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Retrieving metadata

The general command is:

Code Block
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:

Code Block
pawsey:/projects>asset.get :id 69776098 :xpath content/csum
value = 384461DE


Populating metadata

The general command is:


Code Block
asset.set :id ASSET-ID <ELEMENT AND VALUE>


For example, this is equivalent to a rename:


Code Block
asset.set :id 2958 :name "new name"
version="2"     -changed-or-created="true" -id="2958" -stime="12095"

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:

Code Block
asset.set :id 69776160 :geoshape < :point < :latitude -31.95 :longitude 115.86 :elevation 10.0 > >
version="3"     -changed-or-created="true" -id="2958" -stime="12097"

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:

Code Block
<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.

Code Block
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.

Code Block
pawsey:/projects>asset.doc.type.describe :type csiro:seismic
...
    definition    
        element     -type="string" -min-occurs="0" -name="name" -max-occurs="1"
        element     -type="string" -min-occurs="0" -name="geometry" -max-occurs="1"
        element     -type="string" -min-occurs="0" -name="basin" -max-occurs="1"
        element     -type="string" -min-occurs="0" -name="sub-basin" -max-occurs="1"


Applying this template to a piece of data could be achieved as follows:

Code Block
pawsey:/projects>asset.set :id 6977616069776098 :meta < :csiro:seismic < :name "Perth" :geometry "sprawling" > >
version = "5"    { -changed-or-created=true"false" -stime=74452772"76619960"
}

pawsey:/projects>asset.get :id 6977616069776098 :xpath meta/csiro:seismic
value="5"    
value="Perth"    Perth
value = sprawling="sprawling"    


pawsey:/projects>asset.get :id 6977616069776098 :xpath meta/csiro:seismic/name
value = "Perth"


Querying the metadata

The simple form of an asset query is:

Code Block
asset.query :where "LOGICAL-EXPRESSION"


Here is an example of searching for assets in a directory that match a pattern:

Code Block
pawsey:/projects>asset.query :where "namespace='/projects/DemoData Team/seantestfiles' and (name='*007*.JPGjpg'" or
name='*007*')"id="69776098"    id -version= 69776131"5"
id="69776099"    { -version="1 }
id = 69776132"
id="69776101"     -version="1"
id="69776103"    { -version="1 }
id = 69776133"
id="69776104"     -version="1"
id="70486890"    { -version="1 }
id = 69776134"
id="70486891"     -version="1"
id="70486892"    { -version="1 }"
id ="70486893" 69776137    { -version="1 }"


Note that this is equivalent to the pshell "simplified language" command:

Code Block
pawsey:/projects/Demo/sean>ls *007*.jpg
5 items, 29 items per page, remote folder: /projects/Demo/sean
 69776131   | online  |  17.02 KB | i000765.jpg
 69776132   | online  |  17.21 KB | i000767.jpg
 69776133   | online  |     17 KB | i000769.jpg
 69776134   | online  |  19.09 KB | i000768.jpg
 69776137   | online  |  17.59 KB | i000766.jpg
Page 1 of 1, file filter ['*007*.jpg']:


However, using Mediaflux language allows more sophisticated tasks to be performed.

Here's how we could retrieve the checksums of the above matches:

Code Block
pawsey:/projects>asset.query :where "namespace>='/projects/DemoData Team/seantestfiles' and name='*007*.jpg'" :action get-value :xpath content/csum
asset = None    { -version=1"5" -id=69776131"69776098"
}     value="384461DE" = 561CDB00 asset =
Noneasset    { -version="1" -id=69776132"69776099"
}     value = F517536B
asset = None    { version=1 id=69776133 }
    value = 384461DE
asset = None    { version=1 id=69776134 }="561CDB00"    
asset     -version="1" -id="69776101"
    value ="F517536B" 35189B08 asset = None    { version=1 id=69776137 }
    value = 1D206A24
...


Here's how we could sum the content sizes of the files in the above match:

Code Block
pawsey:/projects>asset.query :where "namespace>='/projects/DemoData Team/seantestfiles' and name='*007*.jpg'" :action sum :xpath content/size
value ="143330" 87902    { -nbe=5 }"9"


We could also move those files somewhere else:

Code Block
pawsey:/projects/Demo/sean>mkdir newfolder

pawsey:/projects/Demo/sean>asset.query :where "namespace>='/projects/DemoData Team/seantestfiles' and name='*007*.jpg'" :action pipe :service -name asset.move < :namespace /projects/Demo/sean/newfolder >

pawsey:/projects/Demo/sean>cd newfolder/
Remote: /projects/Demo/sean/newfolder

pawsey:/projects/Demo/sean/newfolder>ls
5 items, 29 items per page, remote folder: /projects/Demo/sean/newfolder
 69776131   | online  |  17.02 KB | i000765.jpg
 69776132   | online  |  17.21 KB | i000767.jpg
 69776133   | online  |     17 KB | i000769.jpg
 69776134   | online  |  19.09 KB | i000768.jpg
 69776137   | online  |  17.59 KB | i000766.jpg


Exercises

Exercise 1 - displaying metadata

Upload an image file (for example one of the jpgs from the previous exercises) and then inspect the metadata in the system.

Remember that you only have readwrite access to /projects/Demo 

Expand
titleSolution to exercise 1


Code Block
pawsey:/projects/Demo/sean>put IMG_0009.jpg
Total files=1, transferring...  
Progress: 100% at 0.0 MB/s  
Completed.

pawsey:/projects/Demo/sean>asset.get :id "path=/projects/Demo/sean/IMG_0009.jpg"
asset     -version="1" -id="69776107" -vid="74447906"
    type="image/jpeg"    
    namespace="/projects/Data Team/testfiles"    
    path="/projects/Data Team/testfiles/IMG_0009.jpg"    
    name="IMG_0009.jpg"    
...


Exercise 2 - modifying metadata

Using the file uploaded above, add geospatial location metadata to the asset and confirm by displaying the metadata.

Expand
titleSolution to exercise 2


Code Block
pawsey:/projects>asset.set :id 6977987269776098 :geoshape < :point < :latitude 17.0 :longitude 178.0 :elevation 30.0 > >
version ="6" 2    { -changed-or-created="true" -stime=74452778 }

"76628158"
pawsey:/projects>asset.get :id 6977987269776098 :xpath geoshape
value = None  
  geoshape = Nonegeoshape    { -type="point" -datum="WGS84"
}        point  point = None
            latitude="17"   = 17
            longitude="178"  =  178
            elevation = "30.0"


Exercise 3 - querying metadata

Recursively search namespaces starting from /projects/Data Team to find the asset where the metadata element mf-note/note has a literal string value equal to cat. Download the file and verify that it is a cute cat.

Expand
titleSolution to exercise 3


Code Block
pawsey:/projects>asset.query :where "namespace>='/projects/Data Team' and mf-note/note='cat'"
id = "69776108"    { -version="2 }
"
pawsey:/projects>asset.get :id 69776108 :xpath namespace :xpath name
value = "/projects/Data Team/testfiles"    
value = "IMG_0033.jpg"    
pawsey:/projects>get /projects/Data Team/testfiles/IMG_0033.jpg
Total files=1, transferring ...  
Progress=100%, rate=0.0 MB/s  
Completed.
pawsey:/projects>exit

iblis:~> open IMG_0033.jpg