Python cURL

Features of cURL

There are numerous characteristics of cURL, some of them are:

• cURL is a command-line tool developed for information transfer across various protocols.
   
• This tool permits proxy utilization, improving web transmission abilities.
   
• cURL can control cookies and sessions, encouraging it to manage authentication.
   
• It delivers the ability to continue interrupted downloads, ensuring data integrity.
   
• The system supports data transfers through diverse protocols and authentication techniques.

Use cases of cURL

There are multiple use cases of cURL, some of them are:

• In web development, cURL recovers a webpage's contents, which can be examined instantly in the terminal. 
   
• cURL supports troubleshooting network issues by transmitting server requests and confirming their availability. Network administrators use cURL to assess connectivity to various servers and ports.
   
• In API development, cURL helps test endpoint’s functionality that requires data submission. cURL allows developers to interact with authenticated APIs by adding authorization tokens to requests.
   
• cURL is integrated into automation scripts to capture data from URLs and preserve it in files for further processing.

Use cURL with Python

First, we must install some entities like Python, Pip, PycURL, and certifi.

Download Python

Steps for adding Python's latest version:

• Go to the official Python website.
   
• Download the latest Python version.
   
• Run the installer and arrange your Python according to your need.

Download Pip

To install the pip, do this:

• Run the following command to check pip is installed.

pip --version

Download PycURL

PycURL's setup process operates curl-config to confirm it uses the same SSL library as libcURL. It even checks that PycURL is functioning correctly.

If you want pycurl, do this:

Run 'pip install pycurl'

Download Certifi

Certifi is a package that delivers a group of SSL certificates. It assures secure transmission over the Internet by confirming the authenticity of websites. Multiple Python applications use Certifi to establish safe links.

To install the Certifi, run the following steps:

pip install certifi

Sending GET Request

A GET request is when you want to get information from a webpage. It's like typing a website address. Then your browser asks the server for the webpage's code. PycURL is a helpful tool in Python that makes handling these requests easier.

Code

• Python

Python

import pycurl
from io import BytesIO

# Create a BytesIO object to store the response
response_buffer = BytesIO()
curl_instance = pycurl.Curl()

# Set the URL for the request
curl_instance.setopt(curl_instance.URL, 'https://www.codingninjas.com/studio/online-compiler')

# Set the write data option to store the response in the buffer
curl_instance.setopt(curl_instance.WRITEDATA, response_buffer)

# Make the GET request
curl_instance.perform()

# Close the connection
curl_instance.close()

# Get the response content from the buffer
response_body = response_buffer.getvalue()

print('Output of the GET request:\n%s' % response_body.decode('utf8'))

You can also try this code with Online Python Compiler

Run Code

Output

Explanation

This Python code operates the pycurl library to perform an HTTP GET request to a designated URL. The code builds a buffer using BytesIO to reserve the response. The code establishes a Curl instance from pycurl to oversee the configuration and execution of the request. The code sets the target URL and directs the response data to the buffer. After performing the GET request, the code closes the connection and recovers the response content from the buffer. Ultimately, the code prints the decoded response content to the console.

Making POST Requests

The POST method enables sending information to a website and adding or modifying data. Think of it like serving out a form or uploading a file. This info is sealed up and transmitted to the website. To start, bring in a few tools: urlencode, pycurl, and certifi. Create a PyCurl object named curl_object. 

Put the information you want to send in a unique form called a dictionary and use urlencode to prepare it. Decide which website to send this to and set its address using the setopt(option, value) method. The option is POSTFIELDS, which says you're sending data, and the value is what you're sending.

Code

• Python

Python

import pycurl
from urllib.parse import urlencode
import certifi

url = 'https://www.codingninjas.com/studio/online-compiler'

# Data sent in the POST request
data_to_post = {'field': 'value'}

encoded_data = urlencode(data_to_post)
response_buffer = []

# Callback function to handle the response data
def write_response(data):
    response_buffer.append(data)  # Append response data to the buffer

# Create a PyCurl object
curl_object = pycurl.Curl()
curl_object.setopt(curl_object.URL, URL)

# Set the POST data to be send
curl_object.setopt(curl_object.POSTFIELDS, encoded_data)
curl_object.setopt(curl_object.CAINFO, certifi.where())

# Set the callback function to handle response data
curl_object.setopt(curl_object.WRITEFUNCTION, write_response)
curl_object.perform()
curl_object.close()
response_body = b''.join(response_buffer).decode('utf-8')

# Print the response body
print("Output of the POST request")
print(response_body)

You can also try this code with Online Python Compiler

Run Code

Output

Explanation

This code uses the PyCurl library in Python to transmit a POST request to a selected URL. It starts by importing essential modules like pycurl for HTTP requests, urlencode for data encoding, and certifi for SSL certificates. The code selects the URL and data. The code performs the request, manages the response data, and interprets it. This code explains how to make a POST request using PyCurl and process the response.

Frequently Asked Questions

What is cURL?

cURL is a remarkable computer tool that communicates to websites using accessible commands. Python developers can use libraries like pycurl to perform HTTP requests and commit to web services actively.

What are the benefits of operating cURL with Python over various HTTP libraries?

cURL provides low-level control, helps various protocols, and is versatile for complicated scenarios, enhancing Python's abilities above reserved HTTP libraries.

What library can you use to work with cURL in Python?

You can use the pycurl library and cURL in Python to efficiently transmit and receive data from websites and online assistance using code.

Do the cURL requests accept user-defined headers?

You can add custom headers to a cURL request in Python using the -H flag followed by the header details within single quotes (').

What does cURL do in Python?

cURL in Python enables making HTTP requests, retrieving or sending data to/from web servers. It simplifies fetching resources, handling APIs, and automating interactions with remote services.

Conclusion

In this article, we learn about Python cURL. We also know about some unique cURL features that make it attractive to the developer. We even explore some use cases of cURL further in the article. We also examine the uses of cURL with Python. We learn how to incorporate cURL in sending GET Requests or making POST requests. 

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