When building applications with aiohttp, you may encounter client errors when making requests. These occur when there is an issue on the client side, such as an invalid request, that prevents the request from completing successfully. Knowing how to handle these errors properly is important for writing robust aiohttp code.
What is a Client Error?
A client error occurs when aiohttp is unable to complete a request due to a client-side issue. Some common examples include:
These indicate an issue with the request itself rather than a problem with the server.
Handling Client Errors
When a client error response is received, aiohttp will raise a
Here is an example of handling a 404 error:
import aiohttp
async with aiohttp.ClientSession() as session:
async with session.get('http://example.com/invalid-url') as resp:
if resp.status == 404:
print('Resource was not found!')It's good practice to check the status code and handle expected errors rather than only relying on exceptions. This allows you to distinguish between different error cases and implement custom logic for each if needed.
For authentication and permission issues, you may wish to prompt the user to login again before retrying the request. For invalid parameters, you can return a 400 error to the client and ask them to resubmit the corrected request.
Key Takeaways
Handling client errors gracefully is essential to providing a good application experience for your users. aiohttp gives you the tools - the rest is up to your logic!