smtp-mail.c (4984B)
1 /*************************************************************************** 2 * _ _ ____ _ 3 * Project ___| | | | _ \| | 4 * / __| | | | |_) | | 5 * | (__| |_| | _ <| |___ 6 * \___|\___/|_| \_\_____| 7 * 8 * Copyright (C) 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.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 * SPDX-License-Identifier: curl 22 * 23 ***************************************************************************/ 24 25 /* <DESC> 26 * Send email with SMTP 27 * </DESC> 28 */ 29 30 #include <stdio.h> 31 #include <string.h> 32 #include <curl/curl.h> 33 34 /* 35 * For an SMTP example using the multi interface please see smtp-multi.c. 36 */ 37 38 /* The libcurl options want plain addresses, the viewable headers in the mail 39 * can get a full name as well. 40 */ 41 #define FROM_ADDR "<sender@example.org>" 42 #define TO_ADDR "<addressee@example.net>" 43 #define CC_ADDR "<info@example.org>" 44 45 #define FROM_MAIL "Sender Person " FROM_ADDR 46 #define TO_MAIL "A Receiver " TO_ADDR 47 #define CC_MAIL "John CC Smith " CC_ADDR 48 49 static const char *payload_text = 50 "Date: Mon, 29 Nov 2010 21:54:29 +1100\r\n" 51 "To: " TO_MAIL "\r\n" 52 "From: " FROM_MAIL "\r\n" 53 "Cc: " CC_MAIL "\r\n" 54 "Message-ID: <dcd7cb36-11db-487a-9f3a-e652a9458efd@" 55 "rfcpedant.example.org>\r\n" 56 "Subject: SMTP example message\r\n" 57 "\r\n" /* empty line to divide headers from body, see RFC 5322 */ 58 "The body of the message starts here.\r\n" 59 "\r\n" 60 "It could be a lot of lines, could be MIME encoded, whatever.\r\n" 61 "Check RFC 5322.\r\n"; 62 63 struct upload_status { 64 size_t bytes_read; 65 }; 66 67 static size_t payload_source(char *ptr, size_t size, size_t nmemb, void *userp) 68 { 69 struct upload_status *upload_ctx = (struct upload_status *)userp; 70 const char *data; 71 size_t room = size * nmemb; 72 73 if((size == 0) || (nmemb == 0) || ((size*nmemb) < 1)) { 74 return 0; 75 } 76 77 data = &payload_text[upload_ctx->bytes_read]; 78 79 if(data) { 80 size_t len = strlen(data); 81 if(room < len) 82 len = room; 83 memcpy(ptr, data, len); 84 upload_ctx->bytes_read += len; 85 86 return len; 87 } 88 89 return 0; 90 } 91 92 int main(void) 93 { 94 CURL *curl; 95 CURLcode res = CURLE_OK; 96 struct curl_slist *recipients = NULL; 97 struct upload_status upload_ctx = { 0 }; 98 99 curl = curl_easy_init(); 100 if(curl) { 101 /* This is the URL for your mailserver */ 102 curl_easy_setopt(curl, CURLOPT_URL, "smtp://mail.example.com"); 103 104 /* Note that this option is not strictly required, omitting it results in 105 * libcurl sending the MAIL FROM command with empty sender data. All 106 * autoresponses should have an empty reverse-path, and should be directed 107 * to the address in the reverse-path which triggered them. Otherwise, 108 * they could cause an endless loop. See RFC 5321 Section 4.5.5 for more 109 * details. 110 */ 111 curl_easy_setopt(curl, CURLOPT_MAIL_FROM, FROM_ADDR); 112 113 /* Add two recipients, in this particular case they correspond to the 114 * To: and Cc: addressees in the header, but they could be any kind of 115 * recipient. */ 116 recipients = curl_slist_append(recipients, TO_ADDR); 117 recipients = curl_slist_append(recipients, CC_ADDR); 118 curl_easy_setopt(curl, CURLOPT_MAIL_RCPT, recipients); 119 120 /* We are using a callback function to specify the payload (the headers and 121 * body of the message). You could just use the CURLOPT_READDATA option to 122 * specify a FILE pointer to read from. */ 123 curl_easy_setopt(curl, CURLOPT_READFUNCTION, payload_source); 124 curl_easy_setopt(curl, CURLOPT_READDATA, &upload_ctx); 125 curl_easy_setopt(curl, CURLOPT_UPLOAD, 1L); 126 127 /* Send the message */ 128 res = curl_easy_perform(curl); 129 130 /* Check for errors */ 131 if(res != CURLE_OK) 132 fprintf(stderr, "curl_easy_perform() failed: %s\n", 133 curl_easy_strerror(res)); 134 135 /* Free the list of recipients */ 136 curl_slist_free_all(recipients); 137 138 /* curl does not send the QUIT command until you call cleanup, so you 139 * should be able to reuse this connection for additional messages 140 * (setting CURLOPT_MAIL_FROM and CURLOPT_MAIL_RCPT as required, and 141 * calling curl_easy_perform() again. It may not be a good idea to keep 142 * the connection open for a long time though (more than a few minutes may 143 * result in the server timing out the connection), and you do want to 144 * clean up in the end. 145 */ 146 curl_easy_cleanup(curl); 147 } 148 149 return (int)res; 150 }