8. Working with URNs


Overview

Batch Builder by default requests public delivery service URNs for deliverable files of still image objects, document objects and text objects. For PDS document objects a public delivery URN is requested for the object itself rather than for a particular file within the object. For opaque objects no public delivery URNs are requested.

File URN authority path and URN resource name pattern value can be entered in the required settings panel for each object or in the object template required setting panel (in which case the settings will propagate to all objects created from the template).


 

Required settings panel – NRS section

Additionally, for PDS Document Objects, Object URN Resource Name Pattern value can be entered in the required settings panel for each object or in the object template required setting panel (in which case the settings will propagate to all objects created from the template).

Required settings panel – PDS object NRS section

Assigning File URN Resource Name Patterns

 The resource name component of the URN must be unique relative to the authority path. Batch Builder can generate all or part of the resource name automatically using mask fields that will be replaced with actual values by the system (shown in the table below). 

Resource names can be composed of alpha-numeric characters (upper and lower case, although all NRS comparisons are case-insensitive) and the following punctuation characters:

     ( ) + , - = @ ; $ _ ! * ' . :

Batch Builder will use {n} as the default resource name mask field ({n} resolves to a unique number). However, Batch Builder supports additional resource name patterns that are described below.

 

File URN resource name pattern fields

Field

Replacement Value

Meaning

{dd}

01 to 31

Day of the month

{hh24}

01 to 24

Current hour of day

{mm}

00 to 59

Current minute of hour

{mo}

01 to 12

Current month of year

{ss}

00 to 59

Current second of hour

{yyyy}

1999 to 9999

Current year

{n}

0 to 10 to the 27th power

Unique numeric value

{fileBaseName}

Name of the file excluding the file extension

Base name of file. Note that this mask works only in Batch Builder. It does not work if assigning URNs to existing objects in Web Admin

{objectName}Owner Supplied Name of the PDS Document ObjectGenerates URN Resource Name based on PDS Document Object Owner Supplied Name. Note that this mask works only in Batch Builder. It does not work if assigning URNs to existing objects in Web Admin.


Here are examples of URN masks and the resulting resource name:

urn-3:dig:{n}   -->   urn-3:dig:75 

urn-3:FAL:{yyyy}{n}   ->   urn-3:FAL:1999-76 

urn-3:HCL-DIG:{yyyy}{mo}{dd}   -->   urn-3:HCL-DIG:20000103 (unique only for one file on any given day) 

urn-3:HCL-DIG:{yyyy}{mo}{dd}{n}   -->   urn-3:HCL-DIG:200001032 (always unique)

Using URNs

Each URN assigned by NRS has the form:

   urn-3:{authorityPath}:{resourceName}   
   urn-3:RAD.SCHL:1081404

where "urn-3" is the Harvard namespace identifier, {authorityPath} is the NRS authority path corresponding to the organizational unit responsible for the URN, and {resourceName} is the unique identifier for the digital file. 

To make a URN actionable (usable in a browser) for DRS 2 objects, you must append it to an NRS URL (http://nrs.harvard.edu/). The full working URL for the example URN above would be: 

http://nrs.harvard.edu/urn-3:HUL.Guest:152824 

New URNs are passed to the NRS name resolution server for activation. A URN requested during DRS2 batch deposit should become active within 15 minutes of successful batch deposit.

Note for large batch deposits:

URNs sometimes don’t activate until the next day for large batches due to the processing of the batch taking more than 10 minutes (NRS update runs every 10 minutes throughout the day. If a batch takes longer than that to process in the DRS loader, there are circumstances under which the NRS update may be unable to catch the new URN transaction generated by the batch).






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