A Quick Guide To Use cURL With Proxy

By
Quick Guide To Use cURL With Proxy

Proxies are one of the essentials for running a data-oriented business. However, when using them regularly, it’s crucial to have a range of tools to help you manage them, and cURL is one of the most effective in that regard.

Are you looking to learn how to use cURL with Python? If so, then you’re in the right place. In this informative guide, we will provide an in-depth understanding of how to set up and use cURL with proxies for various purposes. Let’s dive in.

What is cURL?

cURL simply stands for client URL. It is an easy-to-use open-line command tool that allows you to transfer data over the internet. It can be used to send requests, set up proxies, and debug, all thanks to the command-line curl.exe coupled with a cross-platform library (libcurl), which enables the transfer of data between servers.

cURL code can appear almost everywhere where sending and receiving data is done, including operating systems in laptops and even cars. This is because cURL supports all popular internet protocols, including but not limited to POP3S, RTSP, SCP, SFTP, SMB, GOPHER, and HTTP.

Why do Developers Prefer cURL?

cURL dates back to the mid-’90s. However, it only started to gain popularity in the 2000s and has won the hearts of developers due to its ability to handle rather complex tasks, making them look easy. It is also scriptable and comes with a library, which comes in handy for scraping the internet without writing HTTP or networking code.

Some more benefits that developers find in cURL are:

  • Easy to use while testing and debugging. It inspects endpoints and modifies them to ensure quality and accuracy.
  • Identifies transferred data and provides more detailed information about what has been sent or received.
  • Great error logging to record failures for information purposes or for future fault detection and correction actions.
  • If you give it hints, it can guess what protocol you want to use, and if it doesn’t work, it automatically tries different ones.
  • Useful additional features such as cookies, proxy support, SSL connections, FTP uploads, and user authentication.

There’s clearly more than meets the eye when it comes to using cURL. Moreover, it performs SSL certificate verification automatically and supports HTTPS. This is essential in determining whether a remote server is the same one it claims to be or if it is masked as something else.

How to Use cURL With Proxy

cURL is the preferred command-line tool for most developers, as it is available for use in all contemporary operating systems. At this stage, you should have basic knowledge of how to use cURL with Python, how to identify and manage proxies, and general networking principles.

Installing cURL

To use cURL on a system older than Windows 10, you have to download and install it. The same applies to Linux users whose distributors don’t have cURL. To install it, enter the command:

sudo apt install curl

Once it is installed, type “curl” in the terminal to run it. This brings up an option to use “curl -help,” where the “-help’ command will bring you a list of commands that you can use. However, the input varies according to your operating system. and you may be required to use a double hyphen, like “–help,” when entering the commands. That should not be an issue, though, as cURL will guide you on the correct input to relay the desired results.

Connecting a Proxy

When using a cURL with a proxy, you first need to know the type of proxy you’re using. Whether it’s residential or datacenter, you will need the proxy server address, port, and protocol. If a cURL with proxy authentication is required, you will also need a username and password.

Setting a Proxy Specifically for cURL

If you want to use cURL exclusively with a proxy, you need to create a cURL configuration file. This will enable you to write command lines in a text file so that cURL can read commands from it as well as those in the command lines. This is crucial to preventing cURL from being used by other applications.

To create the file on Linux or MacOS, open the terminal and navigate to your home directory. Here, open the .curlrc file or create one if it’s not there. For Windows, the file should be named _curlrc. After locating and running, run;

cd ~
nano .curlrc

In the new file, add:

proxy="http://usr:[email protected]:0123″

Save the file, and you can now use cURL exclusively with a proxy.

Using cURL with an HTTP/HTTPS Proxy

If you plan to use cURL with HTTP/HTTPS, the first step is to ensure that your proxy is functioning properly. You can do this by running the test line;

curl https://httpbin.org/ip

If the command returns a different IP from your machine’s, the proxy is working properly.

All commands for cURL are case-sensitive. To get the proxy initiated, here is a cURL proxy example for a command line that you can run.

curl -x "http://user:[email protected]:1234" "http://httpbin.org/ip"
curl --proxy "http://user:[email protected]:1234" "http://httpbin.org/ip"

In this case, both the proxy URL and the target URL are surrounded with double quotes. HTTP will act as the default proxy protocol, and these commands will work for the same cURL proxy configuration.

curl --proxy "http://user:[email protected]:1234" "http://httpbin.org/ip"
curl --proxy "user:[email protected]:1234" "http://httpbin.org/ip"

Using cURL with SOCKS Proxy

If you need to use a proxy with the SOCKS protocol, the syntax will remain the same as with HTTPS proxies, that is;

curl -x "socks5://user:[email protected]:1234" "http://httpbin.org/ip"

Sometimes you may need to specify the socks version, and if so, versions such as socks4://, socks4a://, socks5://, or socks5h:// will come in handy.

You can also set a socks5 proxy with cURL by using -socks5 argument instead of -x. Moreover, if you have a username and password, specify them using the -proxy-user switch. An example is;

curl --socks5 "127.0.0.1:1234" "http://httpbin.org/ip" --proxy-user user:pwd

Ignoring or Overriding a Proxy Request for One Request

You can always override your proxy and set another proxy, even if your proxy is set globally or in the .curlrc file. To do so for one request, just set a new proxy with the -x or –proxy switch;

curl --proxy "http://user:[email protected]:8090" "http://httpbin.org/ip"

However, if you want to bypass the global proxies entirely for a request, use switch – noproxy followed by “*.” After this command, the application will avoid the proxy for all URLs.

cURL is a flexible and useful tool for almost anything proxy-related, ranging from setting up proxies to modifying environment variables and using proxies for scraping. You can make the most of their abilities by considering a residential or datacenter proxy, which comes in handy for all your data scraping needs.