Handling Errors with aiohttp ClientResponseError

When making requests with the aiohttp client library in Python, you may occasionally run into ClientResponseError exceptions. These indicate that there was an HTTP error response from the server.

What Causes a ClientResponseError

Common causes of ClientResponseError include:

For example:

async with aiohttp.ClientSession() as session:
  async with session.get('http://example.com/invalid') as resp:
    text = await resp.text() # ClientResponseError raised here

So how do we properly handle these errors?

Checking the Status Code

The ClientResponseError contains the status code that was returned. You can access it through the status attribute:

try:
  async with session.get(url) as resp:
    await resp.text()
except aiohttp.ClientResponseError as e:
  print(e.status) # Print status code
  print(e.message) # Print error message

This allows you to check the status code and handle different cases differently.

Accessing the Response

Even though there was an error, you can still access the response object through the response attribute on the exception:

resp = e.response
print(resp.headers) # Print headers

This allows you to extract additional debug information from the response.

Key Takeaways

Properly handling these client-side errors ensures your aiohttp application is robust and user-friendly.