405 Method Not Allowed

The 405 Method Not Allowed status code is an HTTP response status code indicating that the server recognizes the request method, but the requested method is not allowed for the specified resource. In this article, we will dive into the details of the 405 status code, its implications, and how to handle it.

Understanding the 405 Method Not Allowed Status Code

When a client sends an HTTP request to a server, it uses a specific request method, such as GET, POST, PUT, or DELETE. These methods define the action the client intends to perform on the specified resource. If the server receives a request with a method that is not supported for the targeted resource, it should return a 405 Method Not Allowed response.

Common Causes

There are several reasons why a server might respond with a 405 status code:

1. The server doesn’t support the requested method for any resource.
2. The resource exists, but the requested method is not allowed for that specific resource.
3. The resource does not exist, and the server doesn’t support the requested method for any resource.

Example: Request and Response

Let’s consider a scenario where a client sends a PUT request to a server that only supports GET and POST methods for the requested resource.

Request

PUT /api/v1/users/123 HTTP/1.1
Host: example.com
Content-Type: application/json

{
  "name": "John Doe",
  "email": "john.doe@example.com"
}

Response

HTTP/1.1 405 Method Not Allowed
Allow: GET, POST
Content-Type: application/json

{
  "status": 405,
  "message": "Method Not Allowed"
}

In the response, the server indicates that the PUT method is not allowed for the requested resource by returning a 405 Method Not Allowed status code. Additionally, the Allow header lists the supported methods (GET and POST) for the resource.

Handling the 405 Method Not Allowed Status Code

When a client receives a 405 Method Not Allowed status code, it should take appropriate action based on the server’s response.

Client-Side

1. Ensure that the request method is correct for the intended action and resource.
2. Check the Allow header in the response to determine the supported methods for the resource.
3. If necessary, modify the request method according to the supported methods and resend the request.

Server-Side

To provide a better user experience and avoid confusion, server-side developers should:

1. Ensure that the server returns the correct Allow header listing the supported methods for the requested resource.
2. Provide clear and informative error messages in the response body to guide clients on the appropriate action to take.

Summary

The 405 Method Not Allowed status code indicates that the server recognizes the request method, but it is not allowed for the specified resource. Clients should check the Allow header in the response to determine the supported methods and modify their requests accordingly. Server-side developers should ensure that the server returns the correct Allow header and clear error messages to guide clients.