# Cheat Sheet #day10 - HTTP Methods

### HTTP Methods Cheat Sheet

HTTP methods define the action to be performed for a given resource in a web application. Here's a quick reference to the most commonly used HTTP methods and their typical use cases.

#### GET
- **Purpose**: Retrieve data from a server.
- **Characteristics**:
  - Request data is sent in the URL.
  - Should be idempotent (same request can be made multiple times without changing the result).
  - Safe operation (does not modify resources).
- **Example**:
  ```http
  GET /api/users HTTP/1.1
  Host: cloudtuned.com
  ```

#### POST
- **Purpose**: Submit data to a server to create a new resource.
- **Characteristics**:
  - Data is sent in the request body.
  - Not idempotent (submitting the same data multiple times may result in multiple resources being created).
- **Example**:
  ```http
  POST /api/users HTTP/1.1
  Host: cloudtuned.com
  Content-Type: application/json

  {
    "name": "John Doe",
    "email": "john.doe@cloudtuned.com"
  }
  ```

#### PUT
- **Purpose**: Update an existing resource or create a new one if it does not exist.
- **Characteristics**:
  - Data is sent in the request body.
  - Idempotent (multiple identical requests will result in the same resource state).
- **Example**:
  ```http
  PUT /api/users/1 HTTP/1.1
  Host: cloudtuned.com
  Content-Type: application/json

  {
    "name": "John Doe",
    "email": "john.doe@cloudtuned.com"
  }
  ```

#### PATCH
- **Purpose**: Apply partial modifications to a resource.
- **Characteristics**:
  - Data is sent in the request body.
  - Not necessarily idempotent.
- **Example**:
  ```http
  PATCH /api/users/1 HTTP/1.1
  Host: cloudtuned.com
  Content-Type: application/json

  {
    "email": "john.new@cloudtuned.com"
  }
  ```

#### DELETE
- **Purpose**: Remove a resource from the server.
- **Characteristics**:
  - Idempotent (multiple identical delete requests will have the same effect).
- **Example**:
  ```http
  DELETE /api/users/1 HTTP/1.1
  Host: cloudtuned.com
  ```

#### HEAD
- **Purpose**: Retrieve the headers for a resource, without the response body.
- **Characteristics**:
  - Used for checking what a GET request will return before making the actual request.
  - Idempotent and safe.
- **Example**:
  ```http
  HEAD /api/users HTTP/1.1
  Host: cloudtuned.com
  ```

#### OPTIONS
- **Purpose**: Describe the communication options for the target resource.
- **Characteristics**:
  - Used for CORS preflight requests.
  - Safe and idempotent.
- **Example**:
  ```http
  OPTIONS /api/users HTTP/1.1
  Host: cloudtuned.com
  ```

#### TRACE
- **Purpose**: Perform a message loop-back test along the path to the target resource.
- **Characteristics**:
  - Used mainly for diagnostic purposes.
  - Safe and idempotent.
- **Example**:
  ```http
  TRACE /api/users HTTP/1.1
  Host: cloudtuned.com
  ```

#### CONNECT
- **Purpose**: Establish a tunnel to the server identified by the target resource.
- **Characteristics**:
  - Used mainly for SSL tunneling.
- **Example**:
  ```http
  CONNECT cloudtuned.com:443 HTTP/1.1
  Host: cloudtuned.com
  ```

### Summary

- **Safe Methods**: GET, HEAD, OPTIONS, TRACE
- **Idempotent Methods**: GET, PUT, DELETE, HEAD, OPTIONS, TRACE
- **Common Use Cases**:
  - **GET**: Fetching data, reading resources.
  - **POST**: Creating new resources, submitting forms.
  - **PUT**: Updating or replacing resources.
  - **PATCH**: Partially updating resources.
  - **DELETE**: Removing resources.

Understanding these HTTP methods and their appropriate use cases is crucial for designing RESTful APIs and handling web requests effectively.