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Annotation of embedaddon/curl/docs/examples/pop3-tls.c, revision 1.1

1.1     ! misho       1: /***************************************************************************
        !             2:  *                                  _   _ ____  _
        !             3:  *  Project                     ___| | | |  _ \| |
        !             4:  *                             / __| | | | |_) | |
        !             5:  *                            | (__| |_| |  _ <| |___
        !             6:  *                             \___|\___/|_| \_\_____|
        !             7:  *
        !             8:  * Copyright (C) 1998 - 2016, Daniel Stenberg, <daniel@haxx.se>, et al.
        !             9:  *
        !            10:  * This software is licensed as described in the file COPYING, which
        !            11:  * you should have received as part of this distribution. The terms
        !            12:  * are also available at https://curl.haxx.se/docs/copyright.html.
        !            13:  *
        !            14:  * You may opt to use, copy, modify, merge, publish, distribute and/or sell
        !            15:  * copies of the Software, and permit persons to whom the Software is
        !            16:  * furnished to do so, under the terms of the COPYING file.
        !            17:  *
        !            18:  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
        !            19:  * KIND, either express or implied.
        !            20:  *
        !            21:  ***************************************************************************/
        !            22: 
        !            23: /* <DESC>
        !            24:  * POP3 example using TLS
        !            25:  * </DESC>
        !            26:  */
        !            27: 
        !            28: #include <stdio.h>
        !            29: #include <curl/curl.h>
        !            30: 
        !            31: /* This is a simple example showing how to retrieve mail using libcurl's POP3
        !            32:  * capabilities. It builds on the pop3-retr.c example adding transport
        !            33:  * security to protect the authentication details from being snooped.
        !            34:  *
        !            35:  * Note that this example requires libcurl 7.20.0 or above.
        !            36:  */
        !            37: 
        !            38: int main(void)
        !            39: {
        !            40:   CURL *curl;
        !            41:   CURLcode res = CURLE_OK;
        !            42: 
        !            43:   curl = curl_easy_init();
        !            44:   if(curl) {
        !            45:     /* Set username and password */
        !            46:     curl_easy_setopt(curl, CURLOPT_USERNAME, "user");
        !            47:     curl_easy_setopt(curl, CURLOPT_PASSWORD, "secret");
        !            48: 
        !            49:     /* This will retrieve message 1 from the user's mailbox */
        !            50:     curl_easy_setopt(curl, CURLOPT_URL, "pop3://pop.example.com/1");
        !            51: 
        !            52:     /* In this example, we'll start with a plain text connection, and upgrade
        !            53:      * to Transport Layer Security (TLS) using the STLS command. Be careful of
        !            54:      * using CURLUSESSL_TRY here, because if TLS upgrade fails, the transfer
        !            55:      * will continue anyway - see the security discussion in the libcurl
        !            56:      * tutorial for more details. */
        !            57:     curl_easy_setopt(curl, CURLOPT_USE_SSL, (long)CURLUSESSL_ALL);
        !            58: 
        !            59:     /* If your server doesn't have a valid certificate, then you can disable
        !            60:      * part of the Transport Layer Security protection by setting the
        !            61:      * CURLOPT_SSL_VERIFYPEER and CURLOPT_SSL_VERIFYHOST options to 0 (false).
        !            62:      *   curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0L);
        !            63:      *   curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 0L);
        !            64:      *
        !            65:      * That is, in general, a bad idea. It is still better than sending your
        !            66:      * authentication details in plain text though.  Instead, you should get
        !            67:      * the issuer certificate (or the host certificate if the certificate is
        !            68:      * self-signed) and add it to the set of certificates that are known to
        !            69:      * libcurl using CURLOPT_CAINFO and/or CURLOPT_CAPATH. See docs/SSLCERTS
        !            70:      * for more information. */
        !            71:     curl_easy_setopt(curl, CURLOPT_CAINFO, "/path/to/certificate.pem");
        !            72: 
        !            73:     /* Since the traffic will be encrypted, it is very useful to turn on debug
        !            74:      * information within libcurl to see what is happening during the
        !            75:      * transfer */
        !            76:     curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
        !            77: 
        !            78:     /* Perform the retr */
        !            79:     res = curl_easy_perform(curl);
        !            80: 
        !            81:     /* Check for errors */
        !            82:     if(res != CURLE_OK)
        !            83:       fprintf(stderr, "curl_easy_perform() failed: %s\n",
        !            84:               curl_easy_strerror(res));
        !            85: 
        !            86:     /* Always cleanup */
        !            87:     curl_easy_cleanup(curl);
        !            88:   }
        !            89: 
        !            90:   return (int)res;
        !            91: }