developerworks · November 7, 2017 18:10 · Sep 6, 2012 · Sep 6, 2012 · Sep 6, 2012 · Sep 6, 2012
diff --git a/index.html b/index.html
@@ -7,7 +7,8 @@
             $(function() {
                 window.WebSocket = window.WebSocket || window.MozWebSocket;
 
-                var websocket = new WebSocket('ws://127.0.0.1:9000', 'dumb-increment-protocol');
+                var websocket = new WebSocket('ws://127.0.0.1:9000',
+                                              'dumb-increment-protocol');
 
                 websocket.onopen = function () {
                     $('h1').css('color', 'green');

diff --git a/libwebsockets-websocket.c b/libwebsockets-websocket.c
@@ -1,4 +1,3 @@
-
 #include <stdio.h>
 #include <stdlib.h>
 #include <libwebsockets.h>
@@ -83,7 +82,6 @@ static struct libwebsocket_protocols protocols[] = {
     }
 };
 
-
 int main(void) {
     // server url will be http://localhost:9000
     int port = 9000;
@@ -107,16 +105,16 @@ int main(void) {
 
     printf("starting server...\n");
 
-    // infinite loop, the only option to end this serer is by sending SIGTERM. (CTRL+C)
+    // infinite loop, to end this server send SIGTERM. (CTRL+C)
     while (1) {
         libwebsocket_service(context, 50);
-        // libwebsocket_service will process all waiting events with their callback
-        // functions and then wait 50 ms.
-        // (this is single threaded webserver and this will keep
-        // our server from generating load while there are not requests to process)
+        // libwebsocket_service will process all waiting events with their
+        // callback functions and then wait 50 ms.
+        // (this is a single threaded webserver and this will keep our server
+        // from generating load while there are not requests to process)
     }
 
     libwebsocket_context_destroy(context);
 
     return 0;
-}
+}
diff --git a/libwebsockets-websocket.c b/libwebsockets-websocket.c
@@ -1,49 +1,71 @@
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <libwebsockets.h>
 
+
 static int callback_http(struct libwebsocket_context * this,
                          struct libwebsocket *wsi,
                          enum libwebsocket_callback_reasons reason, void *user,
                          void *in, size_t len)
 {
-    return 0;
+	return 0;
 }
 
+
+
 static int callback_dumb_increment(struct libwebsocket_context * this,
                                    struct libwebsocket *wsi,
                                    enum libwebsocket_callback_reasons reason,
                                    void *user, void *in, size_t len)
 {
     switch (reason) {
-    case LWS_CALLBACK_ESTABLISHED:
-        printf("connection established\n");
-        break;
-    case LWS_CALLBACK_RECEIVE: {
-        unsigned char *buf = (unsigned char*) malloc(LWS_SEND_BUFFER_PRE_PADDING + len +
-                                                     LWS_SEND_BUFFER_POST_PADDING);
-
-        int i;
-        for (i=0; i < len; i++) {
-            buf[LWS_SEND_BUFFER_PRE_PADDING + (len - 1) - i ] = ((char *) in)[i];
+        case LWS_CALLBACK_ESTABLISHED: // just log message that someone is connecting
+            printf("connection established\n");
+            break;
+        case LWS_CALLBACK_RECEIVE: { // the funny part
+            // create a buffer to hold our response
+            // it has to have some pre and post padding. You don't need to care
+            // what comes there, libwebsockets will do everything for you. For more info see
+            // http://git.warmcat.com/cgi-bin/cgit/libwebsockets/tree/lib/libwebsockets.h#n597
+            unsigned char *buf = (unsigned char*) malloc(LWS_SEND_BUFFER_PRE_PADDING + len +
+                                                         LWS_SEND_BUFFER_POST_PADDING);
+
+            int i;
+
+            // pointer to `void *in` holds the incomming request
+            // we're just going to put it in reverse order and put it in `buf` with
+            // correct offset. `len` holds length of the request.
+            for (i=0; i < len; i++) {
+                buf[LWS_SEND_BUFFER_PRE_PADDING + (len - 1) - i ] = ((char *) in)[i];
+            }
+
+            // log what we recieved and what we're going to send as a response.
+            // that disco syntax `%.*s` is used to print just a part of our buffer
+            // http://stackoverflow.com/questions/5189071/print-part-of-char-array
+            printf("received data: %s, replying: %.*s\n", (char *) in, (int) len,
+                   buf + LWS_SEND_BUFFER_PRE_PADDING);
+
+            // send response
+            // just notice that we have to tell where exactly our response starts. That's
+            // why there's `buf[LWS_SEND_BUFFER_PRE_PADDING]` and how long it is.
+            // we know that our response has the same length as request because
+            // it's the same message in reverse order.
+            libwebsocket_write(wsi, &buf[LWS_SEND_BUFFER_PRE_PADDING], len, LWS_WRITE_TEXT);
+
+            // release memory back into the wild
+            free(buf);
+            break;
         }
-
-        // http://stackoverflow.com/questions/5189071/print-part-of-char-array
-        printf("received data: %s, replying: %.*s\n", (char *) in, (int) len, buf + LWS_SEND_BUFFER_PRE_PADDING);
-
-        libwebsocket_write(wsi, &buf[LWS_SEND_BUFFER_PRE_PADDING], len, LWS_WRITE_TEXT);
-
-        free(buf);
-        //libwebsocket_write(wsi, in, len, LWS_WRITE_TEXT);
-        break;
+        default:
+            break;
     }
-    default:
-        break;
-    }
-
+
     return 0;
 }
 
+
+
 static struct libwebsocket_protocols protocols[] = {
     /* first protocol must always be HTTP handler */
     {
@@ -61,30 +83,40 @@ static struct libwebsocket_protocols protocols[] = {
     }
 };
 
+
 int main(void) {
+    // server url will be http://localhost:9000
     int port = 9000;
     const char *interface = NULL;
     struct libwebsocket_context *context;
+    // we're not using ssl
     const char *cert_path = NULL;
     const char *key_path = NULL;
+    // no special options
     int opts = 0;
-
+
+    // create libwebsocket context representing this server
     context = libwebsocket_create_context(port, interface, protocols,
                                           libwebsocket_internal_extensions,
                                           cert_path, key_path, -1, -1, opts);
-
+    
     if (context == NULL) {
         fprintf(stderr, "libwebsocket init failed\n");
         return -1;
     }
-
-    printf("Starting...\n");
-
+
+    printf("starting server...\n");
+
+    // infinite loop, the only option to end this serer is by sending SIGTERM. (CTRL+C)
     while (1) {
         libwebsocket_service(context, 50);
+        // libwebsocket_service will process all waiting events with their callback
+        // functions and then wait 50 ms.
+        // (this is single threaded webserver and this will keep
+        // our server from generating load while there are not requests to process)
     }
-
+    
     libwebsocket_context_destroy(context);
-
+    
     return 0;
-}
+}
diff --git a/index.html b/index.html
@@ -26,6 +26,7 @@
                 $('button').click(function(e) {
                     e.preventDefault();
                     websocket.send($('input').val());
+                    $('input').val('');
                 });
             });
         </script>

diff --git a/index.html b/index.html
@@ -30,10 +30,12 @@
             });
         </script>
         </head>
-   <body>
-      <h1>Websockets test</h1>
-      <input type="text" />
-      <button>Send</button>
-      <div></div>
-   </body>
+    <body>
+        <h1>WebSockets test</h1>
+        <form>
+            <input type="text" />
+            <button>Send</button>
+        </form>
+        <div></div>
+    </body>
 </html>
diff --git a/libwebsockets-websocket.c b/libwebsockets-websocket.c
@@ -1,11 +1,7 @@
-
-
 #include <stdio.h>
-//#include <string.h>
 #include <stdlib.h>
 #include <libwebsockets.h>
 
-
 static int callback_http(struct libwebsocket_context * this,
                          struct libwebsocket *wsi,
                          enum libwebsocket_callback_reasons reason, void *user,
@@ -14,8 +10,6 @@ static int callback_http(struct libwebsocket_context * this,
     return 0;
 }
 
-
-
 static int callback_dumb_increment(struct libwebsocket_context * this,
                                    struct libwebsocket *wsi,
                                    enum libwebsocket_callback_reasons reason,
@@ -50,7 +44,6 @@ static int callback_dumb_increment(struct libwebsocket_context * this,
     return 0;
 }
 
-
 static struct libwebsocket_protocols protocols[] = {
     /* first protocol must always be HTTP handler */
     {
@@ -62,14 +55,12 @@ static struct libwebsocket_protocols protocols[] = {
         "dumb-increment-protocol", // protocol name - very important!
         callback_dumb_increment,   // callback
         0                          // we don't use any per session data
-
     },
     {
         NULL, NULL, 0   /* End of list */
     }
 };
 
-
 int main(void) {
     int port = 9000;
     const char *interface = NULL;
@@ -96,4 +87,4 @@ int main(void) {
     libwebsocket_context_destroy(context);
 
     return 0;
-}
+}
diff --git a/index.html b/index.html
@@ -0,0 +1,39 @@
+<!DOCTYPE html>
+<html>
+    <head>
+        <meta charset="utf-8">
+        <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js"></script>
+        <script type="text/javascript">
+            $(function() {
+                window.WebSocket = window.WebSocket || window.MozWebSocket;
+
+                var websocket = new WebSocket('ws://127.0.0.1:9000', 'dumb-increment-protocol');
+
+                websocket.onopen = function () {
+                    $('h1').css('color', 'green');
+                };
+
+                websocket.onerror = function () {
+                    $('h1').css('color', 'red');
+                };
+
+                websocket.onmessage = function (message) {
+                    console.log(message.data);
+                    $('div').append($('<p>', { text: message.data }));
+                };
+
+
+                $('button').click(function(e) {
+                    e.preventDefault();
+                    websocket.send($('input').val());
+                });
+            });
+        </script>
+        </head>
+   <body>
+      <h1>Websockets test</h1>
+      <input type="text" />
+      <button>Send</button>
+      <div></div>
+   </body>
+</html>
diff --git a/libwebsockets-websocket.c b/libwebsockets-websocket.c
@@ -0,0 +1,99 @@
+
+
+#include <stdio.h>
+//#include <string.h>
+#include <stdlib.h>
+#include <libwebsockets.h>
+
+
+static int callback_http(struct libwebsocket_context * this,
+                         struct libwebsocket *wsi,
+                         enum libwebsocket_callback_reasons reason, void *user,
+                         void *in, size_t len)
+{
+    return 0;
+}
+
+
+
+static int callback_dumb_increment(struct libwebsocket_context * this,
+                                   struct libwebsocket *wsi,
+                                   enum libwebsocket_callback_reasons reason,
+                                   void *user, void *in, size_t len)
+{
+    switch (reason) {
+    case LWS_CALLBACK_ESTABLISHED:
+        printf("connection established\n");
+        break;
+    case LWS_CALLBACK_RECEIVE: {
+        unsigned char *buf = (unsigned char*) malloc(LWS_SEND_BUFFER_PRE_PADDING + len +
+                                                     LWS_SEND_BUFFER_POST_PADDING);
+
+        int i;
+        for (i=0; i < len; i++) {
+            buf[LWS_SEND_BUFFER_PRE_PADDING + (len - 1) - i ] = ((char *) in)[i];
+        }
+
+        // http://stackoverflow.com/questions/5189071/print-part-of-char-array
+        printf("received data: %s, replying: %.*s\n", (char *) in, (int) len, buf + LWS_SEND_BUFFER_PRE_PADDING);
+
+        libwebsocket_write(wsi, &buf[LWS_SEND_BUFFER_PRE_PADDING], len, LWS_WRITE_TEXT);
+
+        free(buf);
+        //libwebsocket_write(wsi, in, len, LWS_WRITE_TEXT);
+        break;
+    }
+    default:
+        break;
+    }
+
+    return 0;
+}
+
+
+static struct libwebsocket_protocols protocols[] = {
+    /* first protocol must always be HTTP handler */
+    {
+        "http-only",   // name
+        callback_http, // callback
+        0              // per_session_data_size
+    },
+    {
+        "dumb-increment-protocol", // protocol name - very important!
+        callback_dumb_increment,   // callback
+        0                          // we don't use any per session data
+
+    },
+    {
+        NULL, NULL, 0   /* End of list */
+    }
+};
+
+
+int main(void) {
+    int port = 9000;
+    const char *interface = NULL;
+    struct libwebsocket_context *context;
+    const char *cert_path = NULL;
+    const char *key_path = NULL;
+    int opts = 0;
+
+    context = libwebsocket_create_context(port, interface, protocols,
+                                          libwebsocket_internal_extensions,
+                                          cert_path, key_path, -1, -1, opts);
+
+    if (context == NULL) {
+        fprintf(stderr, "libwebsocket init failed\n");
+        return -1;
+    }
+
+    printf("Starting...\n");
+
+    while (1) {
+        libwebsocket_service(context, 50);
+    }
+
+    libwebsocket_context_destroy(context);
+
+    return 0;
+}