7.0 refactor

examples/complete/main.c

@@ -0,0 +1,203 @@
+// Copyright (c) 2020 Cesanta Software Limited
+// All rights reserved
+
+#include "mjson.h"
+#include "mongoose.h"
+
+// Authenticated user.
+// A user can be authenticated by:
+//   - a name:pass pair
+//   - a token
+// When a user is shown a login screen, she enters a user:pass. If successful,
+// a server returns user info which includes token. From that point on,
+// client can use token for authentication. Tokens could be refreshed/changed
+// on a server side, forcing clients to re-login.
+struct user {
+  const char *name, *pass, *token;
+};
+
+// This is a configuration structure we're going to show on a dashboard
+static struct config {
+  int value1;
+  char *value2;
+} s_config = {123, NULL};
+
+// Stringifies the config. A caller must free() it.
+static char *stringify_config(struct config *cfg) {
+  char *s = NULL;
+  mjson_printf(mjson_print_dynamic_buf, &s, "{%Q:%d,%Q:%Q}", "value1",
+               cfg->value1, "value2", cfg->value2);
+  return s;
+}
+
+// Update config structure. Return true if changed, false otherwise
+static bool update_config(struct mg_http_message *hm, struct config *cfg) {
+  bool changed = false;
+  char buf[256];
+  double dv;
+  if (mjson_get_number(hm->body.ptr, hm->body.len, "$.value1", &dv)) {
+    s_config.value1 = dv;
+    changed = true;
+  }
+  if (mjson_get_string(hm->body.ptr, hm->body.len, "$.value2", buf,
+                       sizeof(buf)) > 0) {
+    free(s_config.value2);
+    s_config.value2 = strdup(buf);
+    changed = true;
+  }
+  return changed;
+}
+
+// Parse HTTP requests, return authenticated user or NULL
+static struct user *getuser(struct mg_http_message *hm) {
+  // In production, make passwords strong and tokens randomly generated
+  // In this example, user list is kept in RAM. In production, it can
+  // be backed by file, database, or some other method.
+  static struct user users[] = {
+      {"admin", "admin", "admin_token"},
+      {"user1", "pass1", "user1_token"},
+      {"user2", "pass2", "user2_token"},
+      {NULL, NULL, NULL},
+  };
+  char user[256], pass[256];
+  struct user *u;
+  mg_http_creds(hm, user, sizeof(user), pass, sizeof(pass));
+  if (user[0] != '\0' && pass[0] != '\0') {
+    // Both user and password is set, search by user/password
+    for (u = users; u->name != NULL; u++)
+      if (strcmp(user, u->name) == 0 && strcmp(pass, u->pass) == 0) return u;
+  } else if (user[0] == '\0') {
+    // Only password is set, search by token
+    for (u = users; u->name != NULL; u++)
+      if (strcmp(pass, u->token) == 0) return u;
+  }
+  return NULL;
+}
+
+// Notify all config watchers about the config change
+static void notify_config_change(struct mg_mgr *mgr) {
+  struct mg_connection *c;
+  char *s = stringify_config(&s_config);
+  for (c = mgr->conns; c != NULL; c = c->next) {
+    if (c->label[0] == 'W') mg_http_printf_chunk(c, "%s\n", s);
+  }
+  free(s);
+}
+
+// HTTP request handler function
+static void cb(struct mg_connection *c, int ev, void *ev_data, void *fn_data) {
+  if (ev == MG_EV_HTTP_MSG) {
+    struct mg_http_message *hm = (struct mg_http_message *) ev_data;
+    struct user *u = getuser(hm);
+    // LOG(LL_INFO, ("%p [%.*s] auth %s", c->fd, (int) hm->uri.len, hm->uri.ptr,
+    // u ? u->name : "NULL"));
+    if (u == NULL && mg_http_match_uri(hm, "/api/#")) {
+      // All URIs starting with /api/ must be authenticated
+      mg_printf(c, "%s", "HTTP/1.1 403 Denied\r\nContent-Length: 0\r\n\r\n");
+    } else if (mg_http_match_uri(hm, "/api/config/get")) {
+      char *s = stringify_config(&s_config);
+      mg_printf(c, "HTTP/1.1 200 OK\r\nContent-Length: %d\r\n\r\n%s\n",
+                (int) strlen(s) + 1, s);
+      free(s);
+    } else if (mg_http_match_uri(hm, "/api/config/set")) {
+      // Admins only
+      if (strcmp(u->name, "admin") == 0) {
+        if (update_config(hm, &s_config)) notify_config_change(fn_data);
+        mg_printf(c, "HTTP/1.1 200 OK\r\nContent-Length: 0\r\n\r\n");
+      } else {
+        mg_printf(c, "%s", "HTTP/1.1 403 Denied\r\nContent-Length: 0\r\n\r\n");
+      }
+    } else if (mg_http_match_uri(hm, "/api/config/watch")) {
+      c->label[0] = 'W';  // Mark ourselves as a config watcher
+      mg_printf(c, "HTTP/1.1 200 OK\r\nTransfer-Encoding: chunked\r\n\r\n");
+    } else if (mg_http_match_uri(hm, "/api/video1")) {
+      c->label[0] = 'S';  // Mark that connection as live streamer
+      mg_printf(
+          c, "%s",
+          "HTTP/1.0 200 OK\r\n"
+          "Cache-Control: no-cache\r\n"
+          "Pragma: no-cache\r\nExpires: Thu, 01 Dec 1994 16:00:00 GMT\r\n"
+          "Content-Type: multipart/x-mixed-replace; boundary=--foo\r\n\r\n");
+    } else if (mg_http_match_uri(hm, "/api/log/static")) {
+      mg_http_serve_file(c, hm, "log.txt", "text/plain");
+    } else if (mg_http_match_uri(hm, "/api/log/live")) {
+      c->label[0] = 'L';  // Mark that connection as live log listener
+      mg_printf(c, "HTTP/1.1 200 OK\r\nTransfer-Encoding: chunked\r\n\r\n");
+    } else if (mg_http_match_uri(hm, "/api/login")) {
+      mg_printf(c, "HTTP/1.1 200 OK\r\nTransfer-Encoding: chunked\r\n\r\n");
+      mg_http_printf_chunk(c, "{\"user\":\"%s\",\"token\":\"%s\"}\n", u->name,
+                           u->token);
+      mg_http_printf_chunk(c, "");
+    } else {
+      mg_http_serve_dir(c, ev_data, "web_root");
+    }
+  }
+}
+
+// The image stream is simulated by sending MJPEG frames specified by the
+// "files" array of file names.
+static void broadcast_mjpeg_frame(struct mg_mgr *mgr) {
+  const char *files[] = {"images/1.jpg", "images/2.jpg", "images/3.jpg",
+                         "images/4.jpg", "images/5.jpg", "images/6.jpg"};
+  size_t nfiles = sizeof(files) / sizeof(files[0]);
+  static size_t i;
+  const char *path = files[i++ % nfiles];
+  size_t size = mg_file_size(path);
+  char *data = mg_file_read(path);  // Read next file
+  struct mg_connection *c;
+  for (c = mgr->conns; c != NULL; c = c->next) {
+    if (c->label[0] != 'S') continue;      // Skip non-stream connections
+    if (data == NULL || size == 0) continue;  // Skip on file read error
+    mg_printf(c,
+              "--foo\r\nContent-Type: image/jpeg\r\n"
+              "Content-Length: %lu\r\n\r\n",
+              (unsigned long) size);
+    mg_send(c, data, size);
+    mg_send(c, "\r\n", 2);
+  }
+  free(data);
+}
+
+static void mjpeg_cb(void *arg) {
+  broadcast_mjpeg_frame(arg);
+}
+
+static void log_message(const char *filename, const char *message) {
+  FILE *fp = fopen(filename, "a");
+  if (fp != NULL) {
+    fprintf(fp, "%s", message);
+    fclose(fp);
+  }
+}
+
+static void broadcast_message(struct mg_mgr *mgr, const char *message) {
+  struct mg_connection *c;
+  for (c = mgr->conns; c != NULL; c = c->next) {
+    if (c->label[0] == 'L') mg_http_printf_chunk(c, "%s", message);
+  }
+}
+
+// Timer function - called periodically.
+// Prepare log message. Save it to a file, and broadcast.
+static void log_cb(void *arg) {
+  char buf[64];
+  snprintf(buf, sizeof(buf), "Time is: %lu\n", (unsigned long) time(NULL));
+  log_message("log.txt", buf);
+  broadcast_message(arg, buf);
+}
+
+int main(void) {
+  struct mg_mgr mgr;
+  struct mg_timer t1, t2;
+
+  mg_mgr_init(&mgr);
+  mg_http_listen(&mgr, "http://localhost:8000", cb, &mgr);
+  mg_timer_init(&t1, 500, MG_TIMER_REPEAT, mjpeg_cb, &mgr);
+  mg_timer_init(&t2, 1000, MG_TIMER_REPEAT, log_cb, &mgr);
+  for (;;) mg_mgr_poll(&mgr, 50);
+  mg_timer_free(&t1);
+  mg_timer_free(&t2);
+  mg_mgr_free(&mgr);
+
+  return 0;
+}