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feat(mcp): add support for Content-Length framed JSON-RPC messages

Implements readMessage function to handle both raw JSON lines and Content-Length framed messages. Claude Code uses HTTP-style framing (Content-Length: N\r\n\r\n{json}) while other clients may send raw JSON. Auto-detects format by peeking at first bytes. Adds .gitignore for compiled binaries.
This commit is contained in:
2026-04-05 02:24:17 -04:00
parent fd473c298c
commit e88ef02621
2 changed files with 67 additions and 1 deletions

4
.gitignore vendored Normal file
View File

@@ -0,0 +1,4 @@
*.exe
*.dll
*.so
*.dylib

64
main.go
View File

@@ -69,10 +69,11 @@ func main() {
debugLog("Connecting to: %s", giteaURL)
// Read JSON-RPC messages from stdin, forward to Gitea, write responses to stdout
// Supports both raw JSON lines and Content-Length framed messages (Claude Code uses framing)
reader := bufio.NewReader(os.Stdin)
for {
line, err := reader.ReadBytes('\n')
line, err := readMessage(reader)
if err != nil {
if err == io.EOF {
debugLog("EOF received, exiting")
@@ -147,6 +148,67 @@ func forwardToGitea(request []byte) ([]byte, error) {
return body, nil
}
// readMessage reads a JSON-RPC message from stdin.
// Handles both raw JSON lines and Content-Length framed messages.
// Claude Code sends: Content-Length: N\r\n\r\n{json}
func readMessage(reader *bufio.Reader) ([]byte, error) {
// Peek at first bytes to detect format
for {
line, err := reader.ReadBytes('\n')
if err != nil {
return nil, err
}
trimmed := bytes.TrimSpace(line)
if len(trimmed) == 0 {
continue
}
// If it starts with '{', it's a raw JSON line
if trimmed[0] == '{' {
return trimmed, nil
}
// If it starts with "Content-Length:", read the framed message
if bytes.HasPrefix(bytes.ToLower(trimmed), []byte("content-length:")) {
// Parse content length
parts := bytes.SplitN(trimmed, []byte(":"), 2)
if len(parts) != 2 {
continue
}
lengthStr := bytes.TrimSpace(parts[1])
var contentLength int
fmt.Sscanf(string(lengthStr), "%d", &contentLength)
if contentLength <= 0 {
continue
}
// Read until empty line (end of headers)
for {
headerLine, err := reader.ReadBytes('\n')
if err != nil {
return nil, err
}
if len(bytes.TrimSpace(headerLine)) == 0 {
break
}
}
// Read exactly contentLength bytes
body := make([]byte, contentLength)
_, err := io.ReadFull(reader, body)
if err != nil {
return nil, fmt.Errorf("read body: %w", err)
}
return body, nil
}
// Unknown line, skip
debugLog("Skipping unknown line: %s", string(trimmed))
}
}
func writeResponse(resp interface{}) {
data, _ := json.Marshal(resp)
fmt.Println(string(data))