HTTP Methods

An HTTP method indicates the intended action of an HTTP request.

For example:

GET /api/students

Here, GET tells the server that the client wants to retrieve information.

The main HTTP methods used in our REST API course are:

• GET – Retrieve data
• POST – Send or create data
• PUT – Replace or update a resource
• PATCH – Partially update a resource
• DELETE – Delete a resource

HTTP methods are commonly mapped to CRUD operations.

The GET method is commonly used to retrieve data from a server.

Example:

GET /api/students

This request can return a list of students.

GET can also be used to retrieve a specific resource.

GET /api/students/10

Here, 10 identifies a particular student.

The POST method is commonly used to send data to a server and create a new resource.

Example:

POST /api/students

The new student information can be included in the request body.

A POST request can contain JSON data in its request body.

{
    "name": "Rahul",
    "email": "rahul@example.com",
    "course": "React Native"
}

The PHP REST API can validate this information before storing it in MySQL.

The PUT method is commonly used to update or replace an existing resource.

Example:

PUT /api/students/10

The server can use the ID to identify the resource that should be updated.

A PUT request can contain the information needed to update a resource.

{
    "name": "Rahul Kumar",
    "email": "rahulk@example.com",
    "course": "React Native"
}

The backend can update the corresponding database record.

The PATCH method is commonly used when only part of an existing resource needs to be updated.

Example:

PATCH /api/students/10

For example, only the email address could be changed.

A PATCH request may contain only the fields that need to be changed.

{
    "email": "newemail@example.com"
}

The server can update only the specified field.

The DELETE method is commonly used to remove a resource.

Example:

DELETE /api/students/10

The API can process the request and delete the corresponding record from the database.

The exact behavior depends on how the API is designed.

Suppose the mobile application wants to delete student number 25.

DELETE /api/students/25

The PHP API can identify student 25 and perform the required database operation.

GET    /api/students
GET    /api/students/10

POST   /api/students

PUT    /api/students/10

PATCH  /api/students/10

DELETE /api/students/10

These endpoints provide a simple example of CRUD operations for a student resource.

The HTTP method and endpoint work together to describe the requested operation.

GET /api/students

The endpoint identifies the resource, while GET indicates that the client wants to retrieve it.

DELETE /api/students/10

Here, DELETE indicates that the client wants to remove the resource identified by 10.

React Native can send different HTTP methods using Fetch or Axios.

fetch(url, {
    method: "POST"
});

The method property tells Fetch which HTTP method should be used.

fetch("https://example.com/api/students", {
    method: "GET"
})
.then(response => response.json())
.then(data => {
    console.log(data);
});

GET is commonly used when the application needs to retrieve data.

fetch("https://example.com/api/students", {
    method: "POST",
    headers: {
        "Content-Type": "application/json"
    },
    body: JSON.stringify({
        name: "Rahul",
        email: "rahul@example.com"
    })
});

The request sends JSON data to the API.

fetch("https://example.com/api/students/10", {
    method: "PUT",
    headers: {
        "Content-Type": "application/json"
    },
    body: JSON.stringify({
        name: "Rahul Kumar",
        email: "rahulk@example.com"
    })
});

This request can be used to update student number 10.

fetch("https://example.com/api/students/10", {
    method: "PATCH",
    headers: {
        "Content-Type": "application/json"
    },
    body: JSON.stringify({
        email: "newemail@example.com"
    })
});

Only the required field can be sent for a partial update.

fetch("https://example.com/api/students/10", {
    method: "DELETE"
})
.then(response => response.json())
.then(data => {
    console.log(data);
});

This can request deletion of student number 10.

Postman can be used to test different HTTP methods before connecting the API to React Native.

For example:

GET    /api/students
POST   /api/students
PUT    /api/students/10
PATCH  /api/students/10
DELETE /api/students/10

Postman testing will be covered in detail in the upcoming lessons.

The server can return an appropriate HTTP status code after processing a method.

The exact status code depends on how the API is designed.

Use the HTTP method according to the operation you want to perform.

Need to read data?
        ↓
       GET

Need to create data?
        ↓
      POST

Need to update data?
        ↓
   PUT / PATCH

Need to delete data?
        ↓
     DELETE

Consider a student management application.

CREATE
POST /api/students

READ
GET /api/students

READ ONE
GET /api/students/10

UPDATE
PUT /api/students/10

PARTIAL UPDATE
PATCH /api/students/10

DELETE
DELETE /api/students/10

React Native
      ↓
HTTP Method
      ↓
REST API
      ↓
PHP Backend
      ↓
MySQL
      ↓
JSON Response
      ↓
React Native

The HTTP method is one of the first pieces of information the API uses to understand the client's requested operation.

• GET is commonly used for retrieving resources.
• POST is commonly used for creating resources.
• PUT is commonly used for replacing or updating resources.
• PATCH is commonly used for partial updates.
• DELETE is commonly used for removing resources.
• The endpoint identifies the resource being accessed.
• The request body can contain data sent to the server.
• The response contains the result of the operation.

HTTP methods provide a standard way to describe operations in REST API communication.

These methods will be used throughout our PHP REST API and React Native projects.