nodejs scripts to access Amazon market place API and fetch stock and sales

amazon-mws.js

var request   = require("request")
, crypto      = require("crypto")
, querystring = require("querystring")
, assert      = require("assert")
, l           = require("nlogger").logger(module)
, parseString = require("xml2js").parseString
;

function Client( options ) {
    var requiredKeys = [
        "AWSAccessKeyId",
        "SellerId",
        "Secret"
    ];
    for (var i=0,len=requiredKeys.length; i<len; i++) {
        var key = requiredKeys[ i ];
        this[ key ] = options[ key ];
        assert( this[ key ], "options[\""+key+"\"] required" );
    }
}

function hmacSHA256 (method, domain, path, secret, payload) {
    var hmac = crypto.createHmac("sha256", secret);
    hmac.update(method + "\n");
    hmac.update(domain + "\n");
    hmac.update(path + "\n");
    
    var keys = Object.keys(payload).sort();
    var qs = '';
    for (var i=0,len=keys.length; i<len; i++) {
        qs += keys[ i ] + "=" + querystring.escape( payload[ keys[i] ] );
        if (i !== (len-1)) {
            qs += "&";
        }
    }
    hmac.update( qs );

    return hmac.digest('base64');
}

// http://docs.developer.amazonservices.com/en_US/orders/2013-09-01/Orders_ListOrders.html
Client.prototype.ListOrders = function (cond, callback) {
    this.invoke( "POST",
                 "ListOrders",
                 "2013-09-01",
                 "/Orders/2013-09-01",
                 cond,
                 function (responseJSON) {
                     var orders = responseJSON.ListOrdersResponse.ListOrdersResult[0].Orders[0].Order
                     ,  items   = 0
                     , amount   = 0;
                     if (! orders) {
                         return {
                             orders : 0,
                             items  : 0,
                             amount : 0
                         };
                     }
                     for (var i=0,len=orders.length; i<len; i++) {
                         var order = orders[ i ];
                         items  += parseInt(order.NumberOfItemsUnshipped[0], 10) +
                             parseInt(order.NumberOfItemsShipped[0], 10);
                         amount += (order.OrderTotal ? parseInt(order.OrderTotal[0].Amount[0], 10)
                                    : 0);
                     }
                     return {
                         orders : orders.length,
                         items  : items,
                         amount : amount
                     };
                 },
                 callback );
};

// http://docs.developer.amazonservices.com/en_US/fba_inventory/FBAInventory_ListInventorySupply.html
Client.prototype.ListInventorySupply = function(cond, callback) {
    this.invoke( "GET",
                 "ListInventorySupply", 
                 "2010-10-01",
                 "/FulfillmentInventory/2010-10-01",
                 cond,
                 function (responseJSON) {
                     var member = responseJSON.ListInventorySupplyResponse.ListInventorySupplyResult[0].InventorySupplyList[0].member[0];
                     return {
                             InStockSupplyQuantity : parseInt(member.InStockSupplyQuantity[0], 10),
                             TotalSupplyQuantity   : parseInt(member.TotalSupplyQuantity[0], 10),
                     };
                 },
                 callback );
};

Client.prototype.invoke = function (method, action, version, path, cond, parser, callback) {
    var timestamp = (new Date()).toISOString();
    var payload = {
        "Action"             : action,
        "AWSAccessKeyId"     : this[ "AWSAccessKeyId" ],
        "SellerId"           : this[ "SellerId" ],
        "SignatureMethod"    : "HmacSHA256",
        "SignatureVersion"   : "2",
        "Timestamp"          : timestamp,
        "Version"            : version
    };
    for (var k in cond) {
        payload[ k ] = cond[ k ];
    }
    var signature = hmacSHA256( method.toUpperCase(),
                                "mws.amazonservices.jp",
                                path,
                                this.Secret,
                                payload );
    payload.Signature = signature;

    request[ method.toLowerCase() ]({
        url : "https://mws.amazonservices.jp" + path,
        qs  : payload
    }, function (err,response,body) {
        if (err || (response.statusCode !== 200)) {
            l.error( "err, statusCode, res.headers, body: ", err, response.statusCode, response.headers, body );
            callback( err, 0 );
            return;
        }
        parseString( body, function (err, result) {
            if (err) {
                callback( err, 0 );
                return;
            }
            callback( null, parser(result) );
        });
    });
};

module.exports = Client;

// var client = new Client({
//     "AWSAccessKeyId"     : "xxxxxxxxxxxxxxxxxx",
//     "SellerId"           : "xxxxxxxxxxxxxx",
//     "Secret"             : "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
// });

// client.ListOrders({
//     "MarketplaceId.Id.1" : "xxxxxxxxxxxxxxx",
//     "CreatedAfter"       : "2014-03-31T15:00:00Z",
// }, function(err, orders) {
//     if (err) {
//         l.error( err );
//     }
//     l.info( "orders: ", orders );
// });

// client.ListInventorySupply({
//     "SellerSkus.member.1" : "IRKit-001",
//     "ResponseGroup"       : "Basic",
// }, function(err, inventory) {
//     if (err) {
//         l.error( err );
//     }
//     l.info( "inventory: ", inventory );
// });

business.js

var Amazon = require("amazon-mws")
, async    = require("async")
, _        = require("underscore")
, moment   = require("moment")
;

var client = new Amazon({
    "AWSAccessKeyId"     : "xxxxxxxxxxxxxxxxxxxxxxxx",
    "SellerId"           : "xxxxxxxxxxxxx",
    "Secret"             : "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
});

async.parallel([
    function (callback) {
        client.ListInventorySupply({
            "SellerSkus.member.1" : "IRKit-001",
            "ResponseGroup"       : "Basic"
        }, function(err, inventory) {
            if (err) {
                callback( err );
                return;
            }
            callback( null, inventory.InStockSupplyQuantity );
        });
    },
    function (callback) {
        client.ListOrders({
            "MarketplaceId.Id.1" : "xxxxxxxxxxxxxx",
            "CreatedAfter"       : moment().subtract("hours",1).toISOString()
        }, function(err, orders) {
            if (err) {
                callback( err );
                return;
            }
            callback( null, [ orders.orders, orders.amount ] );
        });
    },
], function (err,results) {
    if (err) {
        console.error( err );
        return;
    }
    // amazon.stock,amazon.orders,amazon.amount
    console.log( _.flatten(results).join("\t") );
});