# Restful Shopping Cart Example? **URL:** \ **Category:** Rails\ **Created:** [March 20, 2007, 3:52pm UTC](https://www.ruby-forum.com/t/restful-shopping-cart-example/89450 "2007-03-20T15:52:44Z")\ **Posts on this page:** 15\ **Page:** 1
**Author:** ![jgrosjean](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/ecc23a/32.png) [@jgrosjean](https://www.ruby-forum.com/u/jgrosjean)\ **Post date:** [March 20, 2007, 3:52pm UTC](https://www.ruby-forum.com/t/restful-shopping-cart-example/89450/1 "2007-03-20T15:52:44Z")
I’m still trying to make restful desing click in my head. Yesterday I asked about [good examples apps to learn from](http://www.ruby-forum.com/topic/101827), and there don’t appear to be very many. And most of the examples that do exist seem to be fairly strait forward mappings to rest concepts… posts and comments and such. So I’d like to see some more examples, and in particular I think it would be fun to turn the “Depot” store app from AWDR into a more restful example. For me it would be a nice example because fairly simple and clean and it’s not quite clear to me how a restful desing would be added. Two sets of questsion to get me started. 1. Does this seems like a useful thing to do? Would anyone learning restful design out there like to see this, and for people who already get it is the Depot app a good candidate? 2. And second does anyone have design tips that I should use to get started? So far this is what I’ve done. - used the restful\_authentication plugin to generate an authentication system. - used scaffold\_resource to generate resources to model the store: - use the resources\_controller plugin to simplify the controller implementation for the apps resources. - right now these are what my routes look like: ` map.resources :users, :sessions, :products map.resources :carts do |cart| cart.resources :cart_items end ` `map.resources :orders do |order| order.resources :order_items end ` So now I can browse and edit the model layer of my store, but the view and controller layers are missing a lot and I’m not sure where to go next. Whats the proper way to add the basic Depot style behavior ontop of this structure. The features that I’m missing are: - list of products with “Add to Cart” buttons next to each. - shopping cart on each page showing what I’ve added. - empty cart behavior - checkout behavior that creates a new order I know how to get all of this behavior by copying the Depot example from the book and creating a StoreController, but it seems like that’s not the most restful design. So please helpe point me in the right direction and maybe I’ll be able to get a good example going. Thanks, Jesse ---
**Author:** ![jgrosjean](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/ecc23a/32.png) [@jgrosjean](https://www.ruby-forum.com/u/jgrosjean)\ **Post date:** [March 20, 2007, 7:43pm UTC](https://www.ruby-forum.com/t/restful-shopping-cart-example/89450/2 "2007-03-20T19:43:26Z")
Hey, comments below: On 20-Mar-07, at 10:51 AM, David A. Black wrote: > > - cart\_items > > I’ve thought about what I’d do if I were to rewrite that very > application to use the new REST support. I would still not have a > cart model. But I would have a cart controller, and I would do: > > map.resources :cart This brings up an interesting point: when to use map.resource vs map.resources Unless you’re planning some sort of interface to view _all_ carts, you probably want a singleton resource: map.resource :cart Then adding and removing cart items would be the responsibility of the cart\_items controller: map.resource :cart do |cart| cart.resources :cart\_items end And with that I wouldn’t bother having a cart\_items\_controller#index, I’d just use cart\_controller#show to present the listing. Just another thing to think about. Trevor ---
**Author:** ![jgrosjean](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/ecc23a/32.png) [@jgrosjean](https://www.ruby-forum.com/u/jgrosjean)\ **Post date:** [March 20, 2007, 7:16pm UTC](https://www.ruby-forum.com/t/restful-shopping-cart-example/89450/3 "2007-03-20T19:16:24Z")
Hi – On 3/20/07, Jesse G. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > clean and it’s not quite clear to me how a restful desing would be > added. > > Two sets of questsion to get me started. > > 1. Does this seems like a useful thing to do? Would anyone learning > restful design out there like to see this, and for people who already > get it is the Depot app a good candidate? I think it could be quite worthwhile. > - orders > - order\_items I’d recommend trying a slightly different approach. (I don’t use scaffolding at all, but that’s not my focus here.) In my book, I develop a store application, and one of the things I realized early on was that I didn’t want or need a shopping cart model. The shopping cart was really a virtual thing; it was essentially a view of a collection of orders. I’ve thought about what I’d do if I were to rewrite that very application to use the new REST support. I would still not have a cart model. But I would have a cart controller, and I would do: map.resources :cart (or some nested variant thereof). In my original application, I had actions like customer#view\_cart. That could be turned into cart#show. It’s a good example of a case where the whole controller/model stack is probably too much. The idea of a shopping cart resource need not be wired to a shopping cart model. You can still leverage the full range of named routes and abstraction that the REST techniques give you. Anyway – it’s something to think about. David – Q. What is THE Ruby book for Rails developers? A. RUBY FOR RAILS by David A. Black ([http://www.manning.com/black](http://www.manning.com/black)) (See what readers are saying! [http://www.rubypal.com/r4rrevs.pdf](http://www.rubypal.com/r4rrevs.pdf)) Q. Where can I get Ruby/Rails on-site training, consulting, coaching? A. Ruby Power and Light, LLC ([http://www.rubypal.com](http://www.rubypal.com)) ---
**Author:** ![jgrosjean](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/ecc23a/32.png) [@jgrosjean](https://www.ruby-forum.com/u/jgrosjean)\ **Post date:** [March 21, 2007, 12:44am UTC](https://www.ruby-forum.com/t/restful-shopping-cart-example/89450/4 "2007-03-21T00:44:31Z")
> I don’t think I’d have cart\_items, though; I’d just have orders. The > cart would be implemented as the aggregate of the orders. So an order > would not have any need to know that it was in a cart, and the cart > would only exist as a particular way of representing the orders. I was wondering about this approach earlier. There does seem to be lots of duplication between carts, cart\_items and orders, order\_items, it would be nice to get rid of that. I’ve also found and downloaded your r4rmusic example… nice and short… I like that! To make this work the one trick is that I’ll need some way to mark one order as “in cart”. I guess I can do this by having a new value for the status field, and also by storing that order id in the current session. I think I can even present this order to the user as the shopping cart by creating a new singleton root and controller named cart: map.resources :cart That singleton will actually be backed by the current “in cart” order. Does that all seem to be right? Also are there any other tradeoffs related to getting rid of the carts, cart\_items models that I’m not thinking off? Depot example does use a cart model of sorts as do a few other store example that I came across. Am I giving anything up by getting rid of the cart, cart\_items abstraction? Thanks, Jesse ---
**Author:** ![jgrosjean](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/ecc23a/32.png) [@jgrosjean](https://www.ruby-forum.com/u/jgrosjean)\ **Post date:** [March 21, 2007, 4:10am UTC](https://www.ruby-forum.com/t/restful-shopping-cart-example/89450/5 "2007-03-21T04:10:20Z")
Hi – On 3/20/07, Jesse G. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > found and downloaded your r4rmusic example… nice and short… I like > that! > > To make this work the one trick is that I’ll need some way to mark one > order as “in cart”. I guess I can do this by having a new value for the > status field, and also by storing that order id in the current session. > > I think I can even present this order to the user as the shopping cart > by creating a new singleton root and controller named cart: > > map.resources :cart Do you mean map.resource? (See Trevor’s earlier comment on my earlier post.) > That singleton will actually be backed by the current “in cart” order. > Does that all seem to be right? If an order has a status (pending, confirmed, paid, cancelled, maybe others), then you could just have the cart be all of the pending orders of a particular user, or however you wanted to define it. That way, the order objects don’t need to have any knowledge of a cart. “Shopping cart” would just be a colorful word with which to explain to the customer what they were looking at. David – Q. What is THE Ruby book for Rails developers? A. RUBY FOR RAILS by David A. Black ([http://www.manning.com/black](http://www.manning.com/black)) (See what readers are saying! [http://www.rubypal.com/r4rrevs.pdf](http://www.rubypal.com/r4rrevs.pdf)) Q. Where can I get Ruby/Rails on-site training, consulting, coaching? A. Ruby Power and Light, LLC ([http://www.rubypal.com](http://www.rubypal.com)) ---
**Author:** ![jgrosjean](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/ecc23a/32.png) [@jgrosjean](https://www.ruby-forum.com/u/jgrosjean)\ **Post date:** [March 20, 2007, 8:30pm UTC](https://www.ruby-forum.com/t/restful-shopping-cart-example/89450/6 "2007-03-20T20:30:33Z")
Hi – On 3/20/07, Trevor S. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > > - used the restful\_authentication plugin to generate an > > Then adding and removing cart items would be the responsibility of > the cart\_items controller: > > map.resource :cart do |cart| > cart.resources :cart\_items > end I don’t think I’d have cart\_items, though; I’d just have orders. The cart would be implemented as the aggregate of the orders. So an order would not have any need to know that it was in a cart, and the cart would only exist as a particular way of representing the orders. David – Q. What is THE Ruby book for Rails developers? A. RUBY FOR RAILS by David A. Black ([http://www.manning.com/black](http://www.manning.com/black)) (See what readers are saying! [http://www.rubypal.com/r4rrevs.pdf](http://www.rubypal.com/r4rrevs.pdf)) Q. Where can I get Ruby/Rails on-site training, consulting, coaching? A. Ruby Power and Light, LLC ([http://www.rubypal.com](http://www.rubypal.com)) ---
**Author:** ![jgrosjean](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/ecc23a/32.png) [@jgrosjean](https://www.ruby-forum.com/u/jgrosjean)\ **Post date:** [March 21, 2007, 8:53pm UTC](https://www.ruby-forum.com/t/restful-shopping-cart-example/89450/7 "2007-03-21T20:53:07Z")
> > map.resources :cart > > Do you mean map.resource? (See Trevor’s earlier comment on my earlier > post.) Yes, that was a typo on my part. I’ve not got a first try implementation up for people to look and and more important improve. You can download it here, I’ll put it in svn later: [http://www.hogbaysoftware.com/files/restfulstore.zip](http://www.hogbaysoftware.com/files/restfulstore.zip) It uses an SQLite database. Once you migrate you should be able to go to /store, add items to you cart, and checkout. To access the admin sections the username is ‘admin’ and the password is ‘password’. Please look through the code and help me get this right so that it can be a good example for others. I’m sure there are many ruby and railsisms that I’ve missed, and maybe bigger design issues as well. Also I’ve added a number of “HELP” comments throughout the code in places where even I could tell i was probably going down the wrong path. Here’s a quick overview of the apps structure: 1. The model objects stored in the database are user, product, order, order\_item. 2. The apps routes are: map.resources :users, :sessions map.resource :store do |store| store.resources :products store.resource :cart, :member =\> { :checkout =\> :post, :submit =\> :post, :completed =\> :get, :error =\> :get } do |cart| cart.resources :cart\_items end store.resources :orders do |order| order.resources :order\_items end end 1. And here is a quick overview of the important paths and their intent: /store - list of products along with contents of cart /store/cart - singleton resources of the current (per session) pending order /store/cart/cart\_items - supports create and destroy actions for adding items to cart /store/products - admin section for products /store/orders - admin section for orders I’m trying to use the basic design as discussed above. The users cart is really just a special order who’s status is pending. I’m using a singlton cart controller to represent that pending order. I’ve also given that cart controller cart\_items which are targeted by actions that add or remove items from the cart. 1. Last the view part of the app is still a bit hacky. Probably many of the admin views can be deleted, and I’d also like to make manipulating the cart a bit more ajaxy, but I was having trouble making that work. So for now it’s all quite basic. Thanks for any comment and suggestions. ---
**Author:** ![jgrosjean](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/ecc23a/32.png) [@jgrosjean](https://www.ruby-forum.com/u/jgrosjean)\ **Post date:** [March 22, 2007, 2:25pm UTC](https://www.ruby-forum.com/t/restful-shopping-cart-example/89450/8 "2007-03-22T14:25:29Z")
Hi – On 3/21/07, Jesse G. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > later: > could tell i was probably going down the wrong path. > map.resource :store do |store| > 3. And here is a quick overview of the important paths and their intent: > really just a special order who’s status is pending. I’m using a > singlton cart controller to represent that pending order. I’ve also > given that cart controller cart\_items which are targeted by actions that > add or remove items from the cart. > > 1. Last the view part of the app is still a bit hacky. Probably many of > the admin views can be deleted, and I’d also like to make manipulating > the cart a bit more ajaxy, but I was having trouble making that work. So > for now it’s all quite basic. > > Thanks for any comment and suggestions. I haven’t downloaded the app yet – just responding to what’s above – but just for fun, here’s my minimalist version. It may be too minimalist… but it might be interesting to identify things you can do with yours that you can’t do with mine. This is all untested… just hypothetical code and routes. class Order belongs\_to :user belongs\_to :product end class User has\_many :orders end class Product has\_many :orders has\_many :buyers, :through =\> :orders, :class\_name =\> “User”, :source =\> “user” end map.resources :products map.resources :users do |u| u.resources :orders end Show all available products: GET /products Show a user all their orders (“cart”): GET /users/1/orders Add a product to cart: POST /users/1/orders Remove a product from cart: DELETE /users/1/orders/1 etc. David – Q. What is THE Ruby book for Rails developers? A. RUBY FOR RAILS by David A. Black ([http://www.manning.com/black](http://www.manning.com/black)) (See what readers are saying! [http://www.rubypal.com/r4rrevs.pdf](http://www.rubypal.com/r4rrevs.pdf)) Q. Where can I get Ruby/Rails on-site training, consulting, coaching? A. Ruby Power and Light, LLC ([http://www.rubypal.com](http://www.rubypal.com)) ---
**Author:** ![jgrosjean](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/ecc23a/32.png) [@jgrosjean](https://www.ruby-forum.com/u/jgrosjean)\ **Post date:** [March 22, 2007, 3:54pm UTC](https://www.ruby-forum.com/t/restful-shopping-cart-example/89450/9 "2007-03-22T15:54:25Z")
Hi – On 3/22/07, Jesse G. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > order. For big sites, like amazon, I think that requirement can make > > …Or maybe in your model a visitor can have multiple orders pending and > all pending orders are considered to be in the “cart”. But the problem > with this approach is that I don’t think you have a good place to store > checkout info such as name, address, email, etc. I think you would have > to duplicate that info across each order per checkout? No, I’m assuming it would be stored in the user object. I haven’t drafted the database tables, but it would be in there (or a separate contacts table, or whatever). > In my model there is a single pending Order per visitor which is the > “cart” and it holds multiple order items, each of which is associated > with a specific product and also has a quantity. In my mind the addition > of the order\_items class makes the model work a bit better since it’s > strait forward to order multiple copies of the same product and there is > a single place to store checkout info. The Order model could have a quantity field 🙂 We’re using ‘order’ differently, though. I’m thinking of an order as per user/per product, and the “cart” as a view of the user’s pending orders. > 1. In your routes I’m not sure where the admin interface for editing > products and viewing orders is. I guess the interface for editing and > buying products could both take place at GET /products, but in my model > I’ve instead created the singleton GET /store route/controller that list > the products along with BUY buttons and I have a separate GET > /store/products route that display the admin interface for editing the > existing product collection. I think distinguishing between /store and /store/products, with one being public and one being admin, is a bit obscure. Could you just have /store/products routes (or even just /products?) and just control access to the operations that change them? David – Q. What is THE Ruby book for Rails developers? A. RUBY FOR RAILS by David A. Black ([http://www.manning.com/black](http://www.manning.com/black)) (See what readers are saying! [http://www.rubypal.com/r4rrevs.pdf](http://www.rubypal.com/r4rrevs.pdf)) Q. Where can I get Ruby/Rails on-site training, consulting, coaching? A. Ruby Power and Light, LLC ([http://www.rubypal.com](http://www.rubypal.com)) ---
**Author:** ![jgrosjean](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/ecc23a/32.png) [@jgrosjean](https://www.ruby-forum.com/u/jgrosjean)\ **Post date:** [March 22, 2007, 4:29pm UTC](https://www.ruby-forum.com/t/restful-shopping-cart-example/89450/10 "2007-03-22T16:29:09Z")
> No, I’m assuming it would be stored in the user object. I haven’t > drafted the database tables, but it would be in there (or a separate > contacts table, or whatever). > > … > > The Order model could have a quantity field 🙂 We’re using ‘order’ > differently, though. I’m thinking of an order as per user/per > product, and the “cart” as a view of the user’s pending orders. Ok I think I see what you are doing. I think in my design Order is a lot like the User in your design. And the OrderItem in my design is like your Order. In your design does a visitor to your site require a login to get a User object? Anyway I think I’m pretty comftorable with this difference and I don’t think it has a big impact on the restful aspect of the design. > I think distinguishing between /store and /store/products, with one > being public and one being admin, is a bit obscure. Could you just > have /store/products routes (or even just /products?) and just control > access to the operations that change them? It still seems to me like it would be good to have them separate. For example in the “store” interface I want to show “Add to Cart” buttons and I don’t want the site visitors to see any create, edit, or destroy links. While in the admin list I don’t want to show the “Add to Cart” button, and I do want to show those links. So I think there needs to be two different views, but maybe it would be better modeled by adding a custom action to the products resource? For example: GET /products - shows the public accessible storefront with buy buttons GET /products;admin - shows the admin interface Do people think that’s a better design then using a separate store controller to present a public view on products? ---
**Author:** ![jgrosjean](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/ecc23a/32.png) [@jgrosjean](https://www.ruby-forum.com/u/jgrosjean)\ **Post date:** [March 22, 2007, 3:34pm UTC](https://www.ruby-forum.com/t/restful-shopping-cart-example/89450/11 "2007-03-22T15:34:28Z")
David, Thanks again. Here are a few things that I think are different, though I might also just not be understanding some parts. 1. In my model ‘user’ is really just for administrators. I don’t want visitors to the site to have to create an account before making an order. For big sites, like amazon, I think that requirement can make sense, but for a small site like I’m imagining I don’t want the user to have to decide on a user name and password in the middle of the order process. That does mean that a user can’t use the site to see all of there orders, but instead I can add an interface where they enter their email and are sent an email listing all of there orders. 2. You’ve removed the order\_items model, which I think is important to keep if we want visitors to be able to buy more then one product per checkout. With the current design I’m not sure how your “cart” can hold more then one item… …Or maybe in your model a visitor can have multiple orders pending and all pending orders are considered to be in the “cart”. But the problem with this approach is that I don’t think you have a good place to store checkout info such as name, address, email, etc. I think you would have to duplicate that info across each order per checkout? In my model there is a single pending Order per visitor which is the “cart” and it holds multiple order items, each of which is associated with a specific product and also has a quantity. In my mind the addition of the order\_items class makes the model work a bit better since it’s strait forward to order multiple copies of the same product and there is a single place to store checkout info. 1. In your routes I’m not sure where the admin interface for editing products and viewing orders is. I guess the interface for editing and buying products could both take place at GET /products, but in my model I’ve instead created the singleton GET /store route/controller that list the products along with BUY buttons and I have a separate GET /store/products route that display the admin interface for editing the existing product collection. Thanks, Jesse ---
**Author:** ![jgrosjean](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/ecc23a/32.png) [@jgrosjean](https://www.ruby-forum.com/u/jgrosjean)\ **Post date:** [August 5, 2007, 3:28am UTC](https://www.ruby-forum.com/t/restful-shopping-cart-example/89450/12 "2007-08-05T03:28:17Z")
Hi Jesse, I want to develop a rest-ful shopping cart as well. Any updates regarding your implementation? Oren ---
**Author:** ![jgrosjean](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/ecc23a/32.png) [@jgrosjean](https://www.ruby-forum.com/u/jgrosjean)\ **Post date:** [March 22, 2007, 4:32pm UTC](https://www.ruby-forum.com/t/restful-shopping-cart-example/89450/13 "2007-03-22T16:32:43Z")
I still have one big restful question about making the Depot app design restful, with a possible answer at the end. I’m still really not sure on the best way to do the “add to cart” action. Forgetting the full store design discussed earlier, lets pretend that I’m just trying to model that single operation. To make this simple lets imagine that I’m copying part of the Depot app design and I’m just dealing with two objects, Cart and CartItem. A cart holds items, and each item has a quantity and a string naming a particular product. class Cart has\_many :cart\_items end class CartItem belongs\_to :cart attr\_accessor :quantity attr\_accessor :product\_name end map.resource :cart do |cart| cart.resources :cart\_items end With that design it seems like to add a new item to a cart you would use: POST /cart/cart\_items But the problem here is that items have a quantity, and that means that you really only want to be done a POST the first time you add a specific project, after that you’ll just want to update the items quantity and should be using PUT. And figuring out how to choose between those two actions has always been confusing to me… Is it the case that with the current Depot model design adding an item to a cart can’t really be done in a completely restful manner? I’m starting to think that might be the case, and that the solution is to get rid of the quantity attribute from cart item. Instead if two of the same product is added to a cart then two different CartItems should be created? Does that seem like a better design? It would make it easier to do things restfully… Thanks for any ideas, Jesse ---
**Author:** ![jgrosjean](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/ecc23a/32.png) [@jgrosjean](https://www.ruby-forum.com/u/jgrosjean)\ **Post date:** [March 25, 2008, 8:39am UTC](https://www.ruby-forum.com/t/restful-shopping-cart-example/89450/14 "2008-03-25T08:39:10Z")
We need someone to create a Ruby shopping cart for us or maybe slice our psd file into Substruct. In a perfect world, creating one for us is the key. We also need this to be syndicated into Atom or RSS 2.0 or both such as the G2 Image Gallery Application. We also are wanting to import an existing WordPress MySQL Database into it. More like a Ruby blog/shopping cart that is syndicated with Atom & RSS 2.0. We also need permalinks or URL friendly concepts, however you want to say it now days. We also have an existing G2 MySql database that we want in Ruby too. Can anyone help me? Thanks, sb 🙂 ~~@~~ @~~ oren wrote: > Hi Jesse, > I want to develop a rest-ful shopping cart as well. > Any updates regarding your implementation? > > Oren ---
**Author:** ![jgrosjean](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/ecc23a/32.png) [@jgrosjean](https://www.ruby-forum.com/u/jgrosjean)\ **Post date:** [March 25, 2008, 1:44pm UTC](https://www.ruby-forum.com/t/restful-shopping-cart-example/89450/15 "2008-03-25T13:44:53Z")
The Depot application is the perfect example of a good sample REST application in my opinion. I really wish that the Pragmatic guys would release a AWDR v 3 with a fully RESTified Depot application. Just wanted to put it out there that I agree that this would be a good “real” rest application. I put a little thought into how I would do it and I think the only two database-backed resources would need to be user, order, and product. So those three would have their controllers and then all other controllers would be based on those resources and would use the session. Now I am tempted to try to whip together an exact copy of the Depot application using all the new Rails 2 principles… (Looking through the thread, it appears David beat me to the user / order / product resource idea but I will post this anyways)