mongoose/docs/Embed.md

Mongoose Embedding Guide

Embedding Mongoose is done in two steps:

1. Copy mongoose.c and mongoose.h to your application's source tree and include these two files in the build.
2. Somewhere in the application code, call mg_create_server() to create a server, configure it with mg_set_option() and loop with mg_poll_server() until done. Call mg_destroy_server() to cleanup.

Here's a minimal application app.c that embeds mongoose:

#include "mongoose.h"
int main(void) {
  struct mg_server *server = mg_create_server(NULL);
  mg_set_option(server, "document_root", ".");
  mg_set_option(server, "listening_port", "8080");
  for (;;) mg_poll_server(server, 1000);  // Infinite loop, Ctrl-C to stop
  mg_destroy_server(&server);
  return 0;
}

To compile it, put mongoose.c, mongoose.h and minimal.c into one folder, then run the following UNIX command:

cc app.c mongoose.c -o app

If you're on Windows, run this in a Visual Studio shell:

cl app.c mongoose.c /TC /MD

When run, this simple application opens port 8080 and serves static files, CGI files and lists directory content in the current working directory.

Mongoose can call user-defined functions when certain URIs are requested. These functions are called uri handlers. mg_add_uri_handler() registers an URI handler, and there is no restriction exist on the number of URI handlers. Also, mongoose can call a user-defined function when it is about to send HTTP error back to client. That function is called http error handler and can be registered by mg_set_http_error_handler(). Handlers are called by Mongoose with struct mg_connection * pointer as a parameter, which has all information about the request: HTTP headers, POST or websocket data buffer, etcetera.

Let's extend our minimal application example and create an URI that will be served by user's C code. The app will handle /hello URI by showing a hello message. So, when app is run, http://127.0.0.1:8080/hello will say hello, and here's the code:

#include <string.h>
#include "mongoose.h"

static int handle_hello(struct mg_connection *conn) {
  static const char *reply = "HTTP/1.0 200 OK\r\n\r\nHello world!\n";
  mg_write(conn, reply, strlen(reply));
  return 1;
}

int main(void) {
  struct mg_server *server = mg_create_server(NULL);
  mg_set_option(server, "document_root", ".");
  mg_set_option(server, "listening_port", "8080");
  mg_add_uri_handler(server, "/hello", &handle_hello);
  for (;;) mg_poll_server(server, 1000);  // Infinite loop, Ctrl-C to stop
  mg_destroy_server(&server);
  return 0;
}

Note that URI handler must output valid HTTP response, which includes the reply line with status code HTTP/1.0 200 OK, HTTP headers which are empty in our example, and message body Hello world!\n. Note that reply line is ended with \r\n, and HTTP headers are also ended with \r\n.

Mongoose source code contains a well-commented example code, listed below:

• hello.c shows how to handle form input, file upload, websocket communication, get cookie values.