What are HTTP requests?

HTTP calls

HTTP is the protocol used to communicate on the web

• GET - Retrieve data from a specified resource
• POST - Submit data to be processed to a specified resource
• PUT - Update a specified resource
• DELETE - Delete a specified resource
• PATCH - Update partial resources

You can use postman or insomnia to test your API using HTTP calls. You can also use curl in the terminal. Most of ASRR's API calls are documented in Swagger, which is an online tool that also allows you to try out the API calls.

HTTP (Hypertext Transfer Protocol) requests are the foundation of communication on the World Wide Web. They are the means by which your web browser interacts with websites, allowing you to access web pages, submit forms, and retrieve data. In this article, we'll delve into how HTTP requests work and provide examples of two common types of data formats used in HTTP requests: JSON payloads and multipart form data.

How HTTP Requests Work

At its core, an HTTP request is a message sent from a client (usually a web browser) to a server (a remote computer hosting a website or service). The request initiates a specific action on the server, such as fetching a web page, submitting a form, or requesting data.

HTTP requests consist of several key components:

1. HTTP Method: The HTTP method, also known as an HTTP verb, specifies the type of action the client wants to perform. Common HTTP methods include:

• GET: Used to request data from a server.
• POST: Used to send data to a server, often for form submissions.
• PUT: Typically used to update an existing resource on the server.
• DELETE: Used to request the removal of a resource on the server.

2. URL (Uniform Resource Locator): The URL specifies the address of the resource the client wants to interact with. It includes the domain name (e.g., "www.example.com (opens in a new tab)") and the path to the specific resource (e.g., "/products").

3. Headers: Headers provide additional information about the request, such as the user agent (identifying the client's software), the content type accepted by the client, and more.

4. Request Body: In some cases, the request may include a body that contains data to be sent to the server. This is common in POST and PUT requests when submitting forms or sending JSON data.

Example: JSON Payload

JSON (JavaScript Object Notation) is a lightweight data interchange format that is commonly used in HTTP requests and responses. Here's an example of an HTTP POST request with a JSON payload:

POST /api/users HTTP/1.1
Host: api.example.com
Content-Type: application/json
 
{
  "username": "john_doe",
  "email": "john.doe@example.com",
  "age": 30
}

In this example:

• The HTTP method is POST, indicating that the client is sending data to the server.
• The URL is /api/users, specifying the endpoint for creating a new user.
• The Content-Type header indicates that the request body contains JSON data.
• The JSON payload contains user information, such as the username, email, and age.

Example: Multipart Form Data

Multipart form data is often used when submitting form data with files, such as when uploading images or documents. Here's an example of an HTTP POST request with multipart form data:

POST /upload-image HTTP/1.1
Host: example.com
Content-Type: multipart/form-data; boundary=---------------------------1234567890123456789012345678
 
-----------------------------1234567890123456789012345678
Content-Disposition: form-data; name="file"; filename="example.jpg"
Content-Type: image/jpeg
 
[Binary data of the image file goes here]
-----------------------------1234567890123456789012345678

In this example:

• The HTTP method is POST.
• The URL is /upload-image.
• The Content-Type header specifies that the request body contains multipart form data.
• The boundary marker (---------------------------1234567890123456789012345678) separates different parts of the form data.
• Each part includes a Content-Disposition header indicating the form field name ("file") and the filename.
• The binary data of the image file is included in the request body.

In summary, HTTP requests are the cornerstone of communication on the web, enabling clients to interact with servers by specifying methods, URLs, headers, and request bodies as needed. Understanding how to craft and interpret these requests is essential for web developers and anyone working with web services.