Significant changes were made to the DOI proxy (dx.doi.org), which is maintained by CNRI on behalf of the IDF, in order to implement multiple resolution. Prior to these changes the resolution service provided by the proxy were a very simple redirection to single URL (known by many as the default URL). In this mode each DOI had one URL which would always be selected whenever a user requested resolution. The Handle system stores DOI data in properties or name value pairs and the name for this property was URL.
Multiple resolution required the introduction of an additional Handle property for DOIs to exhibit this new behaviour. This property is called "10320/loc", which is itself a Handle.
Sample Handle record:
In the sample handle record the default URL is set to represent the content's primary location. This is typically the platform of the content owner, or its primary publisher. The presence of property 10320/loc, containing an XML snippet, indicates to the proxy that multiple resolution is enabled for this DOI. The XML is interpreted as follows:
- <locations> element, chooseby: specifies the order of rules to be applied by the proxy when selecting from the<location> elements.
- locatt: used if the DOI request specifies a specific location item
- country: used if any location item specifies a specific country which must match the country of the requester
- weight: a weighted random selection from those <location> elements having weight values
- <location> element identifies a specific location
- id: a unique ID given to each location element
- cr_type: a Crossref property that specifies the type of multiple resolution to support
- cr_src: a Crossref property that identifies which Crossref user deposited the location value
- label: used by Crossref to identify the co-host
- href: the URL of the location
- weight: the weighted value to use when applying the weighted-random selection process
The presence/absence of a rule in the chooseby property will enable/disable that type of selection process by the proxy.
For Crossref's interim page multiple resolution we are setting the weight of the interim page location to 1 and all other locations to zero. This will cause the weighted-random rule to always select the interim page location. Crossref's interim page application will then display to the use the set of choices which will consist of the default URL along with all other <location>s.
DOI resolution requests may be structured to bypass the Crossref interim page using features built into the proxy's multiple resolution capabilities.
To force the DOI to resolve to the primary (original) host location:
To force the DOI to resolve to a specific location: