Gumroad-Onetime

This node package makes handling one-time gumroad urls for managing payments as simple as possible. It uses Redis to store session data and urls, and the gumroad API wrapper to communicate with gumroad (making temprary link urls and removing them once used/purchased).

More detailed description of the process

Install

npm install gumroad-onetime

Setup

Setup your client:

var gr = require('gumroad-onetime');
 
gr.setup({
    // gumroad username/email
    username: "<username/email>",
    
    // gumroad password
    password: "<password>",
    
    // url for handling purchases
    path: "/buy",
 
    // when a user returns from paying, this function will be called 
    // and passed the session data you asked to store, or an error if applicable.
    onPurchase: function(err, req, res, data){
        console.log("Error: ", err);
        console.log("Session Data: ", data);
    }
});

Middleware

Middleware follows the connect style function(req, res, next){} so can either be added to a standard http server, where the middleware will check if it needs to handle the request and if not, passes it to the rest of your app/routes.

http.createServer(function (req, res) {
    gr.middleware(req, res, function(req, res){
        // other routes
        // the rest of your app
        // etc
    });
    
}).listen(80);

The middleware also allows you to add it seemlessly to Express or Connect apps, and any other frameworks that follow the same pattern.

var express = require('express');
var app = express.createServer();
 
app.configure(function(){
    app.use(express.methodOverride());
    app.use(express.bodyParser());
 
    // Insert gumroad-onetime middleware
    app.use(gr.middleware); 
 
    app.use(app.router);
});
 
app.get('/', function(req, res){
  res.send('Hello World');
});
 
app.listen(3000);

Purchases

At any point you can send a user through the purchase process, by passing the request and response objects, the link info for your purchase as well as any session data you want to keep, like so:

var userData = {user: "data", that: ["you'd", "like", "to", "store"], awesome: true};
 
var link = {
    name: "Awesome thing to buy",
    price: 9001,
    desc: "A nice informative description for the purchase"
}
 
gr.purchase(req, res, userData, link, function(err, data) {
    if (err) console.log("Error forwarding user to gumroad for purchase.");
    else console.log("Great success! User should be at gumroad busy paying.");
});

The process explained

When you issue a purchase call, gumroad-onetime creates a gumroad URL with the path you requested (ie: "/buy") and a unique token (uuid v4.) and whatever title, price and description you selected for your link.

The user request is then responded to with a 302 redirect to Gumroad, and any session data you need stored (username, what they're buying etc) is stored in redis.

When the user has completed the purchase, gumroad will give them the url which will be http://<your host>/<gumroad-onetime path>?token=<uuid>, which the middleware then intercepts, validates against the redis store and fires your onPurchase callback, with the session data you asked to be stored, allowing you to then update the users profile/inventory/credits/etc as required.

The gumroad URL is then removed, so no further purchases can be made on that url.

Redis

Currently gumroad-onetime just connects the the default redis instance at localhost:6379 but this will be configurable in the next update.

License

Copyright (C) 2012 Christopher de Beer

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

by @christopherdb