Community identifiers

A Community service is identified by the authority ID in an Ivorn identifier.

For example :

• ivo://org.astrogrid.test.cam /dave/public/data/dataset.2004.03.30.xml
• ivo://org.astrogrid.test.cam /dave#public/data/dataset.2004.03.30.xml

The following test communities are currently available :

• Test community at codon ivo://org.astrogrid.test.codon
• Test community at cambridge ivo://org.astrogrid.test.cam

The following test communities are in progress :

• Test community at mssl ivo://org.astrogrid.test.mssl
• Test community at leicester VM ivo://org.astrogrid.test.le
• Test community at edinburgh VM ivo://org.astrogrid.test.roe

Account identifiers

A Community account is identified by the Community authority ID and the first part of the path.

For example :

• ivo://org.astrogrid.test.cam/dave /public/data/dataset.2004.03.30.xml
• ivo://org.astrogrid.test.cam/dave #public/data/dataset.2004.03.30.xml

The community parsers will also handle this syntax :

• ivo://org.astrogrid.test.cam#dave /public/data/dataset.2004.03.30.xml

However, this may not be compatible with some of the other AstroGrid services.

Service resolvers

The Community component includes a set of tools for resolving service endpoints and delegates from an Ivorn identifier.

These resolvers will parse an Ivorn to get the service identifier, lookup the service endpoint in the Registry, and return a delegate for the services.

The Community services are registered in the Registry, indexed by the service identifier and service type.

For example, given the following identifier,

ivo://org.astrogrid.test.cam/dave/public/data/dataset.2004.03.30.xml

the SecurityServiceResolver^? will parse the IVO identifier to get the service identifier,

ivo://org.astrogrid.test.cam /dave/public/data/dataset.2004.03.30.xml

The AstroGrid Registry should contain an entry for a SecurityService^? with this the authority ID, which includes the URL for the service WSDL.

   <VODescription>
      <Resource>
         <AuthorityID>org.astrogrid.test.cam</AuthorityID>
         <ResourceKey>org.astrogrid.community.common.security.service.SecurityService</ResourceKey>
      </Resource>
      ....
        <Interface>
            <Invocation>WebService</Invocation>
            <AccessURL use="base">http://capc49.ast.cam.ac.uk:8080/astrogrid-community/services/SecurityService?wsdl</AccessURL>
        </Interface>
   </VODescription>

The SecurityServiceResolver^? uses the service identifier lookup the WSDL location in the Registry, resolves the service endpoint from the WSDL, and returns a SecurityServiceDelegate^? for the service.

Account resolver

The Community component includes a set of tools for resolving Community accounts from an Ivorn identifier.

The CommunityAccountResolver^? will parse an Ivorn identifier to get the service identifier, resolve the service endpoint, and call the service to request the account details, and returns an AccountData^? object containing the details of the account.

For example, given the following identifier,

ivo://org.astrogrid.test.cam/dave/public/data/dataset.2004.03.30.xml

the CommunityAccountResolver^? will parse the identifier to get the service identifier,

ivo://org.astrogrid.test.cam /dave/public/data/dataset.2004.03.30.xml

and account identifier,

ivo://org.astrogrid.test.cam/dave /public/data/dataset.2004.03.30.xml

The CommunityAccountResolver^? will call the Registry to lookup Community service endpoint, call the Community service to request the account details, and returns an Accountdata object containing the details of the account.

   <account ident="ivo://org.astrogrid.test.cam/dave">
       <display>Dave Morris</display>
       <description>Astrogrid developer</description>
       <home>ivo://org.astrogrid.test.roe/org.astrogrid.test.cam/dave</home>
       <email>dave@mail.astrogrid.org</email>
   </account>

Account home space resolver

Each account in a Community can have an associated MySpace space allocated on a MySpace service.

The Community component includes a set of tools for resolving MySpace Ivorn identifiers from an account Ivorn identifier.

The CommunityAccountSpaceResolver^? will parse an Ivorn identifier to get the Community service identifier, resolve the service endpoint, and then call the service to request the account details.

The account details contain the Ivorn identifier of the associated MySpace home for the account.

The resolver uses the home space identifier to generate a new Ivorn identifier for the MySpace metadata location.

For example, given the following identifier,

ivo://org.astrogrid.test.cam/dave/public/data/dataset.2004.03.30.xml

The CommunityAccountSpaceResolver^? will parse the identifier to get the service identifier,

ivo://org.astrogrid.test.cam /dave/public/data/dataset.2004.03.30.xml

and account identifier,

ivo://org.astrogrid.test.cam/dave /public/data/dataset.2004.03.30.xml

The CommunityAccountSpaceResolver^? calls the Registry to lookup the Community service with this identifier, and then calls the Community service to request the account details, including the account home space identifier.

   <account ident="ivo://org.astrogrid.test.cam/dave">
       <display>Dave Morris</display>
       <description>Astrogrid developer</description>
       <home>ivo://org.astrogrid.test.roe/org.astrogrid.test.cam/dave</home>
       <email>dave@mail.astrogrid.org</email>
   </account>

In this example, the account has space allocated on a MySpace service at Edinburgh, identified by,

ivo://org.astrogrid.test.roe/org.astrogrid.test.cam/dave

The CommunityAccountSpaceResolver^? will combine the home space identifier with the remainder of the original identifier

ivo://org.astrogrid.test.cam/dave /public/data/dataset.2004.03.30.xml

and returun a new Ivorn identifier for the MySpace meta data,

ivo://org.astrogrid.test.roe/org.astrogrid.test.cam/dave/public/data/dataset.2004.03.30.xml

Context sensitive meaning

The identifiers are context sensitive, which means that the same string can refer to different things, depending on how far it has been resolved.

For example, if we start with the following identifier,

ivo://org.astrogrid.test.cam/dave/public/data/dataset.2004.03.30.xml

If this is an un-resolved identifier, then the authority ID of the identifier

ivo://org.astrogrid.test.cam /dave/public/data/dataset.2004.03.30.xml

refers to the Community service.

However, if the account has been allocated MySpace space at the same institute, then the MySpace service will have the same authority ID as the Community service.

This means that the identifier for the account MySpace home will be

ivo://org.astrogrid.test.cam/org.astrogrid.test.cam/dave

Where the authority ID of the identifier,

ivo://org.astrogrid.test.cam /org.astrogrid.test.cam/dave

refers to the MySPace^? manager.

The two services are distinguished in the Registry by the specifying the service type in the resource key.

   <VODescription>
      <Resource>
         <AuthorityID>org.astrogrid.test.cam</AuthorityID>
         <ResourceKey>org.astrogrid.community.common.security.service.SecurityService</ResourceKey>
      </Resource>
      ....
   </VODescription>

   <VODescription>
      <Resource>
         <AuthorityID>org.astrogrid.test.cam</AuthorityID>
         <ResourceKey>org.astrogrid.store.myspace.MySpaceMgr</ResourceKey>
      </Resource>
      ....
   </VODescription>

Passing the original identifier,

ivo://org.astrogrid.test.cam/dave/public/data/dataset.2004.03.30.xml

to the CommunityAccountSpaceResolver^? will result in the following steps.

1. The resolver will parse the identifier to get the Community service identifier ivo://org.astrogrid.test.cam.

1. The resolver will pass this to the Registry, to lookup a Community PolicyManager^? service endpoint.

   <VODescription>
      <Resource>
         <AuthorityID>org.astrogrid.test.cam</AuthorityID>
         <ResourceKey>org.astrogrid.community.common.policy.manager.PolicyManager</ResourceKey>
      </Resource>
      ....
      <Interface>
         <Invocation>WebService</Invocation>
         <AccessURL use="base">http://capc49.ast.cam.ac.uk:8080/astrogrid-community/services/PolicyManager?wsdl</AccessURL>
      </Interface>
   </VODescription>

1. The resolver uses the service endpoint to request the account details.

   <account ident="ivo://org.astrogrid.test.cam/dave">
       <display>Dave Morris</display>
       <description>Astrogrid developer</description>
       <home>ivo://org.astrogrid.test.cam/org.astrogrid.test.cam/dave</home>
       <email>dave@mail.astrogrid.org</email>
   </account>

1. The resolver gets the home space identifier, ivo://org.astrogrid.test.cam/org.astrogrid.test.cam/dave, from the account details.

1. The resolver combines this with the remainder of the original identifier, public/data/dataset.2004.03.30.xml, to create a new Ivorn.

The resulting Ivorn identifier,

ivo://org.astrogrid.test.cam/org.astrogrid.test.cam/dave/public/data/dataset.2004.03.30.xml

refers to a MySpace metadata location in the MySpace service at Cambridge.

Comparing this with the original identifier, it is not possible to determine what type of service the authority ID refers to.

• ivo://org.astrogrid.test.cam /dave/public/data/dataset.2004.03.30.xml
• ivo://org.astrogrid.test.cam /org.astrogrid.test.cam/dave/public/data/dataset.2004.03.30.xml

This is, I think, how it is supposed to work. However, it means that when we are passing Ivorn identifiers between our components, we need to keep track of what the identifiers mean, and how to resolve them into what we actually need.

-- DaveMorris - 31 Mar 2004