cURL is a powerful command-line tool for transferring data over the internet. One of its many features is the ability to send cookies, which are small pieces of data stored on the client-side and used for authentication, tracking, and other purposes. In this tutorial, we will explore how to use cURL to send cookies.
Understanding Cookies
Cookies are key-value pairs that are sent with HTTP requests. They can be set by a server using the Set-Cookie header in an HTTP response, or they can be manually created and sent with an HTTP request. When sending cookies with cURL, we need to specify the cookie name, value, and any additional attributes such as domain, path, and expiration date.
Using the -b Option
The -b option tells cURL to read cookies from a file before making the request. The file should be in the old Netscape cookie file format, which has seven tab-separated fields:
- Domain
- Tailmatch (Boolean)
- Path
- Secure (Boolean)
- Expires (Unix timestamp)
- Name (cookie name)
- Value (cookie value)
Here is an example of a cookie file:
127.0.0.1 FALSE / FALSE 0 USER_TOKEN in
To send cookies from this file using cURL, use the following command:
curl -b ~/Downloads/cookies.txt http://127.0.0.1:5000/
Using the --cookie Option
Alternatively, you can specify a cookie directly on the command line using the --cookie option. For example:
curl --cookie "USER_TOKEN=Yes" http://127.0.0.1:5000/
This will send a single cookie with the name USER_TOKEN and value Yes.
Using the -c Option
The -c option tells cURL to write cookies received from the server to a file after making the request. For example:
curl -c ~/Downloads/cookies.txt http://127.0.0.1:5000/
This will create or overwrite the cookies.txt file with any cookies received from the server.
Using the -H Option
You can also specify a cookie as an HTTP header using the -H option. For example:
curl -H "Cookie: USER_TOKEN=Yes" http://127.0.0.1:5000/
Or, you can store the header in a file and use the @ symbol to read it from the file:
echo 'Cookie: USER_TOKEN=Yes' > /tmp/cookie
curl -H @/tmp/cookie http://127.0.0.1:5000/
Conclusion
In this tutorial, we have explored how to use cURL to send cookies using various options and methods. Whether you need to read cookies from a file, specify them directly on the command line, or write them to a file after receiving them from a server, cURL provides flexible and powerful tools for working with cookies.