Add testable request builder (sashabaranov#162)

* Add testable request builder

* improve tests

api.go

@@ -1,7 +1,6 @@
 package openai
 
 import (
-	"bytes"
 	"context"
 	"encoding/json"
 	"fmt"
@@ -12,7 +11,7 @@ import (
 type Client struct {
 	config ClientConfig
 
-	marshaller marshaller
+	requestBuilder requestBuilder
 }
 
 // NewClient creates new OpenAI API client.
@@ -24,8 +23,8 @@ func NewClient(authToken string) *Client {
 // NewClientWithConfig creates new OpenAI API client for specified config.
 func NewClientWithConfig(config ClientConfig) *Client {
 	return &Client{
-		config:     config,
-		marshaller: &jsonMarshaller{},
+		config:         config,
+		requestBuilder: newRequestBuilder(),
 	}
 }
 
@@ -91,17 +90,8 @@ func (c *Client) newStreamRequest(
 	ctx context.Context,
 	method string,
 	urlSuffix string,
-	body interface{}) (*http.Request, error) {
-	var reqBody []byte
-	if body != nil {
-		var err error
-		reqBody, err = c.marshaller.marshal(body)
-		if err != nil {
-			return nil, err
-		}
-	}
-
-	req, err := http.NewRequestWithContext(ctx, method, c.fullURL(urlSuffix), bytes.NewBuffer(reqBody))
+	body any) (*http.Request, error) {
+	req, err := c.requestBuilder.build(ctx, method, c.fullURL(urlSuffix), body)
 	if err != nil {
 		return nil, err
 	}

chat.go

@@ -1,7 +1,6 @@
 package openai
 
 import (
-	"bytes"
 	"context"
 	"errors"
 	"net/http"
@@ -72,14 +71,8 @@ func (c *Client) CreateChatCompletion(
 		return
 	}
 
-	var reqBytes []byte
-	reqBytes, err = c.marshaller.marshal(request)
-	if err != nil {
-		return
-	}
-
 	urlSuffix := "/chat/completions"
-	req, err := http.NewRequestWithContext(ctx, http.MethodPost, c.fullURL(urlSuffix), bytes.NewBuffer(reqBytes))
+	req, err := c.requestBuilder.build(ctx, http.MethodPost, c.fullURL(urlSuffix), request)
 	if err != nil {
 		return
 	}

completion.go

@@ -1,7 +1,6 @@
 package openai
 
 import (
-	"bytes"
 	"context"
 	"errors"
 	"net/http"
@@ -105,14 +104,8 @@ func (c *Client) CreateCompletion(
 		return
 	}
 
-	var reqBytes []byte
-	reqBytes, err = c.marshaller.marshal(request)
-	if err != nil {
-		return
-	}
-
 	urlSuffix := "/completions"
-	req, err := http.NewRequestWithContext(ctx, http.MethodPost, c.fullURL(urlSuffix), bytes.NewBuffer(reqBytes))
+	req, err := c.requestBuilder.build(ctx, http.MethodPost, c.fullURL(urlSuffix), request)
 	if err != nil {
 		return
 	}

edits.go

@@ -1,7 +1,6 @@
 package openai
 
 import (
-	"bytes"
 	"context"
 	"net/http"
 )
@@ -32,13 +31,7 @@ type EditsResponse struct {
 
 // Perform an API call to the Edits endpoint.
 func (c *Client) Edits(ctx context.Context, request EditsRequest) (response EditsResponse, err error) {
-	var reqBytes []byte
-	reqBytes, err = c.marshaller.marshal(request)
-	if err != nil {
-		return
-	}
-
-	req, err := http.NewRequestWithContext(ctx, http.MethodPost, c.fullURL("/edits"), bytes.NewBuffer(reqBytes))
+	req, err := c.requestBuilder.build(ctx, http.MethodPost, c.fullURL("/edits"), request)
 	if err != nil {
 		return
 	}

embeddings.go

@@ -1,7 +1,6 @@
 package openai
 
 import (
-	"bytes"
 	"context"
 	"net/http"
 )
@@ -133,14 +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) {
-	var reqBytes []byte
-	reqBytes, err = c.marshaller.marshal(request)
-	if err != nil {
-		return
-	}
-
-	urlSuffix := "/embeddings"
-	req, err := http.NewRequestWithContext(ctx, http.MethodPost, c.fullURL(urlSuffix), bytes.NewBuffer(reqBytes))
+	req, err := c.requestBuilder.build(ctx, http.MethodPost, c.fullURL("/embeddings"), 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 := http.NewRequestWithContext(ctx, http.MethodGet, c.fullURL("/engines"), nil)
+	req, err := c.requestBuilder.build(ctx, http.MethodGet, c.fullURL("/engines"), nil)
 	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 := http.NewRequestWithContext(ctx, http.MethodGet, c.fullURL(urlSuffix), nil)
+	req, err := c.requestBuilder.build(ctx, http.MethodGet, c.fullURL(urlSuffix), nil)
 	if err != nil {
 		return
 	}

files.go

@@ -112,7 +112,7 @@ func (c *Client) CreateFile(ctx context.Context, request FileRequest) (file File
 
 // DeleteFile deletes an existing file.
 func (c *Client) DeleteFile(ctx context.Context, fileID string) (err error) {
-	req, err := http.NewRequestWithContext(ctx, http.MethodDelete, c.fullURL("/files/"+fileID), nil)
+	req, err := c.requestBuilder.build(ctx, http.MethodDelete, c.fullURL("/files/"+fileID), nil)
 	if err != nil {
 		return
 	}
@@ -124,7 +124,7 @@ func (c *Client) DeleteFile(ctx context.Context, fileID string) (err error) {
 // ListFiles Lists the currently available files,
 // and provides basic information about each file such as the file name and purpose.
 func (c *Client) ListFiles(ctx context.Context) (files FilesList, err error) {
-	req, err := http.NewRequestWithContext(ctx, http.MethodGet, c.fullURL("/files"), nil)
+	req, err := c.requestBuilder.build(ctx, http.MethodGet, c.fullURL("/files"), nil)
 	if err != nil {
 		return
 	}
@@ -137,7 +137,7 @@ func (c *Client) ListFiles(ctx context.Context) (files FilesList, err error) {
 // such as the file name and purpose.
 func (c *Client) GetFile(ctx context.Context, fileID string) (file File, err error) {
 	urlSuffix := fmt.Sprintf("/files/%s", fileID)
-	req, err := http.NewRequestWithContext(ctx, http.MethodGet, c.fullURL(urlSuffix), nil)
+	req, err := c.requestBuilder.build(ctx, http.MethodGet, c.fullURL(urlSuffix), nil)
 	if err != nil {
 		return
 	}

fine_tunes.go

@@ -1,7 +1,6 @@
 package openai
 
 import (
-	"bytes"
 	"context"
 	"fmt"
 	"net/http"
@@ -68,14 +67,8 @@ type FineTuneDeleteResponse struct {
 }
 
 func (c *Client) CreateFineTune(ctx context.Context, request FineTuneRequest) (response FineTune, err error) {
-	var reqBytes []byte
-	reqBytes, err = c.marshaller.marshal(request)
-	if err != nil {
-		return
-	}
-
 	urlSuffix := "/fine-tunes"
-	req, err := http.NewRequestWithContext(ctx, http.MethodPost, c.fullURL(urlSuffix), bytes.NewBuffer(reqBytes))
+	req, err := c.requestBuilder.build(ctx, http.MethodPost, c.fullURL(urlSuffix), request)
 	if err != nil {
 		return
 	}
@@ -86,7 +79,7 @@ func (c *Client) CreateFineTune(ctx context.Context, request FineTuneRequest) (r
 
 // CancelFineTune cancel a fine-tune job.
 func (c *Client) CancelFineTune(ctx context.Context, fineTuneID string) (response FineTune, err error) {
-	req, err := http.NewRequestWithContext(ctx, http.MethodPost, c.fullURL("/fine-tunes/"+fineTuneID+"/cancel"), nil)
+	req, err := c.requestBuilder.build(ctx, http.MethodPost, c.fullURL("/fine-tunes/"+fineTuneID+"/cancel"), nil)
 	if err != nil {
 		return
 	}
@@ -96,7 +89,7 @@ func (c *Client) CancelFineTune(ctx context.Context, fineTuneID string) (respons
 }
 
 func (c *Client) ListFineTunes(ctx context.Context) (response FineTuneList, err error) {
-	req, err := http.NewRequestWithContext(ctx, http.MethodGet, c.fullURL("/fine-tunes"), nil)
+	req, err := c.requestBuilder.build(ctx, http.MethodGet, c.fullURL("/fine-tunes"), nil)
 	if err != nil {
 		return
 	}
@@ -107,7 +100,7 @@ func (c *Client) ListFineTunes(ctx context.Context) (response FineTuneList, err
 
 func (c *Client) GetFineTune(ctx context.Context, fineTuneID string) (response FineTune, err error) {
 	urlSuffix := fmt.Sprintf("/fine-tunes/%s", fineTuneID)
-	req, err := http.NewRequestWithContext(ctx, http.MethodGet, c.fullURL(urlSuffix), nil)
+	req, err := c.requestBuilder.build(ctx, http.MethodGet, c.fullURL(urlSuffix), nil)
 	if err != nil {
 		return
 	}
@@ -117,7 +110,7 @@ func (c *Client) GetFineTune(ctx context.Context, fineTuneID string) (response F
 }
 
 func (c *Client) DeleteFineTune(ctx context.Context, fineTuneID string) (response FineTuneDeleteResponse, err error) {
-	req, err := http.NewRequestWithContext(ctx, http.MethodDelete, c.fullURL("/fine-tunes/"+fineTuneID), nil)
+	req, err := c.requestBuilder.build(ctx, http.MethodDelete, c.fullURL("/fine-tunes/"+fineTuneID), nil)
 	if err != nil {
 		return
 	}
@@ -127,7 +120,7 @@ func (c *Client) DeleteFineTune(ctx context.Context, fineTuneID string) (respons
 }
 
 func (c *Client) ListFineTuneEvents(ctx context.Context, fineTuneID string) (response FineTuneEventList, err error) {
-	req, err := http.NewRequestWithContext(ctx, http.MethodGet, c.fullURL("/fine-tunes/"+fineTuneID+"/events"), nil)
+	req, err := c.requestBuilder.build(ctx, http.MethodGet, c.fullURL("/fine-tunes/"+fineTuneID+"/events"), nil)
 	if err != nil {
 		return
 	}

image.go

@@ -45,14 +45,8 @@ type ImageResponseDataInner struct {
 
 // CreateImage - API call to create an image. This is the main endpoint of the DALL-E API.
 func (c *Client) CreateImage(ctx context.Context, request ImageRequest) (response ImageResponse, err error) {
-	var reqBytes []byte
-	reqBytes, err = c.marshaller.marshal(request)
-	if err != nil {
-		return
-	}
-
 	urlSuffix := "/images/generations"
-	req, err := http.NewRequestWithContext(ctx, http.MethodPost, c.fullURL(urlSuffix), bytes.NewBuffer(reqBytes))
+	req, err := c.requestBuilder.build(ctx, http.MethodPost, c.fullURL(urlSuffix), request)
 	if err != nil {
 		return
 	}

moderation.go

@@ -1,7 +1,6 @@
 package openai
 
 import (
-	"bytes"
 	"context"
 	"net/http"
 )
@@ -51,13 +50,7 @@ type ModerationResponse struct {
 // Moderations — perform a moderation api call over a string.
 // Input can be an array or slice but a string will reduce the complexity.
 func (c *Client) Moderations(ctx context.Context, request ModerationRequest) (response ModerationResponse, err error) {
-	var reqBytes []byte
-	reqBytes, err = c.marshaller.marshal(request)
-	if err != nil {
-		return
-	}
-
-	req, err := http.NewRequestWithContext(ctx, http.MethodPost, c.fullURL("/moderations"), bytes.NewBuffer(reqBytes))
+	req, err := c.requestBuilder.build(ctx, http.MethodPost, c.fullURL("/moderations"), request)
 	if err != nil {
 		return
 	}