How to model restrictions on data visible on resources? - api

How to model restrictions on data visible on resources? Different people are accessing the same resources but with different roles so they are not allowed to see all the information.
The case I am working on:
Solution without access restriction on information:
User:
name
phoneNumber
If anyone could access it this would be easy to model as:
GET /User -> [{name:"John", phoneNumber: "322-333"}]
GET /User/{id} -> {name:"John", phoneNumber: "322-333"}
However, say I have two roles, admin and user. The phoneNumber must only be visible to users who are also admins. Authorization token is transmitted in a cookie, header or similar. The server will know which roles a requester has. How would one design an API to handle this? I have a couple of ideas:
1) The naive solution would be to just filter it and leave the fields unset if you arent allowed to access it ie.
If user: GET /User -> [{name:"John"}]
If admin: GET /User -> [{name:"John", phoneNumber: "322-333"}]
2) Embed the role in the url:
If user is wanted as a User: GET /User/User -> [{name:"John"}]
If user is wanted as an Admin: GET /Admin/User -> [{name:"John", phoneNumber: "322-333"}]
3) Define a new resource for each possible subset of fields:
If user is wanted as a User: GET /PublicUserInfo -> [{name:"John"}]
If user is wanted as an Admin: GET /FullUserInfo -> [{name:"John", phoneNumber: "322-333"}]
Would a different approach be better ?
Does anyone have experience with a solution that worked out in practice?

Use option 1 based on the authenticated user. If you opt for 2 or 3 clients implementing your API have to worry about twice as any API endpoints and when they should be used.

Related

Assign different default user groups in Keycloak based on different LDAP user federation

Question is more advanced than usual.
Imagine you have three users groups in Keycloak: Group_Basic, Group_Client_A, Group_Client_B.
You add two different LDAP user federation setting for "Client A" and "Client B".
You make Group_Basic as your default group.
How to automatically assign Group_Client_A to LDAP users from "Client A", and Group_Client_B group to LDAP users from "Client B" ?
Any ideas are welcome! Thanks!
Basically #Vadim pointed to right thing:
Under created LDAP -> Mappers -> Create ->
Mapper type: hadrcoded-ldap-group-mapper
Group: /Group_Client_A
Did synced user, got default Group_Basic group + hardcoded Group_Client_A.
I assume pointing to different group under different LDAP synchronisation will got another group assigned.
Thanks!

How to allow firebase user to only access documents that they created

This, to me, is the most basic authentication scheme for user-generated content, given a collection called "posts":
Allow any authenticated user to insert into "posts" collection
Allow the user who inserted the document into collection "posts", to read, update, and destroy the document, and deny all others
Allow the user to list all documents in collection "posts" if they are the one who created the documents originally
All examples I've found so far seem to rely on the document ID being the same as the user's id, which would only work for user's "profile" data (again, all the examples seem to be for this single limited scenario).
It doesn't seem that there is any sort of metadata for who the authenticated user was when a document was created, so it seems i must store the ID on the doc myself, but I haven't been able to get past this point and create a working example. Also, this opens up the opportunity for user's to create documents as other users, since the user ID is set by the client.
I feel like I am missing something fundamental here since this has to be the most basic scenario but have not yet found any concise examples for doing this.
This answer is from this github gist. Basically, in the document collection posts there is a field called uid and it checks if it matches the users uid.
// Checks auth uid equals database node uid
// In other words, the User can only access their own data
{
"rules": {
"posts": {
"$uid": {
".read": "$uid === auth.uid",
".write": "$uid === auth.uid"
}
}
}
}
-- Edit --
DSL rules
match /Posts/{document=**}{
allow read : if uid == request.auth.uid;
allow write: if uid == request.auth.uid;
}

Firebase simple blog (confused with security rules)

I'm trying to create a simple todo or blog system based on React + ReactFire.
And after a hour of reading firebase tutorial confused about configuring firebase security rules.
Code for saving element :
this.props.itemsStore.push({
text : this.state.text,
done : false,
user : this.props.user.uid
})
Everything ok, but how i can get all records what owns only but authorized user?
This rules doesn't works :
"rules": {
"items" : {
".write" : "auth !== null",
"$item" : {
".read": "data.child('user').val() == auth.uid"
}
}
}
Seems to there no way to get all records only for one user, with security rules, instead of this, i should use something like filter. But again, i don't know how to filter elements in ReactFire, and in manuals no information.
As example how does it work in Parse http://i.stack.imgur.com/l9iXM.png
The Firebase security model has two common pitfalls:
permissions cascade: once you've granted a read or write permission on a specific level, you cannot take this permission away at a lower level
rules are not filters: (this is essentially a consequence of the previous pitfall) you cannot use security rules to return a different subset of children for specific users. Either a user has access to a node, or they don't have access to it.
You seem to be falling for that second pitfall. While the user can access each specific message that they are the user for, they cannot query the higher-level items node since they don't have read access to it.
If you want to secure a list of messages/todos for a specific user, you will need to store that data for that specific user.
items_per_user
$uid
$itemid: true
This is quite common in NoSQL database and is often called denormalizing. See this article called "denormalization is normal" on the Firebase web site. It's a bit outdated as far as the Firebase API goes, but the architectural principles on denormalizing still apply.
To then show the items for a user, you'd do:
ref.child('items_per_user')
.child(ref.getAuth().uid)
.on('child_added', function(snapshot) {
ref.child('items')
.child(itemId.key())
.once('value', function(itemSnapshot) {
console.log(itemSnapshot.val());
});
})
Many developer new to Firebase think that the inner loop will be too slow to load their data. But Firebase is very efficient when it comes to handling multiple requests, since it only opens a connection once per client and pipelines all the requests in the inner loop.
Keep in mind, Rules are not filters. They allow access to nodes based on criteria.
Here's an example simple structure where users 0 and 1 have stored text data within their node.
Data Structure
ToDo
a_user_id_0
text: "some text"
done: yes
a_user_id_1
text: "another text"
done: no
Rules
In this example rule, users can only read/write from nodes that belong to them within the ToDo node, so the path $user_id would be equal to their auth.id. It assumes the users has authenticated as well.
"ToDo": {
"$user_id": {
".read": "auth != null && $user_id == auth.uid",
".write": "auth != null && $user_id == auth.uid"
}
}
If user_0 was auth'd and attempted to read/write data from a_user_id_1 node, it would fail.

Is this a valid REST API?

I am designing an API.
There's the user profile, accessible at
http://example.org/api/v1/users (resp. http://example.org/api/v1/users/:id)
Now, the user's profile will be dynamic.
So we will allow an API function to add a new profile attribute.
Is the following a valid REST API URL for this?
POST http://example.org/api/v1/users/attributes
Indeed, to retrieve a specific user, the user's id would be appended to the .../users/ URL.
Now if I use the "attributes" element after /users/, would that somehow break the user id pattern for the URL?
I'd like to keep the base URL to be api/v1/users though, because logically I am modifying the users profile still...
EDIT: The attributes would be added valid for all profiles, it's independent of a user. Say the profile has "name", "surname", "email", and I want to add "address" to all profiles (Of course I know that users with a missing "address" field would not get the new attribute)
What is a good practice to address such an issue?
I think the id should be kept in the URL because you are adding the attributes to a specific user, right?
It is an acceptable solution to use the /api/v1/users/attributes as long as the :id cannot be the text: "attributes". However I recommend to create your own media type, microformat, or microdata for the attributes, because it is rather a type than a resource.
I think you should check these links:
http://alps.io/spec/index.html
http://www.markus-lanthaler.com/hydra/spec/latest/core/
http://schema.org/
http://microformats.org/wiki/microformats2
http://amundsen.com/media-types/maze/
If the user can set what attributes she can have, only then should you use a resource for attributes. But then each user should have one. But I don't think using resources will be necessary, microdata and microformats both contain more than enough person description attributes...
Some update after 5 months:
Now if I use the "attributes" element after /users/, would that
somehow break the user id pattern for the URL?
From the perspective of the client that "id pattern" does not exist. The client follows links by checking the semantics annotated to them. So REST clients are completely decoupled from the URI structure of the actual REST API (aka. uniform interface constraint). If your pattern breaks, then it is completely a server side, link generation and routing issue, which is not a client side concern.
Say the profile has "name", "surname", "email", and I want to add
"address" to all profiles. What is a good practice to address such an
issue?
Address is an optional field in this case and probably a sub-resource, because it can have further fields, like city, postal code, street, etc... You can add address separately, for example with PUT /users/123/address {city: "", street: "", ...} or you can add those fields to your user form, and add a partial update to the user, like PATCH /users/123 {address: {city: "", street: "", ...}} if only the address changes.
In case you want to update every resource in the entire collection I would send a PATCH request to /users.
While it is a valid URI, I would suggest avoiding POST http://example.org/api/v1/users/attributes. In my opinion, it violates the principle of least surprise when a collection endpoint has a child node which is not a member of the collection. If you want to track user attributes as shared by all users, then that's a separate collection, perhaps /user-attributes.
POST /user-attributes
{
"name": "Email Address",
"type": "String",
...
}
GET /user-attributes would return all the possible attributes, and GET /user-attributes/{id} would return all the metadata around an attribute.
If there's no metadata, then #inf3rno's suggestion to just PUT the attribute up and let the server deal with it is definitely worth considering.
This all presupposes you need to manage attributes through the API. If not, I agree with #inf3rno that media types are the way to go. Of course, in that case you may want a media type for the user-attributes resource ..

Authentication in liferay pages

We are having a portlet on a liferay page. We want to put up up a permission on every action method that is performed. For example on page A we have landed an XYZ portlet. Now we want that whenever there is any action performed form this portlet, we want to check that if the user is having a role to perform this action or not.
It wont be a good approach to put up the code in Action method of the portlet cause we are having approximately 20 such pages and portlets.
Can we have some sort of filter or so, so that each action request is checked if the user is having the access to the content or not.
Thank you...
My idea.
Use a filter to intercept all request
You can add a filter to the Liferay Servlet to check every request.
For that you can use a hook-plugin.
Look at this :
http://www.liferay.com/fr/documentation/liferay-portal/6.1/development/-/ai/other-hooks
http://connect-sam.com/2012/06/creating-servlet-filter-hook-in-liferay-6-1-to-restrict-access-based-on-ip-location/
Issue with filter is that you can't access ThemeDisplay or use PortalUtil.getUser(request).
So you must use work around like that :
private User _getUser(HttpServletRequest request) throws Exception {
HttpSession session = request.getSession();
User user = PortalUtil.getUser(request);
if (user != null) {
return user;
}
String userIdString = (String) session.getAttribute("j_username");
String password = (String) session.getAttribute("j_password");
if ((userIdString != null) && (password != null)) {
long userId = GetterUtil.getLong(userIdString);
user = UserLocalServiceUtil.getUser(userId);
}
return user;
}
Filtering the request
To filter the request you must get :
page id (Layout id in Liferay)
portlet id
portlet lifecycle
One more time using a filter is a pain because you can get the ThemeDisplay. These params are easy to get (with real object instancee) with ThemeDisplay.
So you must get this as parameter in the request.
final String portletId = ParamUtil.get((HttpServletRequest) servletRequest, "p_p_id", "");
final String layoutId = ParamUtil.get((HttpServletRequest) servletRequest, "plid", "");
final String portletLifecycle = ParamUtil.get((HttpServletRequest) servletRequest, "p_p_lifecycle", "");
Lifecycle details :
portletLifecycle is a int and the meaning of value is :
0 : RENDER
1 : ACTION (the one that interests you)
2 : RESOURCE
I think that with this data you can be able to define if user can or cannot make the action.
You can get user roles from the user.
You can get the current page and portlet linked to the request.
And you can know if the request is an action request.
Good luck with Liferay.
You can add freely configurable permissions to Liferay, see the Developer Guide for detailed information. My first guess on this would be that these affect "model resources", e.g. the data that your portlet is dealing with, rather than portlet-resources, e.g. permissions on the individual portlet itself. Think of portlet-permissions as permissions that are defined by Liferay, model-resources as permissions where you can come up with your own vocabulary on the actions, e.g. "UPDATE_ADDRESS" etc.
These permissions will typically be tied to roles, which are granted to users/usergroups/etc.
Based on this variability, it depends on the nature of your permissions if you can write a filter to generically check permissions, or if it depends on more than the individual action call.
If you determine that there is a generic solution, look up PortletFilters, they behave just like ServletFilters. These can easily provide a home for permission checks.
It's quite hard to cover this topic in such a short answer, I hope to have given enough resources for you to continue your quest.
You can abuse some existing portlet permission like "Add to Page" and set it to roles that should call the action.
And by the rendering and action phases validate "has the user necessary permission".
Or you can create new permission and configure it by portlet-configuration. This way is cleaner, but difficulty.