From 57523e3578b17c07b0fbf7b22063544ade3df799 Mon Sep 17 00:00:00 2001
From: Brad Hards <bradh@frogmouth.net>
Date: Fri, 17 Dec 2010 22:55:58 +0100
Subject: [PATCH] smtp-tls: new example
This example shows how to send SMTP with TLS
---
docs/examples/Makefile.inc | 2 +-
docs/examples/smtp-tls.c | 135 +++++++++++++++++++++++++++++++++++++
2 files changed, 136 insertions(+), 1 deletion(-)
create mode 100644 docs/examples/smtp-tls.c
diff --git a/docs/examples/Makefile.inc b/docs/examples/Makefile.inc
index a9379f745e..9a2b48ea15 100644
--- a/docs/examples/Makefile.inc
+++ b/docs/examples/Makefile.inc
@@ -4,7 +4,7 @@ check_PROGRAMS = 10-at-a-time anyauthput cookie_interface debug fileupload \
https multi-app multi-debugcallback multi-double multi-post multi-single \
persistant post-callback postit2 sepheaders simple simplepost simplessl \
sendrecv httpcustomheader certinfo chkspeed ftpgetinfo ftp-wildcard \
- smtp-multi simplesmtp
+ smtp-multi simplesmtp smtp-tls
# These examples require external dependencies that may not be commonly
# available on POSIX systems, so don't bother attempting to compile them here.
diff --git a/docs/examples/smtp-tls.c b/docs/examples/smtp-tls.c
new file mode 100644
index 0000000000..58719ade2a
--- /dev/null
+++ b/docs/examples/smtp-tls.c
@@ -0,0 +1,135 @@
+/*****************************************************************************
+ * _ _ ____ _
+ * Project ___| | | | _ \| |
+ * / __| | | | |_) | |
+ * | (__| |_| | _ <| |___
+ * \___|\___/|_| \_\_____|
+ *
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <curl/curl.h>
+
+/* This is a simple example showing how to send mail using libcurl's SMTP
+ * capabilities. It builds on the simplesmtp.c example, adding some
+ * authentication and transport security.
+ */
+
+#define FROM "sender@example.org"
+#define TO "addressee@example.net"
+#define CC "info@example.org"
+
+static const char *payload_text[]={
+ "Date: Mon, 29 Nov 2010 21:54:29 +1100\n",
+ "To: " TO "\n",
+ "From: " FROM "(Example User)\n",
+ "Cc: " CC "(Another example User)\n"
+ "Subject: SMTP TLS example message\n",
+ "\n", /* empty line to divide headers from body, see RFC5322 */
+ "The body of the message starts here.\n",
+ "\n",
+ "It could be a lot of lines, could be MIME encoded, whatever.\n",
+ "Check RFC5322.\n",
+ NULL
+};
+
+struct upload_status {
+ int lines_read;
+};
+
+static size_t payload_source(void *ptr, size_t size, size_t nmemb, void *userp)
+{
+ struct upload_status *upload_ctx = (struct upload_status *)userp;
+ const char *data;
+
+ if ((size == 0) || (nmemb == 0) || ((size*nmemb) < 1)) {
+ return 0;
+ }
+
+ data = payload_text[upload_ctx->lines_read];
+
+ if (data) {
+ size_t len = strlen(data);
+ memcpy(ptr, data, len);
+ upload_ctx->lines_read ++;
+ return len;
+ }
+ return 0;
+}
+
+
+int main(void)
+{
+ CURL *curl;
+ CURLcode res;
+ struct curl_slist *recipients = NULL;
+ struct upload_status upload_ctx;
+
+ upload_ctx.lines_read = 0;
+
+ curl = curl_easy_init();
+ if (curl) {
+ /* This is the URL for your mailserver. Note the use of port 587 here,
+ * instead of the normal SMTP port (25). Port 587 is commonly used for
+ * secure mail submission (see RFC4403), but you should use whatever
+ * matches your server configuration. */
+ curl_easy_setopt(curl, CURLOPT_URL, "smtp://mainserver.example.net:587");
+
+ /* In this example, we'll start with a plain text connection, and upgrade
+ * to Transport Layer Security (TLS) using the STARTTLS 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, CURLUSESSL_ALL);
+
+ /* If your server doesn't 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, 0);
+ * curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 0);
+ * 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");
+
+ /* A common reason for requiring transport security is to protect
+ * authentication details (user names and passwords) from being "snooped"
+ * on the network. Here is how the user name and password are provided: */
+ curl_easy_setopt(curl, CURLOPT_USERNAME, "user@example.net");
+ curl_easy_setopt(curl, CURLOPT_PASSWORD, "P@ssw0rd");
+
+ /* value for envelope reverse-path */
+ curl_easy_setopt(curl, CURLOPT_MAIL_FROM, FROM);
+ /* Add two recipients, in this particular case they correspond to the
+ * To: and Cc: addressees in the header, but they could be any kind of
+ * recipient. */
+ recipients = curl_slist_append(recipients, TO);
+ recipients = curl_slist_append(recipients, CC);
+ curl_easy_setopt(curl, CURLOPT_MAIL_RCPT, recipients);
+
+ /* In this case, we're using a callback function to specify the data. You
+ * could just use the CURLOPT_READDATA option to specify a FILE pointer to
+ * read from.
+ */
+ curl_easy_setopt(curl, CURLOPT_READFUNCTION, payload_source);
+ curl_easy_setopt(curl, CURLOPT_READDATA, &upload_ctx);
+
+ /* Since the traffic will be encrypted, it is very useful to turn on debug
+ * information within libcurl to see what is happening during the transfer.
+ */
+ curl_easy_setopt(curl, CURLOPT_VERBOSE, 1);
+
+ /* send the message (including headers) */
+ res = curl_easy_perform(curl);
+
+ /* free the list of recipients and clean up */
+ curl_slist_free_all(recipients);
+ curl_easy_cleanup(curl);
+ }
+ return 0;
+}
--
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