The Fedora WebAC authorization Fedora module is an implementation of the W3C's still evolving draft by the W3C that proposes a of an RDF-based decentralized authorization policy mechanism. See WebAccessControl specifications at the W3C website.

W3C's definition of WebAccessControl

From the WebAccessControl description at the W3C website:

WebAccessControl is a decentralized system for allowing different users and groups various forms of access to resources where users and groups are identified by HTTP URIs.

...

The WebAC module will enforce access control based on the Access Control List (ACL) RDF resource associated with the requested resource. The ACL resource should specify the types of access, allowed users or groups, and applicable resources.

User -> Read/Write/Append/Control -> Resource/ResourceType

Example:

In WebAC, an ACL consists of a set of Authorizations. Each Authorization is a single rule for access, such as "users alice and bob may write to resource foo", described with a set of RDF properties. Authorizations have the RDF type http://www.w3.org/ns/auth/acl#Authorization.

For the remainder of this document, the 1. userA can Read document foo
@prefix acl: <http://www.w3.org/ns/auth/acl#>

</acls/read> acl:accessTo </foo> ;
acl:mode acl:Read;
acl:agent </agents/userA> .

...

namespace will be abbreviated with the prefix acl:.

Authorizations

The properties that may be used on an acl:Authorization are:

Property	Meaning
`acl:accessTo`	the URI of the protected resource
`acl:agent`	the user (in the W3C WebAC ontology, the user is named with a URI, but Fedora's implementation supports both URI- and string-based usernames)
`acl:mode`	the type of access (WebAC defines several modes: `acl:Read`, `acl:Write`, `acl:Append`, and `acl:Control`; Fedora implements `acl:Read` and `acl:Write`)
`acl:accessToClass`	an RDF class of protected resources
`acl:agentClass`	a group of users (defined as a `foaf:Group` resource listing its users with the `foaf:member` property)

For a more detailed explanation of Authorizations and their properties, see WebAC Authorizations.

Examples of Authorizations

The user userA can Read document foo
Code Block
language text
@prefix acl

</acls/write> acl:accessToClass </objecttype/news> ;
acl:mode acl:Read, acl:Write;
acl:agentClass </agents/newsEditor> .

Example Request Authorization Flow:

...

Example Scenarios

I want to allow a user with username "smith123" to have read, write access to resource http://localhost:8080/rest/webacl_box1.
@prefix rdf
```
: <http://www.w3.org/
```
1999
```
ns/
```
02/22-rdf-syntax-ns#> . @prefix ldp: <http://www.w3.org/ns/ldp#> . <> a ldp:BasicContainer
```
auth/acl#>

<> a acl:Authorization ;
    acl:accessTo </foo> ;
    acl:mode acl:Read;
   
```
rdf
```
 acl:
```
type ???:WebAcl .
```
agent "userA" .
```
Expand
Using these two "files" to create our Authorization and ACL resources.
Code Block
title Acl.ttl

Users in NewsEditor group can Write to any resource of type ex:News

titleAuthorization.ttl

Code Block

language

text

@prefix acl: <http://www.w3.org/ns/auth/acl#> .
@prefix

rdf

ex: <http://

www.w3

example.org

/1999

02/22-rdf-syntax-

ns#> .

@prefix ldp: <http://www.w3.org/ns/ldp#> .


<> a

ldp

acl:

RDFSource

Authorization ;

rdf:type

 acl:

Authorization ; acl:agent "smith123"

accessToClass ex:News ;
    acl:mode acl:Read, acl:Write

;
    acl:

accessTo

agentClass

<http:

</

/localhost:8080/rest/webacl_box1> .

agents/NewsEditor> .

Code Block

language	text
title	/agents/NewsEditors

@prefix foaf: <http://xmlns.com/foaf/0.1/> .

<> a foaf:Group;
    foaf:member "editor1", "editor2".

The user userB can Read document foo (This involves setting a system property for the servlet container, e.g. -Dfcrepo.auth.webac.userAgent.baseUri=http://example.org/agents/)
> curl -X POST -H "Content-type: text/turtle" --data-binary "@Acl.ttl" "http://localhost:8080/rest" http://localhost:8080/rest/acl > curl -X PUT -H "Content-type: text/turtle" --data-binary "@Authorization.ttl" "http://localhost:8080/rest/acl/auth1" http://localhost:8080/rest/acl/auth1 > echo "PREFIX
```
acl: <http://www.w3.org/ns/auth/acl#>
```
INSERT INTO { <>
```
<> a acl:Authorization ;
    acl:
```
accessControl
```
accessTo 
```
<http://localhost:8080/rest/acl> . }" | curl -X PATCH -H "Content-type: application/sparql-update" --upload-file - "http://localhost:8080/rest/webacl_box1"
```
</foo> ;
    acl:mode acl:Read;
    acl:agent <http://example.org/agents/userB> .
```
Code Block
language text
@prefix
We would execute the following commands.
Code Block

Storing WebAC ACLs in Fedora 4

In Fedora 4, an ACL is a ldp::BasicContainer resource with the additional RDF type of http://fedora.info/definitions/v4/webac#Acl. This class is part of the Fedora WebAC ontology. Its children should each be resources of type acl:Authorization. It is given the namespace prefix webac: by convention.

Protecting Resources

A resource specifies the location of its ACL using the acl:accessControl property. If a resource itself does not specify an ACL, its parent containers are inspected, and the first specified ACL found is used as the ACL for the requested resource. If no ACLs are found, a filesystem-based ACL will be checked, the default policy of which is to deny access to the requested resource.

Example Scenarios

These scenarios assume that Fedora has been configured to use fcrepo.auth.webac.userAgent.baseUri=http://example.org/agent/ and fcrepo.auth.webac.groupAgent.baseUri=http://example.org/group/

I want to allow a user with username "smith123" to have read, write access to resource http://localhost:8080/rest/webacl_box1.

Expand

Using the two "files" below to create our Authorization and ACL resources.

Code Block

title	Acl.ttl

@prefix webac: <http://fedora.info/definitions/v4/webac#> .
<> a webac:Acl .

Code Block

title	Authorization.ttl

@prefix acl: <http://www.w3.org/ns/auth/acl#> .
<> a acl:Authorization ;
   acl:agent <http://example.org/agent/smith123> ;
   acl:mode acl:Read, acl:Write ;
   acl:accessTo <http://localhost:8080/rest/webacl_box1> .

We would execute the following commands.

Code Block

> curl -X PUT -H "Content-type: text/turtle" --data-binary "@Acl.ttl" "http://localhost:8080/rest"

http://localhost:8080/rest/acl

> curl -X PUT -H "Content-type: text/turtle" --data-binary "@Authorization.ttl" "http://localhost:8080/rest/acl/auth1"

http://localhost:8080/rest/acl/auth1

> echo "PREFIX acl: <http://www.w3.org/ns/auth/acl#>
INSERT DATA {
<> acl:accessControl <http://localhost:8080/rest/acl> .
}" | curl -X PATCH -H "Content-type: application/sparql-update" --upload-file - "http://localhost:8080/rest/webacl_box1"

I want to let the group "Editors" have read, write access on all the items in the collection "http://localhost:8080/rest/box/bag/collection"

Expand

Using the two "files" below to create our Authorization and ACL resources.

Code Block

title	Acl.ttl

@prefix webac: <http://fedora.info/definitions/v4/webac#> .
<> a webac:Acl

I want to let the group "Editors" have read, write access on all the items in the collection "http://localhost:8080/rest/box/bag/collection"
Using the below two "files",

Expand

Code Block

title	Acl.ttl

@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix ldp: <http://www.w3.org/ns/ldp#> .
<> a ldp:BasicContainer ;
   rdf:type ???:WebAcl .

Code Block

title	Authorization.ttl

@prefix acl: <http://www.w3.org/ns/auth/acl#> .
@prefix<> rdf:a <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix ldp:acl:Authorization ;
   acl:agent <http://www.w3.org/ns/ldp#> .
<> a ldp:RDFSourceexample.org/group/Editors> ;
   rdf:typeacl:mode acl:Read, acl:AuthorizationWrite ;
   acl:agent "Editors" ;
   acl:mode acl:Read, acl:Write ;
   acl:accessTo <httpaccessTo <http://localhost:8080/rest/box/bag/collection> .

We would execute the following commands.

Code Block
> curl -X POST -H "Content-type: text/turtle" --data-binary "@Acl.ttl" "http://localhost:8080/rest/box/bag/collection> .

We would execute the following commands.

Code Block

"

http://localhost:8080/rest/acl

> curl -X POSTPUT -H "Content-type: text/turtle" --data-binary "@Acl@Authorization.ttl" "http://localhost:8080/rest"

http"http://localhost:8080/rest/acl/auth1"

http://localhost:8080/rest/acl/auth1

> echo "PREFIX acl: <http://www.w3.org/ns/auth/acl#>
INSERT DATA {
<> acl:accessControl <http://localhost:8080/rest/acl

>acl> .
}" | curl -X PUTPATCH -H "Content-type: textapplication/turtlesparql-update" --dataupload-file -binary "@Authorization.ttl" "http://localhost:8080/rest/box/bag/collection"

I would like the collection http://localhost:8080/rest/

acl/auth1"

dark/archive to be viewable only by the groupId "Restricted", but I would like to allow anyone to view the resource http://localhost:8080/rest/dark/archive/sunshine.

Expand

Using the three "files" below to create our Authorization and ACL resources.

Code Block

title	Acl.ttl

@prefix webacacl/auth1

> echo "PREFIX acl: <http://wwwfedora.w3.orginfo/nsdefinitions/authv4/acl#>
INSERT INTO {
<>webac#> .
<> a webac:Acl .

Code Block

title	Auth_restricted.ttl

@prefix acl:accessControl <http://localhost:8080/rest/acl>www.w3.org/ns/auth/acl#> .
}"<> | curl -X PATCH -H "Content-type: application/sparql-update" --upload-file - "http://localhost:8080/rest/box/bag/collection"

I would like the collection http://localhost:8080/rest/dark/archive to be viewable only by the groupId "Restricted", but I would like to allow anyone to view the resource http

a acl:Authorization ;
   acl:agent <http://example.org/group/Restricted> ;
   acl:mode acl:Read ;
   acl:accessTo <http://localhost:8080/rest/dark/

archive/sunshine

archive> .

.

Expand

Using the below three files to setup the Acl and Authorization resources.

Code Block

title	AclAuth_open.ttl

@prefix rdfacl: <http://www.w3.org/1999ns/02/22-rdf-syntax-ns#>auth/acl#> .
@prefix ldpfoaf: <http://www.w3.org/ns/ldp#>xmlns.com/foaf/0.1/> .
<> a ldpacl:BasicContainerAuthorization ;
   rdfacl:typeagent ???:WebAcl .

Code Block

title	Auth_restricted.ttl

@prefixfoaf:Agent ;
   acl: <http://www.w3.org/ns/auth/acl#> .
@prefix rdf:mode acl:Read ;
   acl:accessTo <http:///www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix ldp: <http://www.w3.org/ns/ldp#> .
@prefix foaf: <http://xmlns.com/foaf/0.1/> .
<> a ldp:RDFSource ;
   rdf:type acl:Authorization ;
   acl:agent "Restricted" ;
   acl:mode acl:Read ;
   acl:accessTo <http:localhost:8080/rest/dark/archive/sunshine> .

The I would execute the following commands.

Code Block

> curl -X POST -H "Content-type: text/turtle" --data-binary "@Acl.ttl" "http://localhost:8080/rest"

http://localhost:8080/rest/acl_lock

> curl -X PUT -H "Content-type: text/turtle" --data-binary "@Auth_restricted.ttl" "http://localhost:8080/rest/dark/archive> .

Code Block

title	Auth_open.ttl

@prefix acl: <http://www.w3.org/ns/auth/acl#> .
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix ldpacl_lock/auth1"

http://localhost:8080/rest/acl_lock/auth1

> echo "PREFIX acl: <http://www.w3.org/ns/ldp#> .
@prefix foaf:auth/acl#>
INSERT DATA {
<> acl:accessControl <http://xmlns.com/foaf/0.1/>localhost:8080/rest/acl_lock> .
<>}" a| ldp:RDFSource ;
   rdf:type acl:Authorization ;
   acl:agent foaf:Agent ;
   acl:mode acl:Read ;
   acl:accessTo <httpcurl -X PATCH -H "Content-type: application/sparql-update" --upload-file - "http://localhost:8080/rest/dark/archive"

> curl -X POST -H "Content-type: text/turtle" --data-binary "@Acl.ttl" "http://localhost:8080/rest/dark/archive/sunshine> .

The I would execute the following commands.

Code Block

"

http://localhost:8080/rest/acl_open

> curl -X POSTPUT -H "Content-type: text/turtle" --data-binary "@Acl.ttl" "@Auth_open.ttl" "http://localhost:8080/rest/acl_open/auth2"

http://localhost:8080/rest/acl_open/auth2

> echo "PREFIX acl: <http://www.w3.org/ns/auth/acl#>

httpINSERT DATA {
<> acl:accessControl <http://localhost:8080/rest/acl_lock

>open> .
}" | curl -X PUTPATCH -H "Content-type: textapplication/turtlesparql-update" --data-binary "@Auth_restricted.ttl" "http://localhost:8080/rest/acl_lock/auth1"

http://localhost:8080/rest/acl_lock/auth1

> echo "PREFIX acl: <http://www.w3.org/ns/auth/acl#>
INSERT INTO {
<> acl:accessControl <http:upload-file - "http://localhost:8080/rest/dark/archive/sunshine"

The collection http://localhost:8080/rest/public_collection should be readable by anyone but only editable by users in the group Editors.

Expand

Using the three "files" below to create our Authorization and ACL resources.

Code Block

title	Acl.ttl

@prefix webac: <http://fedora.info/definitions/v4/webac#> .
<> a webac:Acl .

Code Block

title	Auth1.ttl

@prefix acl: <http://www.w3.org/ns/auth/acl#> .
@prefix foaf: <http://xmlns.com/foaf/0.1/> .
<> a acl:Authorization ;
   acl:agent foaf:Agent ;
   acl:mode acl:Read ;
   acl:accessTo <httpacl_lock> .
}" | curl -X PATCH -H "Content-type: application/sparql-update" --upload-file - "http://localhost:8080/rest/dark/archive"

> curl -X POST -H "Content-type: text/turtle" --data-binary "@Acl.ttl" "http://localhost:8080/rest"

http://localhost:8080/rest/acl_open

> curl -X PUT -H "Content-type: text/turtle" --data-binary "@Auth_open.ttl" "http://localhost:8080/rest/acl_open/auth2"

http://localhost:8080/rest/acl_open/auth2

> echo "PREFIX acl:public_collection> .

Code Block

title	Auth2.ttl

@prefix acl: <http://www.w3.org/ns/auth/acl#> .
<> a acl:Authorization ;
   acl:agent <http://www.w3example.org/ns/auth/acl#>
INSERT INTO {
<> acl:accessControlgroup/Editors> ;
   acl:mode acl:Read, acl:Write ;
   acl:accessTo <http://localhost:8080/rest/aclpublic_collection> .

I would execute the following code:

Code Block
>open> . }" \| curl -X PATCHPOST -H "Content-type: applicationtext/sparql-updateturtle" --uploaddata-file -binary "@Acl.ttl" "http://localhost:8080/rest/dark/archive/sunshine"

The collection

"

http://localhost:8080/rest/

public_collection should be readable by anyone but only editable by users in the group Editors.

Expand

Using the following three files to setup the Acl and Authorizations. We would:

Code Block

title	Acl.ttl

@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix ldp: <http://www.w3.org/ns/ldp#> .
<> a ldp:BasicContainer ;
   rdf:type ???:WebAcl .

Code Block

title	Auth1.ttl

@prefix acl: <http://www.w3.org/ns/auth/acl#> .
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix ldpacl

> curl -X PUT -H "Content-type: text/turtle" --data-binary "@Auth1.ttl" "http://localhost:8080/rest/acl/auth1"

http://localhost:8080/rest/acl/auth1

> curl -X PUT -H "Content-type: text/turtle" --data-binary "@Auth2.ttl" "http://localhost:8080/rest/acl/auth2"

http://localhost:8080/rest/acl/auth2

> echo "PREFIX acl: <http://www.w3.org/ns/ldp#> .
@prefix foaf:/auth/acl#>
INSERT DATA {
<> acl:accessControl <http://xmlns.com/foaflocalhost:8080/rest/acl> .
}" | curl -X PATCH -H "Content-type: application/sparql-update" --upload-file - "http://localhost:8080/rest/public_collection"

Only the ex:publicImage type objects in the container http://localhost:8080/rest/mixedCollection are viewable by anyone, all others are only viewable by the group Admins.

Expand

Using the three "files" below to create our Authorization and ACL resources.

Code Block

title	Acl.ttl

@prefix webac: <http://fedora.info/definitions/v4/webac#> .
<> a webac:Acl/0.1/> .
<> a ldp:RDFSource ;
   rdf:type acl:Authorization ;
   acl:agent foaf:Agent ;
   acl:mode acl:Read ;
   acl:accessTo <http://localhost:8080/rest/public_collection> .

Code Block

title	Auth2Auth_restricted.ttl

@prefix acl: <http://www.w3.org/ns/auth/acl#> .
@prefix rdf:
<> a acl:Authorization ;
   acl:agent <http://wwwexample.w3.org/group/Admins> ;
   acl:mode acl:Read ;
   acl:accessTo <http://localhost:8080/rest/mixedCollection> .

Code Block

title	Auth_open.ttl

@prefix acl/1999/02/22-rdf-syntax-ns#> .
@prefix ldp: <http://www.w3.org/ns/auth/ldp#>acl#> .
@prefix foaf: <http://xmlns.com/foaf/0.1/> .
<> a ldp:RDFSource ;
   rdf:type acl:Authorization ;
   acl:agent "Editors"foaf:Agent ;
   acl:mode acl:Read, acl:Write ;
   acl:accessTo <http://localhost:8080/rest/public_collection>accessToClass ex:publicImage .

I would execute the following codecommands:

Code Block

> curl -X POST -H "Content-type: text/turtle" --data-binary "@Acl.ttl" "http://localhost:8080/rest"

http://localhost:8080/rest/acl

> curl -X PUT -H "Content-type: text/turtle" --data-binary "@Auth1@Auth_restricted.ttl" "http://localhost:8080/rest/acl/auth1"

http://localhost:8080/rest/acl/auth1

> curl -X PUT -H "Content-type: text/turtle" --data-binary "@Auth2@Auth_open.ttl" "http://localhost:8080/rest/acl/auth2"

http://localhost:8080/rest/acl/auth2

> echo "PREFIX acl: <http://www.w3.org/ns/auth/acl#>
INSERT INTODATA {
<> acl:accessControl <http://localhost:8080/rest/acl> .
}" | curl -X PATCH -H "Content-type: application/sparql-update" --upload-file - "http://localhost:8080/rest/public_collection"

...

mixedCollection"

Page tree

Versions Compared

Old Version 13

New Version Current

Key

W3C's definition of WebAccessControl

Example:

Authorizations

Examples of Authorizations

Example Request Authorization Flow:

Example Scenarios

Storing WebAC ACLs in Fedora 4

Protecting Resources

Example Scenarios

How-To Guides

More Detailed Documentation

Page tree

Page History

Versions Compared

Old Version 13

New Version Current

Key

W3C's definition of WebAccessControl

Example:

Authorizations

Examples of Authorizations

Example Request Authorization Flow:

Example Scenarios

Storing WebAC ACLs in Fedora 4

Protecting Resources

Example Scenarios

How-To Guides

More Detailed Documentation