From ce5289f43bedd953d1ccede7be18fd5bf39a2648 Mon Sep 17 00:00:00 2001
From: Art Cancro <ajc@citadel.org>
Date: Sat, 28 Oct 2006 16:05:12 +0000
Subject: [PATCH] New server command DLAT (DownLoad ATtachment) which is
 similar to OPNA (OPeN Attachment), except it outputs the entire MIME part in
 a single server operation instead of opening a download file for block
 transfer.  This will be useful for grabbing small components such as calendar
 appointments and address book entries with substantialy less overhead.

---
 citadel/citserver.c          |  4 +++
 citadel/msgbase.c            | 64 ++++++++++++++++++++++++++++++++++++
 citadel/msgbase.h            |  1 +
 citadel/server.h             |  3 +-
 citadel/techdoc/protocol.txt |  8 +++++
 5 files changed, 79 insertions(+), 1 deletion(-)

diff --git a/citadel/citserver.c b/citadel/citserver.c
index e86b1e1bf..95eab2fc6 100644
--- a/citadel/citserver.c
+++ b/citadel/citserver.c
@@ -1077,6 +1077,10 @@ void do_command_loop(void) {
 		cmd_opna(&cmdbuf[5]);
 	}
 
+	else if (!strncasecmp(cmdbuf,"DLAT",4)) {
+		cmd_dlat(&cmdbuf[5]);
+	}
+
 	else if (!strncasecmp(cmdbuf,"INFO",4)) {
 		cmd_info();
 	}
diff --git a/citadel/msgbase.c b/citadel/msgbase.c
index 1a1f984f1..2a6b775c8 100644
--- a/citadel/msgbase.c
+++ b/citadel/msgbase.c
@@ -969,6 +969,27 @@ void mime_download(char *name, char *filename, char *partnum, char *disp,
 
 
 
+/*
+ * Callback function for mime parser that outputs a section all at once
+ */
+void mime_spew_section(char *name, char *filename, char *partnum, char *disp,
+		   void *content, char *cbtype, char *cbcharset, size_t length,
+		   char *encoding, void *cbuserdata)
+{
+	int *found_it = (int *)cbuserdata;
+
+	/* ...or if this is not the desired section */
+	if (strcasecmp(CC->download_desired_section, partnum))
+		return;
+
+	*found_it = 1;
+
+	cprintf("%d %d\n", BINARY_FOLLOWS, length);
+	client_write(content, length);
+}
+
+
+
 /*
  * Load a message from disk into memory.
  * This is used by CtdlOutputMsg() and other fetch functions.
@@ -1492,6 +1513,32 @@ int CtdlOutputPreLoadedMsg(
 		return((CC->download_fp != NULL) ? om_ok : om_mime_error);
 	}
 
+	/* MT_SPEW_SECTION is like MT_DOWNLOAD except it outputs the whole MIME part
+	 * in a single server operation instead of opening a download file.
+	 */
+	if (mode == MT_SPEW_SECTION) {
+		if (TheMessage->cm_format_type != FMT_RFC822) {
+			if (do_proto)
+				cprintf("%d This is not a MIME message.\n",
+				ERROR + ILLEGAL_VALUE);
+		} else {
+			/* Parse the message text component */
+			int found_it = 0;
+
+			mptr = TheMessage->cm_fields['M'];
+			mime_parser(mptr, NULL, *mime_spew_section, NULL, NULL, (void *)&found_it, 0);
+			/* If section wasn't found, print an error
+			 */
+			if (!found_it) {
+				if (do_proto) cprintf(
+					"%d Section %s not found.\n",
+					ERROR + FILE_NOT_FOUND,
+					CC->download_desired_section);
+			}
+		}
+		return((CC->download_fp != NULL) ? om_ok : om_mime_error);
+	}
+
 	/* now for the user-mode message reading loops */
 	if (do_proto) cprintf("%d msg:\n", LISTING_FOLLOWS);
 
@@ -1911,6 +1958,23 @@ void cmd_opna(char *cmdbuf)
 	CtdlOutputMsg(msgid, MT_DOWNLOAD, 0, 1, 1, NULL);
 }			
 
+
+/*
+ * Open a component of a MIME message and transmit it all at once
+ */
+void cmd_dlat(char *cmdbuf)
+{
+	long msgid;
+	char desired_section[128];
+
+	msgid = extract_long(cmdbuf, 0);
+	extract_token(desired_section, cmdbuf, 1, '|', sizeof desired_section);
+	safestrncpy(CC->download_desired_section, desired_section,
+		sizeof CC->download_desired_section);
+	CtdlOutputMsg(msgid, MT_SPEW_SECTION, 0, 1, 1, NULL);
+}			
+
+
 /*
  * Save one or more message pointers into a specified room
  * (Returns 0 for success, nonzero for failure)
diff --git a/citadel/msgbase.h b/citadel/msgbase.h
index 4295d7be3..d06c6398a 100644
--- a/citadel/msgbase.h
+++ b/citadel/msgbase.h
@@ -91,6 +91,7 @@ void cmd_msg3 (char *cmdbuf);
 void cmd_msg4 (char *cmdbuf);
 void cmd_msgp (char *cmdbuf);
 void cmd_opna (char *cmdbuf);
+void cmd_dlat (char *cmdbuf);
 long send_message (struct CtdlMessage *);
 void loadtroom (void);
 long CtdlSubmitMsg(struct CtdlMessage *, struct recptypes *, char *);
diff --git a/citadel/server.h b/citadel/server.h
index 8061e3df0..e76fe1ac8 100644
--- a/citadel/server.h
+++ b/citadel/server.h
@@ -242,7 +242,8 @@ enum {
 	MT_CITADEL,		/* Citadel proprietary */
 	MT_RFC822,		/* RFC822 */
 	MT_MIME,		/* MIME-formatted message */
-	MT_DOWNLOAD		/* Download a component */
+	MT_DOWNLOAD,		/* Download a component */
+	MT_SPEW_SECTION		/* Download a component in a single operation */
 };
 
 /*
diff --git a/citadel/techdoc/protocol.txt b/citadel/techdoc/protocol.txt
index 0586e0bd2..8bba36148 100644
--- a/citadel/techdoc/protocol.txt
+++ b/citadel/techdoc/protocol.txt
@@ -1950,6 +1950,14 @@ appropriate ERROR code will be returned; otherwise, if the open is successful,
 this command will succeed returning the same information as an OPEN command.
 
 
+ DLAT   (DownLoad ATtachment)
+
+ Similar to OPNA, and with the same calling syntax.  The difference is that
+instead of opening a download file for block transfer, this command outputs the
+entire decoded MIME section at once, using a BINARY_FOLLOWS response.  This is
+useful for outputting small objects such as calendar items.
+ 
+ 
  GEXP   (Get instant messages)
 
  This is a more sophisticated way of retrieving instant messages than the old
-- 
2.30.2