Error handling

Introduction to APIs in Python

Chris Ramakers

Engineering Manager

Error status codes

4xx Client Errors

  • Indicate issues on the client's end
  • Common causes: Bad requests, authentication failures, etc ...

Resolution: Fix the request

5xx Server Errors

  • Arises from problems on the server
  • Common causes: Server overloaded, server configuration errors, internal errors

Resolution: Should be fixed by the API administrator

Introduction to APIs in Python

Error status codes: examples

4xx Client Errors

  • 401 Unauthorized - The request lacks valid authentication credentials for the requested resource
  • 404 Not Found - Indicates that the server cannot find the resource that was requested
  • 429 Too Many Requests - The client has sent too many requests in a given amount of time

5xx Server Errors

  • 500 Internal Server Error - The server experienced an unexpected issue which prevents it from responding
  • 502 Bad Gateway - The API server could not successfully reach another server it needed to complete the response
  • 504 Gateway Timeout - The server (which acts as a gateway) did not get a response from the upstream server in time
Introduction to APIs in Python

Handling errors

API errors

import requests

url = 'http://api.music-catalog.com/albums'

r = requests.get(url)

if r.status_code >= 400:
    # Oops, something went wrong

else:
    # All fine, let's do something
    # with the response

Connection errors

import requests

from requests.exceptions import ConnectionError

url = ''


try: 
    r = requests.get(url) 
    print(r.status_code)

except ConnectionError as conn_err: 
    print(f'Connection Error! {conn_err}.')
    print(error)
Introduction to APIs in Python

raise_for_status()

import requests

# 1: Import the requests library exceptions
from requests.exceptions import ConnectionError, HTTPError


try:

    r = requests.get("http://api.music-catalog.com/albums") 


    # 2: Enable raising exceptions for returned error statuscodes
    r.raise_for_status()


    print(r.status_code)


# 3: Catch any connection errors
except ConnectionError as conn_err: 
    print(f'Connection Error! {conn_err}.')


# 4: Catch error responses from the API server
except HTTPError as http_err:
    print(f'HTTP error occurred: {http_err}')
Introduction to APIs in Python

Let's practice!

Introduction to APIs in Python

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