feat: improve OpenAI messages compatibility for Claude Code

backend/internal/service/openai_messages_digest_session.go

@@ -0,0 +1,135 @@
+package service
+
+import (
+	"encoding/json"
+	"fmt"
+	"strings"
+	"time"
+
+	"github.com/Wei-Shaw/sub2api/internal/pkg/apicompat"
+)
+
+type openAICompatAnthropicDigestBinding struct {
+	PromptCacheKey string
+	ExpiresAt      time.Time
+}
+
+func buildOpenAICompatAnthropicDigestChain(req *apicompat.AnthropicRequest) string {
+	if req == nil {
+		return ""
+	}
+
+	parts := make([]string, 0, len(req.Messages)+1)
+	if len(req.System) > 0 && strings.TrimSpace(string(req.System)) != "" && strings.TrimSpace(string(req.System)) != "null" {
+		parts = append(parts, "s:"+shortHash(req.System))
+	}
+	for _, msg := range req.Messages {
+		content := msg.Content
+		if len(content) == 0 || strings.TrimSpace(string(content)) == "" {
+			continue
+		}
+		prefix := "u"
+		if strings.TrimSpace(msg.Role) == "assistant" {
+			prefix = "a"
+		}
+		parts = append(parts, prefix+":"+shortHash(content))
+	}
+	return strings.Join(parts, "-")
+}
+
+func openAICompatAnthropicDigestNamespace(account *Account, cAPIKeyID int64) string {
+	if account == nil || account.ID <= 0 {
+		return ""
+	}
+	return fmt.Sprintf("%d|%d|", account.ID, cAPIKeyID)
+}
+
+func (s *OpenAIGatewayService) findOpenAICompatAnthropicDigestPromptCacheKey(account *Account, cAPIKeyID int64, digestChain string) (promptCacheKey string, matchedChain string) {
+	if s == nil || digestChain == "" {
+		return "", ""
+	}
+	ns := openAICompatAnthropicDigestNamespace(account, cAPIKeyID)
+	if ns == "" {
+		return "", ""
+	}
+	chain := digestChain
+	for {
+		if raw, ok := s.openaiCompatAnthropicDigestSessions.Load(ns + chain); ok {
+			if binding, ok := raw.(openAICompatAnthropicDigestBinding); ok {
+				if binding.ExpiresAt.IsZero() || time.Now().Before(binding.ExpiresAt) {
+					if key := strings.TrimSpace(binding.PromptCacheKey); key != "" {
+						return key, chain
+					}
+				}
+			}
+			s.openaiCompatAnthropicDigestSessions.Delete(ns + chain)
+		}
+		i := strings.LastIndex(chain, "-")
+		if i < 0 {
+			return "", ""
+		}
+		chain = chain[:i]
+	}
+}
+
+func (s *OpenAIGatewayService) bindOpenAICompatAnthropicDigestPromptCacheKey(account *Account, cAPIKeyID int64, digestChain, promptCacheKey, oldDigestChain string) {
+	if s == nil || digestChain == "" || strings.TrimSpace(promptCacheKey) == "" {
+		return
+	}
+	ns := openAICompatAnthropicDigestNamespace(account, cAPIKeyID)
+	if ns == "" {
+		return
+	}
+	binding := openAICompatAnthropicDigestBinding{
+		PromptCacheKey: strings.TrimSpace(promptCacheKey),
+		ExpiresAt:      time.Now().Add(s.openAIWSResponseStickyTTL()),
+	}
+	s.openaiCompatAnthropicDigestSessions.Store(ns+digestChain, binding)
+	if oldDigestChain != "" && oldDigestChain != digestChain {
+		s.openaiCompatAnthropicDigestSessions.Delete(ns + oldDigestChain)
+	}
+}
+
+func promptCacheKeyFromAnthropicDigest(digestChain string) string {
+	if strings.TrimSpace(digestChain) == "" {
+		return ""
+	}
+	return "anthropic-digest-" + hashSensitiveValueForLog(digestChain)
+}
+
+func promptCacheKeyFromAnthropicMetadataSession(req *apicompat.AnthropicRequest) string {
+	if req == nil || len(req.Metadata) == 0 {
+		return ""
+	}
+	var metadata struct {
+		UserID string `json:"user_id"`
+	}
+	if err := json.Unmarshal(req.Metadata, &metadata); err != nil {
+		return ""
+	}
+	parsed := ParseMetadataUserID(metadata.UserID)
+	if parsed == nil || strings.TrimSpace(parsed.SessionID) == "" {
+		return ""
+	}
+	seed := strings.Join([]string{
+		"anthropic-metadata",
+		strings.TrimSpace(parsed.DeviceID),
+		strings.TrimSpace(parsed.AccountUUID),
+		strings.TrimSpace(parsed.SessionID),
+	}, "|")
+	return "anthropic-metadata-" + hashSensitiveValueForLog(seed)
+}
+
+func cloneAnthropicRequestForDigest(req *apicompat.AnthropicRequest) *apicompat.AnthropicRequest {
+	if req == nil {
+		return nil
+	}
+	cp := *req
+	if len(req.System) > 0 {
+		cp.System = append(json.RawMessage(nil), req.System...)
+	}
+	if len(req.Messages) > 0 {
+		cp.Messages = append([]apicompat.AnthropicMessage(nil), req.Messages...)
+	}
+	return &cp
+}