cypress/packages/server/lib/controllers/spec.ts

import Debug from 'debug'
import Promise from 'bluebird'
import { get as errorsGet } from '../errors'
import preprocessor from '../plugins/preprocessor'
import type { Cfg } from '../project-base'
import type { Request, Response } from 'express'

const debug = Debug('cypress:server:controllers:spec')

const ignoreECONNABORTED = () => {
  // https://github.com/cypress-io/cypress/issues/1877
  // now that we are properly catching errors from
  // res.sendFile, sendFile will reject if the browser aborts
  // its internal requests (as it shuts down) with
  // ECONNABORTED. This happens because if a previous spec
  // file is unable to be transpiled correctly, we immediately
  // shut down the run, which closes the browser, triggering
  // the browser to abort the request which would end up here
  // and display two different errors.
}

const ignoreEPIPE = () => {
  // 'write EPIPE' errors can occur if a spec is served and then rerun
  // quickly because it's trying to send the spec file to a socket that
  // has already been closed. this can be ignored because it means
  // another version of the file has already been sent and will
  // be loaded by the browser instead
}

export = {
  handle (spec: any, req: Request, res: Response, config: Cfg, next: any, onError: any) {
    debug('request for %o', { spec })

    res.set({
      'Cache-Control': 'no-cache, no-store, must-revalidate',
      'Pragma': 'no-cache',
      'Expires': '0',
    })

    res.type('js')

    return preprocessor
    .getFile(spec, config)
    .then((filePath: string) => {
      debug('sending spec %o', { filePath })
      const sendFile = Promise.promisify(res.sendFile.bind(res))

      return sendFile(filePath)
    })
    .catch({ code: 'ECONNABORTED' }, ignoreECONNABORTED)
    .catch({ code: 'EPIPE' }, ignoreEPIPE)
    .catch((err: any) => {
      debug(`preprocessor error for spec '%s': %s`, spec, err.stack)

      if (!config.isTextTerminal) {
        return res.send(preprocessor.clientSideError(err))
      }

      // bluebird made a change in 3.4.7 where they handle
      // SyntaxErrors differently here
      // https://github.com/petkaantonov/bluebird/pull/1295
      //
      // their new behavior messes up how we show these errors
      // so we must backup the original stack and replace it here
      if (err.originalStack) {
        err.stack = err.originalStack
      }

      const filePath = err.filePath != null ? err.filePath : spec

      err = errorsGet('BUNDLE_ERROR', filePath, preprocessor.errorMessage(err))

      onError(err)

      return undefined
    })
  },
}