Python Requests

Requests library is one of the integral part of Python for making HTTP requests to a specified URL. Whether it be REST APIs or Web Scrapping, requests is must to be learned for proceeding further with these technologies. When one makes a request to a URI, it returns a response. Python requests provides inbuilt functionalities for managing both the request and response.

Contents

• Why learn Python requests module?
• Installing Requests
• Making a Request
• Http Request Methods
• Response object
• Response Methods
• Authentication using Python Requests
• SSL Certificate Verification
• Session Objects

Why learn Python requests module?

• Requests is an Apache2 Licensed HTTP library, that allows to send HTTP/1.1 requests using Python.
• To play with web, Python Requests is must. Whether it be hitting APIs, downloading entire facebook pages, and much more cool stuff, one will have to make a request to the URL.
• Requests play a major role is dealing with REST APIs, and Web Scrapping.
• Checkout an Example Python Script using Requests and Web Scrapping – Implementing Web Scraping in Python with BeautifulSoup

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Installing Requests

Requests installation depends on type of operating system on eis using, the basic command anywhere would be to open a command terminal and run,

pip install requests

The basic method for installation of requests on any operating system is to grab the base files and install requests manually and Requests is actively developed on GitHub, where the code is always available. For code – visit here.

You can either clone the public repository:

git clone git://github.com/psf/requests.git

Once you have a copy of the source, you can embed it in your own Python package, or install it into your site-packages easily:

cd requests
pip install .

Making a Request

Python requests module has several built-in methods to make Http requests to specified URI using GET, POST, PUT, PATCH or HEAD requests. A Http request is meant to either retrieve data from a specified URI or to push data to a server. It works as a request-response protocol between a client and a server. Let’s demonstrate how to make a GET request to an endpoint.

GET method is used to retrieve information from the given server using a given URI. The GET method sends the encoded user information appended to the page request. The page and the encoded information are separated by the ‘?’ character.

For example:

https://www.google.com/search?q=hello

How to make GET request through Python Requests

Python’s requests module provides in-built method called get() for making a GET request to a specified URI.

Syntax –

requests.get(url, params={key: value}, args)

Example –

Let’s try making a request to github’s APIs for example purposes.

importrequests

# Making a GET request

r =requests.get('https://api.github.com/users/naveenkrnl')

# check status code for response received

# success code - 200

print(r)

# print content of request

print(r.content)

save this file as request.py and through terminal run,https://307e92cdea2530b1634a4d46ded8dc24.safeframe.googlesyndication.com/safeframe/1-0-40/html/container.html

python request.py

Output –

For more, visit GET method – Python requests

Http Request Methods –

Method	Description
GET	GET method is used to retrieve information from the given server using a given URI.
POST	POST request method requests that a web server accepts the data enclosed in the body of the request message, most likely for storing it
PUT	The PUT method requests that the enclosed entity be stored under the supplied URI. If the URI refers to an already existing resource, it is modified and if the URI does not point to an existing resource, then the server can create the resource with that URI.
DELETE	The DELETE method deletes the specified resource
HEAD	The HEAD method asks for a response identical to that of a GET request, but without the response body.
PATCH	It is used for modify capabilities. The PATCH request only needs to contain the changes to the resource, not the complete resource

Response object

When one makes a request to a URI, it returns a response. This Response object in terms of python is returned by requests.method(), method being – get, post, put, etc. Response is a powerful object with lots of functions and attributes that assist in normalizing data or creating ideal portions of code. For example, response.status_code returns the status code from the headers itself, and one can check if the request was processed successfully or not.

Response object can be used to imply lots of features, methods, and functionalities.

Example :

# import requests module

importrequests

# Making a get request

response =requests.get('https://api.github.com/')

# print request object

print(response.url)

# print status code

print(response.status_code)

Save this file as request.py, and run using below command

Python request.py

Status code 200 indicates that request was made successfully.

Response Methods

Method	Description
response.headers	response.headers returns a dictionary of response headers.
response.encoding	response.encoding returns the encoding used to decode response.content.
response.elapsed	response.elapsed returns a timedelta object with the time elapsed from sending the request to the arrival of the response.
response.close()	response.close() closes the connection to the server.
response.content	response.content returns the content of the response, in bytes.
response.cookies	response.cookies returns a CookieJar object with the cookies sent back from the server.
response.history	response.history returns a list of response objects holding the history of request (url).
response.is_permanent_redirect	response.is_permanent_redirect returns True if the response is the permanent redirected url, otherwise False.
response.is_redirect	response.is_redirect returns True if the response was redirected, otherwise False.
response.iter_content()	response.iter_content() iterates over the response.content.
response.json()	response.json() returns a JSON object of the result (if the result was written in JSON format, if not it raises an error).
response.url	response.url returns the URL of the response.
response.text	response.text returns the content of the response, in unicode.
response.status_code	response.status_code returns a number that indicates the status (200 is OK, 404 is Not Found).
response.request	response.request returns the request object that requested this response.
response.reason	response.reason returns a text corresponding to the status code.
response.raise_for_status()	response.raise_for_status() returns an HTTPError object if an error has occurred during the process.
response.ok	response.ok returns True if status_code is less than 200, otherwise False.
response.links	response.links returns the header links.

Authentication using Python Requests

Authentication refers to giving a user permissions to access a particular resource. Since, everyone can’t be allowed to access data from every URL, one would require authentication primarily. To achieve this authentication, typically one provides authentication data through Authorization header or a custom header defined by server.

Example –

# import requests module

importrequests

fromrequests.auth importHTTPBasicAuth

# Making a get request

response =requests.get('https://api.github.com / user, ',

            auth =HTTPBasicAuth('user', 'pass'))

# print request object

print(response)

Replace “user” and “pass” with your username and password. It will authenticate the request and return a response 200 or else it will return error 403.

SSL Certificate Verification

Requests verifies SSL certificates for HTTPS requests, just like a web browser. SSL Certificates are small data files that digitally bind a cryptographic key to an organization’s details. Often, an website with a SSL certificate is termed as secure website. By default, SSL verification is enabled, and Requests will throw a SSLError if it’s unable to verify the certificate.

Disable SSL certificate verification

Let us try to access a website with an invalid SSL certificate, using Python requests

# import requests module

importrequests

# Making a get request

response =requests.get('https://expired.badssl.com/')

# print request object

print(response)

Output :-

This website doesn’t have SSL setup so it raises this error.

one can also pass the link to the certificate for validation via python requests only.

# import requests module

importrequests

# Making a get request

response =requests.get('https://github.com', verify ='/path/to/certfile')

# print request object

print(response)

This would work in case the path provided is correct for SSL certificate for github.com.

For more visit- SSL Certificate Verification – Python requests

Session Objects

Session object allows one to persist certain parameters across requests. It also persists cookies across all requests made from the Session instance and will use urllib3’s connection pooling. So if several requests are being made to the same host, the underlying TCP connection will be reused, which can result in a significant performance increase. A session object all the methods as of requests.

Using Session Objects

Let us illustrate use of session objects by setting a cookie to a url and then making a request again to check if cookie is set.

# import requests module

importrequests

# create a session object

s =requests.Session()

# make a get request

s.get('https://httpbin.org/cookies/set/sessioncookie/123456789')

# again make a get request

r =s.get('https://httpbin.org/cookies')

# check if cookie is still set

print(r.text)

Output: