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API Development

  • API development using GET, POST, PUT, and DELETE methods with structured request and response handling.

  • 🔹 Get, Post, Put, Delete APIs

    HTTP methods define what action the client wants to perform on the server. In RESTful API development, each method has a specific purpose and follows a standard behavior.

    GET – Fetch Data

    Used to retrieve data from the server.
     Does not change server data.

    Example:

    GET /users

    Response:

GET API Request and JSON Response

This example shows how a frontend application requests user data from a backend API using a GET /users request. The server responds with a JSON array containing user information, which the frontend can display or process further. 

[
  { "id": 1, "name": "Amit" },
  { "id": 2, "name": "Neha" }
]

  • POST – Create Data

    Used to send data to the server and create a new resource.

    Example:

    POST /users

    Request Body:

POST Method – Create Data

The POST method is used to send data from the client to the server to create a new resource. In this example, a POST /users request sends user details in the request body, allowing the server to create and store a new user record. 

{ "name": "Rahul", "email": "rahul@gmail.com" }
  • Response:

POST Method Response – User Created

This response confirms that the server has successfully created a new user after receiving a POST request. It returns the newly assigned user ID along with the user’s details, indicating that the data has been stored correctly. 

{ "id": 3, "name": "Rahul" }

  • PUT – Update Data

    Used to update existing data completely.

    Example:

    PUT /users/3

    Request Body:

PUT Method – Update Data

The PUT method is used to completely update an existing resource on the server. In this example, the PUT /users/3 request updates the user’s name by sending new data in the request body, replacing the previous information. 

{ "name": "Rahul Sharma" }

  • DELETE – Remove Data

    Used to delete a resource from the server.

    Example:

    DELETE /users/3

    Response:

DELETE Method – Remove Data

The DELETE method is used to remove an existing resource from the server. In this example, the DELETE /users/3 request deletes the specified user, and the server responds with a confirmation message indicating successful deletion. 

{ "message": "User deleted successfully" }

  • 🔹 Request & Response Handling

    Request and Response handling is the process of receiving client data, processing it on the server, and sending back a structured response.

    Each API call includes:

    • Request → Data sent by client

    • Response → Data sent by server

    Request Components

    • URL → API endpoint

    • Method → GET / POST / PUT / DELETE

    • Headers → Metadata (Authorization, Content-Type)

    • Body → Data (mainly for POST & PUT)

    Example Request:

Request Components in Server Communication

This section explains the main components of a client request sent to the server. A request includes the URL (API endpoint), HTTP method (GET, POST, PUT, DELETE), headers for metadata like authorization and content type, and an optional body containing data, usually used with POST and PUT requests. 

{
  "name": "Neha",
  "email": "neha@gmail.com"
}

  • Response Components

    • Status Code → Result of request

    • Data → JSON response

    • Message → Success or error info

    Common Status Codes:

    • 200 → Success

    • 201 → Resource Created

    • 400 → Bad Request

    • 404 → Not Found

    • 500 → Server Error

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