Add support to get downloaded file when its name is not known.

It would be useful to have an option to parse downloaded files when their name is not known at the moment of download. I tried to create a helper function (task) for that which returns the latest file, however, it’s not reliable as it’s executed when file is not there yet:

// plugins/index.js
const getLastDownloadFilePath = () => {
  const dirPath = 'cypress/downloads';
  const filesOrdered = readdirSync(dirPath)
    .map(entry => path.join(dirPath, entry))
    .filter(entryWithPath => lstatSync(entryWithPath).isFile())
    .map(fileName => ({ fileName, mtime: lstatSync(fileName).mtime }))
    .sort((a, b) => b.mtime.getTime() - a.mtime.getTime());

  return filesOrdered.length ? filesOrdered[0].fileName : false;
};

I believe it may be useful to have the ability to:

1. wait for file download,
2. get the name of the downloaded file.

These two should allow handling such cases.

[jennifer-shehane]

There’s an example of reading a file directly after download by looking for extension. Is this helpful? https://github.com/cypress-io/cypress-example-recipes/blob/master/examples/testing-dom__download/cypress/integration/spec.js#L263

[TomaszG]

@viktorgogulenko thanks for that, that should work when the file is generated in the backend and later sent in the response. Unfortunately, in my case, the file is generated by frontend code with file-saver library. Therefore there’s no additional request with a filename in it.

I managed to create a workaround with:

// plugins/index.js
const path = require('path');
const { existsSync, readdirSync, lstatSync } = require('fs');

const downloadsDirPath = 'cypress/downloads';

const getLastDownloadFilePath = () => {
  if (!existsSync(downloadsDirPath)) {
    return null;
  }

  const filesOrdered = readdirSync(downloadsDirPath)
    .map(entry => path.join(downloadsDirPath, entry))
    .filter(entryWithPath => lstatSync(entryWithPath).isFile())
    .map(fileName => ({ fileName, mtime: lstatSync(fileName).mtime }))
    .sort((a, b) => b.mtime.getTime() - a.mtime.getTime());

  if (!filesOrdered.length) {
    return null;
  }

  // TODO: this works only for chrome family browsers
  if (filesOrdered[0].fileName.indexOf('crdownload') > -1) {
    return null;
  }

  return filesOrdered[0].fileName;
};

and in test, I use it with wait-until plugin:

// integration/test.spec.js
cy.fixture('expectedFile').then(expectedFile => cy
  .waitUntil(() => cy
    .task('getLastDownloadFilePath')
    .then(result => result),
  { timeout: 3000, interval: 100 })
  .then(filePath => {
    cy.readFile(filePath).should(actualFile => {
      // assertion goes here
    });
  })
);