move embedded tutorials out of protocol tree

tutorials/esp32/uart-bridge/main/main.c

@@ -0,0 +1,50 @@
+// Copyright (c) 2020 Cesanta Software Limited
+// All rights reserved
+
+#include "main.h"
+
+const char *s_listening_url = "http://0.0.0.0:80";
+
+struct mg_str config_read(void) {
+  return mg_file_read(&mg_fs_posix, FS_ROOT "/config.json");
+}
+
+void config_write(struct mg_str config) {
+  mg_file_write(&mg_fs_posix, FS_ROOT "/config.json", config.buf, config.len);
+}
+
+void app_main(void) {
+  // Mount filesystem
+  esp_vfs_spiffs_conf_t conf = {
+      .base_path = FS_ROOT, .max_files = 20, .format_if_mount_failed = true};
+  int res = esp_vfs_spiffs_register(&conf);
+  MG_INFO(("FS at %s initialised, status: %d", conf.base_path, res));
+
+  // Try to connect to wifi by using saved WiFi credentials
+  struct mg_str json = mg_file_read(&mg_fs_posix, WIFI_FILE);
+  if (json.buf != NULL) {
+    char *ssid = mg_json_get_str(json, "$.ssid");
+    char *pass = mg_json_get_str(json, "$.pass");
+    while (!wifi_init(ssid, pass)) (void) 0;
+    mg_free(ssid);
+    mg_free(pass);
+    mg_free((void *) json.buf);
+  } else {
+    // If WiFi is not configured, run CLI until configured
+    MG_INFO(("WiFi is not configured, running CLI. Press enter"));
+    cli_init();
+    for (;;) {
+      uint8_t ch = getchar();
+      cli(ch);
+      usleep(10000);
+    }
+  }
+
+  // Connected to WiFi, now start HTTP server
+  struct mg_mgr mgr;
+  mg_mgr_init(&mgr);
+  mg_log_set(MG_LL_DEBUG);  // Set log level
+  MG_INFO(("Mongoose v%s on %s", MG_VERSION, s_listening_url));
+  mg_http_listen(&mgr, s_listening_url, uart_bridge_fn, NULL);
+  for (;;) mg_mgr_poll(&mgr, 10);  // Infinite event loop
+}