I have the following code in Python
:
from selenium.webdriver import Firefox
from contextlib import closing
with closing(Firefox()) as browser:
browser.get(url)
I would like to print the user-agent HTTP header and possibly change it. Is it possible?
To change the user Agent, we shall take the help of ChromeOptions class. Then apply the add_argument method on the object created. We shall pass user-agent and <value of the user Agent> as parameters to that method. Finally, this information shall be passed to the driver object.
There is no way in Selenium to read the request or response headers. You could do it by instructing your browser to connect through a proxy that records this kind of information.
The usual way to change the user agent for Firefox is to set the variable "general.useragent.override"
in your Firefox profile. Note that this is independent from Selenium.
You can direct Selenium to use a profile different from the default one, like this:
from selenium import webdriver
profile = webdriver.FirefoxProfile()
profile.set_preference("general.useragent.override", "whatever you want")
driver = webdriver.Firefox(profile)
With Chrome, what you want to do is use the user-agent
command line option. Again, this is not a Selenium thing. You can invoke Chrome at the command line with chrome --user-agent=foo
to set the agent to the value foo
.
With Selenium you set it like this:
from selenium import webdriver
from selenium.webdriver.chrome.options import Options
opts = Options()
opts.add_argument("user-agent=whatever you want")
driver = webdriver.Chrome(chrome_options=opts)
Both methods above were tested and found to work. I don't know about other browsers.
Selenium does not have methods to query the user agent from an instance of WebDriver
. Even in the case of Firefox, you cannot discover the default user agent by checking what general.useragent.override
would be if not set to a custom value. (This setting does not exist before it is set to some value.)
Once the browser is started, however, you can get the user agent by executing:
agent = driver.execute_script("return navigator.userAgent")
The agent
variable will contain the user agent.
To build on Louis's helpful answer...
from selenium import webdriver
from selenium.webdriver.common.desired_capabilities import DesiredCapabilities
...
caps = DesiredCapabilities.PHANTOMJS
caps["phantomjs.page.settings.userAgent"] = "whatever you want"
driver = webdriver.PhantomJS(desired_capabilities=caps)
The only minor issue is that, unlike for Firefox and Chrome, this does not return your custom setting:
driver.execute_script("return navigator.userAgent")
So, if anyone figures out how to do that in PhantomJS, please edit my answer or add a comment below! Cheers.
This is a short solution to change the request UserAgent on the fly.
Change UserAgent of a request with Chrome
from selenium import webdriver
from selenium.webdriver.common.desired_capabilities import DesiredCapabilities
driver = webdriver.Chrome(driver_path)
driver.execute_cdp_cmd('Network.setUserAgentOverride', {"userAgent":"python 2.7", "platform":"Windows"})
driver.get('http://amiunique.org')
then return your useragent:
agent = driver.execute_script("return navigator.userAgent")
Some sources
The source code of webdriver.py from SeleniumHQ (https://github.com/SeleniumHQ/selenium/blob/11c25d75bd7ed22e6172d6a2a795a1d195fb0875/py/selenium/webdriver/chrome/webdriver.py) extends its functionalities through the Chrome Devtools Protocol
def execute_cdp_cmd(self, cmd, cmd_args):
"""
Execute Chrome Devtools Protocol command and get returned result
We can use the Chrome Devtools Protocol Viewer to list more extended functionalities (https://chromedevtools.github.io/devtools-protocol/tot/Network#method-setUserAgentOverride) as well as the parameters type to use.
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