Sub2API v1.0 - AI API 网关（二开初始版本，基于上游 Wei-Shaw/sub2api）

backend/internal/service/openai_compat_prompt_cache_key.go

@@ -0,0 +1,181 @@
+package service
+
+import (
+	"crypto/sha256"
+	"encoding/json"
+	"fmt"
+	"strings"
+
+	"github.com/Wei-Shaw/sub2api/internal/pkg/apicompat"
+)
+
+const compatPromptCacheKeyPrefix = "compat_cc_"
+
+func shouldAutoInjectPromptCacheKeyForCompat(model string) bool {
+	trimmed := strings.TrimSpace(strings.ToLower(model))
+	// 仅对 Codex OAuth 路径支持的 GPT-5 族开启自动注入，避免 normalizeCodexModel
+	// 的默认兜底把任意模型（如 gpt-4o、claude-*）误判为 gpt-5.4。
+	if !strings.Contains(trimmed, "gpt-5") && !strings.Contains(trimmed, "codex") {
+		return false
+	}
+	normalized := strings.TrimSpace(strings.ToLower(normalizeCodexModel(trimmed)))
+	return strings.HasPrefix(normalized, "gpt-5") || strings.Contains(normalized, "codex")
+}
+
+func deriveCompatPromptCacheKey(req *apicompat.ChatCompletionsRequest, mappedModel string) string {
+	if req == nil {
+		return ""
+	}
+
+	normalizedModel := normalizeCodexModel(strings.TrimSpace(mappedModel))
+	if normalizedModel == "" {
+		normalizedModel = normalizeCodexModel(strings.TrimSpace(req.Model))
+	}
+	if normalizedModel == "" {
+		normalizedModel = strings.TrimSpace(req.Model)
+	}
+
+	seedParts := []string{"model=" + normalizedModel}
+	if req.ReasoningEffort != "" {
+		seedParts = append(seedParts, "reasoning_effort="+strings.TrimSpace(req.ReasoningEffort))
+	}
+	if len(req.ToolChoice) > 0 {
+		seedParts = append(seedParts, "tool_choice="+normalizeCompatSeedJSON(req.ToolChoice))
+	}
+	if len(req.Tools) > 0 {
+		if raw, err := json.Marshal(req.Tools); err == nil {
+			seedParts = append(seedParts, "tools="+normalizeCompatSeedJSON(raw))
+		}
+	}
+	if len(req.Functions) > 0 {
+		if raw, err := json.Marshal(req.Functions); err == nil {
+			seedParts = append(seedParts, "functions="+normalizeCompatSeedJSON(raw))
+		}
+	}
+
+	firstUserCaptured := false
+	for _, msg := range req.Messages {
+		switch strings.TrimSpace(msg.Role) {
+		case "system":
+			seedParts = append(seedParts, "system="+normalizeCompatSeedJSON(msg.Content))
+		case "user":
+			if !firstUserCaptured {
+				seedParts = append(seedParts, "first_user="+normalizeCompatSeedJSON(msg.Content))
+				firstUserCaptured = true
+			}
+		}
+	}
+
+	return compatPromptCacheKeyPrefix + hashSensitiveValueForLog(strings.Join(seedParts, "|"))
+}
+
+func deriveAnthropicCompatPromptCacheKey(req *apicompat.AnthropicRequest, mappedModel string) string {
+	if req == nil {
+		return ""
+	}
+	if anchorKey := deriveAnthropicCacheControlPromptCacheKey(req); anchorKey != "" {
+		return anchorKey
+	}
+
+	normalizedModel := normalizeCodexModel(strings.TrimSpace(mappedModel))
+	if normalizedModel == "" {
+		normalizedModel = normalizeCodexModel(strings.TrimSpace(req.Model))
+	}
+	if normalizedModel == "" {
+		normalizedModel = strings.TrimSpace(req.Model)
+	}
+
+	seedParts := []string{"model=" + normalizedModel}
+	if req.OutputConfig != nil && strings.TrimSpace(req.OutputConfig.Effort) != "" {
+		seedParts = append(seedParts, "effort="+strings.TrimSpace(req.OutputConfig.Effort))
+	}
+	if len(req.ToolChoice) > 0 {
+		seedParts = append(seedParts, "tool_choice="+normalizeCompatSeedJSON(req.ToolChoice))
+	}
+	if len(req.Tools) > 0 {
+		if raw, err := json.Marshal(req.Tools); err == nil {
+			seedParts = append(seedParts, "tools="+normalizeCompatSeedJSON(raw))
+		}
+	}
+	if len(req.System) > 0 {
+		seedParts = append(seedParts, "system="+normalizeCompatSeedJSON(req.System))
+	}
+
+	firstUserCaptured := false
+	for _, msg := range req.Messages {
+		if strings.TrimSpace(msg.Role) != "user" || firstUserCaptured {
+			continue
+		}
+		seedParts = append(seedParts, "first_user="+normalizeCompatSeedJSON(msg.Content))
+		firstUserCaptured = true
+	}
+
+	return compatPromptCacheKeyPrefix + hashSensitiveValueForLog(strings.Join(seedParts, "|"))
+}
+
+func deriveAnthropicCacheControlPromptCacheKey(req *apicompat.AnthropicRequest) string {
+	if req == nil {
+		return ""
+	}
+
+	var parts []string
+	var systemBlocks []apicompat.AnthropicContentBlock
+	if len(req.System) > 0 && json.Unmarshal(req.System, &systemBlocks) == nil {
+		for _, block := range systemBlocks {
+			if block.Type == "text" &&
+				block.CacheControl != nil &&
+				strings.TrimSpace(block.CacheControl.Type) == "ephemeral" &&
+				strings.TrimSpace(block.Text) != "" {
+				parts = append(parts, "system:"+strings.TrimSpace(block.Text))
+			}
+		}
+	}
+
+	firstUserAnchor := ""
+	for _, msg := range req.Messages {
+		var blocks []apicompat.AnthropicContentBlock
+		if len(msg.Content) == 0 || json.Unmarshal(msg.Content, &blocks) != nil {
+			continue
+		}
+		role := strings.TrimSpace(msg.Role)
+		for _, block := range blocks {
+			if block.Type != "text" ||
+				block.CacheControl == nil ||
+				strings.TrimSpace(block.CacheControl.Type) != "ephemeral" ||
+				strings.TrimSpace(block.Text) == "" {
+				continue
+			}
+			switch role {
+			case "user":
+				if firstUserAnchor == "" {
+					firstUserAnchor = strings.TrimSpace(block.Text)
+				}
+			case "assistant":
+				parts = append(parts, "assistant:"+strings.TrimSpace(block.Text))
+			}
+		}
+	}
+	if firstUserAnchor != "" {
+		parts = append(parts, "user_anchor:"+firstUserAnchor)
+	}
+	if len(parts) == 0 {
+		return ""
+	}
+	sum := sha256.Sum256([]byte("anthropic-cache:" + strings.Join(parts, "\n")))
+	return fmt.Sprintf("anthropic-cache-%x", sum[:16])
+}
+
+func normalizeCompatSeedJSON(v json.RawMessage) string {
+	if len(v) == 0 {
+		return ""
+	}
+	var tmp any
+	if err := json.Unmarshal(v, &tmp); err != nil {
+		return string(v)
+	}
+	out, err := json.Marshal(tmp)
+	if err != nil {
+		return string(v)
+	}
+	return string(out)
+}