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Retrieving metadata
The general command is:
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asset.get :id ASSET-ID asset.get :id "path=FULL-PATH-TO-FILE" |
If we wanted to extract a specific piece of information, such as the checksum, we use the optional xpath argument:
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pawsey:/projects/Data Team/testfiles>asset.get :id 69776098 :xpath content/csum value = 384461DE |
Populating metadata
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asset.set :id ASSET-ID <ELEMENT AND VALUE> |
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asset.set :id 69776160 :name "new filename"
version = 2 { changed-or-created=true stime=74452766 } |
Note: a new version of the asset is created - reflecting the fact that the name has been altered.
A more complex example, where we assign a geospatial location (in this case a point) to an asset:
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asset.set :id 69776160 :geoshape < :point < :latitude -31.95 :longitude 115.86 :elevation 10.0 > >
version = 3 { changed-or-created=true stime=74452768 } |
This last case is an example of specifying an XML document that details the xpath + value for metadata items.
It is equivalent to an XML metadata document that looks like this:
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<geoshape> <point> <latitude> -31.95 </latitude> <longitude> 115.86 </longitude> <elevation> 10.0 </elevation> </point> </geoshape> |
Slight digression - metadata templates
The doc type shows the metadata that can be queried and specified.
Custom doc types can be made.
Asset is a special "first-order" type attached to everything.
Custom doc types get added under the <meta> element.
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asset.doc.type.describe :type asset |
Things such as the asset name and the geoshape and other items in the asset template are first order metadata items and treated as described above in terms of asset.get and asset.set.
Custom metadata templates are slightly different, as they sit under the <meta> element of the asset, rather than at the top level.
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pawsey:/projects/Demo/sean>asset.doc.type.describe :type csiro:seismic
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definition = None
element = None { type=string min-occurs=0 name=name }
element = None { type=string min-occurs=0 name=geometry }
element = None { type=string min-occurs=0 name=basin }
element = None { type=string min-occurs=0 name=sub-basin }
element = None { type=string min-occurs=0 name=data-type }
element = None { type=string min-occurs=0 name=vertical-scale }
element = None { type=string min-occurs=0 name=project } |
Applying this template to a piece of data could be achieved as follows:
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pawsey:/projects/Demo/sean>asset.set :id 69776160 :meta < :csiro:seismic < :name "Perth" :geometry "sprawling" > >
version = 5 { changed-or-created=true stime=74452772 }
pawsey:/projects/Demo/sean>asset.get :id 69776160 :xpath meta/csiro:seismic
value = Perth
value = sprawling
pawsey:/projects/Demo/sean>asset.get :id 69776160 :xpath meta/csiro:seismic/name
value = Perth |
Querying the metadata
The simple form of an asset query is:
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asset.query :where "LOGICAL-EXPRESSION" asset.query :where "namespace='/projects/Demo'" asset.query :where "namespace>='/projects/Demo' and name='*.jpg'" asset.query :where "namespace>='/projects/Data Team/sean' and (name='*.JPG' or name='*.PNG')" |
Simple actions on the results
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asset.query :where "namespace>='/projects/Data Team/sean' and name='*.jpg'" :action get-value :xpath -ename name name |
Exercises
Exercise 1 - upload a file and then inspect the metadata in the system.
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put IMG_0222.PNG asset.get :id "path=/projects/Data Team/sean/IMG_0222.PNG" asset = None { version=4 id=1377760 vid=74319092 } type = image/png namespace = /projects/Data Team/sean path = /projects/Data Team/sean/IMG_0222.PNG name = IMG_0222.PNG meta = None { stime=74319092 } etc |
Exercise - querying metadata - geospatial search? TODO - import some geoshape attached
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