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-t taskname: name of task to perform
-T filename: name of file containing list of tasknames
-e epersonID: (email address) will be superuser if unspecified
-i identifier: Id of object to curate. May be (1) a handle (2) a workflow Id or (32) 'all' to operate on the whole repository
-q queue: name of queue to process - -i and -q are mutually exclusive
-l limit: maximum number of objects in Context cache. If absent, unlimited objects may be added.
-s scope: declare a scope for database transactions. Scope must be: (1) 'open' (default value) (2) 'curation' or (3) 'object'
-v emit verbose output
-r - emit reporting to standard out

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The third part (here 'dc.publisher') is simply the name of the metadata field to be updated. These two mandatory properties (template and datamap) are sufficient to describe a large number of web services. All that is required to enable this task is to edit 'config/modules/curate.cfg', add 'issn2pubname' to the list of tasks:

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If you wish the task to be available in the Admin UI, see the Invocation from the Admin UI documentation (above) about how to configure it. The remaining sections describe some more specialized needs using the MetadataWebService task.

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You can specify any number of headers, just separate them with a 'double-pipe' ('||').

Transformations

One potential problem with the simple parameter substitutions performed by the task is that the service might expect a different format or expression of a value than the way it is stored in the item metadata. For example, a DOI service might expect a bare prefix/suffix notation ('10.000/12345'), whereas the DSpace metadata field might have a URI representation ('http://dx.doi.org/10.000/12345'). In these cases one can declare a 'transformation' of a value in the template. For example:

template=http://www.crossref.org/openurl/?id={doi:dc.relation.isversionof}&format=unixref

The 'doi:' prepended to the metadata field name declares that the value of the 'dc.relation.isversionof' field should be transformed before the substitution into the template using a transformation named 'doi'.  The transformation is itself defined in the same configuration file as follows:

transform.doi=match 10. trunc 60

This would be read as: exclude the value string up to the occurrence  of '10.', then truncate any characters after length 60. You may define as many transformations as you want in any task, although generally 1 or 2 will suffice. They keywords 'match', 'trunc', etc are names of 'functions' to be applied (in the order entered). The currently available functions are:

'cut' <number> = remove number leading characters
'trunc' <number> = remove trailing characters after number length
'match' <pattern> = start match at pattern
'text' <characters> = append literal characters (enclose in ' ' when whitespace needed)

When the task is run, if the transformation results in an invalid state (e.g. cutting more characters than there are in the value), the un-transformed value will be used and the condition will be logged

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.  Transformations may also be applied to values returned from the web service. That is, one can apply the transformation to a value before assigning it to a metadata field. In this case, the declaration occurs in the datamap property, not the template:

datamap=//publisher/name=>shorten:dc.publisher,//romeocolor

Here the task will apply the 'shorten' transformation (which must be defined in the same config file) before assigning the value to 'dc.publisher'.

Result String Programatic Use

Normally a task result string appears in a window in the admin UI after it has been invoked. The MedataWebService task will concatenate all the values declared in the 'datamap' property and place them in the result string using the format: 'name:value name:value' for as many values as declared. In the example above we would get a string like 'publisher: Nature romeocolor: green'. This format is fine for simple display purposes, but can be tricky if the values contain spaces. You can override the space separator using an optional property 'separator' (put in the config file, with all other properties). If you use:

separator=||

for example, it becomes easy to parse the result string and preserve spaces in the values. This use of the result string can be very powerful, since you are essentially creating a map of returned values, which can then be used to populate a user interface, or any other way you wish to exploit the data (drive a workflow, etc).

Limits and Use

A few limitations should be noted. FIrst, since the response parsing utilizes XPath, the service can only operate on XML, (not JSON) response documents. Most web services can provide either, so this should not be a major obstacle. The MetadataWebService can be used in many ways: showing an admin a value in the result string in a UI, run in a batch to update a set of items, etc. One excellent configuration is to wire these tasks into submission workflow, so that 'automatic cataloging' of many fields can be performed on ingest.

NoOp Curation Task

This task does absolutely nothing. It is intended as a starting point for developers and administrators wishing to learn more about the curation system.

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