multi-formadd.c
/*************************************************************************** * _ _ ____ _ * 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> * using the multi interface to do a multipart formpost without blocking * </DESC> */ /* * Warning: this example uses the deprecated form api. See "multi-post.c" * for a similar example using the mime api. */ #include <stdio.h> #include <string.h> #include <curl/curl.h> int main(void) { CURL *curl; CURLM *multi_handle; int still_running = 0; struct curl_httppost *formpost = NULL; struct curl_httppost *lastptr = NULL; struct curl_slist *headerlist = NULL; static const char buf[] = "Expect:"; CURL_IGNORE_DEPRECATION( /* Fill in the file upload field. This makes libcurl load data from the given file name when curl_easy_perform() is called. */ curl_formadd(&formpost, &lastptr, CURLFORM_COPYNAME, "sendfile", CURLFORM_FILE, "multi-formadd.c", CURLFORM_END); /* Fill in the filename field */ curl_formadd(&formpost, &lastptr, CURLFORM_COPYNAME, "filename", CURLFORM_COPYCONTENTS, "multi-formadd.c", CURLFORM_END); /* Fill in the submit field too, even if this is rarely needed */ curl_formadd(&formpost, &lastptr, CURLFORM_COPYNAME, "submit", CURLFORM_COPYCONTENTS, "send", CURLFORM_END); ) curl = curl_easy_init(); multi_handle = curl_multi_init(); /* initialize custom header list (stating that Expect: 100-continue is not wanted */ headerlist = curl_slist_append(headerlist, buf); if(curl && multi_handle) { /* what URL that receives this POST */ curl_easy_setopt(curl, CURLOPT_URL, "https://www.example.com/upload.cgi"); curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L); curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headerlist); CURL_IGNORE_DEPRECATION( curl_easy_setopt(curl, CURLOPT_HTTPPOST, formpost); ) curl_multi_add_handle(multi_handle, curl); do { CURLMcode mc = curl_multi_perform(multi_handle, &still_running); if(still_running) /* wait for activity, timeout or "nothing" */ mc = curl_multi_poll(multi_handle, NULL, 0, 1000, NULL); if(mc) break; } while(still_running); curl_multi_cleanup(multi_handle); /* always cleanup */ curl_easy_cleanup(curl); CURL_IGNORE_DEPRECATION( /* then cleanup the formpost chain */ curl_formfree(formpost); ) /* free slist */ curl_slist_free_all(headerlist); } return 0; }
Notice
This source code example is simplified and ignores return
codes and error checks to a large extent. We do this to highlight the libcurl
function calls and related options and reduce unrelated code.
A real-world application will of course properly check every return value and exit correctly at the first serious error.