Embedded websocket example

/* * Copyright (c) 2013-2015 the CivetWeb developers * Copyright (c) 2013 No Face Press, LLC * License http://opensource.org/licenses/mit-license.php MIT License */ /* Simple example program on how to use CivetWeb embedded into a C program. */ #ifdef _WIN32 #include #else #include #endif #include #include #include "civetweb.h" #define DOCUMENT_ROOT "." #ifdef NO_SSL #ifdef USE_IPV6 #define PORT "[::]:8888" #else #define PORT "8888" #endif #else #ifdef USE_IPV6 #define PORT "[::]:8888r,[::]:8843s" #else #define PORT "8888r,8843s" #endif #endif #define EXAMPLE_URI "/example" #define EXIT_URI "/exit" int exitNow = 0; int ExampleHandler(struct mg_connection *conn, void *cbdata) { mg_printf(conn, "HTTP/1.1 200 OK\r\nContent-Type: text/html\r\n\r\n"); mg_printf(conn, ""); mg_printf(conn, "

This is an example text from a C handler

"); mg_printf( conn, "

To see a page from the A handler click A

"); mg_printf(conn, "

To see a page from the A handler click " "A/A

"); mg_printf(conn, "

To see a page from the A/B handler click A/B

"); mg_printf(conn, "

To see a page from the B handler (0) click B

"); mg_printf(conn, "

To see a page from the B handler (1) click B/A

"); mg_printf(conn, "

To see a page from the B handler (2) click B/B

"); mg_printf(conn, "

To see a page from the *.foo handler click xy.foo

"); #ifdef USE_WEBSOCKET mg_printf(conn, "

To test websocket handler click " "websocket

"); #endif mg_printf(conn, "

To exit click exit

", EXIT_URI); mg_printf(conn, "\n"); return 1; } int ExitHandler(struct mg_connection *conn, void *cbdata) { mg_printf(conn, "HTTP/1.1 200 OK\r\nContent-Type: text/plain\r\n\r\n"); mg_printf(conn, "Server will shut down.\n"); mg_printf(conn, "Bye!\n"); exitNow = 1; return 1; } int AHandler(struct mg_connection *conn, void *cbdata) { mg_printf(conn, "HTTP/1.1 200 OK\r\nContent-Type: text/html\r\n\r\n"); mg_printf(conn, ""); mg_printf(conn, "

This is the A handler!!!

"); mg_printf(conn, "\n"); return 1; } int ABHandler(struct mg_connection *conn, void *cbdata) { mg_printf(conn, "HTTP/1.1 200 OK\r\nContent-Type: text/html\r\n\r\n"); mg_printf(conn, ""); mg_printf(conn, "

This is the AB handler!!!

"); mg_printf(conn, "\n"); return 1; } int BXHandler(struct mg_connection *conn, void *cbdata) { /* Handler may access the request info using mg_get_request_info */ const struct mg_request_info *req_info = mg_get_request_info(conn); mg_printf(conn, "HTTP/1.1 200 OK\r\nContent-Type: text/html\r\n\r\n"); mg_printf(conn, ""); mg_printf(conn, "

This is the BX handler %p!!!

", cbdata); mg_printf(conn, "

The actual uri is %s

", req_info->uri); mg_printf(conn, "\n"); return 1; } int FooHandler(struct mg_connection *conn, void *cbdata) { /* Handler may access the request info using mg_get_request_info */ const struct mg_request_info *req_info = mg_get_request_info(conn); mg_printf(conn, "HTTP/1.1 200 OK\r\nContent-Type: text/html\r\n\r\n"); mg_printf(conn, ""); mg_printf(conn, "

This is the Foo handler!!!

"); mg_printf(conn, "

The request was:

%s %s HTTP/%s

", req_info->request_method, req_info->uri, req_info->http_version); mg_printf(conn, "\n"); return 1; } int WebSocketStartHandler(struct mg_connection *conn, void *cbdata) { mg_printf(conn, "HTTP/1.1 200 OK\r\nContent-Type: text/html\r\n\r\n"); mg_printf(conn, "\n"); mg_printf(conn, "\n\n"); mg_printf(conn, "\n"); mg_printf(conn, "Embedded websocket example\n"); #ifdef USE_WEBSOCKET /* mg_printf(conn, "\n"); ... xhtml style */ mg_printf(conn, "\n"); mg_printf(conn, "\n\n"); mg_printf( conn, "

No websocket connection yet

\n"); #else mg_printf(conn, "\n\n"); mg_printf(conn, "Example not compiled with USE_WEBSOCKET\n"); #endif mg_printf(conn, "\n\n"); return 1; } #ifdef USE_WEBSOCKET /* MAX_WS_CLIENTS defines how many clients can connect to a websocket at the * same time. The value 5 is very small and used here only for demonstration; * it can be easily tested to connect more than MAX_WS_CLIENTS clients. * A real server should use a much higher number, or better use a dynamic list * of currently connected websocket clients. */ #define MAX_WS_CLIENTS (5) struct t_ws_client { struct mg_connection *conn; int state; } static ws_clients[MAX_WS_CLIENTS]; #define ASSERT(x) \ { \ if (!(x)) { \ fprintf(stderr, \ "Assertion failed in line %u\n", \ (unsigned)__LINE__); \ } \ } int WebSocketConnectHandler(const struct mg_connection *conn, void *cbdata) { struct mg_context *ctx = mg_get_context(conn); int reject = 1; int i; mg_lock_context(ctx); for (i = 0; i < MAX_WS_CLIENTS; i++) { if (ws_clients[i].conn == NULL) { ws_clients[i].conn = (struct mg_connection *)conn; ws_clients[i].state = 1; mg_set_user_connection_data(conn, (void *)(ws_clients + i)); reject = 0; break; } } mg_unlock_context(ctx); fprintf(stdout, "Websocket client %s\r\n\r\n", (reject ? "rejected" : "accepted")); return reject; } void WebSocketReadyHandler(struct mg_connection *conn, void *cbdata) { const char *text = "Hello from the websocket ready handler"; struct t_ws_client *client = mg_get_user_connection_data(conn); mg_websocket_write(conn, WEBSOCKET_OPCODE_TEXT, text, strlen(text)); fprintf(stdout, "Greeting message sent to websocket client\r\n\r\n"); ASSERT(client->conn == conn); ASSERT(client->state == 1); client->state = 2; } int WebsocketDataHandler(struct mg_connection *conn, int bits, char *data, size_t len, void *cbdata) { struct t_ws_client *client = mg_get_user_connection_data(conn); ASSERT(client->conn == conn); ASSERT(client->state >= 1); fprintf(stdout, "Websocket got data:\r\n"); fwrite(data, len, 1, stdout); fprintf(stdout, "\r\n\r\n"); return 1; } void WebSocketCloseHandler(const struct mg_connection *conn, void *cbdata) { struct mg_context *ctx = mg_get_context(conn); struct t_ws_client *client = mg_get_user_connection_data(conn); ASSERT(client->conn == conn); ASSERT(client->state >= 1); mg_lock_context(ctx); client->state = 0; client->conn = NULL; mg_unlock_context(ctx); fprintf(stdout, "Client droped from the set of webserver connections\r\n\r\n"); } void InformWebsockets(struct mg_context *ctx) { static unsigned long cnt = 0; char text[32]; int i; sprintf(text, "%lu", ++cnt); mg_lock_context(ctx); for (i = 0; i < MAX_WS_CLIENTS; i++) { if (ws_clients[i].state == 2) { mg_websocket_write(ws_clients[i].conn, WEBSOCKET_OPCODE_TEXT, text, strlen(text)); } } mg_unlock_context(ctx); } #endif int main(int argc, char *argv[]) { const char *options[] = {"document_root", DOCUMENT_ROOT, "listening_ports", PORT, "request_timeout_ms", "10000", "error_log_file", "error.log", #ifdef USE_WEBSOCKET "websocket_timeout_ms", "3600000", #endif #ifndef NO_SSL "ssl_certificate", "../../resources/cert/server.pem", #endif 0}; struct mg_callbacks callbacks; struct mg_context *ctx; struct mg_server_ports ports[32]; int port_cnt, n; int err = 0; /* Check if libcivetweb has been built with all required features. */ #ifdef USE_IPV6 if (!mg_check_feature(8)) { fprintf(stderr, "Error: Embedded example built with websocket support, " "but civetweb library build without.\n"); err = 1; } #endif #ifdef USE_WEBSOCKET if (!mg_check_feature(16)) { fprintf(stderr, "Error: Embedded example built with websocket support, " "but civetweb library build without.\n"); err = 1; } #endif #ifndef NO_SSL if (!mg_check_feature(2)) { fprintf(stderr, "Error: Embedded example built with SSL support, " "but civetweb library build without.\n"); err = 1; } #endif if (err) { fprintf(stderr, "Cannot start CivetWeb - inconsistent build.\n"); return EXIT_FAILURE; } /* Start CivetWeb web server */ memset(&callbacks, 0, sizeof(callbacks)); ctx = mg_start(&callbacks, 0, options); /* Add handler EXAMPLE_URI, to explain the example */ mg_set_request_handler(ctx, EXAMPLE_URI, ExampleHandler, 0); mg_set_request_handler(ctx, EXIT_URI, ExitHandler, 0); /* Add handler for /A* and special handler for /A/B */ mg_set_request_handler(ctx, "/A", AHandler, 0); mg_set_request_handler(ctx, "/A/B", ABHandler, 0); /* Add handler for /B, /B/A, /B/B but not for /B* */ mg_set_request_handler(ctx, "/B$", BXHandler, (void *)0); mg_set_request_handler(ctx, "/B/A$", BXHandler, (void *)1); mg_set_request_handler(ctx, "/B/B$", BXHandler, (void *)2); /* Add handler for all files with .foo extention */ mg_set_request_handler(ctx, "**.foo$", FooHandler, 0); /* Add HTTP site to open a websocket connection */ mg_set_request_handler(ctx, "/websocket", WebSocketStartHandler, 0); #ifdef USE_WEBSOCKET /* WS site for the websocket connection */ mg_set_websocket_handler(ctx, "/websocket", WebSocketConnectHandler, WebSocketReadyHandler, WebsocketDataHandler, WebSocketCloseHandler, 0); #endif /* List all listening ports */ memset(ports, 0, sizeof(ports)); port_cnt = mg_get_server_ports(ctx, 32, ports); printf("\n%i listening ports:\n\n", port_cnt); for (n = 0; n < port_cnt && n < 32; n++) { const char *proto = ports[n].is_ssl ? "https" : "http"; const char *host; if ((ports[n].protocol & 1) == 1) { /* IPv4 */ host = "127.0.0.1"; printf("Browse files at %s://%s:%i/\n", proto, host, ports[n].port); printf("Run example at %s://%s:%i%s\n", proto, host, ports[n].port, EXAMPLE_URI); printf( "Exit at %s://%s:%i%s\n", proto, host, ports[n].port, EXIT_URI); printf("\n"); } if ((ports[n].protocol & 2) == 2) { /* IPv6 */ host = "[::1]"; printf("Browse files at %s://%s:%i/\n", proto, host, ports[n].port); printf("Run example at %s://%s:%i%s\n", proto, host, ports[n].port, EXAMPLE_URI); printf( "Exit at %s://%s:%i%s\n", proto, host, ports[n].port, EXIT_URI); printf("\n"); } } /* Wait until the server should be closed */ while (!exitNow) { #ifdef _WIN32 Sleep(1000); #else sleep(1); #endif #ifdef USE_WEBSOCKET InformWebsockets(ctx); #endif } /* Stop the server */ mg_stop(ctx); printf("Server stopped.\n"); printf("Bye!\n"); return EXIT_SUCCESS; }