feat: add main.c

compile.sh

@@ -0,0 +1,2 @@
+gcc main.c -o bot $(pkgconf --libs libcurl) $(pkgconf --libs yyjson)
+./bot YOUR_TOKEN_HERE

main.c

@@ -0,0 +1,125 @@
+#include <curl/curl.h>
+#include <curl/easy.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <yyjson.h>
+
+#define API_LEN 256
+#define URL_LEN 512
+#define TEXT_LEN 4096
+
+typedef struct tgbot {
+  CURL *curl;
+  char api[API_LEN];
+  int64_t offset;
+} tgbot;
+
+typedef struct tgmessage {
+  int64_t chat_id;
+  const char *text;
+} tgmessage;
+
+void send_message(tgbot *bot, tgmessage *message) {
+  char url[512];
+  char *encoded_text = curl_easy_escape(bot->curl, message->text, 0);
+  snprintf(url, sizeof(url), "%ssendMessage?chat_id=%ld&text=%s", bot->api,
+           message->chat_id, encoded_text);
+  curl_free(encoded_text);
+
+  curl_easy_setopt(bot->curl, CURLOPT_URL, url);
+  curl_easy_perform(bot->curl);
+}
+
+size_t write_cb(void *ptr, size_t size, size_t nmemb, char *data) {
+  strncat(data, ptr, size * nmemb);
+  return size * nmemb;
+}
+
+int handle_updates(tgbot *bot) {
+  /* Prepare our update */
+  char url[URL_LEN] = {0};
+  char response[TEXT_LEN] = {0};
+  snprintf(url, sizeof(url), "%sgetUpdates?timeout=30&offset=%ld", bot->api,
+           bot->offset + 1);
+
+  /* A little bit higher than 30s polling */
+  curl_easy_setopt(bot->curl, CURLOPT_TIMEOUT, 35L);
+  curl_easy_setopt(bot->curl, CURLOPT_URL, url);
+  curl_easy_setopt(bot->curl, CURLOPT_WRITEFUNCTION, write_cb);
+  curl_easy_setopt(bot->curl, CURLOPT_WRITEDATA, response);
+
+  int res = curl_easy_perform(bot->curl);
+  if (res != CURLE_OK) {
+    return -1;
+  }
+
+  /* Print json response */
+  fprintf(stdout, "%s\n", response);
+
+  /* Let's parse json */
+  yyjson_doc *doc = yyjson_read(response, strlen(response), 0);
+  yyjson_val *root = yyjson_doc_get_root(doc);
+
+  yyjson_val *ok = yyjson_obj_get(root, "ok");
+  if (yyjson_get_bool(ok) != true) {
+    yyjson_doc_free(doc);
+    return -1;
+  }
+
+  /* Parse result */
+  yyjson_val *result = yyjson_obj_get(root, "result");
+  /* result is an array, so iterate over it */
+  yyjson_val *a_result;
+  size_t idx, max;
+  yyjson_arr_foreach(result, idx, max, a_result) {
+    /* Update offset */
+    yyjson_val *update_id = yyjson_obj_get(a_result, "update_id");
+    bot->offset = yyjson_get_sint(update_id);
+
+    /* Get message */
+    yyjson_val *message = yyjson_obj_get(a_result, "message");
+    yyjson_val *text = yyjson_obj_get(message, "text");
+    yyjson_val *chat = yyjson_obj_get(message, "chat");
+    yyjson_val *id = yyjson_obj_get(chat, "id");
+
+    /* Echo message */
+    tgmessage msg = {
+        .chat_id = yyjson_get_sint(id),
+        .text = yyjson_get_str(text),
+    };
+    send_message(bot, &msg);
+  }
+
+  return 0;
+}
+
+int main(int argc, char **argv) {
+  if (argc < 2) {
+    fprintf(stderr, "Usage: %s <token>", argv[0]);
+    return -1;
+  }
+
+  /* Initialize curl */
+  curl_global_init(CURL_GLOBAL_ALL);
+
+  /* Initialize our bot struct */
+  tgbot bot = {
+      .offset = 0,
+      .curl = curl_easy_init(),
+  };
+
+  /* Retrieve bot token from args */
+  snprintf(bot.api, sizeof(bot.api), "https://api.telegram.org/bot%s/",
+           argv[1]);
+
+  /* Bot loop */
+  int err = 0;
+  while (!err) {
+    /* Find a better way to deal with CTRL-C, etc... and cleanup */
+    err = handle_updates(&bot);
+  }
+
+  /* Cleanup */
+  curl_easy_cleanup(bot.curl);
+  curl_global_cleanup();
+}