Hi,
I am currently evaluating using libcurl in the openchange project
(http://www.openchange.org, an implementation of the Microsoft Exchange RPC
protocols) for both HTTP and SMTP transfers. HTTP looked OK.
However I wasn't able to find an SMTP example, which is a bit unfortunate.
I've developed a (very) simple example of using libcurl to send SMTP - see
attached patch.
I'd appreciate any review comments on this, to improve both the example and my
understanding of libcurl. To assist, I've inlined the source code as well.
Brad
#include <stdio.h>
#include <string.h>
#include <curl/curl.h>
int main(void)
{
CURL *curl;
CURLcode res;
struct curl_slist *recipients = NULL;
/* this becomes the Return-Path header value */
static const char *from = "[email protected]";
/* this becomes the Envelope-to header value */
static const char *to = "[email protected]";
curl = curl_easy_init();
if(curl) {
/* this is the URL for your mailserver - you can also use an smtps:// URL
here */
curl_easy_setopt(curl, CURLOPT_URL, "smtp://mail.example.net.");
/* Note that this option isn't strictly required, omitting it will result
in libcurl
* will sent the MAIL FROM command with no sender data. That may result in
the
* receiving SMTP system rewriting the header, which will look a bit
strange. */
curl_easy_setopt(curl, CURLOPT_MAIL_FROM, from);
/* Note that the CURLOPT_MAIL_RCPT takes a list, not a char array */
recipients = curl_slist_append(recipients, to);
/* You really do have to set this option though - libcurl won't work
without it */
curl_easy_setopt(curl, CURLOPT_MAIL_RCPT, recipients);
/* You provide the remaining headers (including To:, Cc:, Bcc: and From:)
and
* the body of the message as the "data" element. There are two choices -
either
* provide a callback function and specify the function name using the
* CURLOPT_READFUNCTION option; or just provide a FILE pointer that can be
used
* to read the data from. The easiest case is just to read from standard
input,
* (which is available as a FILE pointer) as shown here.
*/
curl_easy_setopt(curl, CURLOPT_READDATA, stdin);
/* send the message (including headers) */
res = curl_easy_perform(curl);
/* free the list of recipients */
curl_slist_free_all(recipients);
/* curl won't send the QUIT command until you call cleanup, so you should
be able
* to re-use this connection for additional messages (setting
CURLOPT_MAIL_FROM and
* CURLOPT_MAIL_RCPT as required, and calling curl_easy_perform() again. It
may not
* be a good idea to keep the connection open for a very long time though,
and
* you do want to clean up in the end.
*/
curl_easy_cleanup(curl);
}
return 0;
}
diff --git a/docs/examples/simplesmtp.c b/docs/examples/simplesmtp.c
new file mode 100644
index 0000000..9bcf770
--- /dev/null
+++ b/docs/examples/simplesmtp.c
@@ -0,0 +1,64 @@
+/*****************************************************************************
+ * _ _ ____ _
+ * Project ___| | | | _ \| |
+ * / __| | | | |_) | |
+ * | (__| |_| | _ <| |___
+ * \___|\___/|_| \_\_____|
+ *
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <curl/curl.h>
+
+int main(void)
+{
+ CURL *curl;
+ CURLcode res;
+ struct curl_slist *recipients = NULL;
+
+ /* this becomes the Return-Path header value */
+ static const char *from = "[email protected]";
+
+ /* this becomes the Envelope-to header value */
+ static const char *to = "[email protected]";
+
+ curl = curl_easy_init();
+ if(curl) {
+ /* this is the URL for your mailserver - you can also use an smtps:// URL here */
+ curl_easy_setopt(curl, CURLOPT_URL, "smtp://mail.example.net.");
+
+ /* Note that this often isn't required, libcurl will sent the MAIL FROM command
+ * with no sender data. That may result in the receive SMTP system rewriting the
+ * header, which will look a bit strange. */
+ curl_easy_setopt(curl, CURLOPT_MAIL_FROM, from);
+
+ /* Note that the CURLOPT_MAIL_RCPT takes a list, not a char array */
+ recipients = curl_slist_append(recipients, to);
+ /* You really do have to set this one though - libcurl won't work without it */
+ curl_easy_setopt(curl, CURLOPT_MAIL_RCPT, recipients);
+
+ /* You provide the remaining headers (including To:, Cc:, Bcc: and From:) and
+ * the body of the message as the "data" element. There are two choices - either
+ * provide a callback function and specify the function name using the
+ * CURLOPT_READFUNCTION option; or just provide a FILE pointer that can be used
+ * to read the data from. The easiest case is just to read from standard input,
+ * as shown here.
+ */
+ curl_easy_setopt(curl, CURLOPT_READDATA, stdin);
+
+ /* send the message (including headers) */
+ res = curl_easy_perform(curl);
+
+ /* always cleanup */
+ curl_slist_free_all(recipients);
+
+ /* curl won't send the QUIT command until you call cleanup, so you should be able
+ * to re-use this connection for additional messages (setting CURLOPT_MAIL_FROM and
+ * CURLOPT_MAIL_RCPT as required, and calling curl_easy_perform() again. It may not
+ * be a good idea to keep the connection open for a very long time though.
+ */
+ curl_easy_cleanup(curl);
+ }
+ return 0;
+}
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