A user agent is a computer program representing a person, for example, a browser in a Web context.
Besides a browser, a user agent could be a bot scraping webpages, a download manager, or another app accessing the Web. Along with each request they make to the server, browsers include a self-identifying User-Agent HTTP header called a user agent (UA) string. This string often identifies the browser, its version number, and its host operating system.
Spam bots, download managers, and some browsers often send a fake UA string to announce themselves as a different client. This is known as user agent spoofing.
A typical user agent string looks like this: "Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:35.0) Gecko/20100101 Firefox/35.0".
But I think this approach is misguided as it may see your crawlers make thousands of requests from very rarely used user agents. Thankfully, the majority of system administrators completely ignore the intricacies of the scent ‘Accept’ headers and simply check if browsers are sending something plausible.
Web servers use this data to assess the capabilities of your computer, optimizing a page’s performance and display. Before we look into rotating user agents, let’s see how to fake or spoof an user agent in a request.
Disclaimer: Any code provided in our tutorials is for illustration and learning purposes only. We are not responsible for how it is used and assume no liability for any detrimental usage of the source code.
The tutorials only help illustrate the technique of programming web scrapers for popular internet websites. We are not obligated to provide any support for the code, however, if you add your questions in the comments section, we may periodically address them.
Accessing websites from a Python program is not very difficult, but using the requests' library makes it even fun. After importing the module we can call its get method passing a URL to it.
We could look at the Content-Type that the server sent us using the simple dictionary access code: r.headers that, in the above case, will print The content that you would get if you opened the page in your browser and the clicked on “view source”, or that you would get if you ran curl with the given URL.
The only thing you need to do is to supply the headers key with a dictionary including the Sergeant : If you run this program it will send the request as if it was Internet Explorer 2.0 and let the system administrator wonder if you are really stuck with such an old browser.
If you have any comments or questions, feel free to post them on the source of this page in GitHub. User _agents is a Python library that provides an easy way to identify/detect devices like mobile phones, tablets and their capabilities by parsing (browser/HTTP) user agent strings.
User _agents relies on the excellent parser to do the actual parsing of the raw user agent string. Alternatively, you can also get the latest source code from GitHub and install it manually.
Various basic information that can help you identify visitors can be accessed browser, device and OS attributes. As for now, these attributes should correctly identify popular platforms/devices, pull requests to support smaller ones are always welcome.
I found myself in the position of being disappointed with the lack of ability to make asynchronous HTTP requests in Python twice without installing (and forcing users to install) some silly library, which means it's time to just roll my own. It uses Python's native Ellis and threading modules.
Particularly this is useful for things like games or other UI apps where blocking a thread is unacceptable. # This module makes asynchronous HTTP requests in Python.
# This runs in Python 2.x* and 3.x # This requires no special library to be installed. # * HTTP header names in the response are all lowercase in Python 2.×.
Nothing I can do about this other than fall back to TCP/IP and # parse the response manually. _ user _ agent = “Blake's Magic Python Asynchronous HTTP Fetcher see one point oh”import threading as _threading_is_old = 3 / 2 == 1# Yeah, I'm sure there's a better way.
This (and the encode method below) just wrap the relevant Python 2 or 3 Ellis libraries so you don't have to worry about compatibility yourself. I just wanted to give a quick shout-out for a weekly Python code golf that I recently started up over on Strings.Io.