add redis

Author: qiaoliuhub

autotagOverflow/config/default.json

@@ -3,5 +3,9 @@
 "contactPoints" : "localhost",
 "keyspace": "autotag",
 "table": "posts"
+},
+"Redis":{
+"host" : "localhost",
+"port" : "6379"
 }
 }

autotagOverflow/index.js

@@ -1,3 +1,5 @@
+//Using nodejs to build a web server
+
 var express = require('express');
 var app = express();
 var bodyParser = require('body-parser');
@@ -8,6 +10,7 @@ var path = require('path');
 var cassandra = require('cassandra-driver');
 var config = require('config');
 var session = require('express-session');
+var redis = require('redis');
 
 //Set up static directiory
 app.use(express.static(path.join(__dirname, 'public')));
@@ -45,6 +48,11 @@ var keySpace = config.get('Cassandra.keyspace');
 var table = config.get('Cassandra.table');
 var cassandraClient = new cassandra.Client({contactPoints: [contactPointIP], keyspace: keySpace});
 
+//Set up redis client
+var redis_host = config.get('Redis.host');
+var redis_port = config.get('Redis.port');
+var redis_client = redis.createClient(redis_port, redis_host);
+
 //Set up route 
 app.get('/logout', function(req, res){
  req.session.user = null;
@@ -71,21 +79,31 @@ app.get('/home', function(req, res){
 
 app.get('/home/:post_id', function(req, res){
 
-//get data from cassandra based on id
+// get data from cassandra or redis based on id 
 var post_id = req.params.post_id;
-console.log('Retriving data for post_id %s', post_id);
 var tag;
-cassandraClient.execute("SELECT tag FROM "+table +" WHERE id = '" + post_id + "'", function(err, result){
-if (!err){
-if ( result.rows.length > 0 ) {
- var user = result.rows[0];
- var tag=user.tag;
- res.send({tag: tag});
- } else {
- console.log("No results");
- }
-}
-});
+ console.log('Retriving data for post_id %s', post_id);
+// cassandraClient.execute("SELECT tag FROM "+table +" WHERE id = '" + post_id + "'", function(err, result){
+//	if (!err){
+//	if ( result.rows.length > 0 ) {
+ // var user = result.rows[0];
+ // var tag=user.tag;
+ // res.send({tag: tag});
+ // } else {
+ // console.log("No results");
+ // }
+//	}
+// });
+ redis_client.hmget(post_id, 'tags', function(err, result){
+ if (!err){
+ if ( result.length > 0 ) {
+ var tag = result[0];
+ res.send({tag: tag});
+ } else {
+ console.log("No results");
+ }
+ }
+ });
 })
 
 app.post('/home', function(req, res){