HTTP methods

Here are the most commonly used HTTP methods, explained with examples from a blog application:

1. GET

• Purpose: Retrieve data from the server.
• Example: Fetch a list of blog posts or a specific blog post.

Use Case:

• Get all blog posts:
  

  GET /api/posts
  

  Response:
  

  [
    {
      "id": 1,
      "title": "First Blog Post",
      "content": "This is my first post.",
      "author": "John Doe"
    },
    {
      "id": 2,
      "title": "Second Blog Post",
      "content": "This is my second post.",
      "author": "Jane Smith"
    }
  ]
  

• Get a single blog post:
  

  GET /api/posts/1
  

  Response:
  

  {
    "id": 1,
    "title": "First Blog Post",
    "content": "This is my first post.",
    "author": "John Doe"
  }
  

2. POST

• Purpose: Create new data on the server.
• Example: Create a new blog post.

Use Case:

• Create a new blog post:
  

  POST /api/posts
  Content-Type: application/json
  
  {
    "title": "My New Blog Post",
    "content": "This is the content of my new blog post.",
    "author": "John Doe"
  }
  

  Response (Success):
  

  {
    "id": 3,
    "title": "My New Blog Post",
    "content": "This is the content of my new blog post.",
    "author": "John Doe"
  }
  

3. PUT

• Purpose: Update an existing resource completely. Typically, the entire object must be sent with the update.
• Example: Update the content of an existing blog post.

Use Case:

• Update an existing blog post:
  

  PUT /api/posts/1
  Content-Type: application/json
  
  {
    "title": "Updated Blog Post",
    "content": "This is the updated content of the blog post.",
    "author": "John Doe"
  }
  

  Response (Success):
  

  {
    "id": 1,
    "title": "Updated Blog Post",
    "content": "This is the updated content of the blog post.",
    "author": "John Doe"
  }
  

4. PATCH

• Purpose: Update part of an existing resource, instead of replacing the entire resource (like PUT).
• Example: Update only the title of a blog post.

Use Case:

• Update the title of an existing blog post:
  

  PATCH /api/posts/1
  Content-Type: application/json
  
  {
    "title": "Partially Updated Blog Post Title"
  }
  

  Response (Success):
  

  {
    "id": 1,
    "title": "Partially Updated Blog Post Title",
    "content": "This is the content of the blog post.",
    "author": "John Doe"
  }
  

5. DELETE

• Purpose: Delete a resource from the server.
• Example: Delete a specific blog post.

Use Case:

• Delete a blog post:
  

  DELETE /api/posts/1
  

  Response (Success):
  

  {
    "message": "Blog post deleted successfully."
  }
  

6. OPTIONS

• Purpose: Describe the communication options for the target resource. It's used to check which HTTP methods are supported by the server for a given resource.
• Example: Check which HTTP methods are allowed on blog posts.

Use Case:

• Request:
  

  OPTIONS /api/posts
  

• Response:
  

  Allow: GET, POST, PUT, PATCH, DELETE
  

7. HEAD

• Purpose: Similar to GET, but it only retrieves the headers of the response, not the body. Used to check if a resource exists or to retrieve meta-information like content type or length.
• Example: Check if a blog post exists.

Use Case:

• Request:
  

  HEAD /api/posts/1
  

• Response (headers only):
  

  HTTP/1.1 200 OK
  Content-Type: application/json
  Content-Length: 345
  

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Example Summary for Blog Application:

• GET: Retrieve blog posts or details of a single blog post.
• POST: Create a new blog post.
• PUT: Fully update an existing blog post (e.g., changing both title and content).
• PATCH: Partially update a blog post (e.g., change only the title).
• DELETE: Remove a blog post.
• OPTIONS: Check allowed HTTP methods.
• HEAD: Check if a blog post exists without retrieving its content.

Each method serves a specific purpose, allowing RESTful APIs to be efficient and maintain the correct behavior across different actions.