un-nest curl

curl-8.15.0/docs/examples/websocket.c

@@ -0,0 +1,167 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution. The terms
+ * are also available at https://curl.se/docs/copyright.html.
+ *
+ * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+ * copies of the Software, and permit persons to whom the Software is
+ * furnished to do so, under the terms of the COPYING file.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ * SPDX-License-Identifier: curl
+ *
+ ***************************************************************************/
+/* <DESC>
+ * WebSocket using CONNECT_ONLY
+ * </DESC>
+ */
+#include <stdio.h>
+#include <string.h>
+#ifdef _WIN32
+#include <winsock2.h>
+#include <windows.h>
+#define sleep(s) Sleep((DWORD)(s))
+#else
+#include <unistd.h>
+#endif
+
+#include <curl/curl.h>
+
+static CURLcode ping(CURL *curl, const char *send_payload)
+{
+  CURLcode res = CURLE_OK;
+  const char *buf = send_payload;
+  size_t sent, blen = strlen(send_payload);
+
+  while(blen) {
+    res = curl_ws_send(curl, buf, blen, &sent, 0, CURLWS_PING);
+    if(!res) {
+      buf += sent; /* deduct what was sent */
+      blen -= sent;
+    }
+    else if(res == CURLE_AGAIN) {  /* blocked on sending */
+      fprintf(stderr, "ws: sent PING blocked, waiting a second\n");
+      sleep(1);  /* either select() on socket or max timeout would
+                    be good here. */
+    }
+    else /* real error sending */
+      break;
+  }
+  if(!res)
+    fprintf(stderr, "ws: sent PING with payload\n");
+  return res;
+}
+
+static CURLcode recv_pong(CURL *curl, const char *expected_payload)
+{
+  size_t rlen;
+  const struct curl_ws_frame *meta;
+  char buffer[256];
+  CURLcode res;
+
+retry:
+  res = curl_ws_recv(curl, buffer, sizeof(buffer), &rlen, &meta);
+  if(!res) {
+    /* on small PING content, this example assumes the complete
+     * PONG content arrives in one go. Larger frames will arrive
+     * in chunks, however. */
+    if(meta->flags & CURLWS_PONG) {
+      int same = 0;
+      if(rlen == strlen(expected_payload)) {
+        if(!memcmp(expected_payload, buffer, rlen))
+          same = 1;
+      }
+      fprintf(stderr, "ws: received PONG with %s payload back\n",
+              same ? "same" : "different");
+    }
+    else if(meta->flags & CURLWS_TEXT) {
+      fprintf(stderr, "ws: received TEXT frame '%.*s'\n", (int)rlen,
+              buffer);
+    }
+    else if(meta->flags & CURLWS_BINARY) {
+      fprintf(stderr, "ws: received BINARY frame of %u bytes\n", (int)rlen);
+    }
+    else {
+      /* some other frame arrived. */
+      fprintf(stderr, "ws: received frame of %u bytes rflags %x\n", (int)rlen,
+              meta->flags);
+      goto retry;
+    }
+  }
+  else if(res == CURLE_AGAIN) {  /* blocked on receiving */
+    fprintf(stderr, "ws: PONG not there yet, waiting a second\n");
+    sleep(1);  /* either select() on socket or max timeout would
+                  be good here. */
+    goto retry;
+  }
+  if(res)
+    fprintf(stderr, "ws: curl_ws_recv returned %u, received %u\n",
+            (unsigned int)res, (unsigned int)rlen);
+  return res;
+}
+
+/* close the connection */
+static void websocket_close(CURL *curl)
+{
+  size_t sent;
+  (void)curl_ws_send(curl, "", 0, &sent, 0, CURLWS_CLOSE);
+}
+
+static CURLcode websocket(CURL *curl)
+{
+  CURLcode res;
+  int i = 0;
+  do {
+    res = ping(curl, "foobar");
+    if(res)
+      break;
+    res = recv_pong(curl, "foobar");
+    if(res)
+      break;
+    sleep(1);
+  } while(i++ < 10);
+  websocket_close(curl);
+  return res;
+}
+
+int main(int argc, const char *argv[])
+{
+  CURL *curl;
+  CURLcode res;
+
+  curl = curl_easy_init();
+  if(!curl) {
+    return 1; /* memory failure */
+  }
+  if(argc == 2)
+    curl_easy_setopt(curl, CURLOPT_URL, argv[1]);
+  else
+    curl_easy_setopt(curl, CURLOPT_URL, "wss://example.com");
+
+  curl_easy_setopt(curl, CURLOPT_CONNECT_ONLY, 2L); /* websocket style */
+
+  /* Perform the request, res gets the return code */
+  res = curl_easy_perform(curl);
+  /* Check for errors */
+  if(res != CURLE_OK)
+    fprintf(stderr, "curl_easy_perform() failed: %s\n",
+            curl_easy_strerror(res));
+  else {
+    /* connected and ready */
+    res = websocket(curl);
+  }
+
+  /* always cleanup */
+  curl_easy_cleanup(curl);
+  return (int)res;
+}