REST Web API - many-to-many relationship - api

Ok, my last question had no answers, so I've the doubt that I'm walking on the wrong way.
I'm developing some Web REST Api for a mobile application, and regarding REST best pratices I don't know how to face a many-to-many relationship.
I have two tables, Wallets and Cateories, between these tables there is a many to many relationship since a category may be associated to different wallets and a wallet may own different categories.
Actually this database is used by a non rest website:
when a user creates a new category, he choose from the list of his own wallets which wallets to connect it to, and with this single POST call the category is created and conneted to the wallets.
I don't think that replicating this behaviour is compliant to REST best pratices.
My first idea was to "expose" the connection between categories and wallets with this form:
http://localhost:8000/categories/77/wallets/4
but I had the problem I wrote on my previous question, and I don't think this is the right way.
Anyone has a valid method to manage a many-to-many realtionship according with REST best pratices?
Thanks in advance.

Namespacing wallets by a category is fine, as in /categories/77/wallets/4. You can also consider a more concise scheme like /categories/77/4 or /wallets/77/4 if there are only wallets in a category.
However, you don't have to namespace. Your wallets presumably have their own IDs, so you could also just expose them as /wallets/4.
Is it worth the effort? I think it can be a good practice if your URLs are also on a public website (in which case you would probably want to support slug IDs as well, e.g. /categories/luxury/wallets/acme). If not, you should be aware it will be a little more configuration work on the server-side and a little more work for clients (clients will have to be aware of 2 IDs instead of 1).

Related

Ways to handle security/authorization in a multi tenant API

I'm playing around with a spare time project, mainly to try out new stuff :)
This involves designing a REST API for a system that is multi tenant. Lets say you have an "organization" that is the "top" entity, this might have an API key assigned that is used for authenticating each request. So on each request we have an organization associated.
Now when a user of the API would like to get a list of, lets say projects, only those that belong to that organization should be returned. The actual implementation, the queries to the database, is pretty straight forward. However the approach is interesting I think.
You could implement the filtering each time you query the database, but a better approach would be a general pre-query applied to all "organization" related queries, like all queries for enities that belong to an organization. It's all about avoiding the wrong entities from being returned. You could isolate the database, but if that is not possible how would you approach it?
Right now I use NancyFX and RavenDB so input for that stack would be appreciated, but general ideas and best practices, do's and don't is very welcome.
In this case you could isolate your collections by prefixing them with the organization_id. It will duplicate maybe many collections.
Use case with mongodb: http://support.mongohq.com/use-cases/multi-tenant.html

REST best practices: should a store also return metadata?

I'm building my first REST API (at least trying) for a personal project.
In this project there are resources called players which hold can be in a team. According to REST API design rulebook a resource should be made either to be a document or a store and one should keeps these roles as segregated as possible.
Yet I would like to append some metadata to the team resource, eg the date the team was founded. Is it okay then for GET /teams/atlanta to return this metadata (making it a document) alongside the list of players in the team (making it a store).
Is this a good idea? If so why? If not why not and how to solve this better?
I know there are no rules to developing a REST API, but there are good practices and I would like to adhere to those. Please also not that this is really my first REST API so pardon my ignorance if there is any.
I would recommend having GET /teams/atlanta return just the information about the team, such as the founding date that you mention, and then having GET /teams/atlanta/players return the list of players for that team. These distinctions become more important when you are presenting an API that uses HTTP methods other than GET.
For example, if you wanted to add a player to a team - this would be a lot easier if you could just POST a player object to /teams/atlanta/players than if you had to PUT the whole team object to /teams/atlanta every time you wanted to add one individual player.
If your API only allows retrieval of data, and if it is for a specific client application, there is an argument for combining all the team data into one object to save the client having to make additional requests for the data, but bear in mind that it is less flexible.
Your application may want to display a list of teams by calling GET /teams but you probably wouldn't want all of the player information included in each object in the list as this is quite a lot of data, but if GET /teams/atlanta returns player information then it would be inconsistent not to include it in the list version too.
I would personally favour splitting up the resources as I've suggested, and live with the fact the client may need to make an extra request or two.

User friendly and restful (rails 3)

i am a rails programmer who is on to his 3rd project now (new of course).I am looking for an answer to a general question about Restful architecture. I am sure i am doing something that has a good established answer already.
In restful approach we expose resources but some times this approach feels a little Non user friendly. For example i can expose a product via a show method and then i have another resource called sales that i can expose via product/:id/sales show template to show all sales for a product. But i am taking the user through an extra click here. The ideal will be to show product and all its associated sales on one page itself. But that is a violation of the Restful rule.
I just wanted to ask that are these rules generally broken to make the site user friendly? Being a new comer i dont want to adopt ways that are non ideal so i thought i should ask this question.
Thanks in advance.
Adding in the sales for a particular product would not be breaking any constraints from the RESTful architecture. You have the product ID in the HTTP request so you can just also get the sales for that product. Your separation of concerns should not be affected and you don't need to store a state to get this information. Just extend the model that you return with the view.
It seems like you are more concerned with straying from the convention over configuration that Rails promotes. This extension means that your model will not correlate with only one table in your database, but that is fine. The conventions are meant to reduce the configuration work that you need to do, not restrict your functionality.

How to organize REST API?

I'm developing a rest API for our business system. We have the following resources so far:
/sales/orders
/sales/orders/{orderno}
/sales/order-items
There will be lots of resources when the API is finished, so we need to structure it in a good way to make it easy to understand. My question is: should /sales/order-items instead be /sales/orders/order-items? There is maybe no correct answer here, but what would you prefer?
One more question: The sales/order-items resource will list either all open items or all shipped items. It will not be possible to get all order-items regardless of status (open/shipped). The resource URI could the be like this sales/order-items?orderstatus={OPEN/SHIPPED} (the orderstatus query parameter would be mandatory then) or it could be two resources like this sales/order-items/open and sales/order-items/shipped. What is the preferred?
A resource is 'any information that can be named'. Your URIs should be entity based. 'order-items' is not an entity, but a data type.
/sales/order/order-1456321 is the Entity you most likely want. Which would contain the data of all order items.
If you wish to restrict access, you can return a client error if no query string is supplied. and having
/sales/order/order-12345?status=open
etc. Hope this helps.
EDIT:
/sales/order-items or /sales/orders/order-items?
This is domain specific, and really should be answered by a domain expert. Your URI Hierarchy provides scope (and so detail) to your resource. So as an educated guess, It does not make sense to have "order-items" within the scope of "/sales/orders/" because "order-items" is not an "order".
/sales/ordered-items
seems the most sensible answer.
On a personal note, and not to question your domain too much, Having a strong understanding of the flow of the business and information that's stored may result in something along the lines of these suggestions;
/sales/orders?status=open - Are all orders shipped at once?
/sales/orders/order-1234/packages?status=open - Are orders split into packages?

Unique identifiers for each resource in RESTful API?

In an ideal RESTful API that supports multiple accounts, should each resource have it's unique identifier across the entire system, or it is OK if that identifier is unique for the specific account that it belongs to.
Are there any pros and cons for each scenario?
To give an example.
Would this be fine from the REST principles?
http://api.example.com/account/1/users/1
...
http://api.example.com/account/50/users/1
or would this approach be recommended?
http://api.example.com/account/1/users/{UNIQUE_IDENTIFIER}
...
http://api.example.com/account/50/users/{ANOTHER_UNIQUE_IDENTIFIER}
You reveal valid user numbers by always having the first user as 1. Someone then knows that any account will also have a user 1. I'm not saying that you should hide user IDs just through obscurity but why make it easy for someone to find the user IDs in another account?
All that really matters is that each resource has a unique identifier. Both of your examples accomplish that, so you seem to be okay (RESTfully speaking)
I don't see any compelling reason to use one over the other. I'd choose whatever makes more sense for your implementation.
Since, from the perspective of an external system using your REST API, the entire address should be considered to be the "identifier" for that resource object, so your first example is fine.