signalapp/Signal-Server · warning

return Response.status(422).build();

Error message

return Response.status(422).build();

What it means

JsonMappingExceptionMapper handles Jackson JsonMappingExceptions during request deserialization. Client-abort cases (Jetty EofException or 'Early EOF' messages) map to 400 Bad Request; every other mapping failure — meaning the JSON was syntactically parsed but did not match the target type — returns HTTP 422 Unprocessable Entity.

Solutions

1. Validate the request JSON against the endpoint's expected schema before sending (correct field names and types)
2. Update the client to match the server's current API model after version changes
3. Capture the 422 and log the request body to identify the offending field
4. If a valid payload is rejected, check custom Jackson deserializers/annotations on the DTO

Example fix

// before
Request.Body("{"deviceId": "17"}"); // deviceId as string, DTO expects int
// after
Request.Body("{"deviceId": 17}"); // match DTO field types

// validate the payload shape before sending
ObjectNode body = mapper.valueToTree(dto);
mapper.readerFor(dto.getClass()).readValue(mapper.writeValueAsBytes(body)); // dry-run roundtrip

if (response.code() == 422) {
  log.error("payload rejected, body=" + lastRequestBody);
  refreshApiModelAndReserialize();
} else if (response.code() == 400) {
  reconnect(); // early EOF / truncated body
}

When it happens

Trigger: Sending a request body whose JSON shape doesn't fit the endpoint's DTO: wrong field types, missing required properties handled as mapping errors, or enum/object coercion failures.

Common situations: API clients sending old/changed payload schemas after a server upgrade; hand-rolled JSON missing nested objects; clients truncating bodies (that path instead yields 400 via Early EOF); content-type mismatches producing wrong binding.

Understand the failure class

Background: Schema validation failed / invalid input schema: payload rejected because its shape doesn't match the expected schema — this error's family across 28 libraries.

Related errors

• Could not interpret identity key bytes as an EC public key
• Could not parse key as a base64-encoded value
• Could not interpret bytes as a ZK credential public key
• return Response.status(429).build();
• return Response.status(404).build();

AI-assisted analysis of signalapp/Signal-Server@100ab61c82 (2026-09-09). Data as JSON: /api/errors/97af1c8d7ef35578. Report an issue: GitHub.

Appendix: source

Thrown at service/src/main/java/org/whispersystems/textsecuregcm/mappers/JsonMappingExceptionMapper.java:18

package org.whispersystems.textsecuregcm.mappers;

import com.fasterxml.jackson.databind.JsonMappingException;
import jakarta.ws.rs.core.Response;
import jakarta.ws.rs.ext.ExceptionMapper;

public class JsonMappingExceptionMapper implements ExceptionMapper<JsonMappingException> {
  @Override
  public Response toResponse(final JsonMappingException exception) {
    if (exception.getCause() instanceof java.util.concurrent.TimeoutException) {
      return Response.status(Response.Status.REQUEST_TIMEOUT).build();
    }
    if (exception.getCause() instanceof org.eclipse.jetty.io.EofException
        || exception.getMessage() != null && exception.getMessage().startsWith("Early EOF")) {
      // Some sort of timeout or broken connection
      return Response.status(Response.Status.BAD_REQUEST).build();
    }
    return Response.status(422).build();
  }
}

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