HTTP Framework for REST Applications in C.

Based on GNU Libmicrohttpd for the backend web server, Jansson for the json manipulation library, and Libcurl for the http/smtp client API.

Used to facilitate creation of web applications in C programs with a small memory footprint, as in embedded systems applications.

You can create webservices in HTTP or HTTPS mode, stream data, or implement server websockets.

The source code of a hello world using Ulfius is the following:

/**
 * test.c
 * Small Hello World! example
 * to compile with gcc, run the following command
 * gcc -o test test.c -lulfius
 */
#include <stdio.h>
#include <ulfius.h>

#define PORT 8080

/**
 * Callback function for the web application on /helloworld url call
 */
int callback_hello_world (const struct _u_request * request, struct _u_response * response, void * user_data) {
  ulfius_set_string_body_response(response, 200, "Hello World!");
  return U_CALLBACK_CONTINUE;
}

/**
 * main function
 */
int main(void) {
  struct _u_instance instance;

  // Initialize instance with the port number
  if (ulfius_init_instance(&instance, PORT, NULL, NULL) != U_OK) {
    fprintf(stderr, "Error ulfius_init_instance, abort\n");
    return(1);
  }

  // Endpoint list declaration
  ulfius_add_endpoint_by_val(&instance, "GET", "/helloworld", NULL, 0, &callback_hello_world, NULL);

  // Start the framework
  if (ulfius_start_framework(&instance) == U_OK) {
    printf("Start framework on port %d\n", instance.port);

    // Wait for the user to press <enter> on the console to quit the application
    getchar();
  } else {
    fprintf(stderr, "Error starting framework\n");
  }
  printf("End framework\n");

  ulfius_stop_framework(&instance);
  ulfius_clean_instance(&instance);

  return 0;
}

• Create a webservice in a separate thread, the endpoint is identified by its method (ex: GET, POST, PUT, DELETE, etc.) and its URL path with its optional parameters (ex: /api/doc/@id). The webservice is executed in a callback function.

• Stream large amount of data with a reduced memory footprint.

• Websocket service, the websocket messages exchange is executed in dedicated callback functions.

• Client http[s] and smtp requests execution, the response is parsed in a dedicated structure.

• Client websocket request execution, the websocket messages exchange is executed in dedicated callback functions.

• Create a websocket service application

• Create websocket client application

• CLI to connect to a remote websocket: uwsc

See INSTALL.md file for installation details

See API.md file for API documentation details

See the online documentation for a doxygen format of the API documentation.

Example programs are available to understand the different functionalities available, see example_programs folder for detailed sample source codes and documentation.

Example callback functions are available in the folder example_callbacks. The example callback functions available are:

• static file server: to provide static files of a specific folder
• oauth2 bearer: to check the validity of a Oauth2 bearer jwt token. Requires libjwt.

• Glewlwyd, a lightweight SSO server that provides OAuth2 and OpenID Connect authentication protocols
• Le Biniou, user-friendly yet powerful music visualization / VJing tool
• Angharad, House automation system for ZWave and other types of devices
• Hutch, a safe locker for passwords and other secrets, using JavaScript client side encryption only
• Taliesin, a lightweight audio streaming server
• Taulas Raspberry Pi Serial interface, an interface for Arduino devices that implement Taulas protocol, a house automation protocol for Angharad

I'm open for questions and suggestions, feel free to open an issue, a pull request or send me an e-mail if you feel like it!

You can visit the IRC channel #ulfius on the Libera.​Chat network.