Merge pull request #809 from alfadb/feature/openai-messages

feat(openai): 添加 /v1/messages 端点和 API 兼容层
This commit is contained in:
Wesley Liddick
2026-03-06 20:16:06 +08:00
committed by GitHub
11 changed files with 2840 additions and 5 deletions

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@@ -5429,6 +5429,11 @@ func extractUpstreamErrorMessage(body []byte) string {
return m
}
// ChatGPT 内部 API 风格:{"detail":"..."}
if d := gjson.GetBytes(body, "detail").String(); strings.TrimSpace(d) != "" {
return d
}
// 兜底:尝试顶层 message
return gjson.GetBytes(body, "message").String()
}

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@@ -0,0 +1,378 @@
package service
import (
"bufio"
"context"
"encoding/json"
"errors"
"fmt"
"io"
"net/http"
"strings"
"time"
"github.com/Wei-Shaw/sub2api/internal/pkg/apicompat"
"github.com/Wei-Shaw/sub2api/internal/pkg/logger"
"github.com/Wei-Shaw/sub2api/internal/util/responseheaders"
"github.com/gin-gonic/gin"
"go.uber.org/zap"
)
// ForwardAsAnthropic accepts an Anthropic Messages request body, converts it
// to OpenAI Responses API format, forwards to the OpenAI upstream, and converts
// the response back to Anthropic Messages format. This enables Claude Code
// clients to access OpenAI models through the standard /v1/messages endpoint.
func (s *OpenAIGatewayService) ForwardAsAnthropic(
ctx context.Context,
c *gin.Context,
account *Account,
body []byte,
promptCacheKey string,
) (*OpenAIForwardResult, error) {
startTime := time.Now()
// 1. Parse Anthropic request
var anthropicReq apicompat.AnthropicRequest
if err := json.Unmarshal(body, &anthropicReq); err != nil {
return nil, fmt.Errorf("parse anthropic request: %w", err)
}
originalModel := anthropicReq.Model
isStream := anthropicReq.Stream
// 2. Convert Anthropic → Responses
responsesReq, err := apicompat.AnthropicToResponses(&anthropicReq)
if err != nil {
return nil, fmt.Errorf("convert anthropic to responses: %w", err)
}
// 3. Model mapping
mappedModel := account.GetMappedModel(originalModel)
responsesReq.Model = mappedModel
logger.L().Info("openai messages: model mapping applied",
zap.Int64("account_id", account.ID),
zap.String("original_model", originalModel),
zap.String("mapped_model", mappedModel),
zap.Bool("stream", isStream),
)
// 4. Marshal Responses request body, then apply OAuth codex transform
responsesBody, err := json.Marshal(responsesReq)
if err != nil {
return nil, fmt.Errorf("marshal responses request: %w", err)
}
if account.Type == AccountTypeOAuth {
var reqBody map[string]any
if err := json.Unmarshal(responsesBody, &reqBody); err != nil {
return nil, fmt.Errorf("unmarshal for codex transform: %w", err)
}
applyCodexOAuthTransform(reqBody, false)
// OAuth codex transform forces stream=true upstream, so always use
// the streaming response handler regardless of what the client asked.
isStream = true
responsesBody, err = json.Marshal(reqBody)
if err != nil {
return nil, fmt.Errorf("remarshal after codex transform: %w", err)
}
}
// 5. Get access token
token, _, err := s.GetAccessToken(ctx, account)
if err != nil {
return nil, fmt.Errorf("get access token: %w", err)
}
// 6. Build upstream request
upstreamReq, err := s.buildUpstreamRequest(ctx, c, account, responsesBody, token, isStream, promptCacheKey, false)
if err != nil {
return nil, fmt.Errorf("build upstream request: %w", err)
}
// 7. Send request
proxyURL := ""
if account.Proxy != nil {
proxyURL = account.Proxy.URL()
}
resp, err := s.httpUpstream.Do(upstreamReq, proxyURL, account.ID, account.Concurrency)
if err != nil {
safeErr := sanitizeUpstreamErrorMessage(err.Error())
setOpsUpstreamError(c, 0, safeErr, "")
appendOpsUpstreamError(c, OpsUpstreamErrorEvent{
Platform: account.Platform,
AccountID: account.ID,
AccountName: account.Name,
UpstreamStatusCode: 0,
Kind: "request_error",
Message: safeErr,
})
writeAnthropicError(c, http.StatusBadGateway, "api_error", "Upstream request failed")
return nil, fmt.Errorf("upstream request failed: %s", safeErr)
}
defer func() { _ = resp.Body.Close() }()
// 8. Handle error response with failover
if resp.StatusCode >= 400 {
if s.shouldFailoverUpstreamError(resp.StatusCode) {
respBody, _ := io.ReadAll(io.LimitReader(resp.Body, 2<<20))
_ = resp.Body.Close()
upstreamMsg := strings.TrimSpace(extractUpstreamErrorMessage(respBody))
upstreamMsg = sanitizeUpstreamErrorMessage(upstreamMsg)
upstreamDetail := ""
if s.cfg != nil && s.cfg.Gateway.LogUpstreamErrorBody {
maxBytes := s.cfg.Gateway.LogUpstreamErrorBodyMaxBytes
if maxBytes <= 0 {
maxBytes = 2048
}
upstreamDetail = truncateString(string(respBody), maxBytes)
}
appendOpsUpstreamError(c, OpsUpstreamErrorEvent{
Platform: account.Platform,
AccountID: account.ID,
AccountName: account.Name,
UpstreamStatusCode: resp.StatusCode,
UpstreamRequestID: resp.Header.Get("x-request-id"),
Kind: "failover",
Message: upstreamMsg,
Detail: upstreamDetail,
})
if s.rateLimitService != nil {
s.rateLimitService.HandleUpstreamError(ctx, account, resp.StatusCode, resp.Header, respBody)
}
return nil, &UpstreamFailoverError{StatusCode: resp.StatusCode, ResponseBody: respBody}
}
// Non-failover error: return Anthropic-formatted error to client
return s.handleAnthropicErrorResponse(resp, c)
}
// 9. Handle normal response
if isStream {
return s.handleAnthropicStreamingResponse(resp, c, originalModel, startTime)
}
return s.handleAnthropicNonStreamingResponse(resp, c, originalModel, startTime)
}
// handleAnthropicErrorResponse reads an upstream error and returns it in
// Anthropic error format.
func (s *OpenAIGatewayService) handleAnthropicErrorResponse(
resp *http.Response,
c *gin.Context,
) (*OpenAIForwardResult, error) {
body, _ := io.ReadAll(io.LimitReader(resp.Body, 2<<20))
upstreamMsg := strings.TrimSpace(extractUpstreamErrorMessage(body))
if upstreamMsg == "" {
upstreamMsg = fmt.Sprintf("Upstream error: %d", resp.StatusCode)
}
upstreamMsg = sanitizeUpstreamErrorMessage(upstreamMsg)
// Record upstream error details for ops logging
upstreamDetail := ""
if s.cfg != nil && s.cfg.Gateway.LogUpstreamErrorBody {
maxBytes := s.cfg.Gateway.LogUpstreamErrorBodyMaxBytes
if maxBytes <= 0 {
maxBytes = 2048
}
upstreamDetail = truncateString(string(body), maxBytes)
}
setOpsUpstreamError(c, resp.StatusCode, upstreamMsg, upstreamDetail)
errType := "api_error"
switch {
case resp.StatusCode == 400:
errType = "invalid_request_error"
case resp.StatusCode == 404:
errType = "not_found_error"
case resp.StatusCode == 429:
errType = "rate_limit_error"
case resp.StatusCode >= 500:
errType = "api_error"
}
writeAnthropicError(c, resp.StatusCode, errType, upstreamMsg)
return nil, fmt.Errorf("upstream error: %d %s", resp.StatusCode, upstreamMsg)
}
// handleAnthropicNonStreamingResponse reads a Responses API JSON response,
// converts it to Anthropic Messages format, and writes it to the client.
func (s *OpenAIGatewayService) handleAnthropicNonStreamingResponse(
resp *http.Response,
c *gin.Context,
originalModel string,
startTime time.Time,
) (*OpenAIForwardResult, error) {
requestID := resp.Header.Get("x-request-id")
respBody, err := io.ReadAll(resp.Body)
if err != nil {
return nil, fmt.Errorf("read upstream response: %w", err)
}
var responsesResp apicompat.ResponsesResponse
if err := json.Unmarshal(respBody, &responsesResp); err != nil {
return nil, fmt.Errorf("parse responses response: %w", err)
}
anthropicResp := apicompat.ResponsesToAnthropic(&responsesResp, originalModel)
var usage OpenAIUsage
if responsesResp.Usage != nil {
usage = OpenAIUsage{
InputTokens: responsesResp.Usage.InputTokens,
OutputTokens: responsesResp.Usage.OutputTokens,
}
if responsesResp.Usage.InputTokensDetails != nil {
usage.CacheReadInputTokens = responsesResp.Usage.InputTokensDetails.CachedTokens
}
}
if s.responseHeaderFilter != nil {
responseheaders.WriteFilteredHeaders(c.Writer.Header(), resp.Header, s.responseHeaderFilter)
}
c.JSON(http.StatusOK, anthropicResp)
return &OpenAIForwardResult{
RequestID: requestID,
Usage: usage,
Model: originalModel,
Stream: false,
Duration: time.Since(startTime),
}, nil
}
// handleAnthropicStreamingResponse reads Responses SSE events from upstream,
// converts each to Anthropic SSE events, and writes them to the client.
func (s *OpenAIGatewayService) handleAnthropicStreamingResponse(
resp *http.Response,
c *gin.Context,
originalModel string,
startTime time.Time,
) (*OpenAIForwardResult, error) {
requestID := resp.Header.Get("x-request-id")
if s.responseHeaderFilter != nil {
responseheaders.WriteFilteredHeaders(c.Writer.Header(), resp.Header, s.responseHeaderFilter)
}
c.Writer.Header().Set("Content-Type", "text/event-stream")
c.Writer.Header().Set("Cache-Control", "no-cache")
c.Writer.Header().Set("Connection", "keep-alive")
c.Writer.WriteHeader(http.StatusOK)
state := apicompat.NewResponsesEventToAnthropicState()
state.Model = originalModel
var usage OpenAIUsage
var firstTokenMs *int
firstChunk := true
scanner := bufio.NewScanner(resp.Body)
scanner.Buffer(make([]byte, 0, 64*1024), 1024*1024)
for scanner.Scan() {
line := scanner.Text()
if !strings.HasPrefix(line, "data: ") || line == "data: [DONE]" {
continue
}
payload := line[6:]
if firstChunk {
firstChunk = false
ms := int(time.Since(startTime).Milliseconds())
firstTokenMs = &ms
}
// Parse the Responses SSE event
var event apicompat.ResponsesStreamEvent
if err := json.Unmarshal([]byte(payload), &event); err != nil {
logger.L().Warn("openai messages stream: failed to parse event",
zap.Error(err),
zap.String("request_id", requestID),
)
continue
}
// Extract usage from completion events
if (event.Type == "response.completed" || event.Type == "response.incomplete") &&
event.Response != nil && event.Response.Usage != nil {
usage = OpenAIUsage{
InputTokens: event.Response.Usage.InputTokens,
OutputTokens: event.Response.Usage.OutputTokens,
}
if event.Response.Usage.InputTokensDetails != nil {
usage.CacheReadInputTokens = event.Response.Usage.InputTokensDetails.CachedTokens
}
}
// Convert to Anthropic events
events := apicompat.ResponsesEventToAnthropicEvents(&event, state)
for _, evt := range events {
sse, err := apicompat.ResponsesAnthropicEventToSSE(evt)
if err != nil {
logger.L().Warn("openai messages stream: failed to marshal event",
zap.Error(err),
zap.String("request_id", requestID),
)
continue
}
if _, err := fmt.Fprint(c.Writer, sse); err != nil {
// Client disconnected — return collected usage
logger.L().Info("openai messages stream: client disconnected",
zap.String("request_id", requestID),
)
return &OpenAIForwardResult{
RequestID: requestID,
Usage: usage,
Model: originalModel,
Stream: true,
Duration: time.Since(startTime),
FirstTokenMs: firstTokenMs,
}, nil
}
}
if len(events) > 0 {
c.Writer.Flush()
}
}
if err := scanner.Err(); err != nil {
if !errors.Is(err, context.Canceled) && !errors.Is(err, context.DeadlineExceeded) {
logger.L().Warn("openai messages stream: read error",
zap.Error(err),
zap.String("request_id", requestID),
)
}
}
// Ensure the Anthropic stream is properly terminated
if finalEvents := apicompat.FinalizeResponsesAnthropicStream(state); len(finalEvents) > 0 {
for _, evt := range finalEvents {
sse, err := apicompat.ResponsesAnthropicEventToSSE(evt)
if err != nil {
continue
}
fmt.Fprint(c.Writer, sse) //nolint:errcheck
}
c.Writer.Flush()
}
return &OpenAIForwardResult{
RequestID: requestID,
Usage: usage,
Model: originalModel,
Stream: true,
Duration: time.Since(startTime),
FirstTokenMs: firstTokenMs,
}, nil
}
// writeAnthropicError writes an error response in Anthropic Messages API format.
func writeAnthropicError(c *gin.Context, statusCode int, errType, message string) {
c.JSON(statusCode, gin.H{
"type": "error",
"error": gin.H{
"type": errType,
"message": message,
},
})
}

View File

@@ -900,6 +900,22 @@ func isOpenAIInstructionsRequiredError(upstreamStatusCode int, upstreamMsg strin
return false
}
// ExtractSessionID extracts the raw session ID from headers or body without hashing.
// Used by ForwardAsAnthropic to pass as prompt_cache_key for upstream cache.
func (s *OpenAIGatewayService) ExtractSessionID(c *gin.Context, body []byte) string {
if c == nil {
return ""
}
sessionID := strings.TrimSpace(c.GetHeader("session_id"))
if sessionID == "" {
sessionID = strings.TrimSpace(c.GetHeader("conversation_id"))
}
if sessionID == "" && len(body) > 0 {
sessionID = strings.TrimSpace(gjson.GetBytes(body, "prompt_cache_key").String())
}
return sessionID
}
// GenerateSessionHash generates a sticky-session hash for OpenAI requests.
//
// Priority: