Introduction
In web development, we have access to multiple HTTP request methods. These allow us to communicate with web servers.
The names of the HTTP request methods are verbs and typically indicate what will happen.
We will briefly look at the different types and then later take a deeper look at the more common requests.
Request methods
We will first look at the four most common request methods:
GET
The GET request gets data from the specified location. This is only for getting data from a resource. We wouldn’t use this method to send data.
An example of a GET request would be fetching a list of articles from a server.
POST
The POST method sends data to a specified location. This is for sending data to a resource, e.g. when we want to create a new item on the server.
An example of a POST request would be where we send data to a server, and a new item gets created, such as a new user.
PATCH
The PATCH method is when we want to update data at a specified location.
An example of a PATCH request is if we had a user with information and we wanted to update their information, such as updating their e-mail address.
PUT
The PUT method is when we want to replace data at a specified location. However, it will also create a new resource if it doesn’t exist.
An example of a PUT request would be where we want to replace one product with another.
DELETE
The DELETE method is when we want to delete data at a specified location.
An example of a DELETE request would be where we would delete an entire item, such as deleting an article or a user.
Additional request methods
The following are more network requests; however, they are less commonly used.
HEAD
The HEAD method is like a GET request, except it will only obtain header information (metadata) and not contain the body.
An example of using the HEAD request would be where you’d want to get meta-information about a server without needing response body.
CONNECT
The CONNECT method starts two-way communication with a specified location and can be used to open a tunnel.
An example of the CONNECT request is when you want to access websites that use SSL.
OPTIONS
The OPTIONS method will request options from a specified location so you can find out more about a specified location.
An example of the OPTIONS method is checking what methods a server would allow.
TRACE
The TRACE method will perform a loop-back test to a specified location and is used for diagnostics. You would send a TRACE request to the server, and the server would respond with the same payload. This is usually disabled on production servers (servers out in the real world) but might be enabled on development servers so you could test that the server is working.
An example of a TRACE method is where you would want to test the server is responding.
Classifying HTTP methods
Safe and non-safe methods
Safe methods never modify resources or change the state of a server. An example of a safe method is GET, as it only obtains data.
The POST method is a non-safe method as it may change the state of the server by creating a new entry/record.
Idempotent methods
Idempotent methods can be made once or several times in a row with the same effect while leaving the server in the same state. Examples of these are GET, HEAD, PUT and DELETE.