如何在机器人框架中使用无头 chrome 浏览器下载文件？

Question

如何使用 chrome 开发工具中的 Page.setDownloadBehavior 进行传递，以便我可以使用以下代码设置 headless chrome 的下载行为？

    Create Chrome Browser
    [Arguments]    ${link_to_open}
    ${chrome_options}=    Evaluate    sys.modules['selenium.webdriver'].ChromeOptions()    sys, selenium.webdriver
    ${prefs}=    Create Dictionary    download.default_directory=${DOWNLOADS_DIR}
   Call Method    ${chrome options}    add_argument    headless 
   Call Method    ${chrome options}    add_argument    disable-gpu
  Selenium2Library.Go To    ${link_to_open}

Answer 1

尝试在无头模式下使用 Chrome 下载文件时似乎存在“安全功能”。这将在Chromium issue tracker 中进一步讨论。这指向了 Downloading with chrome headless and selenium 的 StackOverflow 答案。在这个答案中，给出了一个 Python 示例 (GitHub)，它可以轻松转换为机器人框架库：

headless_download.py

class headless_download(object):

    ROBOT_LIBRARY_VERSION = 1.0

    def __init__(self):
        pass

    def enable_download_in_headless_chrome(self, driver, download_dir):
        """
        there is currently a "feature" in chrome where
        headless does not allow file download: https://bugs.chromium.org/p/chromium/issues/detail?id=696481
        This method is a hacky work-around until the official chromedriver support for this.
        Requires chrome version 62.0.3196.0 or above.
        """

        # add missing support for chrome "send_command"  to selenium webdriver
        driver.command_executor._commands["send_command"] = ("POST", '/session/$sessionId/chromium/send_command')

        params = {'cmd': 'Page.setDownloadBehavior', 'params': {'behavior': 'allow', 'downloadPath': download_dir}}
        command_result = driver.execute("send_command", params)
        print("response from browser:")
        for key in command_result:
            print("result:" + key + ":" + str(command_result[key]))

下载文件时，Robot Framework Download File 的 StackOverlow 答案非常适合此示例。为无头模式、附加库和工作示例添加额外的行：

headless_download.robot

*** Settings ***
Test Teardown     Close All Browsers
Library           Selenium2Library
Library           OperatingSystem
Library           headless_download

*** Test Cases ***
Download PDF
  # create unique folder
  ${now}    Get Time    epoch
  ${download directory}    Join Path    ${OUTPUT DIR}    downloads_${now}
  Create Directory    ${download directory}

  ${chrome options}=    Evaluate    sys.modules['selenium.webdriver'].ChromeOptions()    sys, selenium.webdriver

  # list of plugins to disable. disabling PDF Viewer is necessary so that PDFs are saved rather than displayed
  ${disabled}    Create List    Chrome PDF Viewer
  ${prefs}    Create Dictionary    download.default_directory=${download directory}    plugins.plugins_disabled=${disabled}
  Call Method    ${chrome options}    add_experimental_option    prefs    ${prefs}

  Call Method    ${chrome options}    add_argument    headless 
  Call Method    ${chrome options}    add_argument    disable-gpu

  Create Webdriver    Chrome    chrome_options=${chrome options}

  Go To    http://www.sample-videos.com/download-sample-text-file.php

  ${S2L}           get library instance    Selenium2Library
  ${webdriver}    Call Method             ${S2L}    _current_browser
  Enable Download In Headless Chrome    ${webdriver}    ${download directory} 

  Click Link    xpath=//a[@data='1']

  # wait for download to finish
  ${file}    Wait Until Keyword Succeeds    1 min    2 sec    Download should be done    ${download directory}

*** Keywords ***
Download should be done
  [Arguments]    ${directory}
  [Documentation]    Verifies that the directory has only one folder and it is not a temp file.
  ...
  ...    Returns path to the file
  ${files}    List Files In Directory    ${directory}
  Length Should Be    ${files}    1    Should be only one file in the download folder
  Should Not Match Regexp    ${files[0]}    (?i).*\\.tmp    Chrome is still downloading a file
  ${file}    Join Path    ${directory}    ${files[0]}
  Log    File was successfully downloaded to ${file}
  [Return]    ${file}

所以，简而言之：如果没有其他人在 Stack Overflow 上的贡献，这个答案是不可能的。如果这为您提供了一个可行的解决方案，请点击其他答案的链接并为这些答案投票。