Handling 428 Status Code in Python Requests Module: Fixing POST Request Errors

Fixing HTTP 428 Status Code in Python's Requests Module

This solution leverages Python's requests module, concentrating on resolving the 428 status code in POST requests by supplying missing preconditions such as headers or authorization.

import requests
url = 'https://wizzair.com/en-gb'
link = 'https://be.wizzair.com/24.9.0/Api/search/search'
payload = {"isFlightChange": False, "flightList": [{"departureStation": "TIA", "arrivalStation": "VIE", "departureDate": "2024-09-17"}, {"departureStation": "VIE", "arrivalStation": "TIA", "departureDate": "2024-10-20"}], "adultCount": 1, "childCount": 0, "infantCount": 0, "wdc": True}
# Add If-Match or other required precondition headers
headers = {
    'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64)',
    'Accept': 'application/json, text/plain, */*',
    'Referer': 'https://wizzair.com/en-gb',
    'If-Match': '<your-etag-here>',
    'Content-Type': 'application/json'
}
with requests.Session() as session:
    session.headers.update(headers)
    r = session.get(url)
    print(r.status_code)
    response = session.post(link, json=payload)
    print(response.status_code)
    if response.status_code == 428:
        print('428 Error: Missing required precondition.')

Alternative Approach: Adding Authorization for Precondition

This script provides an authorization token to circumvent the 428 precondition requirement and ensure authenticated access to the API.

import requests
url = 'https://wizzair.com/en-gb'
link = 'https://be.wizzair.com/24.9.0/Api/search/search'
token = 'Bearer your_auth_token'
payload = {"isFlightChange": False, "flightList": [{"departureStation": "TIA", "arrivalStation": "VIE", "departureDate": "2024-09-17"}, {"departureStation": "VIE", "arrivalStation": "TIA", "departureDate": "2024-10-20"}], "adultCount": 1, "childCount": 0, "infantCount": 0, "wdc": True}
headers = {
    'User-Agent': 'Mozilla/5.0',
    'Authorization': token,
    'Content-Type': 'application/json'
}
with requests.Session() as session:
    session.headers.update(headers)
    r = session.get(url)
    print(r.status_code)
    response = session.post(link, json=payload)
    print(response.status_code)
    if response.status_code == 428:
        print('428 Error: Ensure valid authorization or conditions.')

Handling Missing Required Fields in Headers

This method ensures that all required headers are supplied in the POST request to avoid the 428 error due to missing preconditions, such as the If-Unmodified-Since header.

import requests
url = 'https://wizzair.com/en-gb'
link = 'https://be.wizzair.com/24.9.0/Api/search/search'
payload = {"isFlightChange": False, "flightList": [{"departureStation": "TIA", "arrivalStation": "VIE", "departureDate": "2024-09-17"}, {"departureStation": "VIE", "arrivalStation": "TIA", "departureDate": "2024-10-20"}], "adultCount": 1, "childCount": 0, "infantCount": 0, "wdc": True}
headers = {
    'User-Agent': 'Mozilla/5.0',
    'Accept': 'application/json, text/plain, */*',
    'If-Unmodified-Since': 'Wed, 21 Oct 2020 07:28:00 GMT',
    'Content-Type': 'application/json'
}
with requests.Session() as session:
    session.headers.update(headers)
    r = session.get(url)
    print(r.status_code)
    response = session.post(link, json=payload)
    print(response.status_code)
    if response.status_code == 428:
        print('428 Error: Missing required headers.')

Common Questions About HTTP 428 Errors in Python

1. What does the 428 status code mean?
2. The 428 status code indicates that the server requires specific criteria, such as headers or token validation, before processing the request.
3. How do I fix the 428 error in Python?
4. Use headers like If-Match or If-Unmodified-Since, and make sure the session is properly preserved with requests.Session().
5. Why is my POST request returning a 428 error?
6. Before processing the POST request, the server is likely to check for a condition, such as a pre-existing header or token.
7. What is the role of the If-Match header?
8. The If-Match header ensures that the request is handled only if the resource matches the specified ETag value.
9. How can I ensure proper session handling in Python requests?
10. Using requests.Session() keeps your session, including headers and cookies, consistent across subsequent requests.

Final Thoughts on Fixing the 428 Status Code

The 428 status code is often used to indicate missing preconditions, such as essential headers. To resolve this issue, ensure that the request includes the right headers, such as If-Match or If-Unmodified-Since. Managing sessions is also important.

Furthermore, by appropriately managing authentication and other security-related headers, you may ensure that the POST request is handled without issues. By addressing these criteria, the server should return the required 200 status code, indicating that the request was successful.