react-relay-network-layer/lib/createRequestError.js.flow

Network Layer for React Relay and Express (Batch Queries, AuthToken, Logging, Retry)

/* @flow */

import type {
  RelayClassicRequest,
  RRNLRequestObject,
  RRNLResponseObject,
  GraphQLResponseErrors,
} from './definition';

class RRNLRequestError extends Error {
  status: number;
  req: RRNLRequestObject;
  res: ?RRNLResponseObject;

  constructor(msg: string) {
    super(msg);
    this.name = 'RRNLRequestError';
  }
}

/**
 * Formats an error response from GraphQL server request.
 */
function formatRequestErrors(request: RelayClassicRequest, errors: GraphQLResponseErrors): string {
  const CONTEXT_BEFORE = 20;
  const CONTEXT_LENGTH = 60;

  if (!request.getQueryString) {
    return errors.join('\n');
  }

  const queryLines = request.getQueryString().split('\n');
  return errors
    .map(({ locations, message }, ii) => {
      const prefix = `${ii + 1}. `;
      const indent = ' '.repeat(prefix.length);

      // custom errors thrown in graphql-server may not have locations
      const locationMessage = locations
        ? '\n' +
          locations
            .map(({ column, line }) => {
              const queryLine = queryLines[line - 1];
              const offset = Math.min(column - 1, CONTEXT_BEFORE);
              return [
                queryLine.substr(column - 1 - offset, CONTEXT_LENGTH),
                `${' '.repeat(Math.max(offset, 0))}^^^`,
              ]
                .map(messageLine => indent + messageLine)
                .join('\n');
            })
            .join('\n')
        : '';
      return prefix + message + locationMessage;
    })
    .join('\n');
}

function formatResponse(res: RRNLResponseObject): string {
  return [
    `Response:`,
    `   Url: ${res.url}`,
    `   Status code: ${res.status}`,
    `   Status text: ${res.statusText}`,
    `   Response headers: ${JSON.stringify(res.headers)}`,
    `   Body: ${JSON.stringify(res.payload)}`,
  ].join('\n');
}

export function getDebugName(req: RRNLRequestObject): string {
  if (req.relayReqObj) {
    return `${req.relayReqType} ${req.relayReqObj.getDebugName()}`;
  }
  return req.relayReqId;
}

export function createRequestError(req: RRNLRequestObject, res?: RRNLResponseObject) {
  let errorReason = '';

  if (!res || !res.payload) {
    errorReason = 'Server return empty `response`.' + (res ? `\n\n${formatResponse(res)}` : '');
  } else if (res.payload.errors) {
    if (req.relayReqObj) {
      errorReason = formatRequestErrors(req.relayReqObj, res.payload.errors);
    } else {
      errorReason = res.payload.errors.toString();
    }
  } else if (!res.payload.data) {
    errorReason = 'Server return empty `response.data`.\n\n' + formatResponse(res);
  }

  const error = new RRNLRequestError(
    `Server request for \`${getDebugName(req)}\` failed by the following reasons:\n\n${errorReason}`
  );

  error.req = req;
  error.res = res;
  error.status = res ? res.status : 0;
  return error;
}