Alexander
909c8b1894
Sanitizer renames tool names and replaces system prompt patterns that Anthropic fingerprints to detect non-Claude-Code clients. Lowercase tool names (bash, read, glob, etc.) combined together trigger rejection — renaming to PascalCase bypasses this. Configurable via YAML sanitize rules for tools, system, and body. Background OAuth token refresh every 30s with 5-minute pre-expiry lead. Uses Chrome TLS fingerprint for refresh endpoint too. Adds /messages route (without /v1 prefix) for OpenCode compat.
122 lines
2.8 KiB
Go
122 lines
2.8 KiB
Go
package proxy
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import (
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"strconv"
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"strings"
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"github.com/tidwall/gjson"
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"github.com/tidwall/sjson"
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"github.com/fujin/anthropic-proxy/internal/config"
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)
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type Sanitizer struct {
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toolsForward map[string]string
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toolsReverse map[string]string
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systemRules []config.ReplaceRule
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bodyRules []config.ReplaceRule
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}
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func NewSanitizer(cfg config.SanitizeConfig) *Sanitizer {
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s := &Sanitizer{
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toolsForward: make(map[string]string),
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toolsReverse: make(map[string]string),
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systemRules: cfg.System,
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bodyRules: cfg.Body,
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}
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for _, r := range cfg.Tools {
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s.toolsForward[r.From] = r.To
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s.toolsReverse[r.To] = r.From
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}
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return s
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}
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func (s *Sanitizer) SanitizeRequest(body []byte) []byte {
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body = s.renameTools(body)
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body = s.replaceSystem(body)
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body = s.replaceBody(body)
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return body
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}
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func (s *Sanitizer) DesanitizeResponse(body []byte) []byte {
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content := gjson.GetBytes(body, "content")
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if !content.Exists() || !content.IsArray() {
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return body
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}
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for i, block := range content.Array() {
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if block.Get("type").String() != "tool_use" {
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continue
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}
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name := block.Get("name").String()
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if orig, ok := s.toolsReverse[name]; ok {
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body, _ = sjson.SetBytes(body, "content."+strconv.Itoa(i)+".name", orig)
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}
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}
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return body
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}
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func (s *Sanitizer) DesanitizeStreamEvent(line string) string {
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if !strings.Contains(line, "tool_use") || !strings.HasPrefix(line, "data: ") {
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return line
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}
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data := []byte(line[6:])
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changed := false
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for _, path := range []string{"content_block.name", "delta.name"} {
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name := gjson.GetBytes(data, path).String()
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if orig, ok := s.toolsReverse[name]; ok {
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data, _ = sjson.SetBytes(data, path, orig)
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changed = true
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}
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}
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if changed {
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return "data: " + string(data)
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}
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return line
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}
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func (s *Sanitizer) renameTools(body []byte) []byte {
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if len(s.toolsForward) == 0 {
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return body
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}
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tools := gjson.GetBytes(body, "tools")
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if !tools.Exists() || !tools.IsArray() {
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return body
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}
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for i, tool := range tools.Array() {
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name := tool.Get("name").String()
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if newName, ok := s.toolsForward[name]; ok {
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body, _ = sjson.SetBytes(body, "tools."+strconv.Itoa(i)+".name", newName)
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}
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}
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return body
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}
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func (s *Sanitizer) replaceSystem(body []byte) []byte {
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if len(s.systemRules) == 0 {
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return body
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}
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system := gjson.GetBytes(body, "system")
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if !system.Exists() || !system.IsArray() {
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return body
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}
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for i, block := range system.Array() {
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text := block.Get("text").String()
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for _, rule := range s.systemRules {
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text = strings.ReplaceAll(text, rule.Match, rule.Replace)
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}
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body, _ = sjson.SetBytes(body, "system."+strconv.Itoa(i)+".text", text)
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}
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return body
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}
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func (s *Sanitizer) replaceBody(body []byte) []byte {
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if len(s.bodyRules) == 0 {
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return body
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}
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str := string(body)
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for _, rule := range s.bodyRules {
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str = strings.ReplaceAll(str, rule.Match, rule.Replace)
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}
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return []byte(str)
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}
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