PHP
REST API basics
Learn the basics of REST architecture and the resource concept.
REST and the resource concept
REST is a style for designing resource-based APIs over HTTP. A resource is a unit of data on the server: a user, a task, a product. Each resource is addressed by a URL; for example, /users/42 refers to the user with id 42.
The client accesses the resource with HTTP methods: read, create, update, or delete. The server returns the response in a structured data format that the client parses and uses.
The stateless principle
In REST, each request must stand on its own. The server does not keep client state between requests; this is the stateless principle. Every request carries all the information it needs within itself.
This principle simplifies the server and makes scaling easier. Any server handling the request gives the same answer, because state lives in the resource, not the session. Session data is sent as parameters or headers inside the request.
Exercise Return a resource representation as a string
Write a function called getResource. It should take a parameter $id. Inside, build an array with keys id, title and done (title value 'Task', done value false). Encode this array with encode and UNESCAPED_UNICODE, and return it. Then print the result of getResource(7).
Show example solution
Define getResource, put an encode call inside with return, then call it with echo.
Example solution:
function getResource($id) {
$resource = ['id' => $id, 'title' => 'Task', 'done' => false];
return encode($resource, UNESCAPED_UNICODE);
}
echo getResource(7);
Test yourself
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A data unit addressed by a URL
In REST, a data unit addressed by a URL is called a ____; for example, /tasks/7 is a task resource.
Show answer
In REST, a data unit addressed by a URL is called a resource; for example, /tasks/7 is a task resource.
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Match the REST concepts
- resource
- data addressed by URL
- HTTP method
- operation on a resource
- URL
- address of the resource
- response
- server's return value
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What does the stateless principle mean?
- The server re-requests all session data on every request
- Each request is complete on its own; the server keeps no state between requests
- The client only talks to a single server
- Requests only use the GET method
Show answer
Each request is complete on its own; the server keeps no state between requests — Correct. In the stateless principle, each request is complete on its own and the server keeps no state between requests.
Next lesson: HTTP methods
