HTTP 405 error (Method Not Allowed) is a common problem in Python development, especially when doing network requests and web development. This error indicates that the HTTP request method used by the client is not supported or allowed by the server. In order to better understand and solve the 405 error, this article will explain in detail from multiple aspects such as the causes of the error, troubleshooting methods, solutions, and actual cases.
1. The meaning of 405 error
The full name of the HTTP 405 error code is "Method Not Allowed", that is, the requested method is not allowed by the server. HTTP defines many request methods, such as GET, POST, PUT, DELETE, etc. Each method has its own specific purpose. For example, GET is usually used to obtain resources, and POST is used to submit data to the server. When the server receives an unsupported request method, it returns a 405 error.
2. The reason for the 405 error
The request method is incorrect:
The server-side interface only accepts some request method. For example, an API can only process POST requests, but receives a GET request. This is the most common cause of 405 errors.
URL configuration error:
The requested URL may not match the backend processing route. For example, a URL only supports GET requests, but the client also returns a 405 error when trying to access it with a POST request.
Server configuration issues:
Some server configurations may intentionally restrict specific HTTP methods. This is usually caused by a server's security policy or configuration error.
Cross-domain request issues:
When the front-end call the back-end API, if the cross-domain request is not configured correctly, the browser may issue a preflight request (OPTIONS method), and the server does not handle this method, which may also cause a 405 error.
The request header is incorrect:
HTTP requests usually contain request headers, which are used to carry some necessary information, such as User-Agent, Content-Type, etc. If the request header is incorrect, the server may return a 405 error.
3. Methods to troubleshoot 405 errors
Check the request method:
Before initiating a request, determine the support method for the target URL. Many API documentation provides information on this. You can use the OPTIONS method of the requests library to get the allowed method of the specified URL.
import requests url = "# (Replace with the actual URL)#"response = (url) print(['Allow']) # Allowed request method
Check URL:
Ensure the correctness of the URL, including protocol, domain name, path and other parts. If the URL is incorrect, the server will not be able to find the corresponding resource, thus returning a 405 error.
Check the request header:
Make sure the information in the request header is correct. For example, Content-Type should match the type expected by the server.
View server response:
The content of the server response can provide more useful information. The error details can be viewed by printing the text content of the response.
print() # output server response content
Contact the server administrator:
If you are sure that there is no problem with the request method, URL, and request header, then the problem may be on the server side. At this point, you can try contacting the server administrator or API provider for more information and solutions.
4. Solution
Use the correct request method:
Once the request method supported by the target URL is determined, the request can be resented using the corresponding method. For example, if the server only accepts POST requests, it should use the POST method to send the request.
data = {'key': 'value'} # Change to your dataresponse = (url, data=data)
if response.status_code == 200:
print("Send the request successfully!")
else:
print(f"Request failed,Status code:{response.status_code}")
Modify the URL:
If the URL is configured incorrectly, it should be corrected to the correct URL.
Configure the server:
If it is a 405 error caused by server configuration problems, you need to modify the server configuration to support the required HTTP methods.
Handling cross-domain requests:
In frameworks such as Flask or Django, the corresponding CORS library can be used to handle cross-domain requests. For example, the Flask-CORS library can be used in Flask.
from flask import Flask from flask_cors import CORS app = Flask(__name__) CORS(app) # Allow all cross-domain requests
Add error handling:
In frameworks such as Flask, the errorhandler decorator can be used to add 405 error handling capabilities.
@(405)
def method_not_allowed(e):
return "405 Error: Method Not Allowed!", 405
5. Actual cases
405 error in Flask application:
Create a simple Flask application that allows access to specific routes only through POST methods.
from flask import Flask, request, jsonify
app = Flask(__name__)
@('/api/data', methods=['POST'])
def get_data():
data =
return jsonify({"message": "Data received", "data": data})
if __name__ == '__main__':
(debug=True)
Use the requests library to test:
import requests
# Try to use GET requestresponse = ('http://127.0.0.1:5000/api/data')
print(f'Status Code: {response.status_code}')
print('Response:', )
# Try to use POST requestpost_response = ('http://127.0.0.1:5000/api/data', json={"key": "value"})
print(f'Status Code: {post_response.status_code}')
print('Response:', post_response.text)
When executing this code, you will find that the status code returned by the GET request is 405, while the POST request successfully returns the data.
405 error in Django application:
In Django, routing handlers need to explicitly declare supported HTTP methods. If the requested method is not in the declaration, the server will return a 405 error.
from import JsonResponse
from import csrf_exempt
from import require_POST
@csrf_exempt
@require_POST
def my_view(request):
data = ()
return JsonResponse({"message": "Data received", "data": data})
Configure routing in:
from import path
from . import views
urlpatterns = [
path('api/data/', views.my_view),
]
If you try to access /api/data/ using GET request, it returns a 405 error.
405 error caused by cross-domain request:
Suppose you have a Flask API and the front-end page is under a different domain name. If the cross-domain request is not configured correctly, the browser may issue a preflight request (OPTIONS method) and the server does not handle this method, which will result in a 405 error.
The solution is to use the Flask-CORS library in Flask to handle cross-domain requests.
from flask import Flask
from flask_cors import CORS
app = Flask(__name__)
CORS(app) # Allow all cross-domain requests
@('/api/data', methods=['POST'])
def get_data():
data =
return jsonify({"message": "Data received", "data": data})
if __name__ == '__main__':
(debug=True)
After this configuration, the server can correctly respond to the browser's preflight request to avoid 405 errors.
6. Summary
HTTP 405 errors are one of the common errors in web development and are usually related to mismatch in request methods. In Python development, especially when building web applications based on frameworks such as Flask and Django, we need to clarify the HTTP methods supported by each route and ensure that the client requested methods match the server's settings. By carefully configuring routing, handling cross-domain requests correctly, and checking for spelling errors, we can effectively avoid 405 errors.
Mastering different HTTP request methods and how to check URL request capabilities is the key to improving crawler technology. It is also very important to understand the use of HTTP methods when building RESTful APIs. Reasonable error handling and client message prompts can improve the user experience. Hopefully this article can help you better understand the 405 error and its solutions, and quickly solve it when encountering similar problems in development.
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