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backend/internal/auth/claude/oauth_response.go

@@ -0,0 +1,72 @@
+package claude
+
+import (
+	"bytes"
+	"compress/flate"
+	"compress/gzip"
+	"compress/lzw"
+	"compress/zlib"
+	"fmt"
+	"io"
+	"net/http"
+	"strings"
+
+	"github.com/andybalholm/brotli"
+)
+
+func readClaudeOAuthResponseBody(resp *http.Response) ([]byte, error) {
+	if resp == nil || resp.Body == nil {
+		return nil, fmt.Errorf("read Claude OAuth response: body is nil")
+	}
+	encoded, errRead := io.ReadAll(resp.Body)
+	if errRead != nil {
+		return nil, errRead
+	}
+	encodings := strings.Split(strings.Join(resp.Header.Values("Content-Encoding"), ","), ",")
+	for index := len(encodings) - 1; index >= 0; index-- {
+		encoding := strings.ToLower(strings.TrimSpace(encodings[index]))
+		if encoding == "" || encoding == "identity" {
+			continue
+		}
+		var errDecode error
+		encoded, errDecode = decodeClaudeOAuthEncoding(encoded, encoding)
+		if errDecode != nil {
+			return nil, errDecode
+		}
+	}
+	return encoded, nil
+}
+
+func decodeClaudeOAuthEncoding(encoded []byte, encoding string) ([]byte, error) {
+	var reader io.ReadCloser
+	switch encoding {
+	case "gzip":
+		gzipReader, errGzip := gzip.NewReader(bytes.NewReader(encoded))
+		if errGzip != nil {
+			return nil, fmt.Errorf("decode Claude OAuth gzip response: %w", errGzip)
+		}
+		reader = gzipReader
+	case "deflate":
+		zlibReader, errZlib := zlib.NewReader(bytes.NewReader(encoded))
+		if errZlib == nil {
+			reader = zlibReader
+		} else {
+			reader = flate.NewReader(bytes.NewReader(encoded))
+		}
+	case "br":
+		reader = io.NopCloser(brotli.NewReader(bytes.NewReader(encoded)))
+	case "compress":
+		reader = lzw.NewReader(bytes.NewReader(encoded), lzw.MSB, 8)
+	default:
+		return nil, fmt.Errorf("decode Claude OAuth response: unsupported content encoding %q", encoding)
+	}
+	decoded, errDecoded := io.ReadAll(reader)
+	if errDecoded != nil {
+		_ = reader.Close()
+		return nil, fmt.Errorf("decode Claude OAuth %s response: %w", encoding, errDecoded)
+	}
+	if errClose := reader.Close(); errClose != nil {
+		return nil, fmt.Errorf("close Claude OAuth %s decoder: %w", encoding, errClose)
+	}
+	return decoded, nil
+}