Proxying pip

If you’re working with python on your company’s network, chances are you’re behind a firewall and that you may have run into issues whilst trying to install python packages with pip. This is because pip doesn’t know how to use your proxy. Maybe this will help.

What’s a proxy?

A proxy is a server that sits between your computer and the internet. It’s typically used to filter requests and block certain websites.

Getting around it

You can tell pip that it needs to work with your proxy by setting the http_proxy and https_proxy environment variables. Alternatively, you can use the --proxy flag when running a pip command (I’ve personally had a bit more success with this method).

Constructing the proxy url

Assuming you’re on a windows machine, you can find the proxy url by searching for internet options in the start menu. Then go to the Connections tab and click on LAN settings. You should find the proxy url in the Proxy server section. Alternatively you can go to Settings and search for proxy.

The proxy url should look something like this: http://proxy.company.net. The part we care about is the proxy.company.net. Typically 8080 is the default port, but your company may use a different port.

Once you have this url, you can them construct the url that we will pass to pip. It should look something like this:

http://<username>:<uri_encoded_password>@proxy.company.net:8080

The <username> and <uri_encoded_password> are your windows credentials.

The <uri_encoded_password> is the URI encoded version of your password where any special characters are replaced with their % encoded counterparts e.g. password! becomes password%21. Here are the commonly used characters and their encoded counterparts:

Character	Encoded Character
!	%21
@	%40
#	%23
$	%24
%	%25
^	%5E
&	%26
*	%2A

You can find a more comprehensive list of characters here.

Installing packages

Once you have constructed the proxy url, you can pass it to pip using the --proxy flag. Here’s an example:

pip install -r requirements.txt --proxy http://<username>:<uri_encoded_password>@<proxy_url>:<port>