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fix: JSON-encode error body in non-streaming 500 handlers #171

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Merged
solderzzc merged 1 commit into from
Sep 24, 2026
Merged

fix: JSON-encode error body in non-streaming 500 handlers #171

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29 changes: 13 additions & 16 deletions Sources/SwiftLM/Server.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -1321,14 +1321,10 @@ struct MLXServer: AsyncParsableCommand {
mtpAssistant: mtpAssistantModelRef
)
} catch {
let errMsg = String(describing: error).replacingOccurrences(of: "\"", with: "'")
let payload = """
{"error":{"message":"\(errMsg)","type":"server_error","code":"internal_error"}}
"""
return Response(
status: .internalServerError,
headers: jsonHeaders(),
body: .init(byteBuffer: ByteBuffer(string: payload))
body: .init(byteBuffer: ByteBuffer(string: errorJSON(error)))
)
}
}
Expand All @@ -1341,14 +1337,10 @@ struct MLXServer: AsyncParsableCommand {
request: request, bodyData: bodyData, config: config, container: container, semaphore: semaphore, stats: stats
)
} catch {
let errMsg = String(describing: error).replacingOccurrences(of: "\"", with: "'")
let payload = """
{"error":{"message":"\(errMsg)","type":"server_error","code":"internal_error"}}
"""
return Response(
status: .internalServerError,
headers: jsonHeaders(),
body: .init(byteBuffer: ByteBuffer(string: payload))
body: .init(byteBuffer: ByteBuffer(string: errorJSON(error)))
)
}
}
Expand Down Expand Up @@ -3271,10 +3263,9 @@ func sseHeaders() -> HTTPFields {
])
}

/// Build an OpenAI-style SSE `error` event for a failure after the stream's
/// headers are already sent (the client sees HTTP 200). The message is
/// JSON-encoded, so quotes, backslashes and newlines in it stay valid JSON.
func sseErrorChunk(_ error: Error) -> String {
/// Build an OpenAI-style `{"error":{...}}` body for a server error. The message
/// is JSON-encoded, so quotes, backslashes and newlines in it stay valid JSON.
func errorJSON(_ error: Error) -> String {
let payload: [String: Any] = ["error": [
"message": String(describing: error),
"type": "server_error",
Expand All @@ -3283,9 +3274,15 @@ func sseErrorChunk(_ error: Error) -> String {
guard let data = try? JSONSerialization.data(withJSONObject: payload),
let json = String(data: data, encoding: .utf8)
else {
return "data: {\"error\":{\"message\":\"internal error\",\"type\":\"server_error\",\"code\":\"internal_error\"}}\r\n\r\n"
return "{\"error\":{\"message\":\"internal error\",\"type\":\"server_error\",\"code\":\"internal_error\"}}"
}
return "data: \(json)\r\n\r\n"
return json
}

/// Build an OpenAI-style SSE `error` event for a failure after the stream's
/// headers are already sent (the client sees HTTP 200).
func sseErrorChunk(_ error: Error) -> String {
"data: \(errorJSON(error))\r\n\r\n"
}

/// Build a chat.completion.chunk SSE event.
Expand Down
11 changes: 11 additions & 0 deletions tests/SwiftLMTests/ServerSSETests.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -162,4 +162,15 @@ final class ServerSSETests: XCTestCase {
XCTAssertEqual(err["type"] as? String, "server_error")
XCTAssertEqual(err["code"] as? String, "internal_error")
}

func testErrorJSONEncodesMessageAsValidJSON() throws {
let body = errorJSON(MessyError())

let obj = try XCTUnwrap(
JSONSerialization.jsonObject(with: Data(body.utf8)) as? [String: Any])
let err = try XCTUnwrap(obj["error"] as? [String: Any])
XCTAssertEqual(err["message"] as? String, MessyError().description)
XCTAssertEqual(err["type"] as? String, "server_error")
XCTAssertEqual(err["code"] as? String, "internal_error")
}
}
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