server.js

var webpack = require('webpack')
var webpackDevMiddleware = require('webpack-dev-middleware')
var webpackHotMiddleware = require('webpack-hot-middleware')
var config = require('./webpack.config')
var bodyParser = require('body-parser')
var request = require("request")
var url = require("url");

// library for securely handeling hashed cookie objects
var cookieSession = require("cookie-session")

// WePay library
var WePay = require("wepay").WEPAY;

// HTTPS server
var https = require("https")
var http = require("http")

// file reader
var fs = require("fs")

// express library for defining routes
var express = require("express");

// load app configuration settings
var app_config = require('./config')

// create the express app and define what port this is open on
var app = new (express)();
var port = app_config.port;


// load webpack compiler
var compiler = webpack(config);
app.use(webpackDevMiddleware(compiler, { noInfo: true, publicPath: config.output.publicPath }));
app.use(webpackHotMiddleware(compiler));

// support JSON and url encoded bodies
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({extended:true}));

// setup cookie based sessions
app.use(cookieSession({
    name:"session",
    secret: app_config.cookie_secret,
    secure: true
}));

// load ssl certificate
// for more information refer to this StackOverflow post:
//      http://stackoverflow.com/questions/11744975/enabling-https-on-express-js
//
// For help with generating an SSL certificate and key:
//      https://devcenter.heroku.com/articles/ssl-certificate-self
var privateKey = fs.readFileSync(app_config.ssl.privateKey, "utf8");
var certificate = fs.readFileSync(app_config.ssl.certificate, "utf8");
var credentials = {key: privateKey, cert: certificate};


// point the app to the static folder
app.use('/static', express.static('static'));

/**
 * Send main application page
 *
 * This will also invalidate any previously held session on the site.
 * So refreshing the page effectively kills all session information.
 */
app.get("/", function(req, res) {
    // make sure the session is null each time we reload the page
    // dont want things persisting when people come back
    req.session = null
    res.sendFile(__dirname + '/index.html')
})

/**
 * Verify that everything in the app configuration is going to work
 *
 * It checks to make sure that:
 *      - middleware_uri is set to use HTTPS
 *      - the private key and certificates are defined
 */
function verifyConfig(conf) {
    console.log("Checking middleware uri protocol: ", url.parse(conf.middleware_uri).protocol)
    var middleware_protocol = url.parse(conf.middleware_uri).protocol;
    if (middleware_protocol != "https" && middleware_protocol != "https:") {
        throw(new Error("Middleware URI is not HTTPS."));
    }

    if (!privateKey) {
        throw(new Error("Private key is not defined.  Check to make sure that the file actually exists and contains information"));
    }
    if(!certificate) {
        throw(new Error("Private key is not defined.  Check to make sure that the file actually exists and contains information"));
    }
    return true;
}

/**
 * Send a response back to the client.
 * This function also takes care of sending back errors when the WePay request fails.
 * It will include the WePay error_description as well.
 *
 * @param package   - the data to send back to the user
 * @param res       - ExpressJS response object
 */
function sendResponse(package, res) {
    res.setHeader('Content-Type', 'application/json');
    if ("error_code" in package) {
        var error_package = {
            "error_code":500, 
            "error_description":"wepay call died. Check server logs for more details.", 
            "error_message":package.error_description, 
            "original_error":package}
        console.log("Sending error!\t", error_package);
        return res.status(500).send(JSON.stringify(error_package));
    }
    else {
        console.log("Sending package back to client");
        return res.send(JSON.stringify(package));
    }
}

/**
 * Request data from the given wepay_endpoint, using the specified access_token and package.  This function will immediately send the response back to the client
 *
 * @param res               -   Express response object
 * @param wepay_endpoint    -   the WePay API endpoint we want to hit
 * @param access_token      -   the access token we want to use with the request.  NOTE: for certain endpoints, this can be *null*
 * @param package           -   the package of data we want to send along with request.  This can be an empty object depending on the endpoint
 */
function getWePayData(res, wepay_endpoint, access_token, package) {
    
    var wepay_settings = {}

    if (access_token) {
        console.log("Aquired access_token: ", access_token);
        wepay_settings.access_token = access_token;
    }

    var wepay = new WePay(wepay_settings);
    wepay.use_staging();

    console.log("Making request to wepay: ", wepay_endpoint, package);

    try {
        wepay.call(wepay_endpoint, package, function(response) {
            sendResponse(JSON.parse(response.toString()), res);
        });
    }
    catch(error) {
        //res.setHeader('Content-Type', 'application/json');
        console.log("ERROR WITH WEPAY: ", error);
        res.status(500).send(JSON.stringify(error));
    }
}

/*
 * Given a resource, and package of data, send a request to the middleware.
 * Once the request is complete, it will call the callback function provided.
 *
 * Refer to the middleware specification for more details about what resources are available and what each resource expects in it's data package
 *
 * @params resource - the resource that we want to search on the partner's database.  This should be user, account, or payer
 * @params data     - the package we use to query information about the provided resource
 * @params callback - a callback function to execute after the middleware returns information.  Typically this is `parseMiddlewareResponse`
 */
function getDataFromMiddleware(resource, data, callback) {
    var uri = app_config.middleware_uri+"/"+resource;
    console.log("Requesting data from middleware: ", uri, data);
    return request.post(
        {
            url:    uri, 
            json:   data,
            headers: {
                "Authorization":app_config.middleware_secret
            }

        }, 
        callback
    );
}

/*
 * Parse the response from the middleware and decide what to do with it.
 * If the middleware sends an error, raise that error back to the client
 * If a wepay_endpoint is provided, then use the information provided by the client and request information from the provided endpoint with the wepay_package
 * If no wepay_endpoint is provided, then just send the results from the middleware back to the client
 *
 * @params req            -   Expresses Request object
 * @params res            -   Express Response object
 * @params error          -   A JSON structure with error information (empty if no error occured)
 * @params response       -   A detailed response object
 * @params body           -   A JSON structure with returned data
 * @params wepay_endpoint -   The wepay_endpoint to hit after receiving a response from the middleware
 * @params wepay_package  -   The package to send to the wepay_endpoint
 */
function parseMiddlewareResponse(req, res, error, response, body, wepay_endpoint, wepay_package) {
    if (body.error) {
        // send error
        body.error_code = 500;
        body.error_description = body.error_message;
        return sendResponse(body, res);
    }
    else {
        if (body.access_token) {
            console.log("Setting access token cookie:\t", body.access_token);
            //req.session.access_token = body.access_token;
            return getWePayData(res, wepay_endpoint, body.access_token, wepay_package);
        }
        return sendResponse(body, res);
    }
}

/**
 * Get a user's access token from the middleware and then make the associated v2/user lookup call on the WePay API
 *
 * In the request body we expect:
 *  @param email        -   (optional) the email associated with the user
 *  @param account_id   -   (optional) an account_id
 *
 * Given either of these fields, the middleware should be able to handle it and give us back an access token.
 */
app.post("/user", function(req, res) {
    console.log('Incoming user request: ', req.body);
    var package = {};
    
    // get the email from the search
    var email = req.body.email;
    var account_id = req.body.account_id;

    // get the necessary data from our middleware function and then make the corresponding request to WePay
    getDataFromMiddleware(
        "user", 
        {
            "account_owner_email":email,
            "account_id": account_id
        }, 
        function(error, response, body) {
            return parseMiddlewareResponse(req, res, error, response, body, "/user", {});
        }
    );
})

/*
 * Send a request to /v2/account/find and return the response
 *
 * In the request body, we expect:
 *  @param account_id -     (optional) an account_id tied to the access token set in a cookie
 *
 * The account_id field is optional.  If it is present, we fetch only that accounts information via v2/account
 * If it is not present, we fetch all accounts owned by the user who owns the access token via the v2/account/find endpoint
 */
app.post('/account', function(req, res){
    console.log("Received request for account info: ", req.body);
    var package = {};
    var wepay_endpoint = "";

    // if we have an account_id, then just look up that particular account
    if (req.body.account_id) {
        console.log("Received account_id, looking only for account: ", req.body.account_id);
        package['account_id'] = req.body.account_id;
        wepay_endpoint = "/account";
        return getDataFromMiddleware(
            "user", 
            {"account_id":req.body.account_id}, 
            function(error, response, body){
                parseMiddlewareResponse(req, res, error, response, body, wepay_endpoint, package)
        });
    }

    // otherwise lookup all accounts associated with the provided email
    console.log("No account_id.  Looking for all accounts belonging to: ", req.body.email);
    wepay_endpoint = "/account/find";
    return getDataFromMiddleware("user", {"account_owner_email": req.body.email}, function(error, response, body){
        parseMiddlewareResponse(req, res, error, response, body, wepay_endpoint, package);
    });
})

/**
 * This endpoint has two seperate actions depending on the parameters passed
 * If no checkout_id is given, then this will get the 50 most recent checkouts for the given account_id
 * If a checkout_id is given, then this will fetch information for that checkout specifically.
 * Passing the checkout_id is useful for updating a checkout's info after performing an action with the dashboard. 
 */
app.post("/checkout", function(req, res) {
    // prep the package and wepay_endpoint we want to hit
    console.log("Received request for checkout");
    var package = {};
    var wepay_endpoint = "";
    if (req.body.checkout_id) {
        package = {"checkout_id":req.body.checkout_id};
        wepay_endpoint = "/checkout";
    }
    else {
        package = {"account_id": req.body.account_id};
        if (req.body.start && req.body.start != '') {
            package.start = req.body.start;
        }
        wepay_endpoint = "/checkout/find";
    }

    return getDataFromMiddleware("user", {"account_id":req.body.account_id}, function(error, response, body){
        parseMiddlewareResponse(req, res, error, response, body, wepay_endpoint, package);
    });    
})

/**
 * Resend the confirmation email to a user
 */
app.post("/user/resend_confirmation", function(req, res){
    getDataWithPackage(req, res, "/user/resend_confirmation", {});
})

/**
 * Get a list of the 50 most recent withdrawals for the given account_id
 */
app.post("/withdrawal", function(req, res){
    console.log("Received request for withdrawals");
    var package = {"account_id":req.body.account_id};
    return getDataFromMiddleware(
        "user", 
        {"account_id":req.body.account_id}, 
        function(error, response, body) {
            parseMiddlewareResponse(req, res, error, response, body, "/withdrawal/find", package);
    });
})

/**
 * Perform a refund for a given checkout_id.
 * 
 * This endpoint expects the following fields in the body of the request:
 *  @param checkout_id     -   the checkout_id
 *  @param refund_reason   -   the reason that the checkout is being refunded
 *  @param amount          -   (optional) initates a partial refund for the specified amount
 *  @param app_fee         -   (optional) initiates a partial refund for the specified app_fee amount
 * The amount field should be used to perform a partial refund.
 * When doing a partial refund, you can also pass a app_fee that specifies how much of the app_fee you want to refund
 * 
 * If no amount is passed, this will do a full refund
 */
app.post("/refund", function(req, res) {
    console.log("Received request for refund");
    var package = {"checkout_id":req.body.checkout_id, "refund_reason":req.body.refund_reason};
    if (req.body.amount != null || req.body.app_fee != null) {
        if (req.body.amount) {
                package['amount'] = req.body.amount;
            }
            if (req.body.app_fee) {
                package['app_fee'] = req.body.app_fee;
            }
    }

    return getDataFromMiddleware(
        "user", 
        {"account_id":req.body.account_id}, 
        function(error, response, body){
            return parseMiddlewareResponse(req, res, error, response, body, "/checkout/refund", package)
        }
    );
})

/**
 * Get reserve information from the WePay API.
 * Requires an access token and an account_id
 *
 */
app.post("/reserve", function(req, res) {
    console.log("Received request for reserve");
    return getDataFromMiddleware(
        "user",
        {"account_id": req.body.account_id},
        function(error, response, body) {
            return parseMiddlewareResponse(req, res, error, response, body, "/account/get_reserve_details", {"account_id":req.body.account_id});
        }
    );
});

/**
 * Given a payer's unique identifying information (such as their email), get a list of all of their checkouts from the middleware
 */
app.post("/payer", function(req, res) {   
    console.log("Received request for payer"); 
    // get the email from the search
    var email = req.body.email;
    // get the necessary data from our middleware function and then make the corresponding request to WePay
    return getDataFromMiddleware(
        "payer", 
        {"payer_email":email, "num_elements":50}, 
        function(error, response, body) {
            return parseMiddlewareResponse(req, res, error, response, body, null, null);
        }
    );
})

/*
 * Given a credit_card_id (tokenized card) get more information about the card from the v2/credit_card WePay API endpoint
 */
app.post("/credit_card", function(req, res){
    console.log("Received request for credit_card");
    var credit_card_id = parseInt(req.body.credit_card_id);

    getWePayData(res, "/credit_card", null, {"credit_card_id":credit_card_id, "client_id":app_config.client_id, "client_secret":app_config.client_secret});
})


/**
 * Start the application
 *
 * Before we start, make sure that the app configuration meets the requirements
 */
verifyConfig(app_config);

var httpsServer = https.createServer(credentials, app);
httpsServer.listen(port, function(error) {
    if (error) {
        console.error(error)
    } else {
        console.info("==> 🌎  Listening on port %s. Open up https://localhost:%s/ in your browser.", port, port)
    }
});