AddedDocs for Readme.md

index.js

@@ -1,43 +1,46 @@
 require('dotenv').config(); // pull env variables from .env file
 
-const depthLimit = require('graphql-depth-limit');
-const { ApolloServer, PubSub } = require('apollo-server-express');
-const http = require('http');
-const rateLimit = require('express-rate-limit');
-const xss = require('xss-clean');
-const helmet = require('helmet');
-const mongoSanitize = require('express-mongo-sanitize');
-const jwt = require('jsonwebtoken');
-const express = require('express');
-const cors = require('cors');
-const logger = require('logger');
-const requestLogger = require('morgan');
-const path = require('path');
-const i18n = require('i18n');
-const requestContext = require('talawa-request-context');
-const requestTracing = require('request-tracing');
-
+const depthLimit = require('graphql-depth-limit'); // pacakge used to limit the number of recursive calls one can do in graphQL
+const { ApolloServer, PubSub } = require('apollo-server-express'); // A TypeScript GraphQL Server for Express, Koa, Hapi, Lambda, and more.
+const http = require('http'); //The HTTP core module is a key module to Node.js networking.
+const rateLimit = require('express-rate-limit'); // Use to limit repeated requests to public APIs and/or endpoints such as password reset. Plays nice with express-slow-down --  Basic rate-limiting middleware for Express that slows down responses rather than blocking them
+const xss = require('xss-clean'); // to sanitize user input coming from POST body, GET queries, and url param
+const helmet = require('helmet'); //Helmet helps you secure your Express apps by setting various HTTP headers
+const mongoSanitize = require('express-mongo-sanitize'); //Express 4.x middleware which sanitizes user-supplied data to prevent MongoDB Operator Injection
+const jwt = require('jsonwebtoken'); //An implementation of JSON Web Tokens.
+const express = require('express'); // world famous nodejs server
+const cors = require('cors'); // CORS is a node.js package for providing a Connect/Express middleware that can be used to enable CORS with various options.
+const logger = require('logger'); //A simple logging library that combines the simple APIs of Ruby's logger.rb and browser-js console.log()
+const requestLogger = require('morgan'); //HTTP request logger middleware for node.js
+const path = require('path'); // to handle file paths
+const i18n = require('i18n'); // Lightweight simple translation module with dynamic JSON storage stored at the 'locales' folder
+const requestContext = require('talawa-request-context'); // not sure
+const requestTracing = require('request-tracing'); //   NOT SURE:  probably used to trace the incoming request
+// GETTING THE GRAPHQL QUERIES AND MUTATIONS THESE ONE FILES EXPORT EVERY QUERY AND MUTATION
 const Query = require('./lib/resolvers/Query');
 const Mutation = require('./lib/resolvers/Mutation');
+// IMPORTS ALL THE GRAPHQL SCHEMA AND TYPE DEFINITIONS
 const typeDefs = require('./lib/schema/schema.graphql');
+//JWT function
 const isAuth = require('./lib/middleware/is-auth');
-const database = require('./db.js');
+//database file
+const database = require('./db.js'); // provides connect and disconnect functions
 const Organization = require('./lib/resolvers/Organization');
-const MembershipRequest = require('./lib/resolvers/MembershipRequest');
-const DirectChat = require('./lib/resolvers/DirectChat');
-const DirectChatMessage = require('./lib/resolvers/DirectChatMessage');
-const { defaultLocale, supportedLocales } = require('./lib/config/app');
-const GroupChat = require('./lib/resolvers/GroupChat');
-const GroupChatMessage = require('./lib/resolvers/GroupChatMessage');
+const MembershipRequest = require('./lib/resolvers/MembershipRequest'); // finds the org and user by provided id d
+const DirectChat = require('./lib/resolvers/DirectChat'); // helps to find chats
+const DirectChatMessage = require('./lib/resolvers/DirectChatMessage'); // helps to find chat memssages and sender and receiver objects
+const { defaultLocale, supportedLocales } = require('./lib/config/app'); // to get the default locale and supported locales for the i18n
+const GroupChat = require('./lib/resolvers/GroupChat'); //user creator messg org
+const GroupChatMessage = require('./lib/resolvers/GroupChatMessage'); //groupChatMesssageBelonsTo sender
 const Subscription = require('./lib/resolvers/Subscription');
 const AuthenticationDirective = require('./lib/directives/authDirective');
 const RoleAuthorizationDirective = require('./lib/directives/roleDirective');
 
-const app = express();
+const app = express(); // express app
 
-app.use(requestTracing.middleware());
+app.use(requestTracing.middleware()); // adding request tracing in the project
 
-const pubsub = new PubSub();
+const pubsub = new PubSub(); // from apollo express server
 
 const resolvers = {
   Subscription: Subscription,
@@ -50,69 +53,75 @@ const resolvers = {
   GroupChat,
   GroupChatMessage,
 };
-
+// resolvers are provided functions that gets the data for specific models
 const apiLimiter = rateLimit({
   windowMs: 60 * 60 * 1000,
   max: 50000,
   message: 'Too many requests from this IP, please try again after 15 minutes',
-});
+}); // limiting the repeat request by providing time and max no and also error message for an IP
 
 i18n.configure({
-  directory: `${__dirname}/locales`,
+  directory: `${__dirname}/locales`, // speicifying the root JSON folder containing the translations
   staticCatalog: {
     en: require('./locales/en.json'),
     hi: require('./locales/hi.json'),
     zh: require('./locales/zh.json'),
     sp: require('./locales/sp.json'),
     fr: require('./locales/fr.json'),
-  },
-  queryParameter: 'lang',
-  defaultLocale: defaultLocale,
-  locales: supportedLocales,
-  autoReload: process.env.NODE_ENV !== 'production',
-  updateFiles: process.env.NODE_ENV !== 'production',
-  syncFiles: process.env.NODE_ENV !== 'production',
+  }, // specifying path according to the language
+  queryParameter: 'lang', //* Query parameter to switch locale (ie. /home?lang=ch)
+  defaultLocale: defaultLocale, //! Alter a site wide default locale
+  locales: supportedLocales, //  providing the list of locales that our app supports currently
+  //* We are allowing the follwing options only if we are not in the production environment to avoid bugs
+  autoReload: process.env.NODE_ENV !== 'production', //* boolean -   Watch for changes in json files to reload locale on updates
+  updateFiles: process.env.NODE_ENV !== 'production', //* boolean -   Whether to write new locale information to disk
+  syncFiles: process.env.NODE_ENV !== 'production', //* boolean -   Sync locale information across all files
 });
 
-app.use(i18n.init);
-app.use(apiLimiter);
-app.use(xss());
+app.use(i18n.init); // including the internationlization in project
+app.use(apiLimiter); // using the apilimiter  middleware
+app.use(xss()); //* using the xss middleware so that requests will be sanitized
 app.use(
   helmet({
     contentSecurityPolicy:
       process.env.NODE_ENV === 'production' ? undefined : false,
   })
-);
-app.use(mongoSanitize());
-app.use(cors());
+); // * using the helmet middle ware  so that we can add custom headers
+app.use(mongoSanitize()); //* using mongodb sanitizer
+app.use(cors()); //* using cors middleware
+/*! XSS - Cross-origin resource sharing is a mechanism that allows restricted resources on a web page to be
+         requested from another domain outside the domain from which the first resource was served*/
 app.use(
   requestLogger(
     ':remote-addr - :remote-user [:date[clf]] ":method :url HTTP/:http-version" :status :res[content-length] :response-time ms',
     {
       stream: logger.stream,
     }
   )
-);
-app.use('/images', express.static(path.join(__dirname, './images')));
-app.use(requestContext.middleware());
+); // using morgan middleware in nodejs
+app.use('/images', express.static(path.join(__dirname, './images'))); // adding images as a static folder in express
+//To serve static files such as images, CSS files, and JavaScript files, use the express.static built-in middleware function in Express.
+app.use(requestContext.middleware()); // comes from talawa-request context library
 
 app.get('/', (req, res) =>
   res.json({
     'talawa-version': 'v1',
     status: 'healthy',
   })
 );
+// sending response on the root request endpoint
 
-const httpServer = http.createServer(app);
+const httpServer = http.createServer(app); // creating an htppserever from express
 
 const apolloServer = new ApolloServer({
-  typeDefs,
-  resolvers,
-  validationRules: [depthLimit(5)],
+  typeDefs, // providing all the graphql types that we have created
+  resolvers, // providing all the resolvers we have created
+  validationRules: [depthLimit(5)], // how much recrsives nesting should be allowed -upto 5 levels
   schemaDirectives: {
     auth: AuthenticationDirective,
     role: RoleAuthorizationDirective,
-  },
+  }, //A directive decorates part of a GraphQL schema or operation with additional configuration.
+  // Tools like Apollo Server (and Apollo Client) can read a GraphQL document's directives and perform custom logic as appropriate.
   context: ({ req, res, connection }) => {
     if (connection) {
       return {
@@ -143,38 +152,42 @@ const apolloServer = new ApolloServer({
       status: code,
       data,
     };
-  },
+  }, // providing error message on wrong query
   subscriptions: {
+    /*On the client, SubscriptionsClient supports adding token information to connectionParams (example) that will be sent with the first WebSocket message.
+     In the server, all GraphQL subscriptions are delayed until the connection has been fully authenticated and the onConnect callback returns a truthy value.*/
     onConnect: (connection) => {
       if (!connection.authorization) {
         throw new Error('userAuthentication');
-      }
+      } //not authorized
       let userId = null;
       const token = connection.authorization.split(' ')[1];
       if (token) {
         let decodedToken = jwt.verify(token, process.env.ACCESS_TOKEN_SECRET);
         userId = decodedToken.userId;
-      }
+      } //verifyting the token  from the new connction
 
       return {
         currentUserToken: connection,
         currentUserId: userId,
-      };
+      }; // returns  current connection and userId
     },
-  },
+  }, // handling JWT authenticationc
 });
 
 apolloServer.applyMiddleware({
   app,
-});
-apolloServer.installSubscriptionHandlers(httpServer);
+}); // intergrating express with apollo graphql
+apolloServer.installSubscriptionHandlers(httpServer); //
+
 
+console.log(ip.address());
 const serverStart = async () => {
   try {
     await database.connect();
     httpServer.listen(process.env.PORT || 4000, () => {
       logger.info(
-        `🚀 Server ready at http://localhost:${process.env.PORT || 4000}${
+        `🚀 Server ready at http://${ip.address()}:${process.env.PORT || 4000}${
           apolloServer.graphqlPath
         }`
       );
@@ -190,3 +203,4 @@ const serverStart = async () => {
 };
 
 serverStart();
+