From b4498b496e582ffbee4ca7cdc42edc395388d00e Mon Sep 17 00:00:00 2001
From: Jan-Piet Mens <jpmens@gmail.com>
Date: Thu, 24 Sep 2015 13:18:16 +0200
Subject: [PATCH] implement topic2tid 	closes #38

---
 README.md     |  4 ++++
 ot-recorder.c | 28 ++++++++++++++++++++++++++++
 udata.h       |  1 +
 3 files changed, 33 insertions(+)

diff --git a/README.md b/README.md
index 1e03c04..db7b32b 100644
--- a/README.md
+++ b/README.md
@@ -540,3 +540,7 @@ server {
 ### The LMDB database
 
 `ocat --load` and `ocat --dump` can be use to load and dump the lmdb database respectively. There is some support for loading/dumping named databases using `--load=xx` or `--dump=xx` to specify the name. Use the mdb utilities to actually perform backups of these.
+
+#### `topic2tid`
+
+This named lmdb database is keyed on topic name (`owntracks/jane/phone`). If the topic of an incoming message is found in the database, the `tid` member in the JSON payload is replaced by the value of this key.
diff --git a/ot-recorder.c b/ot-recorder.c
index 1b0eabe..1dee602 100644
--- a/ot-recorder.c
+++ b/ot-recorder.c
@@ -451,6 +451,24 @@ void on_message(struct mosquitto *mosq, void *userdata, const struct mosquitto_m
 		}
 	}
 
+#ifdef HAVE_LMDB
+	/*
+	 * If the topic we are handling is in topic2tid, replace the TID
+	 * in this payload with that from the database.
+	 */
+
+	if (ud->t2t) {
+		char newtid[BUFSIZ];
+		long blen;
+
+		if ((blen = gcache_get(ud->t2t, m->topic, newtid, sizeof(newtid))) > 0) {
+			if ((j = json_find_member(json, "tid")) != NULL)
+				json_remove_from_parent(j);
+			json_append_member(json, "tid", json_mkstring(newtid));
+		}
+	}
+#endif
+
 	/*
 	 * Chances are high that what we have now contains lat, lon. Attempt to
 	 * perform or retrieve reverse-geo.
@@ -735,6 +753,7 @@ int main(int argc, char **argv)
 	udata.verbose		= TRUE;
 #ifdef HAVE_LMDB
 	udata.gc		= NULL;
+	udata.t2t		= NULL;		/* Topic to TID */
 #endif
 #ifdef HAVE_HTTP
 	udata.mgserver		= NULL;
@@ -953,6 +972,10 @@ int main(int argc, char **argv)
 		revgeo_init();
 	}
 
+#ifdef HAVE_LMDB
+	snprintf(err, sizeof(err), "%s/ghash", STORAGEDIR);
+	ud->t2t = gcache_open(err, "topic2tid", TRUE);
+#endif
 
 	mosquitto_lib_init();
 
@@ -1074,6 +1097,11 @@ int main(int argc, char **argv)
 
 	json_delete(ud->topics);
 
+#ifdef HAVE_LMDB
+	if (ud->t2t)
+		gcache_close(ud->t2t);
+#endif
+
 #ifdef HAVE_HTTP
 	mg_destroy_server(&udata.mgserver);
 #endif
diff --git a/udata.h b/udata.h
index cd1ce5f..a4b21ea 100644
--- a/udata.h
+++ b/udata.h
@@ -21,6 +21,7 @@ struct udata {
 	int verbose;			/* TRUE if print verbose messages to stdout */
 #ifdef HAVE_LMDB
 	struct gcache *gc;
+	struct gcache *t2t;		/* topic to tid */
 #endif
 #ifdef HAVE_HTTP
 	struct mg_server *mgserver;	/* Mongoose */