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sub2api/backend/internal/service/gateway_claude_oauth_body.go
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package service
import (
"bytes"
"context"
"crypto/sha256"
"encoding/json"
"fmt"
"strconv"
"strings"
"github.com/Wei-Shaw/sub2api/internal/pkg/anthropicfp"
"github.com/Wei-Shaw/sub2api/internal/pkg/claude"
infraerrors "github.com/Wei-Shaw/sub2api/internal/pkg/errors"
"github.com/Wei-Shaw/sub2api/internal/pkg/logger"
"github.com/google/uuid"
"github.com/tidwall/gjson"
"github.com/tidwall/sjson"
"github.com/gin-gonic/gin"
)
type anthropicCacheControlPayload struct {
Type string `json:"type"`
TTL string `json:"ttl,omitempty"`
}
type anthropicSystemTextBlockPayload struct {
Type string `json:"type"`
Text string `json:"text"`
CacheControl *anthropicCacheControlPayload `json:"cache_control,omitempty"`
}
type anthropicMetadataPayload struct {
UserID string `json:"user_id"`
}
// replaceModelInBody 替换请求体中的model字段
// 优先使用定点修改,尽量保持客户端原始字段顺序。
func (s *GatewayService) replaceModelInBody(body []byte, newModel string) []byte {
return ReplaceModelInBody(body, newModel)
}
type claudeOAuthNormalizeOptions struct {
injectMetadata bool
metadataUserID string
stripSystemCacheControl bool
}
// sanitizeSystemText rewrites only the fixed OpenCode identity sentence (if present).
// We intentionally avoid broad keyword replacement in system prompts to prevent
// accidentally changing user-provided instructions.
func sanitizeSystemText(text string) string {
if text == "" {
return text
}
// Some clients include a fixed OpenCode identity sentence. Anthropic may treat
// this as a non-Claude-Code fingerprint, so rewrite it to the canonical
// Claude Code banner before generic "OpenCode"/"opencode" replacements.
text = strings.ReplaceAll(
text,
"You are OpenCode, the best coding agent on the planet.",
strings.TrimSpace(claudeCodeSystemPrompt),
)
return text
}
func marshalAnthropicSystemTextBlock(text string, includeCacheControl bool) ([]byte, error) {
block := anthropicSystemTextBlockPayload{
Type: "text",
Text: text,
}
if includeCacheControl {
block.CacheControl = &anthropicCacheControlPayload{
Type: "ephemeral",
TTL: claude.DefaultCacheControlTTL,
}
}
return json.Marshal(block)
}
func marshalAnthropicSystemTextBlockWithCacheControl(text string, cacheControl any) ([]byte, error) {
block := map[string]any{
"type": "text",
"text": text,
}
if cacheControl != nil {
block["cache_control"] = cacheControl
}
return json.Marshal(block)
}
func marshalAnthropicMetadata(userID string) ([]byte, error) {
return json.Marshal(anthropicMetadataPayload{UserID: userID})
}
func buildJSONArrayRaw(items [][]byte) []byte {
if len(items) == 0 {
return []byte("[]")
}
total := 2
for _, item := range items {
total += len(item)
}
total += len(items) - 1
buf := make([]byte, 0, total)
buf = append(buf, '[')
for i, item := range items {
if i > 0 {
buf = append(buf, ',')
}
buf = append(buf, item...)
}
buf = append(buf, ']')
return buf
}
func setJSONValueBytes(body []byte, path string, value any) ([]byte, bool) {
next, err := sjson.SetBytes(body, path, value)
if err != nil {
return body, false
}
return next, true
}
func setJSONRawBytes(body []byte, path string, raw []byte) ([]byte, bool) {
next, err := sjson.SetRawBytes(body, path, raw)
if err != nil {
return body, false
}
return next, true
}
func deleteJSONPathBytes(body []byte, path string) ([]byte, bool) {
next, err := sjson.DeleteBytes(body, path)
if err != nil {
return body, false
}
return next, true
}
func normalizeClaudeOAuthSystemBody(body []byte, opts claudeOAuthNormalizeOptions) ([]byte, bool) {
sys := gjson.GetBytes(body, "system")
if !sys.Exists() {
return body, false
}
out := body
modified := false
switch {
case sys.Type == gjson.String:
sanitized := sanitizeSystemText(sys.String())
if sanitized != sys.String() {
if next, ok := setJSONValueBytes(out, "system", sanitized); ok {
out = next
modified = true
}
}
case sys.IsArray():
index := 0
sys.ForEach(func(_, item gjson.Result) bool {
if item.Get("type").String() == "text" {
textResult := item.Get("text")
if textResult.Exists() && textResult.Type == gjson.String {
text := textResult.String()
sanitized := sanitizeSystemText(text)
if sanitized != text {
if next, ok := setJSONValueBytes(out, fmt.Sprintf("system.%d.text", index), sanitized); ok {
out = next
modified = true
}
}
}
}
if opts.stripSystemCacheControl && item.Get("cache_control").Exists() {
if next, ok := deleteJSONPathBytes(out, fmt.Sprintf("system.%d.cache_control", index)); ok {
out = next
modified = true
}
}
index++
return true
})
}
return out, modified
}
func ensureClaudeOAuthMetadataUserID(body []byte, userID string) ([]byte, bool) {
if strings.TrimSpace(userID) == "" {
return body, false
}
metadata := gjson.GetBytes(body, "metadata")
if !metadata.Exists() || metadata.Type == gjson.Null {
raw, err := marshalAnthropicMetadata(userID)
if err != nil {
return body, false
}
return setJSONRawBytes(body, "metadata", raw)
}
trimmedRaw := strings.TrimSpace(metadata.Raw)
if strings.HasPrefix(trimmedRaw, "{") {
existing := metadata.Get("user_id")
if existing.Exists() && existing.Type == gjson.String && existing.String() != "" {
return body, false
}
return setJSONValueBytes(body, "metadata.user_id", userID)
}
raw, err := marshalAnthropicMetadata(userID)
if err != nil {
return body, false
}
return setJSONRawBytes(body, "metadata", raw)
}
func normalizeClaudeOAuthRequestBody(body []byte, modelID string, opts claudeOAuthNormalizeOptions) ([]byte, string) {
if len(body) == 0 {
return body, modelID
}
out := body
modified := false
if next, changed := normalizeClaudeOAuthSystemBody(out, opts); changed {
out = next
modified = true
}
rawModel := gjson.GetBytes(out, "model")
if rawModel.Exists() && rawModel.Type == gjson.String {
normalized := claude.NormalizeModelID(rawModel.String())
if normalized != rawModel.String() {
if next, ok := setJSONValueBytes(out, "model", normalized); ok {
out = next
modified = true
}
modelID = normalized
}
}
// 确保 tools 字段存在(即使为空数组)
if !gjson.GetBytes(out, "tools").Exists() {
if next, ok := setJSONRawBytes(out, "tools", []byte("[]")); ok {
out = next
modified = true
}
}
if opts.injectMetadata && opts.metadataUserID != "" {
if next, changed := ensureClaudeOAuthMetadataUserID(out, opts.metadataUserID); changed {
out = next
modified = true
}
}
// temperature:真实 Claude Code CLI 总是发送 temperature(默认 1,客户端可覆盖)。
// 之前的实现直接 delete 会导致 payload 缺字段,与真实 CLI 字节级不一致。
// 策略:客户端传了什么就透传;没传则补默认 1。
if !gjson.GetBytes(out, "temperature").Exists() {
if next, ok := setJSONValueBytes(out, "temperature", 1); ok {
out = next
modified = true
}
}
// max_tokens:真实 CLI 的默认值是 128000。缺失时补齐以对齐指纹。
if !gjson.GetBytes(out, "max_tokens").Exists() {
if next, ok := setJSONValueBytes(out, "max_tokens", 128000); ok {
out = next
modified = true
}
}
// context_managementthinking.type 为 enabled/adaptive 时,真实 CLI 会自动
// 附带 {"edits":[{"type":"clear_thinking_20251015","keep":"all"}]}。
// 客户端显式传了就透传;否则按 CLI 行为补齐。
//
// 注:本函数不按 model 名决定是否保留 context_management。“最终 beta
// header 不含 context-management-2025-06-27 时 strip 字段”的能力维度
// 对称约束由 sanitizeAnthropicBodyForBetaTokens 在 buildUpstreamRequest /
// buildCountTokensRequest 层统一执行,与 Bedrock 路径的
// sanitizeBedrockFieldsForBetaTokens 对称。
if !gjson.GetBytes(out, "context_management").Exists() {
thinkingType := gjson.GetBytes(out, "thinking.type").String()
if thinkingType == "enabled" || thinkingType == "adaptive" {
const cmDefault = `{"edits":[{"type":"clear_thinking_20251015","keep":"all"}]}`
if next, ok := setJSONRawBytes(out, "context_management", []byte(cmDefault)); ok {
out = next
modified = true
}
}
}
// tool_choice:与 Parrot 对齐,不再无条件删除。
// - 客户端传了 {"type":"tool","name":"X"} → 保留结构,name 由
// applyToolNameRewriteToBody 同步映射为假名
// - 其他形态(auto/any/none)原样透传
// 如果 body 里完全没有 tools(空数组),tool_choice 没意义时才删除
if !gjson.GetBytes(out, "tools").IsArray() || len(gjson.GetBytes(out, "tools").Array()) == 0 {
if gjson.GetBytes(out, "tool_choice").Exists() {
if next, ok := deleteJSONPathBytes(out, "tool_choice"); ok {
out = next
modified = true
}
}
}
if !modified {
return body, modelID
}
return out, modelID
}
func (s *GatewayService) buildOAuthMetadataUserID(parsed *ParsedRequest, account *Account, fp *Fingerprint) string {
if parsed == nil || account == nil {
return ""
}
if parsed.MetadataUserID != "" {
return ""
}
userID := strings.TrimSpace(account.GetClaudeUserID())
if userID == "" && fp != nil {
userID = fp.ClientID
}
if userID == "" {
// Fall back to a random, well-formed client id so we can still satisfy
// Claude Code OAuth requirements when account metadata is incomplete.
userID = generateClientID()
}
// session_id 用"会话级稳定种子"派生(账号 + 客户端区分因子 + 首条 user 文本):
// 随对话在尾部追加 messages 时保持不变,贴近真实 CC 进程级稳定的 session_id。
// 不复用 GenerateSessionHash —— 后者是粘性路由键、按设计逐轮变化(见其测试)。
var firstUserText string
if parsed.Body != nil {
firstUserText = extractFirstUserText(parsed.Body.Bytes())
}
seed := buildStableSessionSeed(account.ID, sessionContextDiscriminator(parsed.SessionContext), firstUserText)
sessionID := generateSessionUUID(seed)
// 根据指纹 UA 版本选择输出格式
var uaVersion string
if fp != nil {
uaVersion = ExtractCLIVersion(fp.UserAgent)
}
accountUUID := strings.TrimSpace(account.GetExtraString("account_uuid"))
return FormatMetadataUserID(userID, accountUUID, sessionID, uaVersion)
}
// applyClaudeCodeOAuthMimicryToBody 将"非 Claude Code 客户端 + Claude OAuth 账号"
// 路径上原本只在 /v1/messages 里做的完整伪装应用到任意 body 上。
//
// 这是 /v1/messages 主路径上 rewriteSystemForNonClaudeCode +
// normalizeClaudeOAuthRequestBody 流程的通用版,供 OpenAI 协议兼容层
// (ForwardAsChatCompletions / ForwardAsResponses) 复用。
//
// 未抽离之前,OpenAI 协议兼容层仅做 injectClaudeCodePrompt(前置追加),
// 而仓内 /v1/messages 路径自己的注释明确说过"仅前置追加无法通过 Anthropic
// 第三方检测";那条注释就是本函数存在的根因。
//
// 参数:
// - ctx / c:用于读取指纹和 gateway settingsc 可为 nil(如 count_tokens)。
// - account:必须是 OAuth 账号,且调用方已判断不是 Claude Code 客户端。
// - body:已经 marshal 成 Anthropic /v1/messages 格式的请求体。
// - systemRawbody 中原始 system 字段(用于判断是否需要 rewrite)。
// - model:最终会发给上游的模型 ID(用于模型规范化 + metadata 版本选择)。
//
// 返回:改写后的 body。即使中间任何一步失败,也会退化成原 body(不会 panic)。
func (s *GatewayService) applyClaudeCodeOAuthMimicryToBody(
ctx context.Context,
c *gin.Context,
account *Account,
body []byte,
systemRaw any,
model string,
) []byte {
if account == nil || !account.IsOAuth() || len(body) == 0 {
return body
}
systemPromptInjectionEnabled, systemPrompt, systemPromptBlocks := s.claudeOAuthSystemPromptInjectionSettings(ctx)
systemRewritten := false
if systemPromptInjectionEnabled {
body = rewriteSystemForNonClaudeCodeWithPromptBlocks(body, normalizeSystemParam(systemRaw), systemPrompt, systemPromptBlocks)
systemRewritten = true
}
normalizeOpts := claudeOAuthNormalizeOptions{stripSystemCacheControl: !systemRewritten}
if s.identityService != nil && c != nil && c.Request != nil {
if fp, err := s.identityService.GetOrCreateFingerprint(ctx, account.ID, c.Request.Header); err == nil && fp != nil {
mimicMPT := false
if s.settingService != nil {
_, mimicMPT, _ = s.settingService.GetGatewayForwardingSettings(ctx)
}
if !mimicMPT {
if uid := s.buildOAuthMetadataUserIDFromBody(ctx, account, fp, body); uid != "" {
normalizeOpts.injectMetadata = true
normalizeOpts.metadataUserID = uid
}
}
}
}
body, _ = normalizeClaudeOAuthRequestBody(body, model, normalizeOpts)
// Phase D+E+F: messages cache 策略 + 工具名混淆 + tools[-1] 断点
// 对齐 Parrot transform_request 里剩余的字段级改写。顺序有语义约束:
// 1) messages cache:仅在配置开启时清除客户端断点并注入代理断点
// 2) tool rewrite:最后改 tools[*].name / tool_choice.name 并在 tools[-1]
// 上打断点;mapping 存入 gin.Context 供响应侧 bytes.Replace 还原。
body = s.rewriteMessageCacheControlIfEnabled(ctx, body)
if rw := buildToolNameRewriteFromBody(body); rw != nil {
body = applyToolNameRewriteToBody(body, rw)
if c != nil {
c.Set(toolNameRewriteKey, rw)
}
} else {
body = applyToolsLastCacheBreakpoint(body)
}
return body
}
// buildOAuthMetadataUserIDFromBody 是 buildOAuthMetadataUserID 的变体,
// 适用于调用方手上没有 ParsedRequest 的场景(如 OpenAI 协议兼容层)。
//
// 与 buildOAuthMetadataUserID 的唯一区别:
// - session hash 从 body 本体按同样规则重算,而不是读取 ParsedRequest 缓存值。
// - 如果 body 里已经存在 metadata.user_id,则返回空(由 ensureClaudeOAuthMetadataUserID
// 自行决定是否覆盖)。
func (s *GatewayService) buildOAuthMetadataUserIDFromBody(
ctx context.Context,
account *Account,
fp *Fingerprint,
body []byte,
) string {
_ = ctx
if account == nil {
return ""
}
if existing := gjson.GetBytes(body, "metadata.user_id").String(); existing != "" {
return ""
}
userID := strings.TrimSpace(account.GetClaudeUserID())
if userID == "" && fp != nil {
userID = fp.ClientID
}
if userID == "" {
userID = generateClientID()
}
// 与 buildOAuthMetadataUserID 一致:用会话级稳定种子,避免整 body 哈希导致
// 每轮(甚至每个 token 变化)都重算出不同的 session_id。
var clientDiscriminator string
if fp != nil {
clientDiscriminator = fp.ClientID
}
seed := buildStableSessionSeed(account.ID, clientDiscriminator, extractFirstUserText(body))
sessionID := generateSessionUUID(seed)
var uaVersion string
if fp != nil {
uaVersion = ExtractCLIVersion(fp.UserAgent)
}
accountUUID := strings.TrimSpace(account.GetExtraString("account_uuid"))
return FormatMetadataUserID(userID, accountUUID, sessionID, uaVersion)
}
// buildStableSessionSeed 为伪装路径合成的 metadata.user_id session_id 生成"会话级稳定"种子。
//
// 真实 Claude Code 的 session_id 是进程级随机 UUID,在一段会话内跨请求保持不变。无状态代理
// 无法恢复该值,这里用"会话内不变的锚点"近似:账号 ID + 客户端区分因子 + 首条 user 消息文本。
// 对话在尾部追加 messages 时这三者都不变,因此 generateSessionUUID(seed) 跨轮稳定。
//
// 注意:粘性路由键 GenerateSessionHash 按设计逐轮变化(见其测试),本函数与之独立、互不影响。
// accountID 恒存在,故 seed 永不为空 —— 输出始终是确定性 UUID,而非随机值。
func buildStableSessionSeed(accountID int64, clientDiscriminator, firstUserText string) string {
var b strings.Builder
_, _ = b.WriteString(strconv.FormatInt(accountID, 10))
_, _ = b.WriteString("::")
_, _ = b.WriteString(clientDiscriminator)
_, _ = b.WriteString("::")
_, _ = b.WriteString(firstUserText)
return b.String()
}
// sessionContextDiscriminator 把请求上下文(客户端 IP / 归一化 UA / API Key ID)拼成
// 一个跨客户端的区分因子,避免不同用户的相同首条消息派生出相同 session_id。
func sessionContextDiscriminator(sc *SessionContext) string {
if sc == nil {
return ""
}
return sc.ClientIP + ":" + NormalizeSessionUserAgent(sc.UserAgent) + ":" + strconv.FormatInt(sc.APIKeyID, 10)
}
// GenerateSessionUUID creates a deterministic UUID4 from a seed string.
func GenerateSessionUUID(seed string) string {
return generateSessionUUID(seed)
}
func generateSessionUUID(seed string) string {
if seed == "" {
return uuid.NewString()
}
hash := sha256.Sum256([]byte(seed))
bytes := hash[:16]
bytes[6] = (bytes[6] & 0x0f) | 0x40
bytes[8] = (bytes[8] & 0x3f) | 0x80
return fmt.Sprintf("%x-%x-%x-%x-%x",
bytes[0:4], bytes[4:6], bytes[6:8], bytes[8:10], bytes[10:16])
}
// normalizeSystemParam 将 json.RawMessage 类型的 system 参数转为标准 Go 类型(string / []any / nil),
// 避免 type switch 中 json.RawMessage(底层 []byte)无法匹配 case string / case []any / case nil 的问题。
// 这是 Go 的 typed nil 陷阱:(json.RawMessage, nil) ≠ (nil, nil)。
func normalizeSystemParam(system any) any {
raw, ok := system.(json.RawMessage)
if !ok {
return system
}
if len(raw) == 0 {
return nil
}
var parsed any
if err := json.Unmarshal(raw, &parsed); err != nil {
return nil
}
return parsed
}
// systemIncludesClaudeCodePrompt 检查 system 中是否已包含 Claude Code 提示词
// 使用前缀匹配支持多种变体(标准版、Agent SDK 版等)
func systemIncludesClaudeCodePrompt(system any) bool {
system = normalizeSystemParam(system)
switch v := system.(type) {
case string:
return hasClaudeCodePrefix(v)
case []any:
for _, item := range v {
if m, ok := item.(map[string]any); ok {
if text, ok := m["text"].(string); ok && hasClaudeCodePrefix(text) {
return true
}
}
}
}
return false
}
// hasClaudeCodePrefix 检查文本是否以 Claude Code 提示词的特征前缀开头
func hasClaudeCodePrefix(text string) bool {
for _, prefix := range claudeCodePromptPrefixes {
if strings.HasPrefix(text, prefix) {
return true
}
}
return false
}
// injectClaudeCodePrompt 在 system 开头注入 Claude Code 提示词
// 处理 null、字符串、数组三种格式
func injectClaudeCodePrompt(body []byte, system any) []byte {
system = normalizeSystemParam(system)
claudeCodeBlock, err := marshalAnthropicSystemTextBlock(claudeCodeSystemPrompt, true)
if err != nil {
logger.LegacyPrintf("service.gateway", "Warning: failed to build Claude Code prompt block: %v", err)
return body
}
// Opencode plugin applies an extra safeguard: it not only prepends the Claude Code
// banner, it also prefixes the next system instruction with the same banner plus
// a blank line. This helps when upstream concatenates system instructions.
claudeCodePrefix := strings.TrimSpace(claudeCodeSystemPrompt)
var items [][]byte
switch v := system.(type) {
case nil:
items = [][]byte{claudeCodeBlock}
case string:
// Be tolerant of older/newer clients that may differ only by trailing whitespace/newlines.
if strings.TrimSpace(v) == "" || strings.TrimSpace(v) == strings.TrimSpace(claudeCodeSystemPrompt) {
items = [][]byte{claudeCodeBlock}
} else {
// Mirror opencode behavior: keep the banner as a separate system entry,
// but also prefix the next system text with the banner.
merged := v
if !strings.HasPrefix(v, claudeCodePrefix) {
merged = claudeCodePrefix + "\n\n" + v
}
nextBlock, buildErr := marshalAnthropicSystemTextBlock(merged, false)
if buildErr != nil {
logger.LegacyPrintf("service.gateway", "Warning: failed to build prefixed Claude Code system block: %v", buildErr)
return body
}
items = [][]byte{claudeCodeBlock, nextBlock}
}
case []any:
items = make([][]byte, 0, len(v)+1)
items = append(items, claudeCodeBlock)
prefixedNext := false
systemResult := gjson.GetBytes(body, "system")
if systemResult.IsArray() {
systemResult.ForEach(func(_, item gjson.Result) bool {
textResult := item.Get("text")
if textResult.Exists() && textResult.Type == gjson.String &&
strings.TrimSpace(textResult.String()) == strings.TrimSpace(claudeCodeSystemPrompt) {
return true
}
raw := []byte(item.Raw)
// Prefix the first subsequent text system block once.
if !prefixedNext && item.Get("type").String() == "text" && textResult.Exists() && textResult.Type == gjson.String {
text := textResult.String()
if strings.TrimSpace(text) != "" && !strings.HasPrefix(text, claudeCodePrefix) {
next, setErr := sjson.SetBytes(raw, "text", claudeCodePrefix+"\n\n"+text)
if setErr == nil {
raw = next
prefixedNext = true
}
}
}
items = append(items, raw)
return true
})
} else {
for _, item := range v {
m, ok := item.(map[string]any)
if !ok {
raw, marshalErr := json.Marshal(item)
if marshalErr == nil {
items = append(items, raw)
}
continue
}
if text, ok := m["text"].(string); ok && strings.TrimSpace(text) == strings.TrimSpace(claudeCodeSystemPrompt) {
continue
}
if !prefixedNext {
if blockType, _ := m["type"].(string); blockType == "text" {
if text, ok := m["text"].(string); ok && strings.TrimSpace(text) != "" && !strings.HasPrefix(text, claudeCodePrefix) {
m["text"] = claudeCodePrefix + "\n\n" + text
prefixedNext = true
}
}
}
raw, marshalErr := json.Marshal(m)
if marshalErr == nil {
items = append(items, raw)
}
}
}
default:
items = [][]byte{claudeCodeBlock}
}
result, ok := setJSONRawBytes(body, "system", buildJSONArrayRaw(items))
if !ok {
logger.LegacyPrintf("service.gateway", "Warning: failed to inject Claude Code prompt")
return body
}
return result
}
// rewriteSystemForNonClaudeCode 将非 Claude Code 客户端的 system prompt 迁移至 messages
// system 字段仅保留 Claude Code 标识提示词。
// Anthropic 基于 system 参数内容检测第三方应用,仅前置追加 Claude Code 提示词
// 无法通过检测,因为后续内容仍为非 Claude Code 格式。
// 策略:将原始 system prompt 提取并注入为 user/assistant 消息对,system 仅保留 Claude Code 标识。
func rewriteSystemForNonClaudeCode(body []byte, system any) []byte {
return rewriteSystemForNonClaudeCodeWithPromptBlocks(body, system, "", "")
}
func rewriteSystemForNonClaudeCodeWithPrompt(body []byte, system any, expansionPrompt string) []byte {
return rewriteSystemForNonClaudeCodeWithPromptBlocks(body, system, expansionPrompt, "")
}
type claudeOAuthSystemPromptBlockConfig struct {
Enabled *bool `json:"enabled,omitempty"`
Type string `json:"type,omitempty"`
Text string `json:"text,omitempty"`
CacheControl json.RawMessage `json:"cache_control,omitempty"`
}
type claudeOAuthSystemPromptBlocksEnvelope struct {
Blocks []claudeOAuthSystemPromptBlockConfig `json:"blocks"`
}
func defaultClaudeOAuthExpansionPrompt(expansionPrompt string) string {
expansionPrompt = strings.TrimSpace(expansionPrompt)
if expansionPrompt == "" {
return claudeCodeSystemPromptExpansion
}
return expansionPrompt
}
func parseClaudeOAuthSystemPromptBlocksConfig(raw string) ([]claudeOAuthSystemPromptBlockConfig, error) {
raw = strings.TrimSpace(raw)
if raw == "" {
return nil, nil
}
if strings.HasPrefix(raw, "[") {
var blocks []claudeOAuthSystemPromptBlockConfig
if err := json.Unmarshal([]byte(raw), &blocks); err != nil {
return nil, err
}
return blocks, nil
}
var envelope claudeOAuthSystemPromptBlocksEnvelope
if err := json.Unmarshal([]byte(raw), &envelope); err != nil {
return nil, err
}
return envelope.Blocks, nil
}
func decodeClaudeOAuthSystemPromptCacheControl(raw json.RawMessage) (any, error) {
trimmed := bytes.TrimSpace(raw)
if len(trimmed) == 0 || bytes.Equal(trimmed, []byte("null")) || bytes.Equal(trimmed, []byte("false")) {
return nil, nil
}
if bytes.Equal(trimmed, []byte("true")) {
return map[string]string{
"type": "ephemeral",
"ttl": claude.DefaultCacheControlTTL,
}, nil
}
var value any
if err := json.Unmarshal(trimmed, &value); err != nil {
return nil, err
}
if _, ok := value.(map[string]any); !ok {
return nil, fmt.Errorf("cache_control must be boolean, null, or object")
}
return value, nil
}
func expandClaudeOAuthSystemPromptTextTemplate(body []byte, text string, expansionPrompt string) (string, error) {
if text == "" {
return "", nil
}
expansionPrompt = defaultClaudeOAuthExpansionPrompt(expansionPrompt)
billingText, err := buildBillingAttributionText(body, claude.CLICurrentVersion)
if err != nil {
return "", err
}
fp := computeClaudeCodeFingerprint(body, claude.CLICurrentVersion)
replacer := strings.NewReplacer(
"{billing_header}", billingText,
"{cc_version}", claude.CLICurrentVersion,
"{fp}", fp,
"{claude_code_system_prompt}", claudeCodeSystemPrompt,
"{claude_code_expansion_prompt}", expansionPrompt,
)
return replacer.Replace(text), nil
}
func defaultClaudeOAuthSystemPromptBlockConfig() []claudeOAuthSystemPromptBlockConfig {
enabled := true
return []claudeOAuthSystemPromptBlockConfig{
{
Enabled: &enabled,
Type: "text",
Text: "{billing_header}",
},
{
Enabled: &enabled,
Type: "text",
Text: "{claude_code_system_prompt}",
},
{
Enabled: &enabled,
Type: "text",
Text: "{claude_code_expansion_prompt}",
CacheControl: json.RawMessage(
fmt.Sprintf(`{"type":"ephemeral","ttl":%q}`, claude.DefaultCacheControlTTL),
),
},
}
}
func buildClaudeOAuthSystemPromptBlocksJSON(body []byte, expansionPrompt string, blocksConfig string) ([][]byte, error) {
blocks, err := parseClaudeOAuthSystemPromptBlocksConfig(blocksConfig)
if err != nil {
return nil, err
}
if len(blocks) == 0 {
blocks = defaultClaudeOAuthSystemPromptBlockConfig()
}
items := make([][]byte, 0, len(blocks))
for i, block := range blocks {
if block.Enabled != nil && !*block.Enabled {
continue
}
blockType := strings.TrimSpace(block.Type)
if blockType == "" {
blockType = "text"
}
if blockType != "text" {
return nil, fmt.Errorf("system block %d type %q is not supported", i, block.Type)
}
text, err := expandClaudeOAuthSystemPromptTextTemplate(body, block.Text, expansionPrompt)
if err != nil {
return nil, err
}
if strings.TrimSpace(text) == "" {
continue
}
cacheControl, err := decodeClaudeOAuthSystemPromptCacheControl(block.CacheControl)
if err != nil {
return nil, fmt.Errorf("system block %d cache_control: %w", i, err)
}
raw, err := marshalAnthropicSystemTextBlockWithCacheControl(text, cacheControl)
if err != nil {
return nil, err
}
items = append(items, raw)
}
return items, nil
}
func ValidateClaudeOAuthSystemPromptBlocksConfig(raw string) error {
if strings.TrimSpace(raw) == "" {
return nil
}
blocks, err := parseClaudeOAuthSystemPromptBlocksConfig(raw)
if err != nil {
return infraerrors.BadRequest("INVALID_CLAUDE_OAUTH_SYSTEM_PROMPT_BLOCKS", "claude oauth system prompt blocks must be valid JSON")
}
for i, block := range blocks {
blockType := strings.TrimSpace(block.Type)
if blockType == "" {
blockType = "text"
}
if blockType != "text" {
return infraerrors.BadRequest("INVALID_CLAUDE_OAUTH_SYSTEM_PROMPT_BLOCKS", fmt.Sprintf("system block %d type must be text", i))
}
if _, err := decodeClaudeOAuthSystemPromptCacheControl(block.CacheControl); err != nil {
return infraerrors.BadRequest("INVALID_CLAUDE_OAUTH_SYSTEM_PROMPT_BLOCKS", fmt.Sprintf("system block %d cache_control is invalid", i))
}
}
return nil
}
func extractSystemTextAndCacheControl(system any) (string, any) {
switch v := system.(type) {
case string:
return strings.TrimSpace(v), nil
case []any:
var parts []string
var cacheControl any
for _, item := range v {
m, ok := item.(map[string]any)
if !ok {
continue
}
text, ok := m["text"].(string)
if !ok || strings.TrimSpace(text) == "" {
continue
}
parts = append(parts, text)
// system blocks are collapsed into one messages text block below.
// Preserve the last original breakpoint as the closest equivalent
// boundary, including its client-selected TTL.
if cc, exists := m["cache_control"]; exists && cc != nil {
cacheControl = cc
}
}
return strings.Join(parts, "\n\n"), cacheControl
default:
return "", nil
}
}
func rewriteSystemForNonClaudeCodeWithPromptBlocks(body []byte, system any, expansionPrompt string, blocksConfig string) []byte {
system = normalizeSystemParam(system)
expansionPrompt = defaultClaudeOAuthExpansionPrompt(expansionPrompt)
// 1. 提取原始 system prompt 文本及其缓存断点
originalSystemText, originalSystemCacheControl := extractSystemTextAndCacheControl(system)
// 2. 构造 system 数组,对齐真实 Claude Code CLI 的 3-block 形态:
// [0] billing attribution blockcc_version={cliVer}.{fp}; cc_entrypoint=cli;
// [1] "You are Claude Code..." 身份前缀 block(默认不带 cache_control
// [2] 工具无关的通用提示词扩充 block(带 cache_control 作为稳定缓存断点)
//
// 真实 CC 的 system 在身份前缀之后还有大段提示词,仅有 2 块会在块数/体量上明显
// 区别于真实 CLI。这里注入 claudeCodeSystemPromptExpansion(中性段落)把形态做到
// 接近真实,同时不注入会污染被代理用户行为的工具专属指令。
//
// 缺失 billing block 的系统 payload 是 Anthropic 判定第三方的关键信号之一
// (真实 CLI 每个请求都带)。新版 CLI 已取消 cch=... 签名字段,故 block 不再注入
// cch(见 buildBillingAttributionText)。
systemBlocks, blockErr := buildClaudeOAuthSystemPromptBlocksJSON(body, expansionPrompt, blocksConfig)
if blockErr != nil {
logger.LegacyPrintf("service.gateway", "Warning: failed to build configured Claude OAuth system blocks: %v", blockErr)
systemBlocks, blockErr = buildClaudeOAuthSystemPromptBlocksJSON(body, expansionPrompt, "")
}
if blockErr != nil {
logger.LegacyPrintf("service.gateway", "Warning: failed to build default Claude OAuth system blocks: %v", blockErr)
return body
}
out, ok := setJSONRawBytes(body, "system", buildJSONArrayRaw(systemBlocks))
if !ok {
logger.LegacyPrintf("service.gateway", "Warning: failed to set Claude Code system prompt")
return body
}
// 3. 将原始 system prompt 作为 user/assistant 消息对注入到 messages 开头
// 模型仍通过 messages 接收完整指令,保留客户端功能
ccPromptTrimmed := strings.TrimSpace(claudeCodeSystemPrompt)
if originalSystemText != "" && originalSystemText != ccPromptTrimmed && !hasClaudeCodePrefix(originalSystemText) {
instructionBlock := map[string]any{
"type": "text",
"text": "[System Instructions]\n" + originalSystemText,
}
if originalSystemCacheControl != nil {
instructionBlock["cache_control"] = originalSystemCacheControl
}
instrMsg, err1 := json.Marshal(map[string]any{
"role": "user",
"content": []map[string]any{
instructionBlock,
},
})
ackMsg, err2 := json.Marshal(map[string]any{
"role": "assistant",
"content": []map[string]any{
{"type": "text", "text": "Understood. I will follow these instructions."},
},
})
if err1 != nil || err2 != nil {
logger.LegacyPrintf("service.gateway", "Warning: failed to marshal system-to-messages injection")
return out
}
// 重建 messages 数组:[instruction, ack, ...originalMessages]
items := [][]byte{instrMsg, ackMsg}
messagesResult := gjson.GetBytes(out, "messages")
if messagesResult.IsArray() {
messagesResult.ForEach(func(_, msg gjson.Result) bool {
items = append(items, []byte(msg.Raw))
return true
})
}
if next, setOk := setJSONRawBytes(out, "messages", buildJSONArrayRaw(items)); setOk {
out = next
}
}
return out
}
type cacheControlPath struct {
path string
log string
}
func collectCacheControlPaths(body []byte) (invalidThinking []cacheControlPath, messagePaths []string, toolPaths []string, systemPaths []string) {
system := gjson.GetBytes(body, "system")
if system.IsArray() {
sysIndex := 0
system.ForEach(func(_, item gjson.Result) bool {
if item.Get("cache_control").Exists() {
path := fmt.Sprintf("system.%d.cache_control", sysIndex)
if item.Get("type").String() == "thinking" {
invalidThinking = append(invalidThinking, cacheControlPath{
path: path,
log: "[Warning] Removed illegal cache_control from thinking block in system",
})
} else {
systemPaths = append(systemPaths, path)
}
}
sysIndex++
return true
})
}
messages := gjson.GetBytes(body, "messages")
if messages.IsArray() {
msgIndex := 0
messages.ForEach(func(_, msg gjson.Result) bool {
content := msg.Get("content")
if content.IsArray() {
contentIndex := 0
content.ForEach(func(_, item gjson.Result) bool {
if item.Get("cache_control").Exists() {
path := fmt.Sprintf("messages.%d.content.%d.cache_control", msgIndex, contentIndex)
if item.Get("type").String() == "thinking" {
invalidThinking = append(invalidThinking, cacheControlPath{
path: path,
log: fmt.Sprintf("[Warning] Removed illegal cache_control from thinking block in messages[%d].content[%d]", msgIndex, contentIndex),
})
} else {
messagePaths = append(messagePaths, path)
}
}
contentIndex++
return true
})
}
msgIndex++
return true
})
}
tools := gjson.GetBytes(body, "tools")
if tools.IsArray() {
toolIndex := 0
tools.ForEach(func(_, tool gjson.Result) bool {
if tool.Get("cache_control").Exists() {
toolPaths = append(toolPaths, fmt.Sprintf("tools.%d.cache_control", toolIndex))
}
toolIndex++
return true
})
}
return invalidThinking, messagePaths, toolPaths, systemPaths
}
// enforceCacheControlLimit 强制执行 cache_control 块数量限制(最多 4 个)
// 超限时优先移除工具断点,再移除 messages 断点,最后才移除 system 断点。
func enforceCacheControlLimit(body []byte) []byte {
if len(body) == 0 {
return body
}
invalidThinking, messagePaths, toolPaths, systemPaths := collectCacheControlPaths(body)
out := body
modified := false
// 先清理 thinking 块中的非法 cache_controlthinking 块不支持该字段)
for _, item := range invalidThinking {
if !gjson.GetBytes(out, item.path).Exists() {
continue
}
next, ok := deleteJSONPathBytes(out, item.path)
if !ok {
continue
}
out = next
modified = true
logger.LegacyPrintf("service.gateway", "%s", item.log)
}
count := len(messagePaths) + len(toolPaths) + len(systemPaths)
if count <= maxCacheControlBlocks {
if modified {
return out
}
return body
}
// 超限:优先从 tools 中移除,再从 messages 中移除,最后才从 system 中移除。
remaining := count - maxCacheControlBlocks
for i := len(toolPaths) - 1; i >= 0 && remaining > 0; i-- {
path := toolPaths[i]
if !gjson.GetBytes(out, path).Exists() {
continue
}
next, ok := deleteJSONPathBytes(out, path)
if !ok {
continue
}
out = next
modified = true
remaining--
}
for _, path := range messagePaths {
if remaining <= 0 {
break
}
if !gjson.GetBytes(out, path).Exists() {
continue
}
next, ok := deleteJSONPathBytes(out, path)
if !ok {
continue
}
out = next
modified = true
remaining--
}
for i := len(systemPaths) - 1; i >= 0 && remaining > 0; i-- {
path := systemPaths[i]
if !gjson.GetBytes(out, path).Exists() {
continue
}
next, ok := deleteJSONPathBytes(out, path)
if !ok {
continue
}
out = next
modified = true
remaining--
}
if modified {
return out
}
return body
}
// injectAnthropicCacheControlTTL1h 将已有 ephemeral cache_control 块的 ttl 强制写为 1h。
// 仅修改已经存在的 cache_control,不新增缓存断点。
func injectAnthropicCacheControlTTL1h(body []byte) []byte {
return forceEphemeralCacheControlTTL(body, cacheTTLTarget1h)
}
func forceEphemeralCacheControlTTL(body []byte, ttl string) []byte {
if len(body) == 0 || ttl == "" {
return body
}
out := body
var paths []string
addPath := func(path string, value gjson.Result) {
cc := value.Get("cache_control")
if !cc.Exists() || cc.Get("type").String() != "ephemeral" {
return
}
if cc.Get("ttl").String() == ttl {
return
}
paths = append(paths, path+".cache_control.ttl")
}
if topCC := gjson.GetBytes(body, "cache_control"); topCC.Exists() && topCC.Get("type").String() == "ephemeral" && topCC.Get("ttl").String() != ttl {
paths = append(paths, "cache_control.ttl")
}
system := gjson.GetBytes(body, "system")
if system.IsArray() {
idx := -1
system.ForEach(func(_, block gjson.Result) bool {
idx++
addPath(fmt.Sprintf("system.%d", idx), block)
return true
})
}
messages := gjson.GetBytes(body, "messages")
if messages.IsArray() {
msgIdx := -1
messages.ForEach(func(_, msg gjson.Result) bool {
msgIdx++
content := msg.Get("content")
if !content.IsArray() {
return true
}
contentIdx := -1
content.ForEach(func(_, block gjson.Result) bool {
contentIdx++
addPath(fmt.Sprintf("messages.%d.content.%d", msgIdx, contentIdx), block)
return true
})
return true
})
}
tools := gjson.GetBytes(body, "tools")
if tools.IsArray() {
idx := -1
tools.ForEach(func(_, tool gjson.Result) bool {
idx++
addPath(fmt.Sprintf("tools.%d", idx), tool)
return true
})
}
for _, path := range paths {
if next, err := sjson.SetBytes(out, path, ttl); err == nil {
out = next
}
}
return out
}
func (s *GatewayService) shouldInjectAnthropicCacheTTL1h(ctx context.Context, account *Account) bool {
if account == nil || !account.IsAnthropicOAuthOrSetupToken() || s == nil || s.settingService == nil {
return false
}
return s.settingService.IsAnthropicCacheTTL1hInjectionEnabled(ctx)
}
// shouldNormalizeClientDateline reports whether the request body's client
// dateline should be normalized before forwarding to Anthropic. The switch is
// scoped to Anthropic OAuth/SetupToken accounts only; API-Key accounts and
// non-Anthropic platforms bypass this step entirely.
func (s *GatewayService) shouldNormalizeClientDateline(ctx context.Context, account *Account) bool {
if account == nil || !account.IsAnthropicOAuthOrSetupToken() || s == nil || s.settingService == nil {
return false
}
return s.settingService.IsClientDatelineNormalizationEnabled(ctx)
}
// normalizeClientDatelineIfEnabled applies dateline normalization to body when
// the switch is on and the account qualifies. Returns (nextBody, true) only
// when the body actually changed; otherwise returns (nil, false) so callers
// can skip the writeback.
func (s *GatewayService) normalizeClientDatelineIfEnabled(ctx context.Context, account *Account, body []byte) ([]byte, bool) {
if !s.shouldNormalizeClientDateline(ctx, account) {
return nil, false
}
next, _, changed := anthropicfp.NormalizeDateline(body)
if !changed {
return nil, false
}
return next, true
}
func (s *GatewayService) claudeOAuthSystemPromptInjectionSettings(ctx context.Context) (bool, string, string) {
if s == nil || s.settingService == nil {
return true, "", ""
}
return s.settingService.GetClaudeOAuthSystemPromptInjectionSettings(ctx)
}
// systemHasBillingAttributionBlock 检查请求体的 system 字段中是否包含真实 Claude Code
// 客户端注入的 billing attribution block。该 block 格式稳定(见 gateway_billing_block.go),
// 仅由真实 Claude Code CLI 生成;第三方客户端(opencode 等)不会生成此 block。
//
// 用于识别被上游 API 网关代理的真实 Claude Code 流量:此类请求的 User-Agent 被网关替换
// 为 Go-http-client,但 body 保留了完整的客户端特征。如果不识别这类请求而走 mimicry
// 重写 system,会破坏 Anthropic prompt cache 的前缀一致性,导致 messages 级缓存永不命中。
func systemHasBillingAttributionBlock(body []byte) bool {
system := gjson.GetBytes(body, "system")
if !system.IsArray() {
return false
}
found := false
system.ForEach(func(_, item gjson.Result) bool {
text := item.Get("text").String()
if strings.HasPrefix(text, claudeCodeBillingHeaderPrefix) &&
strings.Contains(text, claudeCodeEntrypointMarker) {
found = true
return false
}
return true
})
return found
}