A Simple RESTful Web Server in PURE C

This project implements a RESTful web server in C, leveraging the libmicrohttpd library. libmicrohttpd is a lightweight, designed for simplicity and efficiency, making it an excellent choice for building low-level web servers.

The server handles HTTP requests, manages routing, and interacts with a PostgreSQL database using the libpq library. It demonstrates core concepts such as:

• HTTP request/response handling
• Database connectivity (via PostgreSQL)
• Memory management in C
• Low-level socket programming

For a deeper dive into the implementation, refer to the official libmicrohttpd manual, which provides a detailed example of a simple HTTP server.

Why Choose C for This Project?

The C programming language was chosen for this project due to its low-level capabilities, which provide fine-grained control over system resources and memory management. By implementing a RESTful web server in C, this project demonstrates how to handle HTTP requests, manage sockets, and interact with system libraries like libmicrohttpd and libpq for database connectivity.

C is particularly well-suited for this type of application because:

• Performance: C allows for highly optimized code, making it ideal for building lightweight and efficient servers.
• Portability: C code can be compiled and run on a wide range of platforms, from embedded systems to modern servers.
• Direct System Interaction: C provides direct access to system calls and hardware, enabling a deeper understanding of how web servers and APIs operate at a lower level.
• Minimal Dependencies: Unlike higher-level languages, C minimizes reliance on external frameworks, resulting in a smaller and more self-contained application.

✏️ Note:: This project serves as a practical example of how to build a RESTful API in a language that is often overlooked for web development but remains foundational in systems programming.

Key Benefits of Using C:

• Efficiency: Low memory footprint and high execution speed.
• Control: Full control over memory allocation, pointers, and system resources.
• Learning Opportunity: A deeper understanding of networking, HTTP protocols, and database interactions without the abstraction of higher-level frameworks.

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Database Configuration

This project uses a PostgreSQL database to store user information. The database is hosted on Supabase, a cloud-based platform that provides a fully managed PostgreSQL database. The server communicates with the database using the libpq library, which is the official C API for PostgreSQL.

Database Schema

The database consists of a single table named users, designed to store user data. Below is the schema for the users table:

Column Name	Data Type	Description
id	SERIAL	Unique identifier for each user.
name	TEXT	The name of the user.
email	TEXT	The email address of the user.

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How to Run the Server

Prerequisites

Before running the server, ensure you have the following installed:

• GCC Compiler: Required to compile the C code.
• Make Utility: Used to simplify the build process.
• Docker (Optional): For running the server in a containerized environment.

Step-by-Step:

1. Clone the Repository

   git clone https://github.com/PedroFnseca/rest-api-C.git
   
   

2. Navigate to the Project Directory

   cd rest-api-C
   
   

3. Update the Database Credentials
   • Open the pg.h file in the src directory.
   • Update the variables with your database credentials.

     #define DB_HOST "your_database_host"
     #define DB_NAME "your_database_name"
     #define DB_USER "your_database_user"
     #define DB_PASSWORD "your_database_password"
     #define DB_PORT "your_database_port"
     
     

4. Running the Server:
   • Enter the folder scripts:

     cd scripts
     
     

   • Option 1: Using Docker (Recommended for Linux):

      ./docker_run.sh
     
     

   • Option 2: Without Docker (Linux):

     ./compiler.sh --run
     
     

5. Access the API at http://localhost:8080

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Endpoints

This RESTful web server provides the following endpoints.

• GET /users: Retrieve a list of users.
• GET /users/{id}: Retrieve detailed information about a specific user.
• POST /users: Create a new user.
• PUT /users/{id}: Update information for a specific user.
• DELETE /users/{id}: Delete a user.

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Related Articles

Here are some articles I’ve written about this project:

• 📚 Growing as a Developer: My Experience Building an API in C (Written in Portuguese)
• 📝 How to create an rest api using C (Written in English)