Handling requests in RESTFul API - Get, Put, Delete | Part 2

POST request

The POST requests are used to build new subordinate resources. A file, for example, is subordinate to the directory in which it resides and a record to a database table. When speaking strictly in terms of REST, POST methods add a new resource to the collection of resources.

Suppose a resource has been generated on the origin server. In that case, the response SHOULD include an entity that explains the request's status and references to the new resource and a Location header.

Often, the POST method's operation does not result in a resource that a URI can identify. In that case, the proper response status is either HTTP response code 200 (OK) or 204 (No Content).

This method's responses are cacheable only if the responses include the necessary Cache-Control or Expires header fields.

If we send two identical POST requests, it will result in two separate resources containing the same data (except resource ids) because POST is not secure nor idempotent.

For example:

app.post("/register", function(req, res){
//.body ..//
});

PUT request

PUT requests are typically used to update an existing resource. In case a resource does not exist, then the API decides to create a new resource or not.

If the PUT request creates a new resource, the origin server MUST inform the user agent via HTTP response code 201 (Created). If an existing resource is updated successfully, then either the 200 (OK) or 204 (No Content) response codes SHOULD be returned to signify successful completion.

Entries are considered stale if the request is cached and the Request-URI specifies one or more currently cached entities. The PUT method's responses are not cacheable.

For example:

app.put('/', (req, res) => {
  res.send("PUT Request Called")
})

DELETE request

DELETE requests are used to delete resources, as the name implies (identified by the Request-URI).

If the response includes an entity specifying the status, the HTTP response code should be 200 (OK), 202 (Accepted) if the action has been queued, or 204 (No Content) if the action has been done, but the answer does not include an entity.

The DELETE command is idempotent. A resource is no longer a part of the collection when we DELETE a resource. 

Repeatedly using the DELETE API request on that resource will have no effect. However, using DELETE on that resource for a second time will result in a 404 (NOT FOUND) error because the resource has already been removed.

If the request is cached and the Request-URI specifies one or more currently cached entities, those entries SHOULD be considered stale. This method's responses are not cacheable.

For example:

app.delete('/', (req, res) => {
  res.send("DELETE Request Called")
})

Frequently asked questions:

1). Explain what is REST and RESTFUL API?

Answer: REST stands for REpresentational State Transfer, and it's a new way of designing web APIs. RESTful APIs are web services created using the REST architectural concept, which focuses on system resources and how those resources are communicated across HTTP protocol to various clients written in multiple languages. 

HTTP methods such as GET, POST, PUT, and DELETE are used to conduct CRUD tasks in a RESTFUL web service, 

2). Mention whether you can use GET requests instead of PUT to create a resource?

Answer: No, PUT isn't designed to be used for GET. GET operations should only have read access, whereas PUT operations are intended to update data.

3). What are resources in a REST architecture?

Answer: REST architecture treats every content as a resource. These resources can be Text Files, Html Pages, Images, Videos or Dynamic Business Data.

Key takeaways

RESTful Web Services are Web Services that are built on the REST Architecture. RESTful web services are often used to construct APIs for web-based applications because they are lightweight, scalable, and maintainable. 

In this article, we've seen some of the fundamentals of RESTful API, like handling requests. You can refer to Part 1 of this series to know more about RESTFul APIs.

Happy Learning!