We are creating a REST API using OpenRasta and apart from regular GET, POST, PUT and DELETE on all resources, we are also providing GET on resources with plural names. So a consumer of the API can GET, POST, PUT and DELETE on User and also perform GET on Users which will return List<Users>. Now we want the clients to be able to filter and sort it by it's properties and allow to support paging for showing data in paged tabular formats.
Although, I looked at WCF Data Services Toolkit home page and looks like it can be useful but after looking at blog posts and Getting Started page, I couldn't understand how I can use it to solve my problem in OpenRasta.
Or is there anything else simpler that I can do?
OR doesn't support stuff like OData for that functionality, mainly because it leads to very unrestful systems.
If /users is "the list of users", then it is a different resource than /users/1 (the first page of users) or /users/byName/1 (the first page of users ordered by name).
You can of course implement all this easily by registering a URI that has query parameters, as those are optional
.AtUri("/users?page={page}&filter={filter}
And your handler can look like
public List<User> Get(int page = 0, string filter = null) { ... }
Related
I'm thinking about using Stormpath with it's Java API as a user storage.
Looks good, except that I can't search for users.
For example, I get this error:
Exception in thread "main" com.stormpath.sdk.resource.ResourceException: HTTP 400, Stormpath 2105 (http://docs.stormpath.com/errors/2105): Account ID is not a supported query property.
when I execute this query:
HashMap<String, Object> queryParams = Maps.newHashMap();
queryParams.put("ID", "4mPXXXXXXXXXX");
searchResult = application.getAccounts(queryParams);
Searching for a user by e-mail however works. I get the same error when I try to search a user by a login-token I stored in the customData property.
It looks like what I want to do is not possible as it looks like the only properties you can query are e-mail and username. But why would they provide this functionality if it didn't work. What am I missing?
There is an impedance mismatch between common relational database behaviors and those in a REST API. Querying by id, while common in relational databases, is not idiomatic behavior for REST APIs (or most HTTP-based web sites). The URL (href) is the canonical 'pointer' to a resource on the web. In other words, in REST APIs, the canonical identifier is the href. Any token inside an href (any internal 'id', special characters, whatever) should be opaque to REST clients and ignored by clients entirely. URLs are king in HTTP and REST.
That being the case, the Stormpath SDK tries to be true to RESTful best practices, so you can obtain any Stormpath resource by using the client.getResource method, which accepts an href and the type of object you expect that href to represent:
String href = "https://api.stormpath.com/v1/accounts/" + id;
Account account = client.getResource(href, Account.class);
That said, there's nothing wrong with wanting this to be more conveniently represented in the client API, for example, client.getAccount(String id) if you want to keep the notion of IDs. If so, please open a new feature request and we'll be very happy to consider it.
As for queryable Account properties, those are documented here. Stormpath will soon make data in Custom Data searchable as well. While Stormpath feature timelines are never announced, it is the company's highest engineering priority and it should be out soon.
One workaround that is helpful for some people is to store data they want to search in Account Fields that you don't use in your applications. For example, you could use the 'middle name' field to store, say, favorite color. This would only be temporary until custom data search is available. HTH!
I am using a filter to apply object level permissions to a collection. Resources in a second collection have a many-to-many relationship with the first. On the browsable API, when creating resources in the second collection, the user is presented with a list of resources from the first to link it to. However, this list is not filtered, so the user can see values that they should not be able to see.
I've poked around the documentation and source a bit and I cannot see a way to add filtering to the queryset that generates the choices without overloading or modifying a bunch of code to pass the request data down (probably removing some of the collection specific data on the way) and then apply the filters.
Is there a better way to achieve this?
Currently there's nothing to support this out of the box. Pull requests are always welcome. If it's something you want to work on you may want to either open a ticket on GitHub or hit up the mailing list to discuss it first.
I want to build a typical mvc app for CRUD of simple items, the api s should be RESTful. The catch here is, that i have a large pallete of items that needs to be initialized. On the server side those items are defined as java beans and the corresponding create form for the item is dynamically created from the field information(data type, validation constraints etc) harvested from the bean.
I am new to REST and just read up about how the urls should be nouns defining the resource and action specified by HTTP verb. In that perspective how to model something like
.../client/showForm?type=xyz from non RESTful way to RESTful one ?? My intention here is to tell the server to dynamically construct and send back a CREATE form for client of type xyz. The obvious problem with url i mentioned above is that it specifies action in the url which, from what i have read, makes it non RESTful.
When I think of REST, I think of resources. I think of data. In other words, I don't think of REST as being something that I would typically use to retrieve a form, which is a user interface component.
REST is an architectural style that is used to identify a resource on a server using a uniform resource identifier, or URI. Additionally, actions performed on those resources identified by the URI are determined based on the specific HTTP Method used in the request: GET, POST, PUT, DELETE, etc.
Thus, let's say you have a Client object. That client object might have the following properties:
Name
Location
AccountNumber
If I wanted to retrieve the data for a single client, I might use the following URI:
GET /client/xyz/ # xyx is the accountnumber used to identify the client.
I would use a GET method, since REST describes GET as being the method to use when retrieving data from the server.
The data could theoretically be returned in HTML, since REST is not a standard but more like a series of flexible guidelines; however, to really decouple my data from my user interface, I would choose to use something platform independent like JSON or XML to represent the data.
Next, when adding a client to the collection on the server, I would use the /client/ URI pattern, but I would use the HTTP Method POST, which is used when adding a resource to a collection on the server.
# Pass the data as JSON to the server and tell the server to add the client to the
# collection
POST /client/ {"accountnumber":"abc" , "Name" : "Jones" , "Location" : "Florida"}
If I were to modify an existing record on the server or replace it, I would most likely use the HTTP Method PUT, since REST guidelines say that PUT should be used if repeating the same operation repeatedly would not change the state of the server.
# Replace the client abc with a new resource
PUT /client/abc/ {"accountnumber":"abc" , "Name" : "Bob Jones" , "Location" : "Florida"}
The general idea behind REST is that it is used to identify a resource and then take action on that resource based on what HTTP Method is used.
If you insist on coupling your data with your view, one way accomplish this and retrieve the actual form, with the client data, could be to represent the form as a resource itself:
GET /client/abc/htmlform/
This URL would of course return your client data for client abc, but in an HTML form that would be rendered by the browser.
While my style of coding utilizes data transports such as JSON or XML to abstract and separate my data from my view, you could very well transport that data as HTML. However, the advantage of using JSON or XML is that your RESTful API becomes platform independent. If you ever expand your API to where other developers wish to consume it, they can do so, regardless of what specific platform or programming language they are using. In other words, the API could be used my PHP, Java, C#, Python, Ruby, or Perl developers.
In other words, any language or platform that can make HTTP requests and can send GET, POST, PUT, DELETE requests can be used to extend or build upon your API. This is the true advantage of REST.
For more information on setting up your controllers to use REST with Spring MVC, see this question. Additionally, check out the Spring MVC Documentation for more information.
Also, if you haven't checked out the Wikipedia article on REST, I strongly encourage you to do so. Finally, another good, classic read on REST is How I Explained REST To My Wife. Enjoy.
I am trying to make a RESTful api and have some function which needs credentials. For example say I'm writing a function which finds all nearby places within a certain radius, but only authorised users can use it.
One way to do it is to send it all using GET like so:
http://myapi.heroku.com/getNearbyPlaces?lon=12.343523&lat=56.123533&radius=30&username=john&password=blabla123
but obviously that's the worst possible way to do it.
Is it possible to instead move the username and password fields and embed them as POST variables over SSL, so the URL will only look like so:
https://myapi.heroku.com/getNearbyPlaces?lon=12.343523&lat=56.123533&radius=30
and the credentials will be sent encrypted.
How would I then in Sinatra and Ruby properly get at the GET and POST variables? Is this The Right Way To Do It? If not why not?
If you are really trying to create a restful API instead if some URL endpoints which happen to speak some HTTP dialect, you should stick to GET. It's even again in your path, so you seem to be pretty sure it's a get.
Instead of trying to hide the username and password in GET or POST parameters, you should instead use Basic authentication, which was invented especially for that purpose and is universally available in clients (and is available using convenience methods in Sinatra).
Also, if you are trying to use REST, you should embrace the concept of resources and resoiurce collections (which is implied by the R and E of REST). So you have a single URL like http://myapi.heroku.com/NearbyPlaces. If you GET there, you gather information about that resource, if you POST, you create a new resource, if you PUT yopu update n existing resource and if you DELETE, well, you delete it. What you should do before is th structure your object space into these resources and design your API around it.
Possibly, you could have a resource collection at http://myapi.heroku.com/places. Each place as a resource has a unique URL like http://myapi.heroku.com/places/123. New polaces can be created by POSTing to http://myapi.heroku.com/places. And nearby places could be gathered by GETing http://myapi.heroku.com/places/nearby?lon=12.343523&lat=56.123533&radius=30. hat call could return an Array or URLs to nearby places, e.g.
[
"http://myapi.heroku.com/places/123",
"http://myapi.heroku.com/places/17",
"http://myapi.heroku.com/places/42"
]
If you want to be truly discoverable, you might also embrace HATEOAS which constraints REST smentics in a way to allows API clients to "browse" through the API as a user with a browser would do. To allow this, you use Hyperlink inside your API which point to other resources, kind of like in the example above.
The params that are part of the url (namely lon, lat and radius) are known as query parameters, the user and password information that you want to send in your form are known as form parameters. In Sinatra both of these type of parameters are made available in the params hash of a controller.
So in Sinatra you would be able to access your lon parameter as params[:lon] and the user parameter as params[:user].
I suggest using basic or digest authentication and a plain GET request. In other words, your request should be "GET /places?lat=x&lon=x&radius=x" and you should let HTTP handle the authentication. If I understand your situation correctly, this is the ideal approach and will certainly be the most RESTful solution.
As an aside, your URI could be improved. Having verbs ("get") and query-like adjectives ("nearby") in your resource names is not really appropriate. In general, resources should be nouns (ie. "places", "person", "books"). See the example request I wrote above; "get" is redundant because you are using a GET request and "nearby" is redundant because you are already querying by location.
I have a RESTful URL that requires either the offset or the prefix request parameter (but not both).
GET /users?offset=0&count=20
GET /users?prefix=J&count=20
What's the best way to enforce this rule? Spring has the #RequestParam annotation with the 'required' property for optional parameters, but I want to enforce an "either-or" rule on these two parameters. I know I could do it in the code, but is there another way to do it?
Also, what's the proper way to handle "impractical" requests? Say I have 100 million users; the following request, although properly RESTful, is not something I want to support:
GET /users <-- Gets all 100 million users, crashes server and browser!
What should I send back?
You can create two methods and choose one of them with #RequestMapping's params attribute:
#RequestMapping(..., params = {"prefix", "!offset"})
public String usersWithPrefix(#RequestParam("prefix") ...) { ... }
#RequestMapping(..., params = {"offset", "!prefix"})
public String usersWithOffset(#RequestParam("offset") ...) { ... }
what's the proper way to handle "impractical" requests?
The lesser-practiced principles of REST include the requirement that resources be "discoverable". If you are asked for a complete list of 800 million users and you don't want to provide it, you might instead consider serving a page that describes in some way how to filter the collection: for example, an XForms document or HTML containing a FORM element with fields for offset/prefix/count, or a URI template with the appropriate parameters
Or you could just send a "413 Entity too large" error - edit: no you can't. Sorry, I misread the description of whath this code is for
If you decide to go down the route of just sending the first page, I think I would send it as an HTTP redirect to /users?offset=0&count=20 so that the client has a better idea they've not got the full collection (and if your response contains a link to access subsequent pages, even better)