Chrome sendChromiumCommand 'Page.setDownloadBehavior' failing - UnsupportedOperationError

Bug report

• Node Version: 10.16.0
• Protractor Version: 5.4.2
• Angular Version: 8
• Browser(s): Chrome (headless / normal)
• Operating System and Version Windows 10
• Your protractor configuration file

capabilities: {
    browserName: 'chrome',

    chromeOptions: {
      args: useHeadlessBrowser ? ["--headless", "--window-size=1920,1080"] : undefined,
      useAutomationExtension: false,

      // Set download path and avoid prompting for download even though
      // this is already the default on Chrome but for completeness
      // https://chromium.googlesource.com/chromium/src/+/master/chrome/common/pref_names.cc
      prefs: {
        "download": {
          "prompt_for_download": false,
          "directory_upgrade": true,
          "default_directory": downloadDirectory,
          "download_directory": downloadDirectory,
          "download_dir": downloadDirectory,
          "download_restrictions": 0,
        }
      }
    }
  },

Before any tests run I send the below command to Chrome to enable file downloads in headless Chrome

    // returns full path
    const downloadDirectory = Utils.getTempDirectoryPath();

    Utils.log(`Setting Chrome download behaviour to directory ${downloadDirectory}`);
    browser.driver.sendChromiumCommand('Page.setDownloadBehavior', {
      behavior: 'allow',
      downloadPath: downloadDirectory
    });

This has stopped working on Chrome 74+ with the error.

UnsupportedOperationError: POST /session/ac771ec3019f7b4c7191e2c9ae2b2056/chromium/send_command

We are unable to run test on Chrome 74 now and cannot get any of our file download tests to work as headless Chrome is unable to download a file with issuing the above command.

Is there any other suggested way to enable file downloads in headless Chrome without issuing the above command?

[BZaldua]

I made it work using this versions:

• Protractor: 5.4.2
• Selenium standalone server: 3.141.59
• Chrome: 77.0.3865.40

I launched Chome in headlles way and everything is fine. Actually, it seems like browser.driver.sendChromiumCommand(...) configuration is not longer necessary. I deleted it and everything works fine for me.

I did not try setting "w3c":false but with the versions I mention and deleting the configuration, everything seems to work.

[vmgustavo]

Using chromedriver from this link and a chromium binary from this link I was able to use the driver.execute_cdp_cmd method.

params = {'behavior': 'allow', 'downloadPath': path}
driver.execute_cdp_cmd('Page.setDownloadBehavior', params)