HTTP methods and response codes facilitate client-server communication. Here’s a concise summary of their functions and key points:
HTTP Methods
HTTP methods specify the action to be performed on a resource. Commonly used methods include:
- GET: Requests a resource. Sent via query strings, e.g.,
?param=value. - POST: Sends data to the server (e.g., forms, logins, or file uploads) in the request body.
- HEAD: Requests headers that would be returned by a GET request without the body.
- PUT: Creates new resource on server. Security controls are essential to prevent misuse.
- DELETE: Removes a specified resource. If unsecured, it can lead to DoS.
- OPTIONS: Retrieves information about the server, such as supported HTTP methods.
- PATCH: Applies partial updates to an existing resource.
While get and post are most commonly used, REST API’s frequently utilize put and delete for CRUD operations.
HTTP Response Codes
Response codes inform the client about the status of their request. They are grouped into five categories:
-
1xx Informational: Provides processing information, e.g.,
100 Continue. -
2xx Success: Indicates a successful request.
- 200 OK: Request succeeded, and the response contains the resource.
-
3xx Redirection: Indicates a resource redirection.
- 302 Found: Redirects to another URL (e.g., after login).
-
4xx Client Errors: Errors due to issues in the client request.
- 400 Bad Request: Malformed request.
- 403 Forbidden: Access to the resource is denied.
- 404 Not Found: Resource doesn’t exist.
-
5xx Server Errors: Server-side issues.
- 500 Internal Server Error: Server failed to process the request.