REST Url ID Placement for Resources with Collections - rest

Is this a good structure for REST URLs?
Assuming:
GET /account <- get list of accounts
GET /account/1234 <- get account 1234
etc.
If the account resource has a collection that I want to interface, is this a good idea?
GET /account/1234/note <- get notes for account 1234
POST /account/1234/note <- add note to account 1234
DELETE /account/1234/note/321 <- delete note 321 on account 1234
Especially that last one gives me pause; typically I wouldn't require both the entity ID and the parent ID when deleting.
Or maybe something like this would be better?
GET /account-note/1234 <- get notes for account 1234
POST /account-note/1234 <- add note to account 1234
DELETE /account-note/321 <- delete note 321 on account 1234 (b/c note 321 is on account 1234)
But then I'd end up with a pretty shallow URL set.
Thanks

There's nothing wrong with your first api. In large part, the idea of the RESTful interface is to go with the natural tree structure of the web, and your first approach is in keeping with that. It's also going to be a structure that does the API's job of abstracting away implicit constraints of your datastore, because the second approach implicitly assumes that the id of note is globally unique. This may be true now, and will probably remain true, but it's also exactly the kind of bug that suddenly appears with disastrous consequences when, down the line, some kind of major db change happens.
I'd go with your first scheme. It's a familiar rest pattern, it's intuitive, and it's not going to blow up in a weird way down the line. Also, in response to #Corwin01 minimize the query params--they're not so RESTful.

I referenced this question in my comments on another question and between the feedback I got there and my own research this is what I've come up with.
Firstly, the question is sort of flawed. RESTful APIs, or to use the perferable term Hypermedia APIs should include the urls of related actions so that the interface is discoverable and changes won't break existing clients, therefore the exact structure has significantly less importance than I was placing on it, these can be changed later.
Secondly, the note in the example will be retrieved as part of an account query, maybe something like this:
<account>
...
<notes>
<note>
...
<link href="/account-note/123" rel="note">
</note>
</notes>
</account>
The client will never be assembling urls to the account on their own, the client will use the link provided. Since the note ID is globally unique in this case, there is no need to include the key twice. Hence the answer to the question is no, the first example is not a good REST url structure, the second one is better. (Although still maybe not the best...)

Mind you, my experience is with JAX-RS and Jersey, so I'm not sure what the exact differences are.
However, this is what I would do:
#GET
#Path ("/account/note/{id}")
public void displayNotes(#PathParam ("accountId") String accountId)
{
//do stuff
}
#POST
#Path ("/account/note")
public void addNote(#FormParam ("accountId") String accountId)
{
//do stuff
}
#POST
#Path ("/account/note/delete")
public void deleteNote(#FormParam ("accountId") String accountId, #FormParam ("noteId") String noteId)
{
//do stuff
}
This way, you don't have cluttered and confusing URLs that the user doesn't need to see anyways, especially if the user tries to navigate there on their own. Which is ok for displaying the accounts, but would confuse them for the URLs that POST, since they would get a 404 and not understand why.
Keep it simple, and just user #FormParams since the user doesn't need to see that anyways.

Related

Generate unpredictable/unforgeable URL from predictable ID

I have a simple API that return Something for a given ID and it must be used without any kind of authentication, the URL should be permanent and yet I want to avoid as much as possible it to be botted.
The Url is something like this:
https://url/{SomeId}/doSomething
The problem is that this is very predicable and a bot could easily try all the ID and get everything associated to it.
I'm looking for a way to make the URL non predictable like for example:
https://url/{SomeId}/doSomething?Key=SomeVeryLongCryptographicKey
In this way except if you run a supercalculator you shouldn't be able to deduce all the URLs
I know that there is probably a lot of ways to do that, like using a DB which I want to avoid.
I guess I'm looking for a kind a JWT associated to the ID without expiration but maybe there is better solution.
Edit: to give a better example i'm looking to do a bit like did Zoom for permanent invitation Links. They had predictable room Ids and they added a password making it unpredictable lie so:
https://us05web.zoom.us/j/132465789?pwd=SUxIU0pLankyhTRtWmlGbFlNZ21Ndz08
What would be the best/light/"secure" way to achieve that ?
Also I'm using .Net if there is a library doing that, it would be great.
I think your idea of using a JWT makes the most sense. Better to use something standard from a cryptographic point of view, and the JSON format allows for encoding whatever you need to provide to the receiving endpoint (user names, entity names, entity IDs, other things).
There are standard Microsoft libraries for building and validating JWTs, but I prefer the library Jwt.Net (https://www.nuget.org/packages/JWT). It lets you do something like this quite easily:
var token = JwtBuilder()
.WithAlgorithm(new RS256Algorithm(publicKey,privateKey))
.AddClaim("uri", String.Format("https://example.com/api/{0}/{1}", entityName, entityId))
.Encode();
Just add whatever claims you like, and the JWT will then contain what you want to transfer (I've used an example of the URI that you want to give to the entity) and a signature with your private key. You could even just give a URL like https://example.com/from_token/eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiJ9.eyJ1cmkiOiJodHRwczovL2V4YW1wbGUuY29tL2FwaS90ZXN0RW50aXR5LzEyMzQifQ.K2P4wSF6g1Kt-IHMzlklWTV09_MIkoiNHQztSIYOohmOWe7aBfFSQLIKSbdTECj9XPjNNG_AjH9fdjFglkPuYfr2G9rtl2eh5vTjwdM-Uc0X6RkBu0Z2j7KyMKjkaI3zfkIwhtL1mH873xEBtNOGOW18fuBpgnm8zhMAj1oD3PlDW8-fYBrfLb6VK97DGh_DyxapbksgUeHst7cAGg3Nz97InDPtYcWDi6lDuVQsj3t4iaJBRL8IM785Q8xjlHHhzdfcX3xU4IhflyNHHXxP56_8ahNNMOZKWdwgbTSIxEEB98b3naY3XknC-ea7Nc1y4_5fszrYdy3LaQWV43jpaA
and have the handler decode the entity name and ID you want to retrieve directly from the URI while verifying the signature. Decoding with the library is just as easy:
var json = JwtBuilder.Create()
.WithAlgorithm(new RS256Algorithm(_key))
.MustVerifySignature()
.Decode(token);

REST - Updating partial data

I am currently programming a REST service and a website that mostly uses this REST service.
Model:
public class User {
private String realname;
private String username;
private String emailAddress;
private String password;
private Role role;
..
}
View:
One form to update
realname
email address
username
Another form to update the role
And a third form to change the password
.
Focussing on the first view, which pattern would be a good practice?
PUT /user/{userId}
imho not because the form contains only partial data (not role, not password). So it cannot send a whole user object.
PATCH /user/{userId}
may be ok. Is a good way to implement it like:
1) read current user entity
2)
if(source.getRealname() != null) // Check if field was set (partial update)
dest.setRealname(source.getRealname());
.. for all available fields
3) save dest
POST /user/{userId}/generalInformation
as summary for realname, email, username
.
Thank you!
One problem with this approach is that user cannot nullify optional fields since code is not applying the value if (input is empty and value) is null.
This might be ok for password or other required entity field but for example if you have an optional Note field then the user cannot "clean" the field.
Also, if you are using a plain FORM you cannot use PATCH method, only GET or POST.
If you are using Ajax you might be interested in JSON Merge Patch (easier) and/or JavaScript Object Notation (JSON) Patch (most complete); for an overview of the problems that one can find in partial updates and in using PATCH see also this page.
A point is that a form can only send empty or filled value, while a JSON object property can have three states: value (update), null (set null) and no-property (ignore).
An implementation I used with success is ZJSONPATCH
Focussing on the first view, which pattern would be a good practice?
My suggestion starts from a simple idea: how would you do this as web pages in HTML?
You probably start from a page that offers a view of the user, with hyperlinks like "Update profile", "Update role", "Change password". Clicking on update profile would load an html form, maybe with a bunch of default values already filled in. The operator would make changes, then submit the form, which would send a message to an endpoint that knows how to decode the message body and update the model.
The first two steps are "safe" -- the operator isn't proposing any changes. In the last step, the operator is proposing a change, so safe methods would not be appropriate.
HTML, as a hypermedia format, is limited to two methods (GET, POST), so we might see the browser do something like
GET /user/:id
GET /forms/updateGeneralInformation?:id
POST /updates/generalInformation/:id
There are lots of different spellings you can use, depending on how to prefer to organize your resources. The browser doesn't care, because it's just following links.
You have that same flexibility in your API. The first trick in the kit should always be "can I solve this with a new resource?".
Ian S Robinson observed: specialization and innovation depend on an open set. If you restrict yourself to a closed vocabulary of HTTP methods, then the open set you need to innovate needs to lie elsewhere: the RESTful approach is to use an open set of resources.
Update of a profile really does sound like an operation that should be idempotent, so you'd like to use PUT if you can. Is there anything wrong with:
GET /user/:id/generalInformation
PUT /user/:id/generalInformation
It's a write, it's idempotent, it's a complete replacement of the generalInformation resource, so the HTTP spec is happy.
Yes, changing the current representation of multiple resources with a single request is valid HTTP. In fact, this is one of the approaches described by RFC 7231
Partial content updates are possible by targeting a separately identified resource with state that overlaps a portion of the larger resource
If you don't like supporting multiple views of a resource and supporting PUT on each, you can apply the same heuristic ("add more resources") by introducing a command queue to handle changes to the underlying model.
GET /user/:id/generalInformation
PUT /changeRequests/:uuid
Up to you whether you want to represent all change requests as entries in the same collection, or having specialized collections of change requests for subsets of operations. Tomato, tomahto.

Why use selectors and not a new URI?

I have a doubt, I have a URI that will bring me all user's account from another rest service. Example:
GET /users/21212/account
Now I have the need to bring 3 kinds of different groups of user's account, something like: "low-account", "medium-account" and "high-account".
But the discussion is, how should I enable this on my endpoint ?
GET /users/21212/accounts/low-account
GET /users/21212/accounts/medium-account
GET /users/21212/accounts/high-account
or
GET /users/21212/accounts/1?selector=low-account
GET /users/21212/accounts/1?selector=medium-account
GET /users/21212/accounts/1?selector=high-account
I'm inclinated to follow the first approach, I think is more intuitive and the manutenability of the code will be easily preserved... What do you think is conceptual right/better and why ?
I would choose the following option:
GET /users/12345/accounts?group=low-account
It will return you all accounts that belong to 'low-account' group for user 12345.
I tend to use query params if they represent something like filtering. Also I would recommend you to take a look at HATEOAS principle. Then you will be more flexible with your URIs.

RESTful Many-to-Many possible?

How to I represent a complex resource for a REST post?
Hello,
Currently I have an application which when the user hits "save" it iterates over all of the form elements and creates one mass object which manages a:
var = params = [{
attributes1: form1.getValues(),
attributes2: form2.getValues(),
.. ..
}];
I then send this mass object via a RPC POST to my "Entity" model service.
This entity which I wish to persist data for is quite complex. All in all, the data is spread accross about 30 tables. To help explain my actual question, the "entity" is a building (as in a physical property/house/apartment).
What I would like, is to be able to turn my mess into a RESTful API for saving properties.
The problem I have is that, saving details for a single model that spans a single table is fine. How do I structure my data object for transport when the model has
many to many relationships
one to many relationships
one to one relationships
For example:
Here is a WATERED down version of what I might have on a property and the sample data
propertyId: 1,
locationId: 231234,
propertyName: "Brentwood",
kitchenFeatures: [
{ featureId: 1, details: "Induction hob"},
{ featureId:23, details: "900W microwave"}
],
propertyThemes: [ 12,32,54,65 ]
This actually goes on a lot more.. but you can get the general gist. kitchenFeatures would be an example of a many-to-many, where I have a featuresTable which has all of the features like so:
`featureId`, `feature`
1 "Oven Hob"
23 "Microwave"
and propertyThemes would be an example of another many-to-many.
How am I expected to form my "object" to my RESTful service? Is this even possible?
ie. If I want to save this property I would send it to:
http://example.com/api/property/1
The approach I would use here is hypermedia and links:
/property
/property/{id}
/property/{id}/features/{id}
Depending on your domain you might even get away with:
/property/{id}/features/{name}
or
/property/{id}/features/byname/{name}
Thus you can do REST operations and serve JSON or XHTML hypermedia.
Property details:
Request: GET /property/1
Response:
{
..
"name": "Brentwood",
"features": "/property/1/features"
..
}
Brentwood's features:
GET /property/1/features
{
..
"Kitchen": "/property/1/features/1",
"Dog Room": "/property/1/features/dog%20room",
..
}
GET /property/1/features/1
{
..
"Induction hob": "/property/1/features/1/1",
"900W microwave": "/property/1/features/1/23",
"nav-next" : "/property/1/features/dog%20room",
..
}
To add a relation you can do something like this:
POST /property/1/features
{
..
"Name": "Oven Hob"
..
}
If you know what the relation will be you use a PUT:
PUT /property/1/features/23
{
..
"Name": "Oven Hob"
..
}
You can serve multiple media types:
GET http://host/property/1/features/dog%20room.json
GET http://host/property/1/features/dog%20room.xhtml
For the response in xhtml the response can use named links like this:
..
Kitchen
..
There are other aspects of REST that you can use such as response code which I did not include above.
Thus, to model relations you make use of links which can be in itself a resource that can be operated on with GET, PUT, POST and DELETE or even custom verbs such as ASSOCIATE or LINK. But the first four are the ones that people are used to. Remember PUT is idempotent but not POST. See PUT vs POST in REST
Edit: You can group your links into JSON arrays to give structure to your hypermedia.
I think you're really asking, "How do I represent complex data in a form suitable for transmission within a POST?", right? It's less to do with REST and more to do with your choice of media type. I would suggest starting with a pure JSON representation, using arrays and cross-referenced ID fields to map the relationships. You could also do this with XML, of course.
The examples you gave look right on the money. You just need to ensure that both parties (browser and server) agree on the structure and interpretation of the media type you use.
I'm dealing with the exact same thing. I opted to not use id's anywhere, but use urls everywhere an id would normally be expected.
So in your case, the kitchenfeatures could simply be an array with urls to:
/feature/1
/feature/23
And the themes to
/propertyTheme/12
/propertyTheme/32
etc..
In the case of many-to-many relationships, we update all the relations as a whole. Usually we simply dump the existing data, and insert the new relationships.
For one to many relationships we sometimes extend the urls a bit where this makes sense. If you were to have comments functionality on a 'property', this could look like
/property/1/comment/5
But this really depends on the situation for us, for other cases we put it in the top-level namespace.
Is this helpful to you?

Best practice for partial updates in a RESTful service

I am writing a RESTful service for a customer management system and I am trying to find the best practice for updating records partially. For example, I want the caller to be able to read the full record with a GET request. But for updating it only certain operations on the record are allowed, like change the status from ENABLED to DISABLED. (I have more complex scenarios than this)
I don't want the caller to submit the entire record with just the updated field for security reasons (it also feels like overkill).
Is there a recommended way of constructing the URIs? When reading the REST books RPC style calls seem to be frowned upon.
If the following call returns the full customer record for the customer with the id 123
GET /customer/123
<customer>
{lots of attributes}
<status>ENABLED</status>
{even more attributes}
</customer>
how should I update the status?
POST /customer/123/status
<status>DISABLED</status>
POST /customer/123/changeStatus
DISABLED
...
Update: To augment the question. How does one incorporate 'business logic calls' into a REST api? Is there an agreed way of doing this? Not all of the methods are CRUD by nature. Some are more complex, like 'sendEmailToCustomer(123)', 'mergeCustomers(123, 456)', 'countCustomers()'
POST /customer/123?cmd=sendEmail
POST /cmd/sendEmail?customerId=123
GET /customer/count
You basically have two options:
Use PATCH (but note that you have to define your own media type that specifies what will happen exactly)
Use POST to a sub resource and return 303 See Other with the Location header pointing to the main resource. The intention of the 303 is to tell the client: "I have performed your POST and the effect was that some other resource was updated. See Location header for which resource that was." POST/303 is intended for iterative additions to a resources to build up the state of some main resource and it is a perfect fit for partial updates.
You should use POST for partial updates.
To update fields for customer 123, make a POST to /customer/123.
If you want to update just the status, you could also PUT to /customer/123/status.
Generally, GET requests should not have any side effects, and PUT is for writing/replacing the entire resource.
This follows directly from HTTP, as seen here: http://en.wikipedia.org/wiki/HTTP_PUT#Request_methods
You should use PATCH for partial updates - either using json-patch documents (see https://datatracker.ietf.org/doc/html/draft-ietf-appsawg-json-patch-08 or http://www.mnot.net/blog/2012/09/05/patch) or the XML patch framework (see https://www.rfc-editor.org/rfc/rfc5261). In my opinion though, json-patch is the best fit for your kind of business data.
PATCH with JSON/XML patch documents has very strait forward semantics for partial updates. If you start using POST, with modified copies of the original document, for partial updates you soon run into problems where you want missing values (or, rather, null values) to represent either "ignore this property" or "set this property to the empty value" - and that leads down a rabbit hole of hacked solutions that in the end will result in your own kind of patch format.
You can find a more in-depth answer here: http://soabits.blogspot.dk/2013/01/http-put-patch-or-post-partial-updates.html.
I am running into a similar problem. PUT on a sub-resource seems to work when you want to update only a single field. However, sometimes you want to update a bunch of things: Think of a web form representing the resource with option to change some entries. The user's submission of form should not result in a multiple PUTs.
Here are two solution that I can think of:
do a PUT with the entire resource. On the server-side, define the semantics that a PUT with the entire resource ignores all the values that haven't changed.
do a PUT with a partial resource. On the server-side, define the semantics of this to be a merge.
2 is just a bandwidth-optimization of 1. Sometimes 1 is the only option if the resource defines some fields are required fields (think proto buffers).
The problem with both these approaches is how to clear a field. You will have to define a special null value (especially for proto buffers since null values are not defined for proto buffers) that will cause clearing of the field.
Comments?
RFC 7396: JSON Merge Patch (published four years after the question was posted) describes the best practices for a PATCH in terms of the format and processing rules.
In a nutshell, you submit an HTTP PATCH to a target resource with the application/merge-patch+json MIME media type and a body representing only the parts that you want to be changed/added/removed and then follow the below processing rules.
Rules:
If the provided merge patch contains members that do not appear within the target, those members are added.
If the target does contain the member, the value is replaced.
Null values in the merge patch are given special meaning to indicate the removal of existing values in the target.
Example test cases that illustrate the rules above (as seen in the appendix of that RFC):
ORIGINAL PATCH RESULT
--------------------------------------------
{"a":"b"} {"a":"c"} {"a":"c"}
{"a":"b"} {"b":"c"} {"a":"b",
"b":"c"}
{"a":"b"} {"a":null} {}
{"a":"b", {"a":null} {"b":"c"}
"b":"c"}
{"a":["b"]} {"a":"c"} {"a":"c"}
{"a":"c"} {"a":["b"]} {"a":["b"]}
{"a": { {"a": { {"a": {
"b": "c"} "b": "d", "b": "d"
} "c": null} }
} }
{"a": [ {"a": [1]} {"a": [1]}
{"b":"c"}
]
}
["a","b"] ["c","d"] ["c","d"]
{"a":"b"} ["c"] ["c"]
{"a":"foo"} null null
{"a":"foo"} "bar" "bar"
{"e":null} {"a":1} {"e":null,
"a":1}
[1,2] {"a":"b", {"a":"b"}
"c":null}
{} {"a": {"a":
{"bb": {"bb":
{"ccc": {}}}
null}}}
For modifying the status I think a RESTful approach is to use a logical sub-resource which describes the status of the resources. This IMO is pretty useful and clean when you have a reduced set of statuses. It makes your API more expressive without forcing the existing operations for your customer resource.
Example:
POST /customer/active <-- Providing entity in the body a new customer
{
... // attributes here except status
}
The POST service should return the newly created customer with the id:
{
id:123,
... // the other fields here
}
The GET for the created resource would use the resource location:
GET /customer/123/active
A GET /customer/123/inactive should return 404
For the PUT operation, without providing a Json entity it will just update the status
PUT /customer/123/inactive <-- Deactivating an existing customer
Providing an entity will allow you to update the contents of the customer and update the status at the same time.
PUT /customer/123/inactive
{
... // entity fields here except id and status
}
You are creating a conceptual sub-resource for your customer resource. It is also consistent with Roy Fielding's definition of a resource: "...A resource is a conceptual mapping to a set of entities, not the entity that corresponds to the mapping at any particular point in time..." In this case the conceptual mapping is active-customer to customer with status=ACTIVE.
Read operation:
GET /customer/123/active
GET /customer/123/inactive
If you make those calls one right after the other one of them must return status 404, the successful output may not include the status as it is implicit. Of course you can still use GET /customer/123?status=ACTIVE|INACTIVE to query the customer resource directly.
The DELETE operation is interesting as the semantics can be confusing. But you have the option of not publishing that operation for this conceptual resource, or use it in accordance with your business logic.
DELETE /customer/123/active
That one can take your customer to a DELETED/DISABLED status or to the opposite status (ACTIVE/INACTIVE).
Things to add to your augmented question. I think you can often perfectly design more complicated business actions. But you have to give away the method/procedure style of thinking and think more in resources and verbs.
mail sendings
POST /customers/123/mails
payload:
{from: x#x.com, subject: "foo", to: y#y.com}
The implementation of this resource + POST would then send out the mail. if necessary you could then offer something like /customer/123/outbox and then offer resource links to /customer/mails/{mailId}.
customer count
You could handle it like a search resource (including search metadata with paging and num-found info, which gives you the count of customers).
GET /customers
response payload:
{numFound: 1234, paging: {self:..., next:..., previous:...} customer: { ...} ....}
Use PUT for updating incomplete/partial resource.
You can accept jObject as parameter and parse its value to update the resource.
Below is the Java function which you can use as a reference :
public IHttpActionResult Put(int id, JObject partialObject) {
Dictionary < string, string > dictionaryObject = new Dictionary < string, string > ();
foreach(JProperty property in json.Properties()) {
dictionaryObject.Add(property.Name.ToString(), property.Value.ToString());
}
int id = Convert.ToInt32(dictionaryObject["id"]);
DateTime startTime = Convert.ToDateTime(orderInsert["AppointmentDateTime"]);
Boolean isGroup = Convert.ToBoolean(dictionaryObject["IsGroup"]);
//Call function to update resource
update(id, startTime, isGroup);
return Ok(appointmentModelList);
}
Check out http://www.odata.org/
It defines the MERGE method, so in your case it would be something like this:
MERGE /customer/123
<customer>
<status>DISABLED</status>
</customer>
Only the status property is updated and the other values are preserved.
Regarding your Update.
The concept of CRUD I believe has caused some confusion regarding API design. CRUD is a general low level concept for basic operations to perform on data, and HTTP verbs are just request methods (created 21 years ago) that may or may not map to a CRUD operation. In fact, try to find the presence of the CRUD acronym in the HTTP 1.0/1.1 specification.
A very well explained guide that applies a pragmatic convention can be found in the Google cloud platform API documentation. It describes the concepts behind the creation of a resource based API, one that emphasizes a big amount of resources over operations, and includes the use cases that you are describing. Although is a just a convention design for their product, I think it makes a lot of sense.
The base concept here (and one that produces a lot of confusion) is the mapping between "methods" and HTTP verbs. One thing is to define what "operations" (methods) your API will do over which types of resources (for example, get a list of customers, or send an email), and another are the HTTP verbs. There must be a definition of both, the methods and the verbs that you plan to use and a mapping between them.
It also says that, when an operation does not map exactly with a standard method (List, Get, Create, Update, Delete in this case), one may use "Custom methods", like BatchGet, which retrieves several objects based on several object id input, or SendEmail.
It doesn't matter. In terms of REST, you can't do a GET, because it's not cacheable, but it doesn't matter if you use POST or PATCH or PUT or whatever, and it doesn't matter what the URL looks like. If you're doing REST, what matters is that when you get a representation of your resource from the server, that representation is able give the client state transition options.
If your GET response had state transitions, the client just needs to know how to read them, and the server can change them if needed. Here an update is done using POST, but if it was changed to PATCH, or if the URL changes, the client still knows how to make an update:
{
"customer" :
{
},
"operations":
[
"update" :
{
"method": "POST",
"href": "https://server/customer/123/"
}]
}
You could go as far as to list required/optional parameters for the client to give back to you. It depends on the application.
As far as business operations, that might be a different resource linked to from the customer resource. If you want to send an email to the customer, maybe that service is it's own resource that you can POST to, so you might include the following operation in the customer resource:
"email":
{
"method": "POST",
"href": "http://server/emailservice/send?customer=1234"
}
Some good videos, and example of the presenter's REST architecture are these. Stormpath only uses GET/POST/DELETE, which is fine since REST has nothing to do with what operations you use or how URLs should look (except GETs should be cacheable):
https://www.youtube.com/watch?v=pspy1H6A3FM,
https://www.youtube.com/watch?v=5WXYw4J4QOU,
http://docs.stormpath.com/rest/quickstart/