Generate unpredictable/unforgeable URL from predictable ID - rest

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);

Related

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.

REST Resource route naming for get and ResourceByID and ResourceByName

I am trying to write 2 Rest GET methods.
Get user by Id
Get user by userName.
I need to know if there is any resource naming convention for this. Both my id and username are strings.
I came up with:
/api/{v}/users/{userid}
/api/{v}/users/username/{username}
However, 2) doesn't seem correct and if I change 2) to /api/{v}/users/{username}, I am mapping to 1) as both id and username are strings. Or is it considered acceptable to use /api/{v}/userbyName/{username}?
How should I name my resource route in case 2) ?
First of all: https://vimeo.com/17785736 (15 minutes which will solve all your questions)
And what is unique? Is the username unique or only the id or both are unique?
There is a simple rule for all that:
/collection/item
However, 2) doesn't seem correct and if I change 2) to /api/{v}/users/{username}, I am mapping to 1) as both id and username are strings.
If your item can be identified with an id and also with an unique username - it doesn't matter if it's the username or the id - simply look for both (of course your backend needs to handle that) and retrieve it.
According to your needs this would be correct:
/api/{v}/users/{userid}
/api/{v}/users/{username}
but I would choose only to use: /api/{v}/users/{userid} and filter by username only with a query parameter (description for that down there below)
Also will I break any rules if I come up with
/api/{v}/userbyName/{username}
Yes - /api/{v}/userbyName/{username} will break the rule about /collection/item because userByName is clearly not a collection it would be a function - but with a real restful thinking api there is no function in the path.
Another way to get the user by name would be using a filter/query paramter - so the ID will be available for the PathParameter and the username only as filter. which than would look like this:
/api/{v}/users/?username={username}
This also don't break any rules - because the query parameter simply filters the whole collection and retrieves only the one where username = username.
How should I name my resource route in case 2) ?
Your 2) will break a rule - so I can't/won't suggest you a way to do it like this.
Have a look at this: https://vimeo.com/17785736 this simple presentation will help you a lot about understanding rest.
Why would you go this way?
Ever had a look at a javascript framework like - let's say ember. (Ember Rest-Adapter). If you follow the idea described up there and maybe also have a look at the json format used by ember and their rest adapter - you can make your frontend developer speed up their process and save a lot of money + time.
By REST you send back links, which can contain URI templates. For example: /api/{v}/users/{userid} in your case, where v and userid are template variables. Since the URI structure does not matter from a client perspective you can use whatever structure you want. Ofc. it is more convenient to use nice and short URIs, because it is easier to write the routing with them.
According to the URI standard the path contains the hierarchical while the query contains the non-hierarchical part of the URI, but this is just a loose constraint, in practice ppl use both one.
/api/{v}/users/name/{username}
/api/{v}/users/name:{username}
/api/{v}/users?name="{username}"
Ofc. you can use a custom convention, for example I use the following:
I don't use plural resource name by collections
I end collection path with slash
I use slash by reducing a collection to sub-collections or individual items
I don't use slash to give the value of a variable in the path, I use colon instead
I use as few variables and as short URI as I can
I use query by reducing a collection to sub-collections especially by defining complex filters with logical operators
So in you case my solution would be
/api/{v}/user/
/api/{v}/user/name:{username}
/api/{v}/user/{userid}
and
/api/{v}/user/?firstName="John"
/api/{v}/user/?firstName="John|Susan"&birthYear="1980-2005"
or
/api/{v}/user/firstName:John/
/api/{v}/user/firstName:John|Susan/birthYear:1980-2005/
etc...
But that's just my own set of constraints.
Each resource should have a unique URI.
GET /users/7
{
"id": 7,
"username": "jsmith",
"country": "USA"
}
Finding the user(s) that satisfy a certain predicate should be done with query parameters.
GET /users?username=jsmith
[
"/users/7"
]

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.

ServiceStack Routing with ravendb ids

I've an entity with an ID of
public string ID {get;set;}
activities/1
(which comes from RavenDB).
I'm registering the following routes in my ServiceStack AppHost
Routes
.Add<Activity>("/activities")
.Add<Activity("/activities/{id}");
I'm using a backbone app to POST and PUT to my REST Service.
What happens out-of-the-box:
id property is serialized into the json as "activities/1"
id property is encoded into route as "activities%2F1"
ServiceStack gives precedence to the URL based id property, so my string gets the encoded value which is no use to RavenDb directly.
The options I'm aware of:
Change backbone to post to "/activities" and let the JSON Serialiser kick in
Change RavenDb ID generation to use hyphens rather than slashes
Make my Id property parse for the encoded %2F on set and convert to a slash
Both have disadvantages in that I either lose RESTfulness in my API, which is undesirable, or I don't follow RavenDb conventions, which are usually sensible out-of-the-fox. Also, I've a personal preference for having slashes.
So I'm wondering if there are any other options in servicestack that I could use to sort this issue that involve less compromise? Either Serialiser customisation or wildcard routing are in my head....
I have the same problem with ASP.Net WebAPI, so I don't think this is so much a ServiceStack issue, but just a general concern with dealing with Raven style id's on a REST URL.
For example, let's say I query GET: /api/users and return a result like:
[{
Id:"users/1",
Name:"John"
},
{
Id:"users/2",
Name:"Mary"
}]
Now I want to get a specific user. If I follow pure REST approach, the Id would be gathered from this document, and then I would pass it in the id part of the url. The problem here is that this ends up looking like GET: /api/users/users/1 which is not just confusing, but the slash gets in the way of how WebAPI (and ServiceStack) route url parameters to action methods.
The compromise I made was to treat the id as an integer from the URL's perspective only. So the client calls GET: /api/users/1, and I define my method as public User Get(int id).
The cool part is that Raven's session.Load(id) has overloads that take either the full string form, or the integer form, so you don't have to translate most of the time.
If you DO find yourself needing to translate the id, you can use this extension method:
public static string GetStringIdFor<T>(this IDocumentSession session, int id)
{
var c = session.Advanced.DocumentStore.Conventions;
return c.FindFullDocumentKeyFromNonStringIdentifier(id, typeof (T), false);
}
Calling it is simple as session.GetStringIdFor<User>(id). I usually only have to translate manually if I'm doing something with the id other than immediately loading a document.
I understand that by translating the ids like this, that I'm breaking some REST purist conventions, but I think this is reasonable given the circumstances. I'd be interested in any alternative approaches anyone comes up with.
I had this problem when trying out Durandal JS with RavenDB.
My workaround was to change the URL very slightly to get it to work. So in your example:
GET /api/users/users/1
Became
GET /api/users/?id=users/1
From jQuery, this becomes:
var vm = {};
vm.users = [];
$.get("/api/users/?" + $.param( { id: "users/1" })
.done(function(data) {
vm.users = data;
});

REST Url ID Placement for Resources with Collections

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.