curl-w32/docs/examples/pop3-tls.c

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/***************************************************************************
* _ _ ____ _
* 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>
* POP3 using TLS
* </DESC>
*/
#include <stdio.h>
#include <curl/curl.h>
/* This is a simple example showing how to retrieve mail using libcurl's POP3
* capabilities. It builds on the pop3-retr.c example adding transport
* security to protect the authentication details from being snooped.
*
* Note that this example requires libcurl 7.20.0 or above.
*/
int main(void)
{
CURL *curl;
CURLcode res = CURLE_OK;
curl = curl_easy_init();
if(curl) {
/* Set username and password */
curl_easy_setopt(curl, CURLOPT_USERNAME, "user");
curl_easy_setopt(curl, CURLOPT_PASSWORD, "secret");
/* This will retrieve message 1 from the user's mailbox */
curl_easy_setopt(curl, CURLOPT_URL, "pop3://pop.example.com/1");
/* In this example, we will start with a plain text connection, and upgrade
* to Transport Layer Security (TLS) using the STLS command. Be careful of
* using CURLUSESSL_TRY here, because if TLS upgrade fails, the transfer
* will continue anyway - see the security discussion in the libcurl
* tutorial for more details. */
curl_easy_setopt(curl, CURLOPT_USE_SSL, (long)CURLUSESSL_ALL);
/* If your server does not have a valid certificate, then you can disable
* part of the Transport Layer Security protection by setting the
* CURLOPT_SSL_VERIFYPEER and CURLOPT_SSL_VERIFYHOST options to 0 (false).
* curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0L);
* curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 0L);
*
* That is, in general, a bad idea. It is still better than sending your
* authentication details in plain text though. Instead, you should get
* the issuer certificate (or the host certificate if the certificate is
* self-signed) and add it to the set of certificates that are known to
* libcurl using CURLOPT_CAINFO and/or CURLOPT_CAPATH. See docs/SSLCERTS
* for more information. */
curl_easy_setopt(curl, CURLOPT_CAINFO, "/path/to/certificate.pem");
/* Since the traffic will be encrypted, it is useful to turn on debug
* information within libcurl to see what is happening during the
* transfer */
curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
/* Perform the retr */
res = curl_easy_perform(curl);
/* Check for errors */
if(res != CURLE_OK)
fprintf(stderr, "curl_easy_perform() failed: %s\n",
curl_easy_strerror(res));
/* Always cleanup */
curl_easy_cleanup(curl);
}
return (int)res;
}