invalid return signature", func() {
-			src := `package host
-
-import "context"
-
-//nd:hostservice name=Test permission=test
-type TestService interface {
-	//nd:hostfunc raw=true
-	BadRaw(ctx context.Context, uri string) (result string, err error)
-}
-`
-			err := os.WriteFile(filepath.Join(tmpDir, "test.go"), []byte(src), 0600)
-			Expect(err).NotTo(HaveOccurred())
-
-			_, err = ParseDirectory(tmpDir)
-			Expect(err).To(HaveOccurred())
-			Expect(err.Error()).To(ContainSubstring("raw=true"))
-			Expect(err.Error()).To(ContainSubstring("must return (string, []byte, error)"))
-		})
-
-		It("should reject raw=true without error return", func() {
-			src := `package host
-
-import "context"
-
-//nd:hostservice name=Test permission=test
-type TestService interface {
-	//nd:hostfunc raw=true
-	BadRaw(ctx context.Context, uri string) (contentType string, data []byte)
-}
-`
-			err := os.WriteFile(filepath.Join(tmpDir, "test.go"), []byte(src), 0600)
-			Expect(err).NotTo(HaveOccurred())
-
-			_, err = ParseDirectory(tmpDir)
-			Expect(err).To(HaveOccurred())
-			Expect(err.Error()).To(ContainSubstring("raw=true"))
-		})
-
-		It("should parse mixed raw and non-raw methods", func() {
-			src := `package host
-
-import "context"
-
-//nd:hostservice name=API permission=api
-type APIService interface {
-	//nd:hostfunc
-	Call(ctx context.Context, uri string) (responseJSON string, err error)
-
-	//nd:hostfunc raw=true
-	CallRaw(ctx context.Context, uri string) (contentType string, data []byte, err error)
-}
-`
-			err := os.WriteFile(filepath.Join(tmpDir, "api.go"), []byte(src), 0600)
-			Expect(err).NotTo(HaveOccurred())
-
-			services, err := ParseDirectory(tmpDir)
-			Expect(err).NotTo(HaveOccurred())
-			Expect(services).To(HaveLen(1))
-			Expect(services[0].Methods).To(HaveLen(2))
-			Expect(services[0].Methods[0].Raw).To(BeFalse())
-			Expect(services[0].Methods[1].Raw).To(BeTrue())
-			Expect(services[0].HasRawMethods()).To(BeTrue())
-		})
-
 		It("should handle custom export name", func() {
 			src := `package host
 

plugins/cmd/ndpgen/internal/templates/base64_bytes.rs.tmpl

@@ -0,0 +1,25 @@
+{{define "base64_bytes_module"}}
+use base64::Engine as _;
+use base64::engine::general_purpose::STANDARD as BASE64;
+
+mod base64_bytes {
+    use serde::{self, Deserialize, Deserializer, Serializer};
+    use base64::Engine as _;
+    use base64::engine::general_purpose::STANDARD as BASE64;
+
+    pub fn serialize<S>(bytes: &Vec<u8>, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        serializer.serialize_str(&BASE64.encode(bytes))
+    }
+
+    pub fn deserialize<'de, D>(deserializer: D) -> Result<Vec<u8>, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        let s = String::deserialize(deserializer)?;
+        BASE64.decode(&s).map_err(serde::de::Error::custom)
+    }
+}
+{{- end}}

plugins/cmd/ndpgen/internal/templates/capability.rs.tmpl

@@ -7,6 +7,7 @@ use serde::{Deserialize, Serialize};
 {{- if hasHashMap .Capability}}
 use std::collections::HashMap;
 {{- end}}
+{{- if .Capability.HasByteFields}}{{template "base64_bytes_module" .}}{{- end}}
 
 // Helper functions for skip_serializing_if with numeric types
 #[allow(dead_code)]
@@ -70,6 +71,9 @@ pub struct {{.Name}} {
     #[serde(default, skip_serializing_if = "{{skipSerializingFunc .Type}}")]
 {{- else}}
     #[serde(default)]
+{{- end}}
+{{- if .IsByteSlice}}
+    #[serde(with = "base64_bytes")]
 {{- end}}
     pub {{rustFieldName .Name}}: {{fieldRustType .}},
 {{- end}}

plugins/cmd/ndpgen/internal/templates/client.go.tmpl

@@ -8,9 +8,6 @@
 package {{.Package}}
 
 import (
-{{- if .Service.HasRawMethods}}
-	"encoding/binary"
-{{- end}}
 	"encoding/json"
 {{- if .Service.HasErrors}}
 	"errors"
@@ -52,7 +49,7 @@ type {{requestType .}} struct {
 {{- end}}
 }
 {{- end}}
-{{- if and (not .IsErrorOnly) (not .Raw)}}
+{{- if not .IsErrorOnly}}
 
 type {{responseType .}} struct {
 {{- range .Returns}}
@@ -98,27 +95,7 @@ func {{$.Service.Name}}{{.Name}}({{range $i, $p := .Params}}{{if $i}}, {{end}}{{
 	// Read the response from memory
 	responseMem := pdk.FindMemory(responsePtr)
 	responseBytes := responseMem.ReadBytes()
-{{- if .Raw}}
+{{- if .IsErrorOnly}}
-
-	// Parse binary-framed response
-	if len(responseBytes) == 0 {
-		return "", nil, errors.New("empty response from host")
-	}
-	if responseBytes[0] == 0x01 { // error
-		return "", nil, errors.New(string(responseBytes[1:]))
-	}
-	if responseBytes[0] != 0x00 {
-		return "", nil, errors.New("unknown response status")
-	}
-	if len(responseBytes) < 5 {
-		return "", nil, errors.New("malformed raw response: incomplete header")
-	}
-	ctLen := binary.BigEndian.Uint32(responseBytes[1:5])
-	if uint32(len(responseBytes)) < 5+ctLen {
-		return "", nil, errors.New("malformed raw response: content-type overflow")
-	}
-	return string(responseBytes[5 : 5+ctLen]), responseBytes[5+ctLen:], nil
-{{- else if .IsErrorOnly}}
 
 	// Parse error-only response
 	var response struct {

plugins/cmd/ndpgen/internal/templates/client.py.tmpl

@@ -8,12 +8,12 @@
 # main __init__.py file. Copy the needed functions from this file into your plugin.
 
 from dataclasses import dataclass
-from typing import Any{{- if .Service.HasRawMethods}}, Tuple{{end}}
+from typing import Any
 
 import extism
 import json
-{{- if .Service.HasRawMethods}}
+{{- if .Service.HasByteFields}}
-import struct
+import base64
 {{- end}}
 
 
@@ -32,7 +32,7 @@ def _{{exportName .}}(offset: int) -> int:
 {{- end}}
 {{- /* Generate dataclasses for multi-value returns */ -}}
 {{range .Service.Methods}}
-{{- if and .NeedsResultClass (not .Raw)}}
+{{- if .NeedsResultClass}}
 
 
 @dataclass
@@ -47,7 +47,7 @@ class {{pythonResultType .}}:
 {{range .Service.Methods}}
 
 
-def {{pythonFunc .}}({{range $i, $p := .Params}}{{if $i}}, {{end}}{{$p.PythonName}}: {{$p.PythonType}}{{end}}){{if .Raw}} -> Tuple[str, bytes]{{else if .NeedsResultClass}} -> {{pythonResultType .}}{{else if .HasReturns}} -> {{(index .Returns 0).PythonType}}{{else}} -> None{{end}}:
+def {{pythonFunc .}}({{range $i, $p := .Params}}{{if $i}}, {{end}}{{$p.PythonName}}: {{$p.PythonType}}{{end}}){{if .NeedsResultClass}} -> {{pythonResultType .}}{{else if .HasReturns}} -> {{(index .Returns 0).PythonType}}{{else}} -> None{{end}}:
     """{{if .Doc}}{{.Doc}}{{else}}Call the {{exportName .}} host function.{{end}}
 {{- if .HasParams}}
 
@@ -56,11 +56,7 @@ def {{pythonFunc .}}({{range $i, $p := .Params}}{{if $i}}, {{end}}{{$p.PythonNam
         {{.PythonName}}: {{.PythonType}} parameter.
 {{- end}}
 {{- end}}
-{{- if .Raw}}
+{{- if .HasReturns}}
-
-    Returns:
-        Tuple of (content_type, data) with the raw binary response.
-{{- else if .HasReturns}}
 
     Returns:
 {{- if .NeedsResultClass}}
@@ -76,7 +72,11 @@ def {{pythonFunc .}}({{range $i, $p := .Params}}{{if $i}}, {{end}}{{$p.PythonNam
 {{- if .HasParams}}
     request = {
 {{- range .Params}}
+{{- if .IsByteSlice}}
+        "{{.JSONName}}": base64.b64encode({{.PythonName}}).decode("ascii"),
+{{- else}}
         "{{.JSONName}}": {{.PythonName}},
+{{- end}}
 {{- end}}
     }
     request_bytes = json.dumps(request).encode("utf-8")
@@ -86,24 +86,6 @@ def {{pythonFunc .}}({{range $i, $p := .Params}}{{if $i}}, {{end}}{{$p.PythonNam
     request_mem = extism.memory.alloc(request_bytes)
     response_offset = _{{exportName .}}(request_mem.offset)
     response_mem = extism.memory.find(response_offset)
-{{- if .Raw}}
-    response_bytes = response_mem.bytes()
-
-    if len(response_bytes) == 0:
-        raise HostFunctionError("empty response from host")
-    if response_bytes[0] == 0x01:
-        raise HostFunctionError(response_bytes[1:].decode("utf-8"))
-    if response_bytes[0] != 0x00:
-        raise HostFunctionError("unknown response status")
-    if len(response_bytes) < 5:
-        raise HostFunctionError("malformed raw response: incomplete header")
-    ct_len = struct.unpack(">I", response_bytes[1:5])[0]
-    if len(response_bytes) < 5 + ct_len:
-        raise HostFunctionError("malformed raw response: content-type overflow")
-    content_type = response_bytes[5:5 + ct_len].decode("utf-8")
-    data = response_bytes[5 + ct_len:]
-    return content_type, data
-{{- else}}
     response = json.loads(extism.memory.string(response_mem))
 {{if .HasError}}
     if response.get("error"):
@@ -112,10 +94,17 @@ def {{pythonFunc .}}({{range $i, $p := .Params}}{{if $i}}, {{end}}{{$p.PythonNam
 {{- if .NeedsResultClass}}
     return {{pythonResultType .}}(
 {{- range .Returns}}
+{{- if .IsByteSlice}}
+        {{.PythonName}}=base64.b64decode(response.get("{{.JSONName}}", "")),
+{{- else}}
         {{.PythonName}}=response.get("{{.JSONName}}"{{pythonDefault .}}),
+{{- end}}
 {{- end}}
     )
 {{- else if .HasReturns}}
+{{- if (index .Returns 0).IsByteSlice}}
+    return base64.b64decode(response.get("{{(index .Returns 0).JSONName}}", ""))
+{{- else}}
     return response.get("{{(index .Returns 0).JSONName}}"{{pythonDefault (index .Returns 0)}})
 {{- end}}
 {{- end}}

plugins/cmd/ndpgen/internal/templates/client.rs.tmpl

@@ -5,6 +5,7 @@
 
 use extism_pdk::*;
 use serde::{Deserialize, Serialize};
+{{- if .Service.HasByteFields}}{{template "base64_bytes_module" .}}{{- end}}
 {{- /* Generate struct definitions */ -}}
 {{- range .Service.Structs}}
 {{if .Doc}}
@@ -16,6 +17,9 @@ pub struct {{.Name}} {
 {{- range .Fields}}
 {{- if .NeedsDefault}}
     #[serde(default)]
+{{- end}}
+{{- if .IsByteSlice}}
+    #[serde(with = "base64_bytes")]
 {{- end}}
     pub {{.RustName}}: {{fieldRustType .}},
 {{- end}}
@@ -29,17 +33,22 @@ pub struct {{.Name}} {
 #[serde(rename_all = "camelCase")]
 struct {{requestType .}} {
 {{- range .Params}}
+{{- if .IsByteSlice}}
+    #[serde(with = "base64_bytes")]
+{{- end}}
     {{.RustName}}: {{rustType .}},
 {{- end}}
 }
 {{- end}}
-{{- if not .Raw}}
 
 #[derive(Debug, Clone, Deserialize)]
 #[serde(rename_all = "camelCase")]
 struct {{responseType .}} {
 {{- range .Returns}}
     #[serde(default)]
+{{- if .IsByteSlice}}
+    #[serde(with = "base64_bytes")]
+{{- end}}
     {{.RustName}}: {{rustType .}},
 {{- end}}
 {{- if .HasError}}
@@ -48,92 +57,16 @@ struct {{responseType .}} {
 {{- end}}
 }
 {{- end}}
-{{- end}}
 
 #[host_fn]
 extern "ExtismHost" {
 {{- range .Service.Methods}}
-{{- if not .Raw}}
     fn {{exportName .}}(input: Json<{{if .HasParams}}{{requestType .}}{{else}}serde_json::Value{{end}}>) -> Json<{{responseType .}}>;
 {{- end}}
-{{- end}}
 }
-{{- /* Declare raw extern "C" imports for raw methods */ -}}
-{{- range .Service.Methods}}
-{{- if .Raw}}
-
-#[link(wasm_import_module = "extism:host/user")]
-extern "C" {
-    fn {{exportName .}}(offset: u64) -> u64;
-}
-{{- end}}
-{{- end}}
 
 {{- /* Generate wrapper functions */ -}}
 {{range .Service.Methods}}
-{{- if .Raw}}
-
-{{if .Doc}}{{rustDocComment .Doc}}{{else}}/// Calls the {{exportName .}} host function.{{end}}
-{{- if .HasParams}}
-///
-/// # Arguments
-{{- range .Params}}
-/// * `{{.RustName}}` - {{rustType .}} parameter.
-{{- end}}
-{{- end}}
-///
-/// # Returns
-/// A tuple of (content_type, data) with the raw binary response.
-///
-/// # Errors
-/// Returns an error if the host function call fails.
-pub fn {{rustFunc .}}({{range $i, $p := .Params}}{{if $i}}, {{end}}{{$p.RustName}}: {{rustParamType $p}}{{end}}) -> Result<(String, Vec<u8>), Error> {
-{{- if .HasParams}}
-    let req = {{requestType .}} {
-{{- range .Params}}
-        {{.RustName}}: {{.RustName}}{{if .NeedsToOwned}}.to_owned(){{end}},
-{{- end}}
-    };
-    let input_bytes = serde_json::to_vec(&req).map_err(|e| Error::msg(e.to_string()))?;
-{{- else}}
-    let input_bytes = b"{}".to_vec();
-{{- end}}
-    let input_mem = Memory::from_bytes(&input_bytes).map_err(|e| Error::msg(e.to_string()))?;
-
-    let response_offset = unsafe { {{exportName .}}(input_mem.offset()) };
-
-    let response_mem = Memory::find(response_offset)
-        .ok_or_else(|| Error::msg("empty response from host"))?;
-    let response_bytes = response_mem.to_vec();
-
-    if response_bytes.is_empty() {
-        return Err(Error::msg("empty response from host"));
-    }
-    if response_bytes[0] == 0x01 {
-        let msg = String::from_utf8_lossy(&response_bytes[1..]).to_string();
-        return Err(Error::msg(msg));
-    }
-    if response_bytes[0] != 0x00 {
-        return Err(Error::msg("unknown response status"));
-    }
-    if response_bytes.len() < 5 {
-        return Err(Error::msg("malformed raw response: incomplete header"));
-    }
-    let ct_len = u32::from_be_bytes([
-        response_bytes[1],
-        response_bytes[2],
-        response_bytes[3],
-        response_bytes[4],
-    ]) as usize;
-    if ct_len > response_bytes.len() - 5 {
-        return Err(Error::msg("malformed raw response: content-type overflow"));
-    }
-    let ct_end = 5 + ct_len;
-    let content_type = String::from_utf8_lossy(&response_bytes[5..ct_end]).to_string();
-    let data = response_bytes[ct_end..].to_vec();
-    Ok((content_type, data))
-}
-{{- else}}
 
 {{if .Doc}}{{rustDocComment .Doc}}{{else}}/// Calls the {{exportName .}} host function.{{end}}
 {{- if .HasParams}}
@@ -209,4 +142,3 @@ pub fn {{rustFunc .}}({{range $i, $p := .Params}}{{if $i}}, {{end}}{{$p.RustName
 }
 {{- end}}
 {{- end}}
-{{- end}}

plugins/cmd/ndpgen/internal/templates/host.go.tmpl

@@ -4,9 +4,6 @@ package {{.Package}}
 
 import (
 	"context"
-{{- if .Service.HasRawMethods}}
-	"encoding/binary"
-{{- end}}
 	"encoding/json"
 
 	extism "github.com/extism/go-sdk"
@@ -23,7 +20,6 @@ type {{requestType .}} struct {
 {{- end}}
 }
 {{- end}}
-{{- if not .Raw}}
 
 // {{responseType .}} is the response type for {{$.Service.Name}}.{{.Name}}.
 type {{responseType .}} struct {
@@ -34,7 +30,6 @@ type {{responseType .}} struct {
 	Error string `json:"error,omitempty"`
 {{- end}}
 }
-{{- end}}
 {{end}}
 
 // Register{{.Service.Name}}HostFunctions registers {{.Service.Name}} service host functions.
@@ -56,48 +51,18 @@ func new{{$.Service.Name}}{{.Name}}HostFunction(service {{$.Service.Interface}})
 			// Read JSON request from plugin memory
 			reqBytes, err := p.ReadBytes(stack[0])
 			if err != nil {
-{{- if .Raw}}
-				{{$.Service.Name | lower}}WriteRawError(p, stack, err)
-{{- else}}
 				{{$.Service.Name | lower}}WriteError(p, stack, err)
-{{- end}}
 				return
 			}
 			var req {{requestType .}}
 			if err := json.Unmarshal(reqBytes, &req); err != nil {
-{{- if .Raw}}
-				{{$.Service.Name | lower}}WriteRawError(p, stack, err)
-{{- else}}
 				{{$.Service.Name | lower}}WriteError(p, stack, err)
-{{- end}}
 				return
 			}
 {{- end}}
 
 			// Call the service method
-{{- if .Raw}}
+{{- if .HasReturns}}
-			{{range $i, $r := .Returns}}{{if $i}}, {{end}}{{lower $r.Name}}{{end}}, svcErr := service.{{.Name}}(ctx{{range .Params}}, req.{{title .Name}}{{end}})
-			if svcErr != nil {
-				{{$.Service.Name | lower}}WriteRawError(p, stack, svcErr)
-				return
-			}
-
-			// Write binary-framed response to plugin memory:
-			// [0x00][4-byte content-type length (big-endian)][content-type string][raw data]
-			ctBytes := []byte({{lower (index .Returns 0).Name}})
-			frame := make([]byte, 1+4+len(ctBytes)+len({{lower (index .Returns 1).Name}}))
-			frame[0] = 0x00 // success
-			binary.BigEndian.PutUint32(frame[1:5], uint32(len(ctBytes)))
-			copy(frame[5:5+len(ctBytes)], ctBytes)
-			copy(frame[5+len(ctBytes):], {{lower (index .Returns 1).Name}})
-
-			respPtr, err := p.WriteBytes(frame)
-			if err != nil {
-				stack[0] = 0
-				return
-			}
-			stack[0] = respPtr
-{{- else if .HasReturns}}
 {{- if .HasError}}
 			{{range $i, $r := .Returns}}{{if $i}}, {{end}}{{lower $r.Name}}{{end}}, svcErr := service.{{.Name}}(ctx{{range .Params}}, req.{{title .Name}}{{end}})
 			if svcErr != nil {
@@ -162,16 +127,3 @@ func {{.Service.Name | lower}}WriteError(p *extism.CurrentPlugin, stack []uint64
 	respPtr, _ := p.WriteBytes(respBytes)
 	stack[0] = respPtr
 }
-{{- if .Service.HasRawMethods}}
-
-// {{.Service.Name | lower}}WriteRawError writes a binary-framed error response to plugin memory.
-// Format: [0x01][UTF-8 error message]
-func {{.Service.Name | lower}}WriteRawError(p *extism.CurrentPlugin, stack []uint64, err error) {
-	errMsg := []byte(err.Error())
-	frame := make([]byte, 1+len(errMsg))
-	frame[0] = 0x01 // error
-	copy(frame[1:], errMsg)
-	respPtr, _ := p.WriteBytes(frame)
-	stack[0] = respPtr
-}
-{{- end}}

plugins/cmd/ndpgen/internal/types.go

@@ -173,16 +173,6 @@ func (s Service) HasErrors() bool {
 	return false
 }
 
-// HasRawMethods returns true if any method in the service uses raw binary framing.
-func (s Service) HasRawMethods() bool {
-	for _, m := range s.Methods {
-		if m.Raw {
-			return true
-		}
-	}
-	return false
-}
-
 // Method represents a host function method within a service.
 type Method struct {
 	Name       string  // Go method name (e.g., "Call")
@@ -191,7 +181,6 @@ type Method struct {
 	Returns    []Param // Return values (excluding error)
 	HasError   bool    // Whether the method returns an error
 	Doc        string  // Documentation comment for the method
-	Raw        bool    // If true, response uses binary framing instead of JSON
 }
 
 // FunctionName returns the Extism host function export name.
@@ -343,6 +332,52 @@ type Param struct {
 	JSONName string // JSON field name (camelCase)
 }
 
+// IsByteSlice returns true if the parameter type is []byte.
+func (p Param) IsByteSlice() bool {
+	return p.Type == "[]byte"
+}
+
+// IsByteSlice returns true if the field type is []byte.
+func (f FieldDef) IsByteSlice() bool {
+	return f.Type == "[]byte"
+}
+
+// HasByteFields returns true if any method params, returns, or struct fields use []byte.
+func (s Service) HasByteFields() bool {
+	for _, m := range s.Methods {
+		for _, p := range m.Params {
+			if p.IsByteSlice() {
+				return true
+			}
+		}
+		for _, r := range m.Returns {
+			if r.IsByteSlice() {
+				return true
+			}
+		}
+	}
+	for _, st := range s.Structs {
+		for _, f := range st.Fields {
+			if f.IsByteSlice() {
+				return true
+			}
+		}
+	}
+	return false
+}
+
+// HasByteFields returns true if any capability struct fields use []byte.
+func (c Capability) HasByteFields() bool {
+	for _, st := range c.Structs {
+		for _, f := range st.Fields {
+			if f.IsByteSlice() {
+				return true
+			}
+		}
+	}
+	return false
+}
+
 // NewParam creates a Param with auto-generated JSON name.
 func NewParam(name, typ string) Param {
 	return Param{

plugins/cmd/ndpgen/testdata/codec_client_expected.py

@@ -12,6 +12,7 @@ from typing import Any
 
 import extism
 import json
+import base64
 
 
 class HostFunctionError(Exception):
@@ -38,7 +39,7 @@ def codec_encode(data: bytes) -> bytes:
         HostFunctionError: If the host function returns an error.
     """
     request = {
-        "data": data,
+        "data": base64.b64encode(data).decode("ascii"),
     }
     request_bytes = json.dumps(request).encode("utf-8")
     request_mem = extism.memory.alloc(request_bytes)
@@ -49,4 +50,4 @@ def codec_encode(data: bytes) -> bytes:
     if response.get("error"):
         raise HostFunctionError(response["error"])
 
-    return response.get("result", b"")
+    return base64.b64decode(response.get("result", ""))

plugins/cmd/ndpgen/testdata/codec_client_expected.rs

@@ -5,10 +5,34 @@
 
 use extism_pdk::*;
 use serde::{Deserialize, Serialize};
+use base64::Engine as _;
+use base64::engine::general_purpose::STANDARD as BASE64;
+
+mod base64_bytes {
+    use serde::{self, Deserialize, Deserializer, Serializer};
+    use base64::Engine as _;
+    use base64::engine::general_purpose::STANDARD as BASE64;
+
+    pub fn serialize<S>(bytes: &Vec<u8>, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        serializer.serialize_str(&BASE64.encode(bytes))
+    }
+
+    pub fn deserialize<'de, D>(deserializer: D) -> Result<Vec<u8>, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        let s = String::deserialize(deserializer)?;
+        BASE64.decode(&s).map_err(serde::de::Error::custom)
+    }
+}
 
 #[derive(Debug, Clone, Serialize)]
 #[serde(rename_all = "camelCase")]
 struct CodecEncodeRequest {
+    #[serde(with = "base64_bytes")]
     data: Vec<u8>,
 }
 
@@ -16,6 +40,7 @@ struct CodecEncodeRequest {
 #[serde(rename_all = "camelCase")]
 struct CodecEncodeResponse {
     #[serde(default)]
+    #[serde(with = "base64_bytes")]
     result: Vec<u8>,
     #[serde(default)]
     error: Option<String>,

plugins/cmd/ndpgen/testdata/comprehensive_client_expected.py

@@ -12,6 +12,7 @@ from typing import Any
 
 import extism
 import json
+import base64
 
 
 class HostFunctionError(Exception):
@@ -327,7 +328,7 @@ def comprehensive_byte_slice(data: bytes) -> bytes:
         HostFunctionError: If the host function returns an error.
     """
     request = {
-        "data": data,
+        "data": base64.b64encode(data).decode("ascii"),
     }
     request_bytes = json.dumps(request).encode("utf-8")
     request_mem = extism.memory.alloc(request_bytes)
@@ -338,4 +339,4 @@ def comprehensive_byte_slice(data: bytes) -> bytes:
     if response.get("error"):
         raise HostFunctionError(response["error"])
 
-    return response.get("result", b"")
+    return base64.b64decode(response.get("result", ""))

plugins/cmd/ndpgen/testdata/comprehensive_client_expected.rs

@@ -5,6 +5,29 @@
 
 use extism_pdk::*;
 use serde::{Deserialize, Serialize};
+use base64::Engine as _;
+use base64::engine::general_purpose::STANDARD as BASE64;
+
+mod base64_bytes {
+    use serde::{self, Deserialize, Deserializer, Serializer};
+    use base64::Engine as _;
+    use base64::engine::general_purpose::STANDARD as BASE64;
+
+    pub fn serialize<S>(bytes: &Vec<u8>, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        serializer.serialize_str(&BASE64.encode(bytes))
+    }
+
+    pub fn deserialize<'de, D>(deserializer: D) -> Result<Vec<u8>, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        let s = String::deserialize(deserializer)?;
+        BASE64.decode(&s).map_err(serde::de::Error::custom)
+    }
+}
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
 #[serde(rename_all = "camelCase")]
@@ -144,6 +167,7 @@ struct ComprehensiveMultipleReturnsResponse {
 #[derive(Debug, Clone, Serialize)]
 #[serde(rename_all = "camelCase")]
 struct ComprehensiveByteSliceRequest {
+    #[serde(with = "base64_bytes")]
     data: Vec<u8>,
 }
 
@@ -151,6 +175,7 @@ struct ComprehensiveByteSliceRequest {
 #[serde(rename_all = "camelCase")]
 struct ComprehensiveByteSliceResponse {
     #[serde(default)]
+    #[serde(with = "base64_bytes")]
     result: Vec<u8>,
     #[serde(default)]
     error: Option<String>,

plugins/cmd/ndpgen/testdata/raw_client_expected.go.txt

@@ -1,66 +0,0 @@
-// Code generated by ndpgen. DO NOT EDIT.
-//
-// This file contains client wrappers for the Stream host service.
-// It is intended for use in Navidrome plugins built with TinyGo.
-//
-//go:build wasip1
-
-package ndpdk
-
-import (
-	"encoding/binary"
-	"encoding/json"
-	"errors"
-
-	"github.com/navidrome/navidrome/plugins/pdk/go/pdk"
-)
-
-// stream_getstream is the host function provided by Navidrome.
-//
-//go:wasmimport extism:host/user stream_getstream
-func stream_getstream(uint64) uint64
-
-type streamGetStreamRequest struct {
-	Uri string `json:"uri"`
-}
-
-// StreamGetStream calls the stream_getstream host function.
-// GetStream returns raw binary stream data with content type.
-func StreamGetStream(uri string) (string, []byte, error) {
-	// Marshal request to JSON
-	req := streamGetStreamRequest{
-		Uri: uri,
-	}
-	reqBytes, err := json.Marshal(req)
-	if err != nil {
-		return "", nil, err
-	}
-	reqMem := pdk.AllocateBytes(reqBytes)
-	defer reqMem.Free()
-
-	// Call the host function
-	responsePtr := stream_getstream(reqMem.Offset())
-
-	// Read the response from memory
-	responseMem := pdk.FindMemory(responsePtr)
-	responseBytes := responseMem.ReadBytes()
-
-	// Parse binary-framed response
-	if len(responseBytes) == 0 {
-		return "", nil, errors.New("empty response from host")
-	}
-	if responseBytes[0] == 0x01 { // error
-		return "", nil, errors.New(string(responseBytes[1:]))
-	}
-	if responseBytes[0] != 0x00 {
-		return "", nil, errors.New("unknown response status")
-	}
-	if len(responseBytes) < 5 {
-		return "", nil, errors.New("malformed raw response: incomplete header")
-	}
-	ctLen := binary.BigEndian.Uint32(responseBytes[1:5])
-	if uint32(len(responseBytes)) < 5+ctLen {
-		return "", nil, errors.New("malformed raw response: content-type overflow")
-	}
-	return string(responseBytes[5 : 5+ctLen]), responseBytes[5+ctLen:], nil
-}

plugins/cmd/ndpgen/testdata/raw_client_expected.py

@@ -1,63 +0,0 @@
-# Code generated by ndpgen. DO NOT EDIT.
-#
-# This file contains client wrappers for the Stream host service.
-# It is intended for use in Navidrome plugins built with extism-py.
-#
-# IMPORTANT: Due to a limitation in extism-py, you cannot import this file directly.
-# The @extism.import_fn decorators are only detected when defined in the plugin's
-# main __init__.py file. Copy the needed functions from this file into your plugin.
-
-from dataclasses import dataclass
-from typing import Any, Tuple
-
-import extism
-import json
-import struct
-
-
-class HostFunctionError(Exception):
-    """Raised when a host function returns an error."""
-    pass
-
-
-@extism.import_fn("extism:host/user", "stream_getstream")
-def _stream_getstream(offset: int) -> int:
-    """Raw host function - do not call directly."""
-    ...
-
-
-def stream_get_stream(uri: str) -> Tuple[str, bytes]:
-    """GetStream returns raw binary stream data with content type.
-
-    Args:
-        uri: str parameter.
-
-    Returns:
-        Tuple of (content_type, data) with the raw binary response.
-
-    Raises:
-        HostFunctionError: If the host function returns an error.
-    """
-    request = {
-        "uri": uri,
-    }
-    request_bytes = json.dumps(request).encode("utf-8")
-    request_mem = extism.memory.alloc(request_bytes)
-    response_offset = _stream_getstream(request_mem.offset)
-    response_mem = extism.memory.find(response_offset)
-    response_bytes = response_mem.bytes()
-
-    if len(response_bytes) == 0:
-        raise HostFunctionError("empty response from host")
-    if response_bytes[0] == 0x01:
-        raise HostFunctionError(response_bytes[1:].decode("utf-8"))
-    if response_bytes[0] != 0x00:
-        raise HostFunctionError("unknown response status")
-    if len(response_bytes) < 5:
-        raise HostFunctionError("malformed raw response: incomplete header")
-    ct_len = struct.unpack(">I", response_bytes[1:5])[0]
-    if len(response_bytes) < 5 + ct_len:
-        raise HostFunctionError("malformed raw response: content-type overflow")
-    content_type = response_bytes[5:5 + ct_len].decode("utf-8")
-    data = response_bytes[5 + ct_len:]
-    return content_type, data

plugins/cmd/ndpgen/testdata/raw_client_expected.rs

@@ -1,73 +0,0 @@
-// Code generated by ndpgen. DO NOT EDIT.
-//
-// This file contains client wrappers for the Stream host service.
-// It is intended for use in Navidrome plugins built with extism-pdk.
-
-use extism_pdk::*;
-use serde::{Deserialize, Serialize};
-
-#[derive(Debug, Clone, Serialize)]
-#[serde(rename_all = "camelCase")]
-struct StreamGetStreamRequest {
-    uri: String,
-}
-
-#[host_fn]
-extern "ExtismHost" {
-}
-
-#[link(wasm_import_module = "extism:host/user")]
-extern "C" {
-    fn stream_getstream(offset: u64) -> u64;
-}
-
-/// GetStream returns raw binary stream data with content type.
-///
-/// # Arguments
-/// * `uri` - String parameter.
-///
-/// # Returns
-/// A tuple of (content_type, data) with the raw binary response.
-///
-/// # Errors
-/// Returns an error if the host function call fails.
-pub fn get_stream(uri: &str) -> Result<(String, Vec<u8>), Error> {
-    let req = StreamGetStreamRequest {
-        uri: uri.to_owned(),
-    };
-    let input_bytes = serde_json::to_vec(&req).map_err(|e| Error::msg(e.to_string()))?;
-    let input_mem = Memory::from_bytes(&input_bytes).map_err(|e| Error::msg(e.to_string()))?;
-
-    let response_offset = unsafe { stream_getstream(input_mem.offset()) };
-
-    let response_mem = Memory::find(response_offset)
-        .ok_or_else(|| Error::msg("empty response from host"))?;
-    let response_bytes = response_mem.to_vec();
-
-    if response_bytes.is_empty() {
-        return Err(Error::msg("empty response from host"));
-    }
-    if response_bytes[0] == 0x01 {
-        let msg = String::from_utf8_lossy(&response_bytes[1..]).to_string();
-        return Err(Error::msg(msg));
-    }
-    if response_bytes[0] != 0x00 {
-        return Err(Error::msg("unknown response status"));
-    }
-    if response_bytes.len() < 5 {
-        return Err(Error::msg("malformed raw response: incomplete header"));
-    }
-    let ct_len = u32::from_be_bytes([
-        response_bytes[1],
-        response_bytes[2],
-        response_bytes[3],
-        response_bytes[4],
-    ]) as usize;
-    if ct_len > response_bytes.len() - 5 {
-        return Err(Error::msg("malformed raw response: content-type overflow"));
-    }
-    let ct_end = 5 + ct_len;
-    let content_type = String::from_utf8_lossy(&response_bytes[5..ct_end]).to_string();
-    let data = response_bytes[ct_end..].to_vec();
-    Ok((content_type, data))
-}

plugins/cmd/ndpgen/testdata/raw_service.go.txt

@@ -1,10 +0,0 @@
-package testpkg
-
-import "context"
-
-//nd:hostservice name=Stream permission=stream
-type StreamService interface {
-	// GetStream returns raw binary stream data with content type.
-	//nd:hostfunc raw=true
-	GetStream(ctx context.Context, uri string) (contentType string, data []byte, err error)
-}

plugins/host/subsonicapi.go

@@ -17,8 +17,8 @@ type SubsonicAPIService interface {
 	Call(ctx context.Context, uri string) (responseJSON string, err error)
 
 	// CallRaw executes a Subsonic API request and returns the raw binary response.
-	// Optimized for binary endpoints like getCoverArt and stream that return
+	// Designed for binary endpoints like getCoverArt and stream that return
-	// non-JSON data. The response is returned as raw bytes without JSON encoding overhead.
+	// non-JSON data. The data is base64-encoded over JSON on the wire.
-	//nd:hostfunc raw=true
+	//nd:hostfunc
 	CallRaw(ctx context.Context, uri string) (contentType string, data []byte, err error)
 }

plugins/host/subsonicapi_gen.go

@@ -4,7 +4,6 @@ package host
 
 import (
 	"context"
-	"encoding/binary"
 	"encoding/json"
 
 	extism "github.com/extism/go-sdk"
@@ -26,6 +25,13 @@ type SubsonicAPICallRawRequest struct {
 	Uri string `json:"uri"`
 }
 
+// SubsonicAPICallRawResponse is the response type for SubsonicAPI.CallRaw.
+type SubsonicAPICallRawResponse struct {
+	ContentType string `json:"contentType,omitempty"`
+	Data        []byte `json:"data,omitempty"`
+	Error       string `json:"error,omitempty"`
+}
+
 // RegisterSubsonicAPIHostFunctions registers SubsonicAPI service host functions.
 // The returned host functions should be added to the plugin's configuration.
 func RegisterSubsonicAPIHostFunctions(service SubsonicAPIService) []extism.HostFunction {
@@ -76,37 +82,28 @@ func newSubsonicAPICallRawHostFunction(service SubsonicAPIService) extism.HostFu
 			// Read JSON request from plugin memory
 			reqBytes, err := p.ReadBytes(stack[0])
 			if err != nil {
-				subsonicapiWriteRawError(p, stack, err)
+				subsonicapiWriteError(p, stack, err)
 				return
 			}
 			var req SubsonicAPICallRawRequest
 			if err := json.Unmarshal(reqBytes, &req); err != nil {
-				subsonicapiWriteRawError(p, stack, err)
+				subsonicapiWriteError(p, stack, err)
 				return
 			}
 
 			// Call the service method
 			contenttype, data, svcErr := service.CallRaw(ctx, req.Uri)
 			if svcErr != nil {
-				subsonicapiWriteRawError(p, stack, svcErr)
+				subsonicapiWriteError(p, stack, svcErr)
 				return
 			}
 
-			// Write binary-framed response to plugin memory:
+			// Write JSON response to plugin memory
-			// [0x00][4-byte content-type length (big-endian)][content-type string][raw data]
+			resp := SubsonicAPICallRawResponse{
-			ctBytes := []byte(contenttype)
+				ContentType: contenttype,
-			frame := make([]byte, 1+4+len(ctBytes)+len(data))
+				Data:        data,
-			frame[0] = 0x00 // success
-			binary.BigEndian.PutUint32(frame[1:5], uint32(len(ctBytes)))
-			copy(frame[5:5+len(ctBytes)], ctBytes)
-			copy(frame[5+len(ctBytes):], data)
-
-			respPtr, err := p.WriteBytes(frame)
-			if err != nil {
-				stack[0] = 0
-				return
 			}
-			stack[0] = respPtr
+			subsonicapiWriteResponse(p, stack, resp)
 		},
 		[]extism.ValueType{extism.ValueTypePTR},
 		[]extism.ValueType{extism.ValueTypePTR},
@@ -137,14 +134,3 @@ func subsonicapiWriteError(p *extism.CurrentPlugin, stack []uint64, err error) {
 	respPtr, _ := p.WriteBytes(respBytes)
 	stack[0] = respPtr
 }
-
-// subsonicapiWriteRawError writes a binary-framed error response to plugin memory.
-// Format: [0x01][UTF-8 error message]
-func subsonicapiWriteRawError(p *extism.CurrentPlugin, stack []uint64, err error) {
-	errMsg := []byte(err.Error())
-	frame := make([]byte, 1+len(errMsg))
-	frame[0] = 0x01 // error
-	copy(frame[1:], errMsg)
-	respPtr, _ := p.WriteBytes(frame)
-	stack[0] = respPtr
-}

plugins/pdk/go/host/nd_host_subsonicapi.go

@@ -8,7 +8,6 @@
 package host
 
 import (
-	"encoding/binary"
 	"encoding/json"
 	"errors"
 
@@ -38,6 +37,12 @@ type subsonicAPICallRawRequest struct {
 	Uri string `json:"uri"`
 }
 
+type subsonicAPICallRawResponse struct {
+	ContentType string `json:"contentType,omitempty"`
+	Data        []byte `json:"data,omitempty"`
+	Error       string `json:"error,omitempty"`
+}
+
 // SubsonicAPICall calls the subsonicapi_call host function.
 // Call executes a Subsonic API request and returns the JSON response.
 //
@@ -78,8 +83,8 @@ func SubsonicAPICall(uri string) (string, error) {
 
 // SubsonicAPICallRaw calls the subsonicapi_callraw host function.
 // CallRaw executes a Subsonic API request and returns the raw binary response.
-// Optimized for binary endpoints like getCoverArt and stream that return
+// Designed for binary endpoints like getCoverArt and stream that return
-// non-JSON data. The response is returned as raw bytes without JSON encoding overhead.
+// non-JSON data. The data is base64-encoded over JSON on the wire.
 func SubsonicAPICallRaw(uri string) (string, []byte, error) {
 	// Marshal request to JSON
 	req := subsonicAPICallRawRequest{
@@ -99,22 +104,16 @@ func SubsonicAPICallRaw(uri string) (string, []byte, error) {
 	responseMem := pdk.FindMemory(responsePtr)
 	responseBytes := responseMem.ReadBytes()
 
-	// Parse binary-framed response
+	// Parse the response
-	if len(responseBytes) == 0 {
+	var response subsonicAPICallRawResponse
-		return "", nil, errors.New("empty response from host")
+	if err := json.Unmarshal(responseBytes, &response); err != nil {
+		return "", nil, err
 	}
-	if responseBytes[0] == 0x01 { // error
+
-		return "", nil, errors.New(string(responseBytes[1:]))
+	// Convert Error field to Go error
+	if response.Error != "" {
+		return "", nil, errors.New(response.Error)
 	}
-	if responseBytes[0] != 0x00 {
+
-		return "", nil, errors.New("unknown response status")
+	return response.ContentType, response.Data, nil
-	}
-	if len(responseBytes) < 5 {
-		return "", nil, errors.New("malformed raw response: incomplete header")
-	}
-	ctLen := binary.BigEndian.Uint32(responseBytes[1:5])
-	if uint32(len(responseBytes)) < 5+ctLen {
-		return "", nil, errors.New("malformed raw response: content-type overflow")
-	}
-	return string(responseBytes[5 : 5+ctLen]), responseBytes[5+ctLen:], nil
 }

plugins/pdk/go/host/nd_host_subsonicapi_stub.go

@@ -42,8 +42,8 @@ func (m *mockSubsonicAPIService) CallRaw(uri string) (string, []byte, error) {
 
 // SubsonicAPICallRaw delegates to the mock instance.
 // CallRaw executes a Subsonic API request and returns the raw binary response.
-// Optimized for binary endpoints like getCoverArt and stream that return
+// Designed for binary endpoints like getCoverArt and stream that return
-// non-JSON data. The response is returned as raw bytes without JSON encoding overhead.
+// non-JSON data. The data is base64-encoded over JSON on the wire.
 func SubsonicAPICallRaw(uri string) (string, []byte, error) {
 	return SubsonicAPIMock.CallRaw(uri)
 }

plugins/pdk/python/host/nd_host_cache.py

@@ -12,6 +12,7 @@ from typing import Any
 
 import extism
 import json
+import base64
 
 
 class HostFunctionError(Exception):
@@ -337,7 +338,7 @@ Returns an error if the operation fails.
     """
     request = {
         "key": key,
-        "value": value,
+        "value": base64.b64encode(value).decode("ascii"),
         "ttlSeconds": ttl_seconds,
     }
     request_bytes = json.dumps(request).encode("utf-8")
@@ -382,7 +383,7 @@ or the stored value is not a byte slice, exists will be false.
         raise HostFunctionError(response["error"])
 
     return CacheGetBytesResult(
-        value=response.get("value", b""),
+        value=base64.b64decode(response.get("value", "")),
         exists=response.get("exists", False),
     )
 

plugins/pdk/python/host/nd_host_http.py

@@ -12,6 +12,7 @@ from typing import Any
 
 import extism
 import json
+import base64
 
 
 class HostFunctionError(Exception):

plugins/pdk/python/host/nd_host_kvstore.py

@@ -12,6 +12,7 @@ from typing import Any
 
 import extism
 import json
+import base64
 
 
 class HostFunctionError(Exception):
@@ -80,7 +81,7 @@ Returns an error if the storage limit would be exceeded or the operation fails.
     """
     request = {
         "key": key,
-        "value": value,
+        "value": base64.b64encode(value).decode("ascii"),
     }
     request_bytes = json.dumps(request).encode("utf-8")
     request_mem = extism.memory.alloc(request_bytes)
@@ -123,7 +124,7 @@ Returns the value and whether the key exists.
         raise HostFunctionError(response["error"])
 
     return KVStoreGetResult(
-        value=response.get("value", b""),
+        value=base64.b64decode(response.get("value", "")),
         exists=response.get("exists", False),
     )
 

plugins/pdk/python/host/nd_host_subsonicapi.py

@@ -8,11 +8,11 @@
 # main __init__.py file. Copy the needed functions from this file into your plugin.
 
 from dataclasses import dataclass
-from typing import Any, Tuple
+from typing import Any
 
 import extism
 import json
-import struct
+import base64
 
 
 class HostFunctionError(Exception):
@@ -32,6 +32,13 @@ def _subsonicapi_callraw(offset: int) -> int:
     ...
 
 
+@dataclass
+class SubsonicAPICallRawResult:
+    """Result type for subsonicapi_call_raw."""
+    content_type: str
+    data: bytes
+
+
 def subsonicapi_call(uri: str) -> str:
     """Call executes a Subsonic API request and returns the JSON response.
 
@@ -62,16 +69,16 @@ e.g., "getAlbumList2?type=random&size=10". The response is returned as raw JSON.
     return response.get("responseJson", "")
 
 
-def subsonicapi_call_raw(uri: str) -> Tuple[str, bytes]:
+def subsonicapi_call_raw(uri: str) -> SubsonicAPICallRawResult:
     """CallRaw executes a Subsonic API request and returns the raw binary response.
-Optimized for binary endpoints like getCoverArt and stream that return
+Designed for binary endpoints like getCoverArt and stream that return
-non-JSON data. The response is returned as raw bytes without JSON encoding overhead.
+non-JSON data. The data is base64-encoded over JSON on the wire.
 
     Args:
         uri: str parameter.
 
     Returns:
-        Tuple of (content_type, data) with the raw binary response.
+        SubsonicAPICallRawResult containing content_type, data,.
 
     Raises:
         HostFunctionError: If the host function returns an error.
@@ -83,19 +90,12 @@ non-JSON data. The response is returned as raw bytes without JSON encoding overh
     request_mem = extism.memory.alloc(request_bytes)
     response_offset = _subsonicapi_callraw(request_mem.offset)
     response_mem = extism.memory.find(response_offset)
-    response_bytes = response_mem.bytes()
+    response = json.loads(extism.memory.string(response_mem))
 
-    if len(response_bytes) == 0:
+    if response.get("error"):
-        raise HostFunctionError("empty response from host")
+        raise HostFunctionError(response["error"])
-    if response_bytes[0] == 0x01:
+
-        raise HostFunctionError(response_bytes[1:].decode("utf-8"))
+    return SubsonicAPICallRawResult(
-    if response_bytes[0] != 0x00:
+        content_type=response.get("contentType", ""),
-        raise HostFunctionError("unknown response status")
+        data=base64.b64decode(response.get("data", "")),
-    if len(response_bytes) < 5:
+    )
-        raise HostFunctionError("malformed raw response: incomplete header")
-    ct_len = struct.unpack(">I", response_bytes[1:5])[0]
-    if len(response_bytes) < 5 + ct_len:
-        raise HostFunctionError("malformed raw response: content-type overflow")
-    content_type = response_bytes[5:5 + ct_len].decode("utf-8")
-    data = response_bytes[5 + ct_len:]
-    return content_type, data

plugins/pdk/python/host/nd_host_websocket.py

@@ -12,6 +12,7 @@ from typing import Any
 
 import extism
 import json
+import base64
 
 
 class HostFunctionError(Exception):
@@ -134,7 +135,7 @@ Returns an error if the connection is not found or if sending fails.
     """
     request = {
         "connectionId": connection_id,
-        "data": data,
+        "data": base64.b64encode(data).decode("ascii"),
     }
     request_bytes = json.dumps(request).encode("utf-8")
     request_mem = extism.memory.alloc(request_bytes)

plugins/pdk/rust/nd-pdk-capabilities/Cargo.toml

@@ -11,6 +11,7 @@ path = "src/lib.rs"
 crate-type = ["rlib"]
 
 [dependencies]
+base64 = "0.22"
 extism-pdk = "1.2"
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"

plugins/pdk/rust/nd-pdk-host/Cargo.toml

@@ -11,6 +11,7 @@ readme = "README.md"
 crate-type = ["rlib"]
 
 [dependencies]
+base64 = "0.22"
 extism-pdk = "1.2"
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"

plugins/pdk/rust/nd-pdk-host/src/nd_host_cache.rs

@@ -5,6 +5,29 @@
 
 use extism_pdk::*;
 use serde::{Deserialize, Serialize};
+use base64::Engine as _;
+use base64::engine::general_purpose::STANDARD as BASE64;
+
+mod base64_bytes {
+    use serde::{self, Deserialize, Deserializer, Serializer};
+    use base64::Engine as _;
+    use base64::engine::general_purpose::STANDARD as BASE64;
+
+    pub fn serialize<S>(bytes: &Vec<u8>, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        serializer.serialize_str(&BASE64.encode(bytes))
+    }
+
+    pub fn deserialize<'de, D>(deserializer: D) -> Result<Vec<u8>, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        let s = String::deserialize(deserializer)?;
+        BASE64.decode(&s).map_err(serde::de::Error::custom)
+    }
+}
 
 #[derive(Debug, Clone, Serialize)]
 #[serde(rename_all = "camelCase")]
@@ -106,6 +129,7 @@ struct CacheGetFloatResponse {
 #[serde(rename_all = "camelCase")]
 struct CacheSetBytesRequest {
     key: String,
+    #[serde(with = "base64_bytes")]
     value: Vec<u8>,
     ttl_seconds: i64,
 }
@@ -127,6 +151,7 @@ struct CacheGetBytesRequest {
 #[serde(rename_all = "camelCase")]
 struct CacheGetBytesResponse {
     #[serde(default)]
+    #[serde(with = "base64_bytes")]
     value: Vec<u8>,
     #[serde(default)]
     exists: bool,

plugins/pdk/rust/nd-pdk-host/src/nd_host_http.rs

@@ -5,6 +5,29 @@
 
 use extism_pdk::*;
 use serde::{Deserialize, Serialize};
+use base64::Engine as _;
+use base64::engine::general_purpose::STANDARD as BASE64;
+
+mod base64_bytes {
+    use serde::{self, Deserialize, Deserializer, Serializer};
+    use base64::Engine as _;
+    use base64::engine::general_purpose::STANDARD as BASE64;
+
+    pub fn serialize<S>(bytes: &Vec<u8>, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        serializer.serialize_str(&BASE64.encode(bytes))
+    }
+
+    pub fn deserialize<'de, D>(deserializer: D) -> Result<Vec<u8>, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        let s = String::deserialize(deserializer)?;
+        BASE64.decode(&s).map_err(serde::de::Error::custom)
+    }
+}
 
 /// HTTPRequest represents an outbound HTTP request from a plugin.
 #[derive(Debug, Clone, Serialize, Deserialize)]
@@ -15,6 +38,7 @@ pub struct HTTPRequest {
     #[serde(default)]
     pub headers: std::collections::HashMap<String, String>,
     #[serde(default)]
+    #[serde(with = "base64_bytes")]
     pub body: Vec<u8>,
     #[serde(default)]
     pub timeout_ms: i32,
@@ -28,6 +52,7 @@ pub struct HTTPResponse {
     #[serde(default)]
     pub headers: std::collections::HashMap<String, String>,
     #[serde(default)]
+    #[serde(with = "base64_bytes")]
     pub body: Vec<u8>,
 }
 

plugins/pdk/rust/nd-pdk-host/src/nd_host_kvstore.rs

@@ -5,11 +5,35 @@
 
 use extism_pdk::*;
 use serde::{Deserialize, Serialize};
+use base64::Engine as _;
+use base64::engine::general_purpose::STANDARD as BASE64;
+
+mod base64_bytes {
+    use serde::{self, Deserialize, Deserializer, Serializer};
+    use base64::Engine as _;
+    use base64::engine::general_purpose::STANDARD as BASE64;
+
+    pub fn serialize<S>(bytes: &Vec<u8>, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        serializer.serialize_str(&BASE64.encode(bytes))
+    }
+
+    pub fn deserialize<'de, D>(deserializer: D) -> Result<Vec<u8>, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        let s = String::deserialize(deserializer)?;
+        BASE64.decode(&s).map_err(serde::de::Error::custom)
+    }
+}
 
 #[derive(Debug, Clone, Serialize)]
 #[serde(rename_all = "camelCase")]
 struct KVStoreSetRequest {
     key: String,
+    #[serde(with = "base64_bytes")]
     value: Vec<u8>,
 }
 
@@ -30,6 +54,7 @@ struct KVStoreGetRequest {
 #[serde(rename_all = "camelCase")]
 struct KVStoreGetResponse {
     #[serde(default)]
+    #[serde(with = "base64_bytes")]
     value: Vec<u8>,
     #[serde(default)]
     exists: bool,

plugins/pdk/rust/nd-pdk-host/src/nd_host_subsonicapi.rs

@@ -5,6 +5,29 @@
 
 use extism_pdk::*;
 use serde::{Deserialize, Serialize};
+use base64::Engine as _;
+use base64::engine::general_purpose::STANDARD as BASE64;
+
+mod base64_bytes {
+    use serde::{self, Deserialize, Deserializer, Serializer};
+    use base64::Engine as _;
+    use base64::engine::general_purpose::STANDARD as BASE64;
+
+    pub fn serialize<S>(bytes: &Vec<u8>, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        serializer.serialize_str(&BASE64.encode(bytes))
+    }
+
+    pub fn deserialize<'de, D>(deserializer: D) -> Result<Vec<u8>, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        let s = String::deserialize(deserializer)?;
+        BASE64.decode(&s).map_err(serde::de::Error::custom)
+    }
+}
 
 #[derive(Debug, Clone, Serialize)]
 #[serde(rename_all = "camelCase")]
@@ -27,14 +50,22 @@ struct SubsonicAPICallRawRequest {
     uri: String,
 }
 
+#[derive(Debug, Clone, Deserialize)]
+#[serde(rename_all = "camelCase")]
+struct SubsonicAPICallRawResponse {
+    #[serde(default)]
+    content_type: String,
+    #[serde(default)]
+    #[serde(with = "base64_bytes")]
+    data: Vec<u8>,
+    #[serde(default)]
+    error: Option<String>,
+}
+
 #[host_fn]
 extern "ExtismHost" {
     fn subsonicapi_call(input: Json<SubsonicAPICallRequest>) -> Json<SubsonicAPICallResponse>;
-}
+    fn subsonicapi_callraw(input: Json<SubsonicAPICallRawRequest>) -> Json<SubsonicAPICallRawResponse>;
-
-#[link(wasm_import_module = "extism:host/user")]
-extern "C" {
-    fn subsonicapi_callraw(offset: u64) -> u64;
 }
 
 /// Call executes a Subsonic API request and returns the JSON response.
@@ -65,54 +96,27 @@ pub fn call(uri: &str) -> Result<String, Error> {
 }
 
 /// CallRaw executes a Subsonic API request and returns the raw binary response.
-/// Optimized for binary endpoints like getCoverArt and stream that return
+/// Designed for binary endpoints like getCoverArt and stream that return
-/// non-JSON data. The response is returned as raw bytes without JSON encoding overhead.
+/// non-JSON data. The data is base64-encoded over JSON on the wire.
 ///
 /// # Arguments
 /// * `uri` - String parameter.
 ///
 /// # Returns
-/// A tuple of (content_type, data) with the raw binary response.
+/// A tuple of (content_type, data).
 ///
 /// # Errors
 /// Returns an error if the host function call fails.
 pub fn call_raw(uri: &str) -> Result<(String, Vec<u8>), Error> {
-    let req = SubsonicAPICallRawRequest {
+    let response = unsafe {
-        uri: uri.to_owned(),
+        subsonicapi_callraw(Json(SubsonicAPICallRawRequest {
+            uri: uri.to_owned(),
+        }))?
     };
-    let input_bytes = serde_json::to_vec(&req).map_err(|e| Error::msg(e.to_string()))?;
-    let input_mem = Memory::from_bytes(&input_bytes).map_err(|e| Error::msg(e.to_string()))?;
 
-    let response_offset = unsafe { subsonicapi_callraw(input_mem.offset()) };
+    if let Some(err) = response.0.error {
+        return Err(Error::msg(err));
+    }
 
-    let response_mem = Memory::find(response_offset)
+    Ok((response.0.content_type, response.0.data))
-        .ok_or_else(|| Error::msg("empty response from host"))?;
-    let response_bytes = response_mem.to_vec();
-
-    if response_bytes.is_empty() {
-        return Err(Error::msg("empty response from host"));
-    }
-    if response_bytes[0] == 0x01 {
-        let msg = String::from_utf8_lossy(&response_bytes[1..]).to_string();
-        return Err(Error::msg(msg));
-    }
-    if response_bytes[0] != 0x00 {
-        return Err(Error::msg("unknown response status"));
-    }
-    if response_bytes.len() < 5 {
-        return Err(Error::msg("malformed raw response: incomplete header"));
-    }
-    let ct_len = u32::from_be_bytes([
-        response_bytes[1],
-        response_bytes[2],
-        response_bytes[3],
-        response_bytes[4],
-    ]) as usize;
-    if ct_len > response_bytes.len() - 5 {
-        return Err(Error::msg("malformed raw response: content-type overflow"));
-    }
-    let ct_end = 5 + ct_len;
-    let content_type = String::from_utf8_lossy(&response_bytes[5..ct_end]).to_string();
-    let data = response_bytes[ct_end..].to_vec();
-    Ok((content_type, data))
 }

plugins/pdk/rust/nd-pdk-host/src/nd_host_websocket.rs

@@ -5,6 +5,29 @@
 
 use extism_pdk::*;
 use serde::{Deserialize, Serialize};
+use base64::Engine as _;
+use base64::engine::general_purpose::STANDARD as BASE64;
+
+mod base64_bytes {
+    use serde::{self, Deserialize, Deserializer, Serializer};
+    use base64::Engine as _;
+    use base64::engine::general_purpose::STANDARD as BASE64;
+
+    pub fn serialize<S>(bytes: &Vec<u8>, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        serializer.serialize_str(&BASE64.encode(bytes))
+    }
+
+    pub fn deserialize<'de, D>(deserializer: D) -> Result<Vec<u8>, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        let s = String::deserialize(deserializer)?;
+        BASE64.decode(&s).map_err(serde::de::Error::custom)
+    }
+}
 
 #[derive(Debug, Clone, Serialize)]
 #[serde(rename_all = "camelCase")]
@@ -41,6 +64,7 @@ struct WebSocketSendTextResponse {
 #[serde(rename_all = "camelCase")]
 struct WebSocketSendBinaryRequest {
     connection_id: String,
+    #[serde(with = "base64_bytes")]
     data: Vec<u8>,
 }