Add simple logging of data to csv.

.gitignore

@@ -3,3 +3,4 @@ node_modules
 *.sublime-*
 public/css/style.css
 serial_incoming*.log
+data_log/*

modules/sensors/TM.js

@@ -21,6 +21,8 @@ var TMtempTime = "no reading yet";
 var TMbatt = "??";
 var TMbattTime = "no reading yet";
 
+var logger = require('../simple_log.js');
+
 exports.init = function(socket){
 };
 
@@ -35,10 +37,12 @@ exports.onDataOverSerial = function(sockets,message){
 		TMtemp = message.substring(4,9);
 		sockets.emit('received-TM-temp',
 			{ content: ("Temp: "+TMtemp+" ºC")});
+		logger.log('TM-temp',TMtemp);
 	}
 	if(message.substring(0,4) == "BATT") {
 		TMbatt = message.substring(4,9);
 		sockets.emit('received-TM-batt',
 			{ content: ("Batt: "+TMbatt+" V")});
+		logger.log('TM-batt',TMbatt);
 	}
 };

modules/simple_log.js

@@ -0,0 +1,26 @@
+/*
+ * - implement logging
+ * - well, I got tired of fighting with streams, so here goes a trivial data logger
+ * NOTES:
+ * - logging should be done to a transport, which then takes care to chunk to
+ *    files by itself
+ * - reading on streams:
+ *   - https://github.com/substack/stream-handbook
+ *   - http://codewinds.com/blog/2013-08-19-nodejs-writable-streams.html
+ */
+
+// this is relative to process.cwd();
+var logDir = './data_log/';
+
+var fs = require('fs');
+
+var strftime = require('strftime');
+
+exports.log = function(sensor, data){
+	fs.appendFile(logDir+sensor+strftime('-%Y-%m.csv'),
+		strftime('%Y,%m,%d,%H,%M,%S,')+data+'\n',
+		function (err) {
+			if (err)
+				console.log(strftime('%F %H:%M:%S: ')+sensor+': could not log to csv file: '+err);
+		});
+};

package.json

@@ -16,7 +16,8 @@
 		"stylus": "0.41.0",
 		"socket.io": "0.9.16",
 		"serialport": "1.2.5",
-		"winston": "0.7.2"
+		"winston": "0.7.2",
+		"strftime": "0.7.0"
 	},
 	"engines": {
 		"node": "0.10.22",