python爬虫基础08-selenium大全2/8-Chrome Webdriver启动选项

Selenium笔记（2）Chrome Webdriver启动选项

本文集链接：https://www.jianshu.com/nb/25338984

在Selenium中使用不同的Webdriver可能会有不一样的方法，有些相同的操作会得到不一样的结果，本文主要介绍的是Chrome()的使用方法。

其他Webdriver可以查阅官方文档。

Chrome WebDriver Options

简介

这是一个Chrome的参数对象，在此对象中使用add_argument()方法可以添加启动参数，添加完毕后可以在初始化Webdriver对象时将此Options对象传入，则可以实现以特定参数启动Chrome。

例子

from selenium import webdriver
from selenium.webdriver.chrome.options import Options
​
# 实例化一个启动参数对象
chrome_options = Options()
# 添加启动参数
chrome_options.add_argument('--window-size=1366,768')
# 将参数对象传入Chrome，则启动了一个设置了窗口大小的Chrome
browser = webdriver.Chrome(chrome_options=chrome_options)

常用的启动参数

启动参数	作用
--user-agent=""	设置请求头的User-Agent
--window-size=1366,768	设置浏览器分辨率
--headless	无界面运行
--start-maximized	最大化运行
--incognito	隐身模式
--disable-javascript	禁用javascript
--disable-infobars	禁用浏览器正在被自动化程序控制的提示

完整启动参数可以到此页面查看：

https://peter.sh/experiments/chromium-command-line-switches/

禁用图片加载

Chrome的禁用图片加载参数设置比较复杂，如下所示：

prefs = {
    'profile.default_content_setting_values' : {
        'images' : 2
    }
}
options.add_experimental_option('prefs',prefs)

禁用浏览器弹窗

使用浏览器时常常会有弹窗弹出，以下选项可以禁止弹窗：

prefs = {  
    'profile.default_content_setting_values' :  {  
        'notifications' : 2  
     }  
}  
options.add_experimental_option('prefs',prefs) 

完整文档

class selenium.webdriver.chrome.options.Options

Bases: object

Method

• __init__()

• add_argument(argument)

  Adds an argument to the listArgs:Sets the arguments

• add_encoded_extension(extension)

  Adds Base64 encoded string with extension data to a list that will be used to extract it to the ChromeDriverArgs:extension: Base64 encoded string with extension data

• add_experimental_option(name, value)

  Adds an experimental option which is passed to chrome.Args:name: The experimental option name. value: The option value.

• add_extension(extension)

  Adds the path to the extension to a list that will be used to extract it to the ChromeDriverArgs:extension: path to the *.crx file

• set_headless(headless=True)

  Sets the headless argumentArgs:headless: boolean value indicating to set the headless option

• to_capabilities()

  Creates a capabilities with all the options that have been set andreturns a dictionary with everything

Values

• KEY = 'goog:chromeOptions'

• arguments

  Returns a list of arguments needed for the browser

• binary_location

  Returns the location of the binary otherwise an empty string

• debugger_address

  Returns the address of the remote devtools instance

• experimental_options

  Returns a dictionary of experimental options for chrome.

• extensions

  Returns a list of encoded extensions that will be loaded into chrome

• headless

  Returns whether or not the headless argument is set

Chrome WebDriver对象

简介

这个对象继承自selenium.webdriver.remote.webdriver.WebDriver，这个类会在下一章讲到，Chrome的WebDriver作为子类增添了几个方法。

指定chromedriver.exe的位置

chromedriver.exe一般可以放在环境文件中，但是有时候为了方便部署项目，或者为了容易打包，我们可以将chromedriver.exe放到我们的项目目录中，然后在初始化Chrome Webdriver对象时，传入chromedriver.exe的路径。

如下所示：

from selenium import webdriver
browser = webdriver.Chrome(executable_path='chromedriver.exe')

完整文档

class selenium.webdriver.chrome.webdriver.WebDriver(executable_path='chromedriver', port=0, options=None, service_args=None, desired_capabilities=None, service_log_path=None, chrome_options=None)

Bases: selenium.webdriver.remote.webdriver.WebDriver

Controls the ChromeDriver and allows you to drive the browser.

You will need to download the ChromeDriver executable fromhttp://chromedriver.storage.googleapis.com/index.html

• __init__(executable_path='chromedriver', port=0, options=None, service_args=None, desired_capabilities=None, service_log_path=None, chrome_options=None)

  Creates a new instance of the chrome driver.

  Starts the service and then creates new instance of chrome driver.

  Args:

  • executable_path - path to the executable. If the default is used it assumes the executable is in the $PATHport

  • port you would like the service to run, if left as 0, a free port will be found.

  • desired_capabilities: Dictionary object with non-browser specific capabilities only, such as “proxy” or “loggingPref”.

  • options: this takes an instance of ChromeOptions

• create_options()

• get_network_conditions()

  Gets Chrome network emulation settings.

  Returns:A dict. For example:

  {‘latency’: 4, ‘download_throughput’: 2, ‘upload_throughput’: 2, ‘offline’: False}

• launch_app(id)

  Launches Chrome app specified by id.

• quit()

  Closes the browser and shuts down the ChromeDriver executable that is started when starting the ChromeDriver

• set_network_conditions(**network_conditions)

  Sets Chrome network emulation settings.

  Args:

  • network_conditions: A dict with conditions specification.

  Usage:

  driver.set_network_conditions(offline=False, latency=5, # additional latency (ms)
                                download_throughput=500 * 1024, # maximal throughput
                                upload_throughput=500 * 1024) # maximal throughput

  Note: ‘throughput’ can be used to set both (for download and upload).