Replace trivial websocket example by a more illustrated one

examples/websocket/WebSockCallbacks.c

@@ -0,0 +1,180 @@
+#include <assert.h>
+#include <stdlib.h>
+#include <time.h>
+#include "WebSockCallbacks.h"
+
+#ifdef _WIN32
+#include <Windows.h>
+typedef HANDLE pthread_mutex_t;
+static int pthread_mutex_init(pthread_mutex_t *mutex, void *unused) {
+  unused = NULL;
+  *mutex = CreateMutex(NULL, FALSE, NULL);
+  return *mutex == NULL ? -1 : 0;
+}
+
+static int pthread_mutex_destroy(pthread_mutex_t *mutex) {
+  return CloseHandle(*mutex) == 0 ? -1 : 0;
+}
+
+static int pthread_mutex_lock(pthread_mutex_t *mutex) {
+  return WaitForSingleObject(*mutex, INFINITE) == WAIT_OBJECT_0? 0 : -1;
+}
+
+static int pthread_mutex_unlock(pthread_mutex_t *mutex) {
+  return ReleaseMutex(*mutex) == 0 ? -1 : 0;
+}
+#define mg_sleep(x) Sleep(x)
+#else
+#include <unistd.h>
+#include <pthread.h>
+#define mg_sleep(x) usleep((x) * 1000)
+#endif
+
+
+typedef struct tWebSockInfo {
+  int webSockState;
+  unsigned long initId;
+  struct mg_connection *conn;
+} tWebSockInfo;
+
+static pthread_mutex_t sMutex;
+
+#define MAX_NUM_OF_WEBSOCKS (256)
+static tWebSockInfo *socketList[MAX_NUM_OF_WEBSOCKS];
+
+
+void websocket_ready_handler(struct mg_connection *conn) {
+
+  int i;
+  struct mg_request_info * rq = mg_get_request_info(conn);
+  tWebSockInfo * wsock = malloc(sizeof(tWebSockInfo));
+  assert(wsock);
+  wsock->webSockState = 0;
+  rq->conn_data = wsock;
+
+  pthread_mutex_lock(&sMutex);
+  for (i=0;i<MAX_NUM_OF_WEBSOCKS;i++) {
+    if (0==socketList[i]) {
+      socketList[i] = wsock;
+      wsock->conn = conn;
+      wsock->webSockState = 1;
+      break;
+    }
+  }
+  pthread_mutex_unlock(&sMutex);
+}
+
+
+static void websocket_done(tWebSockInfo * wsock) { 
+  int i;
+  if (wsock) {
+    wsock->webSockState = 99;
+    for (i=0;i<MAX_NUM_OF_WEBSOCKS;i++) {
+      if (wsock==socketList[i]) {
+        socketList[i] = 0;
+        break;
+      }
+    }
+    free(wsock);
+  }
+}
+
+
+int websocket_data_handler(struct mg_connection *conn, int flags, char *data, size_t data_len) {
+  struct mg_request_info * rq = mg_get_request_info(conn);
+  tWebSockInfo * wsock = (tWebSockInfo*)rq->conn_data;
+  char msg[128];
+  int i;
+
+  pthread_mutex_lock(&sMutex);
+  if (flags==136) {
+    // close websock
+    websocket_done(wsock);
+    rq->conn_data = 0;
+    pthread_mutex_unlock(&sMutex);
+    return 1;
+  }
+  if ((data_len>=5) && (data_len<100) && (flags==129) || (flags==130)) {
+
+    // init command
+    if ((wsock->webSockState==1) && (!memcmp(data,"init ",5))) {
+      char * chk;
+      unsigned long gid;
+      memcpy(msg,data+5,data_len-5);
+      msg[data_len-5]=0;
+      gid = strtoul(msg,&chk,10);
+      wsock->initId = gid;
+      if (gid>0 && chk!=NULL && *chk==0) {
+        wsock->webSockState = 2;
+      }
+      pthread_mutex_unlock(&sMutex);
+      return 1;
+    }
+        
+    // chat message
+    if ((wsock->webSockState==2) && (!memcmp(data,"msg ",4))) {     
+      for (i=0;i<MAX_NUM_OF_WEBSOCKS;i++) {
+        if (socketList[i] && (socketList[i]->webSockState==2)) {
+          mg_websocket_write(socketList[i]->conn, WEBSOCKET_OPCODE_TEXT, data, data_len);
+        }
+      }
+      pthread_mutex_unlock(&sMutex);
+      return 1;
+    }
+  }
+
+  // keep alive
+  if ((data_len==4) && !memcmp(data,"ping",4)) {
+    pthread_mutex_unlock(&sMutex);
+    return 1;
+  }
+
+  pthread_mutex_unlock(&sMutex);
+  return 0;
+}
+
+
+void connection_close_handler(struct mg_connection *conn) {   
+  struct mg_request_info * rq = mg_get_request_info(conn);
+  tWebSockInfo * wsock = (tWebSockInfo*)rq->conn_data;
+
+  pthread_mutex_lock(&sMutex);
+  websocket_done(wsock);
+  rq->conn_data = 0;
+  pthread_mutex_unlock(&sMutex);
+}
+
+
+static void * eventMain(void * _ignored) {
+  int i;
+  char msg[256];
+  for (;;) {
+    time_t t = time(0);
+    struct tm * timestr = localtime(&t);
+    sprintf(msg,"title %s",asctime(timestr));
+
+    pthread_mutex_lock(&sMutex);
+    for (i=0;i<MAX_NUM_OF_WEBSOCKS;i++) {
+      if (socketList[i] && (socketList[i]->webSockState==2)) {
+        mg_websocket_write(socketList[i]->conn, WEBSOCKET_OPCODE_TEXT, msg, strlen(msg));
+      }
+    }
+    pthread_mutex_unlock(&sMutex);
+
+    mg_sleep(1000);
+  }
+
+  return _ignored;
+}
+
+
+void websock_init_lib(void) {
+  int ret;
+  ret = pthread_mutex_init(&sMutex, 0);
+  assert(ret==0);
+
+  memset(socketList,0,sizeof(socketList));
+
+  mg_start_thread(eventMain, 0);
+}
+