Untitled

console.log('Loading function');

// dependencies
var AWS = require('aws-sdk');
var crypto = require('crypto');
var util = require('util');
var config = require('./config.json');

// Get reference to AWS clients
var dynamodb = new AWS.DynamoDB();
var ses = new AWS.SES();

function computeHash(password, salt, fn) {
    // Bytesize
    var len = 128;
    var iterations = 4096;

    if (3 == arguments.length) {
        crypto.pbkdf2(password, salt, iterations, len, fn);
    } else {
        fn = salt;
        crypto.randomBytes(len, function(err, salt) {
            if (err) return fn(err);
            salt = salt.toString('base64');
            crypto.pbkdf2(password, salt, iterations, len, function(err, derivedKey) {
                if (err) return fn(err);
                fn(null, salt, derivedKey.toString('base64'));
            });
        });
    }
}

function storeUser(email, password, salt, fn) {
    // Bytesize
    var len = 128;
    crypto.randomBytes(len, function(err, token) {
        if (err) return fn(err);
        token = token.toString('hex');
        dynamodb.putItem({
            TableName: config.DDB_TABLE,
            Item: {
                email: {
                    S: email
                },
                passwordHash: {
                    S: password
                },
                passwordSalt: {
                    S: salt
                },
                verified: {
                    BOOL: false
                },
                verifyToken: {
                    S: token
                }
            },
            ConditionExpression: 'attribute_not_exists (email)'
        }, function(err, data) {
            if (err) return fn(err);
            else fn(null, token);
        });
    });
}

function sendVerificationEmail(email, token, fn) {
    var subject = 'Verification Email for ' + config.EXTERNAL_NAME;
    var verificationLink = config.VERIFICATION_PAGE + '?email=' + encodeURIComponent(email) + '&verify=' + token;
    ses.sendEmail({
        Source: config.EMAIL_SOURCE,
        Destination: {
            ToAddresses: [
                email
            ]
        },
        Message: {
            Subject: {
                Data: subject
            },
            Body: {
                Html: {
                    Data: '<html><head>'
                    + '<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />'
                    + '<title>' + subject + '</title>'
                    + '</head><body>'
                    + 'Please <a href="' + verificationLink + '">click here to verify your email address</a> or copy & paste the following link in a browser:'
                    + '<br><br>'
                    + '<a href="' + verificationLink + '">' + verificationLink + '</a>'
                    + '</body></html>'
                }
            }
        }
    }, fn);
}

exports.handler = function(event, context) {
    var email = event.email;
    var clearPassword = event.password;

    computeHash(clearPassword, function(err, salt, hash) {
        if (err) {
            context.fail('Error in hash: ' + err);
        } else {
            storeUser(email, hash, salt, function(err, token) {
                if (err) {
                    if (err.code == 'ConditionalCheckFailedException') {
                        // userId already found
                        context.succeed({
                            created: false
                        });
                    } else {
                        context.fail('Error in storeUser: ' + err);
                    }
                } else {
                    sendVerificationEmail(email, token, function(err, data) {
                        if (err) {
                            context.fail('Error in sendVerificationEmail: ' + err);
                        } else {
                            context.succeed({
                                created: true
                            });
                        }
                    });
                }
            });
        }
    });
}