CLIProxyAPI/internal/api/handlers/openai/openai-handlers.go

// Package openai provides HTTP handlers for OpenAI API endpoints.
// This package implements the OpenAI-compatible API interface, including model listing
// and chat completion functionality. It supports both streaming and non-streaming responses,
// and manages a pool of clients to interact with backend services.
// The handlers translate OpenAI API requests to the appropriate backend format and
// convert responses back to OpenAI-compatible format.
package openai

import (
	"context"
	"fmt"
	"github.com/luispater/CLIProxyAPI/internal/api/handlers"
	"github.com/luispater/CLIProxyAPI/internal/api/translator/openai"
	"github.com/luispater/CLIProxyAPI/internal/client"
	log "github.com/sirupsen/logrus"
	"github.com/tidwall/gjson"
	"net/http"
	"time"

	"github.com/gin-gonic/gin"
)

// OpenAIAPIHandlers contains the handlers for OpenAI API endpoints.
// It holds a pool of clients to interact with the backend service.
type OpenAIAPIHandlers struct {
	*handlers.APIHandlers
}

// NewOpenAIAPIHandlers creates a new OpenAI API handlers instance.
// It takes an APIHandlers instance as input and returns an OpenAIAPIHandlers.
func NewOpenAIAPIHandlers(apiHandlers *handlers.APIHandlers) *OpenAIAPIHandlers {
	return &OpenAIAPIHandlers{
		APIHandlers: apiHandlers,
	}
}

// Models handles the /v1/models endpoint.
// It returns a hardcoded list of available AI models.
func (h *OpenAIAPIHandlers) Models(c *gin.Context) {
	c.JSON(http.StatusOK, gin.H{
		"data": []map[string]any{
			{
				"id":                    "gemini-2.5-pro",
				"object":                "model",
				"version":               "2.5",
				"name":                  "Gemini 2.5 Pro",
				"description":           "Stable release (June 17th, 2025) of Gemini 2.5 Pro",
				"context_length":        1048576,
				"max_completion_tokens": 65536,
				"supported_parameters": []string{
					"tools",
					"temperature",
					"top_p",
					"top_k",
				},
				"temperature":    1,
				"topP":           0.95,
				"topK":           64,
				"maxTemperature": 2,
				"thinking":       true,
			},
			{
				"id":                    "gemini-2.5-flash",
				"object":                "model",
				"version":               "001",
				"name":                  "Gemini 2.5 Flash",
				"description":           "Stable version of Gemini 2.5 Flash, our mid-size multimodal model that supports up to 1 million tokens, released in June of 2025.",
				"context_length":        1048576,
				"max_completion_tokens": 65536,
				"supported_parameters": []string{
					"tools",
					"temperature",
					"top_p",
					"top_k",
				},
				"temperature":    1,
				"topP":           0.95,
				"topK":           64,
				"maxTemperature": 2,
				"thinking":       true,
			},
		},
	})
}

// ChatCompletions handles the /v1/chat/completions endpoint.
// It determines whether the request is for a streaming or non-streaming response
// and calls the appropriate handler.
func (h *OpenAIAPIHandlers) ChatCompletions(c *gin.Context) {
	rawJSON, err := c.GetRawData()
	// If data retrieval fails, return a 400 Bad Request error.
	if err != nil {
		c.JSON(http.StatusBadRequest, handlers.ErrorResponse{
			Error: handlers.ErrorDetail{
				Message: fmt.Sprintf("Invalid request: %v", err),
				Type:    "invalid_request_error",
			},
		})
		return
	}

	// Check if the client requested a streaming response.
	streamResult := gjson.GetBytes(rawJSON, "stream")
	if streamResult.Type == gjson.True {
		h.handleStreamingResponse(c, rawJSON)
	} else {
		h.handleNonStreamingResponse(c, rawJSON)
	}
}

// handleNonStreamingResponse handles non-streaming chat completion responses.
// It selects a client from the pool, sends the request, and aggregates the response
// before sending it back to the client.
func (h *OpenAIAPIHandlers) handleNonStreamingResponse(c *gin.Context, rawJSON []byte) {
	c.Header("Content-Type", "application/json")

	modelName, systemInstruction, contents, tools := openai.PrepareRequest(rawJSON)
	cliCtx, cliCancel := context.WithCancel(context.Background())
	var cliClient *client.Client
	defer func() {
		if cliClient != nil {
			cliClient.RequestMutex.Unlock()
		}
	}()

	for {
		var errorResponse *client.ErrorMessage
		cliClient, errorResponse = h.GetClient(modelName)
		if errorResponse != nil {
			c.Status(errorResponse.StatusCode)
			_, _ = fmt.Fprint(c.Writer, errorResponse.Error)
			cliCancel()
			return
		}

		isGlAPIKey := false
		if glAPIKey := cliClient.GetGenerativeLanguageAPIKey(); glAPIKey != "" {
			log.Debugf("Request use generative language API Key: %s", glAPIKey)
			isGlAPIKey = true
		} else {
			log.Debugf("Request use account: %s, project id: %s", cliClient.GetEmail(), cliClient.GetProjectID())
		}

		resp, err := cliClient.SendMessage(cliCtx, rawJSON, modelName, systemInstruction, contents, tools)
		if err != nil {
			if err.StatusCode == 429 && h.Cfg.QuotaExceeded.SwitchProject {
				continue
			} else {
				c.Status(err.StatusCode)
				_, _ = c.Writer.Write([]byte(err.Error.Error()))
				cliCancel()
			}
			break
		} else {
			openAIFormat := openai.ConvertCliToOpenAINonStream(resp, time.Now().Unix(), isGlAPIKey)
			if openAIFormat != "" {
				_, _ = c.Writer.Write([]byte(openAIFormat))
			}
			cliCancel()
			break
		}
	}
}

// handleStreamingResponse handles streaming responses
func (h *OpenAIAPIHandlers) handleStreamingResponse(c *gin.Context, rawJSON []byte) {
	c.Header("Content-Type", "text/event-stream")
	c.Header("Cache-Control", "no-cache")
	c.Header("Connection", "keep-alive")
	c.Header("Access-Control-Allow-Origin", "*")

	// Get the http.Flusher interface to manually flush the response.
	flusher, ok := c.Writer.(http.Flusher)
	if !ok {
		c.JSON(http.StatusInternalServerError, handlers.ErrorResponse{
			Error: handlers.ErrorDetail{
				Message: "Streaming not supported",
				Type:    "server_error",
			},
		})
		return
	}

	// Prepare the request for the backend client.
	modelName, systemInstruction, contents, tools := openai.PrepareRequest(rawJSON)
	cliCtx, cliCancel := context.WithCancel(context.Background())
	var cliClient *client.Client
	defer func() {
		// Ensure the client's mutex is unlocked on function exit.
		if cliClient != nil {
			cliClient.RequestMutex.Unlock()
		}
	}()

outLoop:
	for {
		var errorResponse *client.ErrorMessage
		cliClient, errorResponse = h.GetClient(modelName)
		if errorResponse != nil {
			c.Status(errorResponse.StatusCode)
			_, _ = fmt.Fprint(c.Writer, errorResponse.Error)
			flusher.Flush()
			cliCancel()
			return
		}

		isGlAPIKey := false
		if glAPIKey := cliClient.GetGenerativeLanguageAPIKey(); glAPIKey != "" {
			log.Debugf("Request use generative language API Key: %s", glAPIKey)
			isGlAPIKey = true
		} else {
			log.Debugf("Request use account: %s, project id: %s", cliClient.GetEmail(), cliClient.GetProjectID())
		}
		// Send the message and receive response chunks and errors via channels.
		respChan, errChan := cliClient.SendMessageStream(cliCtx, rawJSON, modelName, systemInstruction, contents, tools)
		hasFirstResponse := false
		for {
			select {
			// Handle client disconnection.
			case <-c.Request.Context().Done():
				if c.Request.Context().Err().Error() == "context canceled" {
					log.Debugf("Client disconnected: %v", c.Request.Context().Err())
					cliCancel() // Cancel the backend request.
					return
				}
			// Process incoming response chunks.
			case chunk, okStream := <-respChan:
				if !okStream {
					// Stream is closed, send the final [DONE] message.
					_, _ = fmt.Fprintf(c.Writer, "data: [DONE]\n\n")
					flusher.Flush()
					cliCancel()
					return
				}
				// Convert the chunk to OpenAI format and send it to the client.
				hasFirstResponse = true
				openAIFormat := openai.ConvertCliToOpenAI(chunk, time.Now().Unix(), isGlAPIKey)
				if openAIFormat != "" {
					_, _ = fmt.Fprintf(c.Writer, "data: %s\n\n", openAIFormat)
					flusher.Flush()
				}
			// Handle errors from the backend.
			case err, okError := <-errChan:
				if okError {
					if err.StatusCode == 429 && h.Cfg.QuotaExceeded.SwitchProject {
						continue outLoop
					} else {
						c.Status(err.StatusCode)
						_, _ = fmt.Fprint(c.Writer, err.Error.Error())
						flusher.Flush()
						cliCancel()
					}
					return
				}
			// Send a keep-alive signal to the client.
			case <-time.After(500 * time.Millisecond):
				if hasFirstResponse {
					_, _ = c.Writer.Write([]byte(": CLI-PROXY-API PROCESSING\n\n"))
					flusher.Flush()
				}
			}
		}
	}
}