[ai] Reponse serialization, http.Header standard

Replace map[string]string with http.Header throughout the AI SDK for better idiomatic Go code and support for multiple header values. Also add JSON unmarshaling support for Response type.

Author: loreto

aisdk/ai/api/embedding_model.go

@@ -2,6 +2,7 @@ package api
 
 import (
 	"context"
+	"net/http"
 )
 
 // Embedding is a vector, i.e. an array of numbers.
@@ -60,5 +61,5 @@ type EmbeddingUsage struct {
 // EmbeddingRawResponse contains raw response information for debugging.
 type EmbeddingRawResponse struct {
 	// Headers are the response headers.
-	Headers map[string]string
+	Headers http.Header
 }

aisdk/ai/api/embedding_options.go

@@ -1,11 +1,13 @@
 package api
 
+import "net/http"
+
 // EmbeddingOption represent the options for generating embeddings.
 type EmbeddingOption func(*EmbeddingOptions)
 
 // WithEmbeddingHeaders sets HTTP headers to be sent with the request.
 // Only applicable for HTTP-based providers.
-func WithEmbeddingHeaders(headers map[string]string) EmbeddingOption {
+func WithEmbeddingHeaders(headers http.Header) EmbeddingOption {
 	return func(o *EmbeddingOptions) {
 		o.Headers = headers
 	}
@@ -15,5 +17,5 @@ func WithEmbeddingHeaders(headers map[string]string) EmbeddingOption {
 type EmbeddingOptions struct {
 	// Headers are additional HTTP headers to be sent with the request.
 	// Only applicable for HTTP-based providers.
-	Headers map[string]string
+	Headers http.Header
 }

aisdk/ai/api/image_model.go

@@ -2,6 +2,7 @@ package api
 
 import (
 	"context"
+	"net/http"
 	"time"
 )
 
@@ -69,5 +70,5 @@ type ImageResponseMetadata struct {
 	ModelID string
 
 	// Headers are the response headers.
-	Headers map[string]string
+	Headers http.Header
 }

aisdk/ai/api/image_model_call_options.go

@@ -1,5 +1,7 @@
 package api
 
+import "net/http"
+
 // ImageCallOptions represents the options for generating images.
 type ImageCallOptions struct {
 	// N is the number of images to generate.
@@ -40,7 +42,7 @@ type ImageCallOptions struct {
 
 	// Headers are additional HTTP headers to be sent with the request.
 	// Only applicable for HTTP-based providers.
-	Headers map[string]string
+	Headers http.Header
 }
 
 // ImageCallOption is a function that modifies ImageCallOptions.
@@ -106,7 +108,7 @@ func WithImageProviderOptions(options map[string]map[string]any) ImageCallOption
 
 // WithImageHeaders sets additional HTTP headers to be sent with the request.
 // Only applicable for HTTP-based providers.
-func WithImageHeaders(headers map[string]string) ImageCallOption {
+func WithImageHeaders(headers http.Header) ImageCallOption {
 	return func(o *ImageCallOptions) {
 		o.Headers = headers
 	}

aisdk/ai/api/llm_call_options.go

@@ -3,6 +3,7 @@ package api
 import (
 	"encoding/json"
 	"fmt"
+	"net/http"
 
 	jsonschema "github.com/sashabaranov/go-openai/jsonschema"
 	"github.com/tidwall/gjson"
@@ -59,7 +60,7 @@ type CallOptions struct {
 
 	// Headers specifies additional HTTP headers to send with the request.
 	// Only applicable for HTTP-based providers.
-	Headers map[string]string `json:"headers,omitempty"`
+	Headers http.Header `json:"headers,omitempty"`
 
 	// ProviderMetadata contains additional provider-specific metadata.
 	// The metadata is passed through to the provider from the AI SDK and enables

aisdk/ai/api/llm_call_options_test.go

@@ -14,19 +14,12 @@ func TestCallOptions_JSON(t *testing.T) {
 		jsonStr string
 	}{
 		{
-			name: "basic_options",
+			name: "basic_fields",
 			jsonStr: `{
-				"max_output_tokens": 1000,
+				"max_output_tokens": 1500,
 				"temperature": 0.7,
+				"stop_sequences": ["STOP", "END"],
 				"top_p": 0.9,
-				"stop_sequences": ["STOP", "END"]
-			}`,
-		},
-		{
-			name: "complex_options_with_response_format",
-			jsonStr: `{
-				"max_output_tokens": 2000,
-				"temperature": 0.5,
 				"top_k": 40,
 				"presence_penalty": 0.1,
 				"frequency_penalty": 0.2,
@@ -37,8 +30,8 @@ func TestCallOptions_JSON(t *testing.T) {
 					"description": "A structured response"
 				},
 				"headers": {
-					"X-Custom-Header": "custom-value",
-					"Authorization": "Bearer token"
+					"X-Custom-Header": ["custom-value"],
+					"Authorization": ["Bearer token"]
 				}
 			}`,
 		},
@@ -97,9 +90,9 @@ func TestCallOptions_JSON(t *testing.T) {
 					"tool_name": "get_weather"
 				},
 				"headers": {
-					"X-API-Key": "test-key",
-					"User-Agent": "test-agent",
-					"Content-Type": "application/json"
+					"X-API-Key": ["test-key"],
+					"User-Agent": ["test-agent"],
+					"Content-Type": ["application/json"]
 				},
 				"provider_metadata": {
 					"openai": {
@@ -187,9 +180,9 @@ func BenchmarkCallOptionsUnmarshal(b *testing.B) {
 			"tool_name": "get_weather"
 		},
 		"headers": {
-			"X-API-Key": "test-key",
-			"User-Agent": "test-agent",
-			"Content-Type": "application/json"
+			"X-API-Key": ["test-key"],
+			"User-Agent": ["test-agent"],
+			"Content-Type": ["application/json"]
 		},
 		"provider_metadata": {
 			"openai": {

aisdk/ai/api/llm_language_model.go

@@ -2,6 +2,7 @@ package api
 
 import (
 	"context"
+	"encoding/json"
 	"iter"
 	"net/http"
 	"time"
@@ -86,6 +87,33 @@ type Response struct {
 
 func (r Response) GetProviderMetadata() *ProviderMetadata { return r.ProviderMetadata }
 
+// UnmarshalJSON implements custom JSON unmarshaling for Response
+func (r *Response) UnmarshalJSON(data []byte) error {
+	// Use a temporary struct to unmarshal everything except content
+	type ResponseAlias Response
+	temp := struct {
+		*ResponseAlias
+		Content []json.RawMessage `json:"content,omitempty"`
+	}{
+		ResponseAlias: (*ResponseAlias)(r),
+	}
+
+	if err := json.Unmarshal(data, &temp); err != nil {
+		return err
+	}
+
+	// Handle content blocks
+	if temp.Content != nil {
+		content, err := unmarshalContentBlocks(temp.Content)
+		if err != nil {
+			return err
+		}
+		r.Content = content
+	}
+
+	return nil
+}
+
 // StreamResponse represents the result of a streaming language model call.
 type StreamResponse struct {
 	// Stream is the sequence of events received from the model.
@@ -150,8 +178,8 @@ type ResponseInfo struct {
 	// ModelID of the model that was used to generate the response, if the provider sends one.
 	ModelID string `json:"model_id,omitzero"`
 
-	// Header contains a map of the HTTP response headers.
-	Header http.Header
+	// Headers contains the HTTP response headers.
+	Headers http.Header `json:"headers,omitzero"`
 
 	// Body is the raw HTTP body that was returned by the provider.
 	// Not provided for streaming responses.