Issues with uri mirroring

Enabling use of external data

#Issues with uri mirroring - Introduction

URI Mirroring

URI mirroring allow developers to use URIs that don't belong to their namespace by translating them into a local namespace. For example it is possible to translate any URI of the form http://logd.tw.rpi.edu/source/data-gov/dataset/4383/* into http://localhost/data/*. In this way people can reuse the information and relations in the data in their own domain.

##Automatic CURIE creation

By default, LODSPeaKr will define two basic namespaces with their respective CURIEs. This namespaces will be used in settings.inc.php as well as when obtaining results in queries:

• local is the original namespace, e.g., http://logd.tw.rpi.edu/source/data-gov/dataset/4383/
• base is the namespace served in this particular installation of LODSPeaKr, e.g., http://localhost/data/

In the current implementation, a URI as http://logd.tw.rpi.edu/source/data-gov/dataset/4383/foo will be translated into local:foo. However, if there are more segments divided by a slash, LODSPeaKr will create new CURIEs. For example http://logd.tw.rpi.edu/source/data-gov/dataset/4383/foo/bar/123/xyz will be translated into local_foo_bar_123:xyz.

Current problems

Bad naming

For historical reasons, local was used for the "main" namespace, which was usually thought to be served by the machine where LOSPeaKr was installed. This is certainly not the case in many use cases.

local should be assigned to the namespaces where LODSPeaKr is installed, while other (remote, mirror) should be defined for the namespace that is being mirrored.

Types and local CURIE

One problem occurs when the type of an instance is in the namespace used to publish. For example, the following configuration

$conf['ns']['base']   = 'http://alia/myapp/';
$conf['ns']['local']   = 'http://logd.tw.rpi.edu/source/data-gov/dataset/4383/';

will display base_vocab:State. However, when creating a type component (using util/lodspk.sh), the developer needs to specify

utils/lodspk.sh create type local_vocab:State

Which is confusing for the developer.

Name of mirrored value in results

The current data structure for results including a mirrored URI is

• variable.value: URI translated to the local namespace
• variable.curie CURIE version of variable.value
• variable.mirroredUri: Original URI

A more comprehensive name for mirroredUri can be developed, as well as include the CURIE version of it.