refactor: refactoring http request creation and sending (#395)

* refactoring http request creation and sending

* fix lint error

* increase the test coverage of client.go

* refactor: Change the style of HTTPRequestBuilder.Build func to one-argument-per-line.

Author: vvatanabe

api_internal_test.go

@@ -94,7 +94,7 @@ func TestRequestAuthHeader(t *testing.T) {
 			az.OrgID = c.OrgID
 
 			cli := NewClientWithConfig(az)
-			req, err := cli.newStreamRequest(context.Background(), "POST", "/chat/completions", nil, "")
+			req, err := cli.newRequest(context.Background(), "POST", "/chat/completions")
 			if err != nil {
 				t.Errorf("Failed to create request: %v", err)
 			}

audio.go

@@ -95,11 +95,11 @@ func (c *Client) callAudioAPI(
 	}
 
 	urlSuffix := fmt.Sprintf("/audio/%s", endpointSuffix)
-	req, err := http.NewRequestWithContext(ctx, http.MethodPost, c.fullURL(urlSuffix, request.Model), &formBody)
+	req, err := c.newRequest(ctx, http.MethodPost, c.fullURL(urlSuffix, request.Model),
+		withBody(&formBody), withContentType(builder.FormDataContentType()))
 	if err != nil {
 		return AudioResponse{}, err
 	}
-	req.Header.Add("Content-Type", builder.FormDataContentType())
 
 	if request.HasJSONResponse() {
 		err = c.sendRequest(req, &response)

chat.go

@@ -152,7 +152,7 @@ func (c *Client) CreateChatCompletion(
 		return
 	}
 
-	req, err := c.requestBuilder.Build(ctx, http.MethodPost, c.fullURL(urlSuffix, request.Model), request)
+	req, err := c.newRequest(ctx, http.MethodPost, c.fullURL(urlSuffix, request.Model), withBody(request))
 	if err != nil {
 		return
 	}

chat_stream.go

@@ -1,10 +1,8 @@
 package openai
 
 import (
-	"bufio"
 	"context"
-
-	utils "github.com/sashabaranov/go-openai/internal"
+	"net/http"
 )
 
 type ChatCompletionStreamChoiceDelta struct {
@@ -48,27 +46,17 @@ func (c *Client) CreateChatCompletionStream(
 	}
 
 	request.Stream = true
-	req, err := c.newStreamRequest(ctx, "POST", urlSuffix, request, request.Model)
+	req, err := c.newRequest(ctx, http.MethodPost, c.fullURL(urlSuffix, request.Model), withBody(request))
 	if err != nil {
-		return
+		return nil, err
 	}
 
-	resp, err := c.config.HTTPClient.Do(req) //nolint:bodyclose // body is closed in stream.Close()
+	resp, err := sendRequestStream[ChatCompletionStreamResponse](c, req)
 	if err != nil {
 		return
 	}
-	if isFailureStatusCode(resp) {
-		return nil, c.handleErrorResp(resp)
-	}
-
 	stream = &ChatCompletionStream{
-		streamReader: &streamReader[ChatCompletionStreamResponse]{
-			emptyMessagesLimit: c.config.EmptyMessagesLimit,
-			reader:             bufio.NewReader(resp.Body),
-			response:           resp,
-			errAccumulator:     utils.NewErrorAccumulator(),
-			unmarshaler:        &utils.JSONUnmarshaler{},
-		},
+		streamReader: resp,
 	}
 	return
 }

client.go

@@ -1,6 +1,7 @@
 package openai
 
 import (
+	"bufio"
 	"context"
 	"encoding/json"
 	"fmt"
@@ -45,6 +46,42 @@ func NewOrgClient(authToken, org string) *Client {
 	return NewClientWithConfig(config)
 }
 
+type requestOptions struct {
+	body   any
+	header http.Header
+}
+
+type requestOption func(*requestOptions)
+
+func withBody(body any) requestOption {
+	return func(args *requestOptions) {
+		args.body = body
+	}
+}
+
+func withContentType(contentType string) requestOption {
+	return func(args *requestOptions) {
+		args.header.Set("Content-Type", contentType)
+	}
+}
+
+func (c *Client) newRequest(ctx context.Context, method, url string, setters ...requestOption) (*http.Request, error) {
+	// Default Options
+	args := &requestOptions{
+		body:   nil,
+		header: make(http.Header),
+	}
+	for _, setter := range setters {
+		setter(args)
+	}
+	req, err := c.requestBuilder.Build(ctx, method, url, args.body, args.header)
+	if err != nil {
+		return nil, err
+	}
+	c.setCommonHeaders(req)
+	return req, nil
+}
+
 func (c *Client) sendRequest(req *http.Request, v any) error {
 	req.Header.Set("Accept", "application/json; charset=utf-8")
 
@@ -55,8 +92,6 @@ func (c *Client) sendRequest(req *http.Request, v any) error {
 		req.Header.Set("Content-Type", "application/json; charset=utf-8")
 	}
 
-	c.setCommonHeaders(req)
-
 	res, err := c.config.HTTPClient.Do(req)
 	if err != nil {
 		return err
@@ -71,6 +106,41 @@ func (c *Client) sendRequest(req *http.Request, v any) error {
 	return decodeResponse(res.Body, v)
 }
 
+func (c *Client) sendRequestRaw(req *http.Request) (body io.ReadCloser, err error) {
+	resp, err := c.config.HTTPClient.Do(req)
+	if err != nil {
+		return
+	}
+
+	if isFailureStatusCode(resp) {
+		err = c.handleErrorResp(resp)
+		return
+	}
+	return resp.Body, nil
+}
+
+func sendRequestStream[T streamable](client *Client, req *http.Request) (*streamReader[T], error) {
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("Accept", "text/event-stream")
+	req.Header.Set("Cache-Control", "no-cache")
+	req.Header.Set("Connection", "keep-alive")
+
+	resp, err := client.config.HTTPClient.Do(req) //nolint:bodyclose // body is closed in stream.Close()
+	if err != nil {
+		return new(streamReader[T]), err
+	}
+	if isFailureStatusCode(resp) {
+		return new(streamReader[T]), client.handleErrorResp(resp)
+	}
+	return &streamReader[T]{
+		emptyMessagesLimit: client.config.EmptyMessagesLimit,
+		reader:             bufio.NewReader(resp.Body),
+		response:           resp,
+		errAccumulator:     utils.NewErrorAccumulator(),
+		unmarshaler:        &utils.JSONUnmarshaler{},
+	}, nil
+}
+
 func (c *Client) setCommonHeaders(req *http.Request) {
 	// https://learn.microsoft.com/en-us/azure/cognitive-services/openai/reference#authentication
 	// Azure API Key authentication
@@ -138,26 +208,6 @@ func (c *Client) fullURL(suffix string, args ...any) string {
 	return fmt.Sprintf("%s%s", c.config.BaseURL, suffix)
 }
 
-func (c *Client) newStreamRequest(
-	ctx context.Context,
-	method string,
-	urlSuffix string,
-	body any,
-	model string) (*http.Request, error) {
-	req, err := c.requestBuilder.Build(ctx, method, c.fullURL(urlSuffix, model), body)
-	if err != nil {
-		return nil, err
-	}
-
-	req.Header.Set("Content-Type", "application/json")
-	req.Header.Set("Accept", "text/event-stream")
-	req.Header.Set("Cache-Control", "no-cache")
-	req.Header.Set("Connection", "keep-alive")
-
-	c.setCommonHeaders(req)
-	return req, nil
-}
-
 func (c *Client) handleErrorResp(resp *http.Response) error {
 	var errRes ErrorResponse
 	err := json.NewDecoder(resp.Body).Decode(&errRes)

client_test.go

@@ -16,7 +16,7 @@ var errTestRequestBuilderFailed = errors.New("test request builder failed")
 
 type failingRequestBuilder struct{}
 
-func (*failingRequestBuilder) Build(_ context.Context, _, _ string, _ any) (*http.Request, error) {
+func (*failingRequestBuilder) Build(_ context.Context, _, _ string, _ any, _ http.Header) (*http.Request, error) {
 	return nil, errTestRequestBuilderFailed
 }
 
@@ -41,9 +41,10 @@ func TestDecodeResponse(t *testing.T) {
 	stringInput := ""
 
 	testCases := []struct {
-		name  string
-		value interface{}
-		body  io.Reader
+		name     string
+		value    interface{}
+		body     io.Reader
+		hasError bool
 	}{
 		{
 			name:  "nil input",
@@ -60,18 +61,32 @@ func TestDecodeResponse(t *testing.T) {
 			value: &map[string]interface{}{},
 			body:  bytes.NewReader([]byte(`{"test": "test"}`)),
 		},
+		{
+			name:     "reader return error",
+			value:    &stringInput,
+			body:     &errorReader{err: errors.New("dummy")},
+			hasError: true,
+		},
 	}
 
 	for _, tc := range testCases {
 		t.Run(tc.name, func(t *testing.T) {
 			err := decodeResponse(tc.body, tc.value)
-			if err != nil {
+			if (err != nil) != tc.hasError {
 				t.Errorf("Unexpected error: %v", err)
 			}
 		})
 	}
 }
 
+type errorReader struct {
+	err error
+}
+
+func (e *errorReader) Read(_ []byte) (n int, err error) {
+	return 0, e.err
+}
+
 func TestHandleErrorResp(t *testing.T) {
 	// var errRes *ErrorResponse
 	var errRes ErrorResponse

completion.go

@@ -165,7 +165,7 @@ func (c *Client) CreateCompletion(
 		return
 	}
 
-	req, err := c.requestBuilder.Build(ctx, http.MethodPost, c.fullURL(urlSuffix, request.Model), request)
+	req, err := c.newRequest(ctx, http.MethodPost, c.fullURL(urlSuffix, request.Model), withBody(request))
 	if err != nil {
 		return
 	}

edits.go

@@ -32,7 +32,7 @@ type EditsResponse struct {
 
 // Perform an API call to the Edits endpoint.
 func (c *Client) Edits(ctx context.Context, request EditsRequest) (response EditsResponse, err error) {
-	req, err := c.requestBuilder.Build(ctx, http.MethodPost, c.fullURL("/edits", fmt.Sprint(request.Model)), request)
+	req, err := c.newRequest(ctx, http.MethodPost, c.fullURL("/edits", fmt.Sprint(request.Model)), withBody(request))
 	if err != nil {
 		return
 	}

embeddings.go

@@ -132,7 +132,7 @@ type EmbeddingRequest struct {
 // CreateEmbeddings returns an EmbeddingResponse which will contain an Embedding for every item in |request.Input|.
 // https://beta.openai.com/docs/api-reference/embeddings/create
 func (c *Client) CreateEmbeddings(ctx context.Context, request EmbeddingRequest) (resp EmbeddingResponse, err error) {
-	req, err := c.requestBuilder.Build(ctx, http.MethodPost, c.fullURL("/embeddings", request.Model.String()), request)
+	req, err := c.newRequest(ctx, http.MethodPost, c.fullURL("/embeddings", request.Model.String()), withBody(request))
 	if err != nil {
 		return
 	}

engines.go

@@ -22,7 +22,7 @@ type EnginesList struct {
 // ListEngines Lists the currently available engines, and provides basic
 // information about each option such as the owner and availability.
 func (c *Client) ListEngines(ctx context.Context) (engines EnginesList, err error) {
-	req, err := c.requestBuilder.Build(ctx, http.MethodGet, c.fullURL("/engines"), nil)
+	req, err := c.newRequest(ctx, http.MethodGet, c.fullURL("/engines"))
 	if err != nil {
 		return
 	}
@@ -38,7 +38,7 @@ func (c *Client) GetEngine(
 	engineID string,
 ) (engine Engine, err error) {
 	urlSuffix := fmt.Sprintf("/engines/%s", engineID)
-	req, err := c.requestBuilder.Build(ctx, http.MethodGet, c.fullURL(urlSuffix), nil)
+	req, err := c.newRequest(ctx, http.MethodGet, c.fullURL(urlSuffix))
 	if err != nil {
 		return
 	}