ocat/storage: FEATURE: produce GPX output

closes #9

ocat.c

@@ -108,6 +108,7 @@ void usage(char *prog)
 	printf("  --format json    	-f     output format (default: JSON)\n");
 	printf("           csv                 (overrides $OCAT_FORMAT\n");
 	printf("           geojson\n");
+	printf("           gpx\n");
 	printf("           raw\n");
 	printf("  --fields tst,lat,lon,...     Choose fields for CSV. (dflt: ALL)\n");
 	printf("  --last		-L     JSON object with last users\n");
@@ -205,6 +206,8 @@ int main(int argc, char **argv)
 					otype = GEOJSON;
 				else if (!strcmp(optarg, "raw"))
 					otype = RAW;
+				else if (!strcmp(optarg, "gpx"))
+					otype = GPX;
 				else if (!strcmp(optarg, "csv"))
 					otype = CSV;
 				else {
@@ -388,6 +391,11 @@ int main(int argc, char **argv)
 			}
 			json_delete(geojson);
 		}
+	} else if (otype == GPX) {
+		char *xml = gpx_string(locs);
+
+		if (xml)
+			printf("%s\n", xml);
 	}
 
 	json_delete(obj);

storage.c

@@ -673,6 +673,46 @@ JsonNode *geo_json(JsonNode *location_array)
 	return (fcollection);
 }
 
+/*
+ * Turn our JSON location array into a GPX XML string.
+ */
+
+char *gpx_string(JsonNode *location_array)
+{
+	JsonNode *one;
+        static UT_string *xml = NULL;
+
+	if (location_array->tag != JSON_ARRAY)
+		return (NULL);
+
+	utstring_renew(xml);
+
+	utstring_printf(xml, "%s", "<?xml version='1.0' encoding='UTF-8' standalone='no' ?>\n\
+<gpx version='1.1' creator='OwnTracks-Recorder'>\n\
+  <trk>\n\
+    <trkseg>\n");
+
+      // <trkpt lat="xx.xxx" lon="yy.yyy"> <!-- Attribute des Trackpunkts --> </trkpt>
+
+	json_foreach(one, location_array) {
+		double lat = 0.0, lon = 0.0;
+		JsonNode *j;
+
+                if ((j = json_find_member(one, "lat")) != NULL) {
+                        lat = j->number_;
+                }
+
+                if ((j = json_find_member(one, "lon")) != NULL) {
+                        lon = j->number_;
+                }
+
+		utstring_printf(xml, "<trkpt lat='%lf' lon='%lf' />\n", lat, lon);
+	}
+
+	utstring_printf(xml, "%s", " </trkseg>\n</trk>\n</gpx>\n");
+	return (utstring_body(xml));
+}
+
 /*
  * Remove all data for a user's device. Return a JSON object with a status
  * and an array of deleted files.

storage.h

@@ -9,6 +9,7 @@ typedef enum {
 	CSV,
 	JSON,
 	RAW,
+	GPX,
 } output_type;
 
 JsonNode *lister(char *username, char *device, time_t s_lo, time_t s_hi, int reverse);
@@ -17,5 +18,6 @@ int make_times(char *time_from, time_t *s_lo, char *time_to, time_t *s_to);
 JsonNode *geo_json(JsonNode *json);
 JsonNode *kill_datastore(char *username, char *device);
 JsonNode *last_users();
+char *gpx_string(JsonNode *json);
 
 #endif