Api calls caching via redis - Closes #484

.gitignore

@@ -15,3 +15,5 @@ stacktrace*
 test/.coverage-unit
 tmp
 sftp-config.json
+*.swp
+*.swo

.travis.yml

@@ -8,6 +8,7 @@ cache:
     - node_modules
 services:
   - postgresql
+  - redis-server
 addons:
   postgresql: '9.6'
 install:
@@ -19,6 +20,7 @@ before_script:
   - tar -zxvf lisk-node-Linux-x86_64.tar.gz
   - cd test/lisk-js/; npm install; cd ../..
   - cp test/config.json test/genesisBlock.json .
+  - redis-server --port 6380 &
   - node app.js &> .app.log &
 notifications:
   webhooks: https://coveralls.io/webhook?repo_token=l6rLvPBYHIwA92FQQmCUUTLI4zPuS4r5C

api/http/blocks.js

@@ -27,10 +27,15 @@ var httpApi = require('../../helpers/httpApi');
  * @param {scope} app - Network app.
  */
 // Constructor
-function BlocksHttpApi (blocksModule, app) {
+function BlocksHttpApi (blocksModule, app, logger, cache) {
 
 	var router = new Router();
 
+	// attach a middlware to endpoints
+	router.attachMiddlwareForUrls(httpApi.middleware.useCache.bind(null, logger, cache), [
+		'get /'
+	]);
+
 	router.map(blocksModule.shared, {
 		'get /get': 'getBlock',
 		'get /': 'getBlocks',

api/http/delegates.js

@@ -31,10 +31,13 @@ var httpApi = require('../../helpers/httpApi');
  * @param {scope} app - Network app.
  */
 // Constructor
-function DelegatesHttpApi (delegatesModule, app) {
+function DelegatesHttpApi (delegatesModule, app, logger, cache) {
 
 	var router = new Router();
 
+	// attach a middlware to endpoints
+	router.attachMiddlwareForUrls(httpApi.middleware.useCache.bind(null, logger, cache), ['get /']);
+
 	router.map(delegatesModule.shared, {
 		'get /count': 'count',
 		'get /search': 'search',

api/http/transactions.js

@@ -25,10 +25,15 @@ var httpApi = require('../../helpers/httpApi');
  * @param {scope} app - Network app.
  */
 // Constructor
-function TransactionsHttpApi (transactionsModule, app) {
+function TransactionsHttpApi (transactionsModule, app, logger, cache) {
 
 	var router = new Router();
 
+	// attach a middlware to endpoints
+	router.attachMiddlwareForUrls(httpApi.middleware.useCache.bind(null, logger, cache), [
+		'get /'
+	]);
+
 	router.map(transactionsModule.shared, {
 		'get /': 'getTransactions',
 		'get /get': 'getTransaction',

api/http/transport.js

@@ -29,7 +29,7 @@ var schema = require('../../schema/transport');
  * @param {function} logger
  */
 // Constructor
-function TransportHttpApi (transportModule, app, logger) {
+function TransportHttpApi (transportModule, app, logger, cache) {
 
 	var router = new Router();
 

app.js

@@ -120,6 +120,8 @@ process.env.TOP = appConfig.topAccounts;
  */
 var config = {
 	db: appConfig.db,
+	cache: appConfig.redis,
+	cacheEnabled: appConfig.cacheEnabled,
 	modules: {
 		server: './modules/server.js',
 		accounts: './modules/accounts.js',
@@ -135,7 +137,8 @@ var config = {
 		multisignatures: './modules/multisignatures.js',
 		dapps: './modules/dapps.js',
 		crypto: './modules/crypto.js',
-		sql: './modules/sql.js'
+		sql: './modules/sql.js',
+		cache: './modules/cache.js'
 	},
 	api: {
 		accounts: { http: './api/http/accounts.js' },
@@ -431,12 +434,18 @@ d.run(function () {
 			};
 			cb(null, new bus());
 		}],
-
 		db: function (cb) {
 			var db = require('./helpers/database.js');
 			db.connect(config.db, logger, cb);
 		},
-
+		/**
+		 * It tries to connect with redis server based on config. provided in config.json file
+		 * @param {function} cb
+		 */
+		cache: function (cb) {
+			var cache = require('./helpers/cache.js');
+			cache.connect(config.cacheEnabled, config.cache, logger, cb);
+		},
 		/**
 		 * Once db, bus, schema and genesisblock are completed,
 		 * loads transaction, block, account and peers from logic folder.
@@ -486,7 +495,6 @@ d.run(function () {
 				}
 			}, cb);
 		}],
-
 		/**
 		 * Once network, connect, config, logger, bus, sequence,
 		 * dbSequence, balancesSequence, db and logic are completed,
@@ -496,7 +504,8 @@ d.run(function () {
 		 * at leats will contain the required elements.
 		 * @param {nodeStyleCallback} cb - Callback function with resulted load.
 		 */
-		modules: ['network', 'connect', 'config', 'logger', 'bus', 'sequence', 'dbSequence', 'balancesSequence', 'db', 'logic', function (scope, cb) {
+		modules: ['network', 'connect', 'config', 'logger', 'bus', 'sequence', 'dbSequence', 'balancesSequence', 'db', 'logic', 'cache', function (scope, cb) {
+
 			var tasks = {};
 
 			Object.keys(config.modules).forEach(function (name) {
@@ -535,7 +544,7 @@ d.run(function () {
 					var apiEndpointPath = config.api[moduleName][protocol];
 					try {
 						var ApiEndpoint = require(apiEndpointPath);
-						new ApiEndpoint(scope.modules[moduleName], scope.network.app, scope.logger);
+						new ApiEndpoint(scope.modules[moduleName], scope.network.app, scope.logger, scope.modules.cache);
 					} catch (e) {
 						scope.logger.error('Unable to load API endpoint for ' + moduleName + ' of ' + protocol, e);
 					}

config.json

@@ -8,6 +8,7 @@
     "consoleLogLevel": "info",
     "trustProxy": false,
     "topAccounts": false,
+    "cacheEnabled": false,
     "db": {
         "host": "localhost",
         "port": 5432,
@@ -21,6 +22,13 @@
             "error"
         ]
     },
+		"redis": {
+			"host": "127.0.0.1",
+			"port": 6380,
+			"db": 0,
+			"user": "",
+			"password": ""
+		},
     "api": {
         "enabled": true,
         "access": {

helpers/cache.js

@@ -0,0 +1,38 @@
+'use strict';
+
+var redis = require('redis');
+
+/**
+ * Connects with redis server using the config provided via parameters
+ * @param {Boolean} cacheEnabled
+ * @param {Object} config - Redis configuration
+ * @param {Object} logger
+ * @param {Function} cb
+ */
+module.exports.connect = function (cacheEnabled, config, logger, cb) {
+	var isRedisLoaded = false;
+
+	if (!cacheEnabled) {
+		return cb(null, { cacheEnabled: cacheEnabled, client: null });
+	}
+
+	var client = redis.createClient(config);
+
+	client.on('connect', function () {
+		logger.info('App connected with redis server');
+
+		if (!isRedisLoaded) {
+			isRedisLoaded = true;
+			return cb(null, { cacheEnabled: cacheEnabled, client: client });
+		}
+	});
+
+	client.on('error', function (err) {
+		logger.error('Redis:', err);
+		// Only throw an error if cache was enabled in config but were unable to load it properly
+		if (!isRedisLoaded) {
+			isRedisLoaded = true;
+			return cb('Unable to connect to redis server', { cacheEnabled: cacheEnabled, client: null });
+		}
+	});
+};

helpers/httpApi.js

@@ -140,6 +140,39 @@ var middleware = {
 	attachResponseHeaders: function (getHeaders, req, res, next) {
 		res.set(getHeaders());
 		return next();
+	},
+
+	/**
+	 * Lookup cache, and reply with cached response if it's a hit.
+	 * If it's a miss, forward the request but cache the response if it's a success.
+	 * @param {Object} req
+	 * @param {Object} res
+	 * @param {Function} next
+	 */
+	useCache: function (logger, cache, req, res, next) {
+		if (!cache.isReady()) {
+			return next();
+		}
+
+		var key = req.originalUrl;
+		cache.getJsonForKey(key, function (err, cachedValue) {
+			//there was an error or value doesn't exist for key
+			if (err || !cachedValue) {
+				// Monkey patching res.json function only if we expect to cache response
+				var expressSendJson = res.json;
+				res.json = function (response) {
+					if (response.success) {
+						logger.debug('cached response for key: ', req.url);
+						cache.setJsonForKey(key, response);
+					}
+					expressSendJson.call(res, response);
+				};
+				next();
+			} else {
+				logger.debug(['serving response for url:', req.url, 'from cache'].join(' '));
+				res.json(cachedValue);
+			}
+		});
 	}
 };
 

helpers/router.js

@@ -10,7 +10,6 @@ var extend = require('extend');
  * @returns {Object} router express
  * @throws {Error} If config is invalid
  */
-
 var Router = function () {
 	var router = require('express').Router();
 
@@ -34,8 +33,24 @@ var Router = function () {
 			});
 		});
 	};
+	/**
+	 * Adds one middleware to an array of routes.
+	 * @param {Function} middleware
+	 * @param {String} routes
+	 */
+	router.attachMiddlwareForUrls = function (middleware, routes) {
+		routes.forEach(function (entry) {
+			var route = entry.split(' ');
+
+			if (route.length !== 2 || ['post', 'get', 'put'].indexOf(route[0]) === -1) {
+				throw Error('Invalid map config');
+			}
+			router[route[0]](route[1], middleware);
+		});
+	};
 
 	return router;
+
 };
 
 module.exports = Router;

modules/blocks/chain.js

@@ -100,6 +100,7 @@ Chain.prototype.saveBlock = function (block, cb) {
  * @return {Object}   cb.err Error if occurred
  */
 __private.afterSave = function (block, cb) {
+	library.bus.message('transactionsSaved', block.transactions);
 	// Execute afterSave callbacks for each transaction, depends on tx type
 	// see: logic.outTransfer.afterSave, logic.dapp.afterSave
 	async.eachSeries(block.transactions, function (transaction, cb) {