feat(express-middleware): Add DataLoader middleware

Added an express middleware to provide per-request DataLoaders for fetching data from the
HealthGraph API to prevent multiple calls to the same URI in the same request.

package.json

@@ -21,6 +21,7 @@
 	},
 	"dependencies": {
 		"cookie-parser": "^1.4.3",
+		"dataloader": "^1.3.0",
 		"ejs": "^2.5.6",
 		"express": "^4.15.2",
 		"express-graphql": "^0.6.3",

res/i18n/en.json

@@ -115,6 +115,7 @@
 			"USERID": "The unique ID for the user"
 		}
 	},
-	"RUNKEEPER_REQUEST": "Request made to Runkeeper API %{endpoint}",
+	"HEALTHGRAP_LOADER_REQUEST": "Request made to loader for %{uri}",
+	"HEALTHGRAPH_REQUEST": "Request made to Runkeeper API %{uri}",
 	"SERVER_START": "Server started on port %{port}"
 }

src/app.js

@@ -2,13 +2,14 @@ const cookieParser = require('cookie-parser');
 const express = require('express');
 const log = require('./helpers/logging');
 const path = require('path');
+const HealthGraphLoader = require('./middleware/healthgraph-loader');
 
 
 /*  Create application */
 const app = express();
 app.use(cookieParser());
 app.use(express.static(path.join(__dirname, 'public')));
-
+app.use(HealthGraphLoader);
 
 /* Server settings */
 app.set('view engine', 'ejs');

src/data-types/fitness-activities.js

@@ -5,7 +5,6 @@ const GraphQLList = graphql.GraphQLList;
 const GraphQLInt = graphql.GraphQLInt;
 const GraphQLBoolean = graphql.GraphQLBoolean;
 const CommentType = require('./comment');
-const fetch = require('../helpers/fetch');
 const resolveItems = require('../helpers/resolve-items');
 const i18n = require('../helpers/i18n');
 
@@ -99,7 +98,7 @@ const FitnessImage = new GraphQLObjectType({
 		uri: {
 			description: i18n.t('GRAPHQL.FITNESS.IMAGE.URI'),
 			type: GraphQLString
-		},
+		}
 	}
 });
 
@@ -109,42 +108,42 @@ const FitnessItem = new GraphQLObjectType({
 		activity: {
 			description: i18n.t('GRAPHQL.FITNESS.ITEM.ACTIVITY'),
 			resolve (parent, args, req) {
-				return fetch(parent.uri, req).then(d => d.activity);
+				return req.healthGraphLoader.load(parent.uri).then(d => d.activity);
 			},
 			type: GraphQLString
 		},
 		average_heart_rate: {
 			description: i18n.t('GRAPHQL.FITNESS.ITEM.AVERAGE_HEART_RATE'),
 			resolve (parent, args, req) {
-				return fetch(parent.uri, req).then(d => d.average_heart_rate);
+				return req.healthGraphLoader.load(parent.uri).then(d => d.average_heart_rate);
 			},
 			type: GraphQLInt
 		},
 		calories: {
 			description: i18n.t('GRAPHQL.FITNESS.ITEM.CALORIES'),
 			resolve (parent, args, req) {
-				return fetch(parent.uri, req).then(d => d.calories);
+				return req.healthGraphLoader.load(parent.uri).then(d => d.calories);
 			},
 			type: new GraphQLList(FitnessCalories)
 		},
 		climb: {
 			description: i18n.t('GRAPHQL.FITNESS.ITEM.CLIMB'),
 			resolve (parent, args, req) {
-				return fetch(parent.uri, req).then(d => d.climb);
+				return req.healthGraphLoader.load(parent.uri).then(d => d.climb);
 			},
 			type: GraphQLInt
 		},
 		comments: {
 			description: i18n.t('GRAPHQL.FITNESS.ITEM.COMMENTS'),
 			resolve (parent, args, req) {
-				return fetch(parent.uri, req).then(d => fetch(d.comments, req)).then(c => c.comments);
+				return req.healthGraphLoader.load(parent.uri).then(d => req.healthGraphLoader.load(d.comments)).then(c => c.comments);
 			},
 			type: new GraphQLList(CommentType)
 		},
 		distance: {
 			description: i18n.t('GRAPHQL.FITNESS.ITEM.DISTANCE'),
 			resolve (parent, args, req) {
-				return fetch(parent.uri, req).then(d => d.distance);
+				return req.healthGraphLoader.load(parent.uri).then(d => d.distance);
 			},
 			type: new GraphQLList(FitnessDistance)
 		},
@@ -160,7 +159,7 @@ const FitnessItem = new GraphQLObjectType({
 
 			description: i18n.t('GRAPHQL.FITNESS.ITEM.EQUIPMENT'),
 			resolve (parent, args, req) {
-				return fetch(parent.uri, req).then(d => d.equipment);
+				return req.healthGraphLoader.load(parent.uri).then(d => d.equipment);
 			},
 			type: GraphQLString
 		},
@@ -171,59 +170,59 @@ const FitnessItem = new GraphQLObjectType({
 		heart_rate: {
 			description: i18n.t('GRAPHQL.FITNESS.ITEM.HEART_RATE'),
 			resolve (parent, args, req) {
-				return fetch(parent.uri, req).then(d => d.heart_rate);
+				return req.healthGraphLoader.load(parent.uri).then(d => d.heart_rate);
 			},
 			type: new GraphQLList(FitnessHeartRate)
 		},
 		images: {
 			description: i18n.t('GRAPHQL.FITNESS.ITEM.IMAGES'),
 			resolve (parent, args, req) {
-				return fetch(parent.uri, req).then(d => d.images);
+				return req.healthGraphLoader.load(parent.uri).then(d => d.images);
 			},
 			type: new GraphQLList(FitnessImage)
 		},
 		is_live: {
 
 			description: i18n.t('GRAPHQL.FITNESS.ITEM.IS_LIVE'),
 			resolve (parent, args, req) {
-				return fetch(parent.uri, req).then(d => d.is_live);
+				return req.healthGraphLoader.load(parent.uri).then(d => d.is_live);
 			},
 			type: GraphQLBoolean
 		},
 		notes: {
 			description: i18n.t('GRAPHQL.FITNESS.ITEM.NOTES'),
 			resolve (parent, args, req) {
-				return fetch(parent.uri, req).then(d => d.notes);
+				return req.healthGraphLoader.load(parent.uri).then(d => d.notes);
 			},
 			type: GraphQLString
 		},
 		path: {
 			description: i18n.t('GRAPHQL.FITNESS.ITEM.PATH'),
 			resolve (parent, args, req) {
-				return fetch(parent.uri, req).then(d => d.path);
+				return req.healthGraphLoader.load(parent.uri).then(d => d.path);
 			},
 			type: new GraphQLList(FitnessPath)
 		},
 		secondary_type: {
 			description: i18n.t('GRAPHQL.FITNESS.ITEM.SECONDARY_TYPE'),
 			resolve (parent, args, req) {
-				return fetch(parent.uri, req).then(d => d.secondary_type);
+				return req.healthGraphLoader.load(parent.uri).then(d => d.secondary_type);
 			},
 			type: GraphQLString
 		},
 		share: {
 			description: i18n.t('GRAPHQL.FITNESS.ITEM.SHARE'),
 			resolve (parent, args, req) {
-				return fetch(parent.uri, req).then(d => d.share);
+				return req.healthGraphLoader.load(parent.uri).then(d => d.share);
 			},
-			type: GraphQLString,
+			type: GraphQLString
 		},
 		share_map: {
 			description: i18n.t('GRAPHQL.FITNESS.ITEM.SHARE_MAP'),
 			resolve (parent, args, req) {
-				return fetch(parent.uri, req).then(d => d.share_map);
+				return req.healthGraphLoader.load(parent.uri).then(d => d.share_map);
 			},
-			type: GraphQLString,
+			type: GraphQLString
 		},
 		source: {
 			description: i18n.t('GRAPHQL.FITNESS.ITEM.SOURCE'),
@@ -252,7 +251,7 @@ const FitnessItem = new GraphQLObjectType({
 		userID: {
 			description: i18n.t('GRAPHQL.FITNESS.ITEM.USERID'),
 			resolve (parent, args, req) {
-				return fetch(parent.uri, req).then(d => d.userID);
+				return req.healthGraphLoader.load(parent.uri).then(d => d.userID);
 			},
 			type: GraphQLString
 		},

src/data-types/strength-training-activities.js

@@ -3,7 +3,6 @@ const GraphQLObjectType = graphql.GraphQLObjectType;
 const GraphQLString = graphql.GraphQLString;
 const GraphQLList = graphql.GraphQLList;
 const GraphQLInt = graphql.GraphQLInt;
-const fetch = require('../helpers/fetch');
 const CommentType = require('./comment');
 const resolveItems = require('../helpers/resolve-items');
 const i18n = require('../helpers/i18n');
@@ -66,30 +65,30 @@ const StrengthTrainingItem = new GraphQLObjectType({
 		comments: {
 			description: i18n.t('GRAPHQL.STRENGTH_TRAINING.ITEM.COMMENTS'),
 			resolve (parent, args, req) {
-				return fetch(parent.uri, req)
-					.then(d => fetch(d.comments, req))
+				return req.healthGraphLoader.load(parent.uri)
+					.then(d => req.healthGraphLoader.load(d.comments))
 					.then(c => c.comments);
 			},
 			type: new GraphQLList(CommentType)
 		},
 		exercises: {
 			description: i18n.t('GRAPHQL.STRENGTH_TRAINING.ITEM.EXERCISES'),
 			resolve (parent, args, req) {
-				return fetch(parent.uri, req).then(d => d.exercises);
+				return req.healthGraphLoader.load(parent.uri).then(d => d.exercises);
 			},
 			type: new GraphQLList(StrengthTrainingExercise)
 		},
 		notes: {
 			description: i18n.t('GRAPHQL.STRENGTH_TRAINING.ITEM.NOTES'),
 			resolve (parent, args, req) {
-				return fetch(parent.uri, req).then(d => d.notes);
+				return req.healthGraphLoader.load(parent.uri).then(d => d.notes);
 			},
 			type: GraphQLString
 		},
 		source: {
 			description: i18n.t('GRAPHQL.STRENGTH_TRAINING.ITEM.SOURCE'),
 			resolve (parent, args, req) {
-				return fetch(parent.uri, req).then(d => d.source);
+				return req.healthGraphLoader.load(parent.uri).then(d => d.source);
 			},
 			type: GraphQLString
 		},
@@ -100,14 +99,14 @@ const StrengthTrainingItem = new GraphQLObjectType({
 		total_calories: {
 			description: i18n.t('GRAPHQL.STRENGTH_TRAINING.ITEM.TOTAL_CALORIES'),
 			resolve (parent, args, req) {
-				return fetch(parent.uri, req).then(d => d.total_calories);
+				return req.healthGraphLoader.load(parent.uri).then(d => d.total_calories);
 			},
 			type: GraphQLInt
 		},
 		userID: {
 			description: i18n.t('GRAPHQL.STRENGTH_TRAINING.ITEM.USERID'),
 			resolve (parent, args, req) {
-				return fetch(parent.uri, req).then(d => d.userID);
+				return req.healthGraphLoader.load(parent.uri).then(d => d.userID);
 			},
 			type: GraphQLString
 		}
@@ -120,7 +119,7 @@ const StrengthTrainingActivities = new GraphQLObjectType({
 	fields: {
 		size: {
 			description: i18n.t('GRAPHQL.STRENGTH_TRAINING.ACTIVITIES.SIZE'),
-			type: GraphQLInt,
+			type: GraphQLInt
 		},
 		items: {
 			args: resolveItems.args,

src/data-types/user.js

@@ -2,7 +2,6 @@ const graphql = require('graphql');
 const GraphQLObjectType = graphql.GraphQLObjectType;
 const GraphQLString = graphql.GraphQLString;
 const i18n = require('../helpers/i18n');
-const fetch = require('../helpers/fetch');
 const ProfileType = require('./profile');
 const StrengthTrainingActivitiesType = require('./strength-training-activities').StrengthTrainingActivities;
 const FitnessActivitiesType = require('./fitness-activities').FitnessActivities;
@@ -13,28 +12,36 @@ module.exports = new GraphQLObjectType({
 		fitness_activities: {
 			description: i18n.t('GRAPHQL.USER.FITNESS_ACTIVITIES'),
 			resolve (parent, args, req) {
-				return fetch('/user', req).then(data => fetch(data.fitness_activities, req));
+				return req.healthGraphLoader
+					.load('/user')
+					.then(data => req.healthGraphLoader.load(data.fitness_activities));
 			},
 			type: FitnessActivitiesType
 		},
 		profile: {
 			description: i18n.t('GRAPHQL.USER.PROFILE'),
 			resolve (parent, args, req) {
-				return fetch('/user', req).then(data => fetch(data.profile, req));
+				return req.healthGraphLoader
+					.load('/user')
+					.then(data => req.healthGraphLoader.load(data.profile));
 			},
 			type: ProfileType
 		},
 		strength_training_activities: {
 			description: i18n.t('GRAPHQL.USER.STRENGTH_TRAINING_ACTIVITIES'),
 			resolve (parent, args, req) {
-				return fetch('/user', req).then(data => fetch(data.strength_training_activities, req));
+				return req.healthGraphLoader
+					.load('/user')
+					.then(data => req.healthGraphLoader.load(data.strength_training_activities));
 			},
 			type: StrengthTrainingActivitiesType
 		},
 		userID: {
 			description: i18n.t('GRAPHQL.USER.USERID'),
 			resolve (parent, args, req) {
-				return fetch('/user', req).then(data => data.userID);
+				return req.healthGraphLoader
+					.load('/user')
+					.then(data => data.userID);
 			},
 			type: GraphQLString
 		}

src/helpers/resolve-items.js

@@ -1,4 +1,3 @@
-const fetch = require('./fetch');
 const graphql = require('graphql');
 const GraphQLInt = graphql.GraphQLInt;
 const GraphQLString = graphql.GraphQLString;
@@ -36,9 +35,9 @@ module.exports = {
 			let items = parent.items.filter(filterItems);
 
 			function getItems (count, next) {
-				return new Promise(res => {
+				return new Promise(resolveItems => {
 
-					fetch(next, req).then(data => { // eslint-disable-line consistent-return
+					req.healthGraphLoader.load(next).then(data => {
 						items = items.concat(data.items).filter(filterItems);
 
 						let stopGettingItems = false;
@@ -50,10 +49,12 @@ module.exports = {
 						}
 
 						if (!stopGettingItems && count > items.length && data.next) {
-							return getItems(count, data.next);
+							return getItems(count, data.next).then(resolveItems);
 						}
 
-					}).then(res);
+						return resolveItems();
+
+					});
 
 				});
 			}

src/middleware/healthgraph-loader.js

@@ -0,0 +1,27 @@
+const request = require('superagent-promise')(require('superagent'), Promise);
+const DataLoader = require('dataloader');
+const log = require('./../helpers/logging');
+
+module.exports = function createLoader (req, res, next) {
+
+	const HealthGraphLoader = new DataLoader(
+		urls => Promise.all(urls.map(uri => {
+
+			log.info('HEALTHGRAPH_REQUEST', {uri});
+
+			return request
+				.get(`https://api.runkeeper.com${uri}`)
+				.query({
+					access_token: req.cookies.auth
+				})
+				.end()
+				.then(data => data.body);
+
+		}))
+	);
+
+	req.healthGraphLoader = HealthGraphLoader; // eslint-disable-line no-param-reassign
+
+	next();
+
+};

src/routes/graphql.js

@@ -1,7 +1,6 @@
 const graphqlHTTP = require('express-graphql');
 const graphql = require('graphql');
 const GraphQLSchema = graphql.GraphQLSchema;
-const fetch = require('../helpers/fetch');
 const UserType = require('../data-types/user');
 
 module.exports = function (app) {