Files
sub2api/backend/internal/service/gateway_request.go
erio 35598d5648 fix: parse Gemini native request format in ParseGatewayRequest for correct session hash generation
ParseGatewayRequest only parsed Anthropic format (system/messages),
ignoring Gemini native format (systemInstruction/contents). This caused
GenerateSessionHash to produce identical hashes for all Gemini sessions.

Add protocol parameter to ParseGatewayRequest to branch between
Anthropic and Gemini parsing. Update GenerateSessionHash message
traversal to extract text from both formats.
2026-02-09 06:47:22 +08:00

591 lines
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package service
import (
"bytes"
"encoding/json"
"fmt"
"math"
"github.com/Wei-Shaw/sub2api/internal/domain"
"github.com/Wei-Shaw/sub2api/internal/pkg/antigravity"
)
// SessionContext 粘性会话上下文,用于区分不同来源的请求。
// 仅在 GenerateSessionHash 第 3 级 fallback消息内容 hash时混入
// 避免不同用户发送相同消息产生相同 hash 导致账号集中。
type SessionContext struct {
ClientIP string
UserAgent string
APIKeyID int64
}
// ParsedRequest 保存网关请求的预解析结果
//
// 性能优化说明:
// 原实现在多个位置重复解析请求体Handler、Service 各解析一次):
// 1. gateway_handler.go 解析获取 model 和 stream
// 2. gateway_service.go 再次解析获取 system、messages、metadata
// 3. GenerateSessionHash 又一次解析获取会话哈希所需字段
//
// 新实现一次解析,多处复用:
// 1. 在 Handler 层统一调用 ParseGatewayRequest 一次性解析
// 2. 将解析结果 ParsedRequest 传递给 Service 层
// 3. 避免重复 json.Unmarshal减少 CPU 和内存开销
type ParsedRequest struct {
Body []byte // 原始请求体(保留用于转发)
Model string // 请求的模型名称
Stream bool // 是否为流式请求
MetadataUserID string // metadata.user_id用于会话亲和
System any // system 字段内容
Messages []any // messages 数组
HasSystem bool // 是否包含 system 字段(包含 null 也视为显式传入)
ThinkingEnabled bool // 是否开启 thinking部分平台会影响最终模型名
MaxTokens int // max_tokens 值(用于探测请求拦截)
SessionContext *SessionContext // 可选请求上下文区分因子nil 时行为不变)
}
// ParseGatewayRequest 解析网关请求体并返回结构化结果。
// protocol 指定请求协议格式domain.PlatformAnthropic / domain.PlatformGemini
// 不同协议使用不同的 system/messages 字段名。
func ParseGatewayRequest(body []byte, protocol string) (*ParsedRequest, error) {
var req map[string]any
if err := json.Unmarshal(body, &req); err != nil {
return nil, err
}
parsed := &ParsedRequest{
Body: body,
}
if rawModel, exists := req["model"]; exists {
model, ok := rawModel.(string)
if !ok {
return nil, fmt.Errorf("invalid model field type")
}
parsed.Model = model
}
if rawStream, exists := req["stream"]; exists {
stream, ok := rawStream.(bool)
if !ok {
return nil, fmt.Errorf("invalid stream field type")
}
parsed.Stream = stream
}
if metadata, ok := req["metadata"].(map[string]any); ok {
if userID, ok := metadata["user_id"].(string); ok {
parsed.MetadataUserID = userID
}
}
switch protocol {
case domain.PlatformGemini:
// Gemini 原生格式: systemInstruction.parts / contents
if sysInst, ok := req["systemInstruction"].(map[string]any); ok {
if parts, ok := sysInst["parts"].([]any); ok {
parsed.System = parts
}
}
if contents, ok := req["contents"].([]any); ok {
parsed.Messages = contents
}
default:
// Anthropic / OpenAI 格式: system / messages
// system 字段只要存在就视为显式提供(即使为 null
// 以避免客户端传 null 时被默认 system 误注入。
if system, ok := req["system"]; ok {
parsed.HasSystem = true
parsed.System = system
}
if messages, ok := req["messages"].([]any); ok {
parsed.Messages = messages
}
}
// thinking: {type: "enabled"}
if rawThinking, ok := req["thinking"].(map[string]any); ok {
if t, ok := rawThinking["type"].(string); ok && t == "enabled" {
parsed.ThinkingEnabled = true
}
}
// max_tokens
if rawMaxTokens, exists := req["max_tokens"]; exists {
if maxTokens, ok := parseIntegralNumber(rawMaxTokens); ok {
parsed.MaxTokens = maxTokens
}
}
return parsed, nil
}
// parseIntegralNumber 将 JSON 解码后的数字安全转换为 int。
// 仅接受“整数值”的输入,小数/NaN/Inf/越界值都会返回 false。
func parseIntegralNumber(raw any) (int, bool) {
switch v := raw.(type) {
case float64:
if math.IsNaN(v) || math.IsInf(v, 0) || v != math.Trunc(v) {
return 0, false
}
if v > float64(math.MaxInt) || v < float64(math.MinInt) {
return 0, false
}
return int(v), true
case int:
return v, true
case int8:
return int(v), true
case int16:
return int(v), true
case int32:
return int(v), true
case int64:
if v > int64(math.MaxInt) || v < int64(math.MinInt) {
return 0, false
}
return int(v), true
case json.Number:
i64, err := v.Int64()
if err != nil {
return 0, false
}
if i64 > int64(math.MaxInt) || i64 < int64(math.MinInt) {
return 0, false
}
return int(i64), true
default:
return 0, false
}
}
// FilterThinkingBlocks removes thinking blocks from request body
// Returns filtered body or original body if filtering fails (fail-safe)
// This prevents 400 errors from invalid thinking block signatures
//
// Strategy:
// - When thinking.type != "enabled": Remove all thinking blocks
// - When thinking.type == "enabled": Only remove thinking blocks without valid signatures
// (blocks with missing/empty/dummy signatures that would cause 400 errors)
func FilterThinkingBlocks(body []byte) []byte {
return filterThinkingBlocksInternal(body, false)
}
// FilterThinkingBlocksForRetry strips thinking-related constructs for retry scenarios.
//
// Why:
// - Upstreams may reject historical `thinking`/`redacted_thinking` blocks due to invalid/missing signatures.
// - Anthropic extended thinking has a structural constraint: when top-level `thinking` is enabled and the
// final message is an assistant prefill, the assistant content must start with a thinking block.
// - If we remove thinking blocks but keep top-level `thinking` enabled, we can trigger:
// "Expected `thinking` or `redacted_thinking`, but found `text`"
//
// Strategy (B: preserve content as text):
// - Disable top-level `thinking` (remove `thinking` field).
// - Convert `thinking` blocks to `text` blocks (preserve the thinking content).
// - Remove `redacted_thinking` blocks (cannot be converted to text).
// - Ensure no message ends up with empty content.
func FilterThinkingBlocksForRetry(body []byte) []byte {
hasThinkingContent := bytes.Contains(body, []byte(`"type":"thinking"`)) ||
bytes.Contains(body, []byte(`"type": "thinking"`)) ||
bytes.Contains(body, []byte(`"type":"redacted_thinking"`)) ||
bytes.Contains(body, []byte(`"type": "redacted_thinking"`)) ||
bytes.Contains(body, []byte(`"thinking":`)) ||
bytes.Contains(body, []byte(`"thinking" :`))
// Also check for empty content arrays that need fixing.
// Note: This is a heuristic check; the actual empty content handling is done below.
hasEmptyContent := bytes.Contains(body, []byte(`"content":[]`)) ||
bytes.Contains(body, []byte(`"content": []`)) ||
bytes.Contains(body, []byte(`"content" : []`)) ||
bytes.Contains(body, []byte(`"content" :[]`))
// Fast path: nothing to process
if !hasThinkingContent && !hasEmptyContent {
return body
}
var req map[string]any
if err := json.Unmarshal(body, &req); err != nil {
return body
}
modified := false
messages, ok := req["messages"].([]any)
if !ok {
return body
}
// Disable top-level thinking mode for retry to avoid structural/signature constraints upstream.
if _, exists := req["thinking"]; exists {
delete(req, "thinking")
modified = true
}
newMessages := make([]any, 0, len(messages))
for _, msg := range messages {
msgMap, ok := msg.(map[string]any)
if !ok {
newMessages = append(newMessages, msg)
continue
}
role, _ := msgMap["role"].(string)
content, ok := msgMap["content"].([]any)
if !ok {
// String content or other format - keep as is
newMessages = append(newMessages, msg)
continue
}
newContent := make([]any, 0, len(content))
modifiedThisMsg := false
for _, block := range content {
blockMap, ok := block.(map[string]any)
if !ok {
newContent = append(newContent, block)
continue
}
blockType, _ := blockMap["type"].(string)
// Convert thinking blocks to text (preserve content) and drop redacted_thinking.
switch blockType {
case "thinking":
modifiedThisMsg = true
thinkingText, _ := blockMap["thinking"].(string)
if thinkingText == "" {
continue
}
newContent = append(newContent, map[string]any{
"type": "text",
"text": thinkingText,
})
continue
case "redacted_thinking":
modifiedThisMsg = true
continue
}
// Handle blocks without type discriminator but with a "thinking" field.
if blockType == "" {
if rawThinking, hasThinking := blockMap["thinking"]; hasThinking {
modifiedThisMsg = true
switch v := rawThinking.(type) {
case string:
if v != "" {
newContent = append(newContent, map[string]any{"type": "text", "text": v})
}
default:
if b, err := json.Marshal(v); err == nil && len(b) > 0 {
newContent = append(newContent, map[string]any{"type": "text", "text": string(b)})
}
}
continue
}
}
newContent = append(newContent, block)
}
// Handle empty content: either from filtering or originally empty
if len(newContent) == 0 {
modified = true
placeholder := "(content removed)"
if role == "assistant" {
placeholder = "(assistant content removed)"
}
newContent = append(newContent, map[string]any{
"type": "text",
"text": placeholder,
})
msgMap["content"] = newContent
} else if modifiedThisMsg {
modified = true
msgMap["content"] = newContent
}
newMessages = append(newMessages, msgMap)
}
if modified {
req["messages"] = newMessages
} else {
// Avoid rewriting JSON when no changes are needed.
return body
}
newBody, err := json.Marshal(req)
if err != nil {
return body
}
return newBody
}
// FilterSignatureSensitiveBlocksForRetry is a stronger retry filter for cases where upstream errors indicate
// signature/thought_signature validation issues involving tool blocks.
//
// This performs everything in FilterThinkingBlocksForRetry, plus:
// - Convert `tool_use` blocks to text (name/id/input) so we stop sending structured tool calls.
// - Convert `tool_result` blocks to text so we keep tool results visible without tool semantics.
//
// Use this only when needed: converting tool blocks to text changes model behaviour and can increase the
// risk of prompt injection (tool output becomes plain conversation text).
func FilterSignatureSensitiveBlocksForRetry(body []byte) []byte {
// Fast path: only run when we see likely relevant constructs.
if !bytes.Contains(body, []byte(`"type":"thinking"`)) &&
!bytes.Contains(body, []byte(`"type": "thinking"`)) &&
!bytes.Contains(body, []byte(`"type":"redacted_thinking"`)) &&
!bytes.Contains(body, []byte(`"type": "redacted_thinking"`)) &&
!bytes.Contains(body, []byte(`"type":"tool_use"`)) &&
!bytes.Contains(body, []byte(`"type": "tool_use"`)) &&
!bytes.Contains(body, []byte(`"type":"tool_result"`)) &&
!bytes.Contains(body, []byte(`"type": "tool_result"`)) &&
!bytes.Contains(body, []byte(`"thinking":`)) &&
!bytes.Contains(body, []byte(`"thinking" :`)) {
return body
}
var req map[string]any
if err := json.Unmarshal(body, &req); err != nil {
return body
}
modified := false
// Disable top-level thinking for retry to avoid structural/signature constraints upstream.
if _, exists := req["thinking"]; exists {
delete(req, "thinking")
modified = true
}
messages, ok := req["messages"].([]any)
if !ok {
return body
}
newMessages := make([]any, 0, len(messages))
for _, msg := range messages {
msgMap, ok := msg.(map[string]any)
if !ok {
newMessages = append(newMessages, msg)
continue
}
role, _ := msgMap["role"].(string)
content, ok := msgMap["content"].([]any)
if !ok {
newMessages = append(newMessages, msg)
continue
}
newContent := make([]any, 0, len(content))
modifiedThisMsg := false
for _, block := range content {
blockMap, ok := block.(map[string]any)
if !ok {
newContent = append(newContent, block)
continue
}
blockType, _ := blockMap["type"].(string)
switch blockType {
case "thinking":
modifiedThisMsg = true
thinkingText, _ := blockMap["thinking"].(string)
if thinkingText == "" {
continue
}
newContent = append(newContent, map[string]any{"type": "text", "text": thinkingText})
continue
case "redacted_thinking":
modifiedThisMsg = true
continue
case "tool_use":
modifiedThisMsg = true
name, _ := blockMap["name"].(string)
id, _ := blockMap["id"].(string)
input := blockMap["input"]
inputJSON, _ := json.Marshal(input)
text := "(tool_use)"
if name != "" {
text += " name=" + name
}
if id != "" {
text += " id=" + id
}
if len(inputJSON) > 0 && string(inputJSON) != "null" {
text += " input=" + string(inputJSON)
}
newContent = append(newContent, map[string]any{"type": "text", "text": text})
continue
case "tool_result":
modifiedThisMsg = true
toolUseID, _ := blockMap["tool_use_id"].(string)
isError, _ := blockMap["is_error"].(bool)
content := blockMap["content"]
contentJSON, _ := json.Marshal(content)
text := "(tool_result)"
if toolUseID != "" {
text += " tool_use_id=" + toolUseID
}
if isError {
text += " is_error=true"
}
if len(contentJSON) > 0 && string(contentJSON) != "null" {
text += "\n" + string(contentJSON)
}
newContent = append(newContent, map[string]any{"type": "text", "text": text})
continue
}
if blockType == "" {
if rawThinking, hasThinking := blockMap["thinking"]; hasThinking {
modifiedThisMsg = true
switch v := rawThinking.(type) {
case string:
if v != "" {
newContent = append(newContent, map[string]any{"type": "text", "text": v})
}
default:
if b, err := json.Marshal(v); err == nil && len(b) > 0 {
newContent = append(newContent, map[string]any{"type": "text", "text": string(b)})
}
}
continue
}
}
newContent = append(newContent, block)
}
if modifiedThisMsg {
modified = true
if len(newContent) == 0 {
placeholder := "(content removed)"
if role == "assistant" {
placeholder = "(assistant content removed)"
}
newContent = append(newContent, map[string]any{"type": "text", "text": placeholder})
}
msgMap["content"] = newContent
}
newMessages = append(newMessages, msgMap)
}
if !modified {
return body
}
req["messages"] = newMessages
newBody, err := json.Marshal(req)
if err != nil {
return body
}
return newBody
}
// filterThinkingBlocksInternal removes invalid thinking blocks from request
// Strategy:
// - When thinking.type != "enabled": Remove all thinking blocks
// - When thinking.type == "enabled": Only remove thinking blocks without valid signatures
func filterThinkingBlocksInternal(body []byte, _ bool) []byte {
// Fast path: if body doesn't contain "thinking", skip parsing
if !bytes.Contains(body, []byte(`"type":"thinking"`)) &&
!bytes.Contains(body, []byte(`"type": "thinking"`)) &&
!bytes.Contains(body, []byte(`"type":"redacted_thinking"`)) &&
!bytes.Contains(body, []byte(`"type": "redacted_thinking"`)) &&
!bytes.Contains(body, []byte(`"thinking":`)) &&
!bytes.Contains(body, []byte(`"thinking" :`)) {
return body
}
var req map[string]any
if err := json.Unmarshal(body, &req); err != nil {
return body
}
// Check if thinking is enabled
thinkingEnabled := false
if thinking, ok := req["thinking"].(map[string]any); ok {
if thinkType, ok := thinking["type"].(string); ok && thinkType == "enabled" {
thinkingEnabled = true
}
}
messages, ok := req["messages"].([]any)
if !ok {
return body
}
filtered := false
for _, msg := range messages {
msgMap, ok := msg.(map[string]any)
if !ok {
continue
}
role, _ := msgMap["role"].(string)
content, ok := msgMap["content"].([]any)
if !ok {
continue
}
newContent := make([]any, 0, len(content))
filteredThisMessage := false
for _, block := range content {
blockMap, ok := block.(map[string]any)
if !ok {
newContent = append(newContent, block)
continue
}
blockType, _ := blockMap["type"].(string)
if blockType == "thinking" || blockType == "redacted_thinking" {
// When thinking is enabled and this is an assistant message,
// only keep thinking blocks with valid signatures
if thinkingEnabled && role == "assistant" {
signature, _ := blockMap["signature"].(string)
if signature != "" && signature != antigravity.DummyThoughtSignature {
newContent = append(newContent, block)
continue
}
}
filtered = true
filteredThisMessage = true
continue
}
// Handle blocks without type discriminator but with "thinking" key
if blockType == "" {
if _, hasThinking := blockMap["thinking"]; hasThinking {
filtered = true
filteredThisMessage = true
continue
}
}
newContent = append(newContent, block)
}
if filteredThisMessage {
msgMap["content"] = newContent
}
}
if !filtered {
return body
}
newBody, err := json.Marshal(req)
if err != nil {
return body
}
return newBody
}