Python Requests - response.raise_for_status()

Imagine you are developing a Python project that needs to make HTTP requests. And when you send a request to a specific URI and wait for a response from the server. But how do you know if the server raises an error? At that time, the response.raise_for_status() method becomes vital in the context of checking the occurrences of server errors. It checks for errors in the response and warns you if it finds one. Let's dive into this powerful method, which is important in Python's requests module.

Purpose of Using response.raise_for_status()

So, why do we use a response.raise_for_status() method? It's like an error detector in your code. It checks whether a mistake has occurred during the request process. If it catches a mistake, i.e., a 404 status code, it will improve an HTTPError object. This method guarantees that the reaction is justifiable and doesn't bring about patron or server mistakes. It's a dominant method for debugging your code and ensuring the reliability of your HTTP requests.

How do we use response.raise_for_status()?

Let's say you're building a weather app that fetches data from a weather API. After requesting the API, you can call response.raise_for_status() to verify the status code. If the status code indicates a successful request, the program proceeds without raising an exception. But if the status code falls within the range of 400 to 600 (client or server errors), an exception is raised, and you can handle it accordingly in your code.

An exception is raised if the status code falls within the range of 400 to 600 (client or server errors). If the status code indicates a successful request (e.g., 200 OK), the program proceeds without raising an exception.

Example

Let's illustrate the use of response.raise_for_status() by pinging two URLs: github.com and seowebfix.com.

Note: To run the code below, first, you must have installed Python's latest version on your system. Then, install the requests library using the Command Prompt or CMD:

The command for installing the requests library in Windows OS:

For Linux

First, install Python, in which pip will be installed by default. Then run the below command:

For macOS

Like Windows and Linux, install Python first then, go with the command to install the pip and requests library:

Command to Install PIP

Command to Install Requests

Code

Output

C:\Users\hp\Desktop>python request.py
<Response [200]>
None
Traceback (most recent call last):
  File "C:\Users\hp\Desktop\request.py", line 17, in <module>
    print(response.raise_for_status())
 
  File "C:\Users\hp\AppData\Local\Programs\Python\Python312\Lib\site-packages\requests\models.py", line 1021, in raise_for_status
    raise HTTPError(http_error_msg, response=self)
requests.exceptions.HTTPError: 404 Client Error: Not Found for url: https://seowebfix.com/vivek/

Explanation

In the program mentioned above, we import the 'requests' module in the above code to make HTTP requests. Then, it sends a GET request to 'https://api.random.org/json-rpc/1/invoke' and prints the response object. After that, it sends another GET request to an incorrect URL, 'https://www.javatpoint.com/vivek/', and raises an error with that request.

Important Concepts:

• While there are several libraries for making HTTP requests in Python (e.g., httplib, urllib), requests stand out due to their cool features.
• If any attribute of the request object specifies NULL, you can use response.status_code to check the status code.
• If the status_code is outside the range of 200 to 299, review the request method and the URL you're using for resources.

Conclusion

In Python, the requests library offers a convenient method, response.raise_for_status(), to handle HTTP errors gracefully. When called on a response object, this method raises an exception if the response status code indicates an error (4xx or 5xx). It streamlines error handling in HTTP requests, allowing developers to promptly identify and address issues such as broken URLs, server errors, or unauthorized access. Implementing raise_for_status() enhances code reliability, simplifies debugging, and ensures robust error management in Python web applications.