source: branches/PublicaMundi_David-devel/docs/services/process-profiles.rst @ 684

.. _process-profiles:
    
Process profiles registry
================

WPS Services belonging to the same Services provider often share the
same inputs and outputs. In such a case, every :ref:`ZCFG
<services-zcfg>` file would contain the same metadata information and
this may be a waste of time to write them all.

:ref:`ZOO-Kernel <kernel_index>` is able to handle metadata inheritance from `rev. 607 <http://www.zoo-project.org/trac/changeset/607>`__, and this solves the issue of writing many ZCFG with same input and output. A registry can be loaded (before any other ZCFG files) and contain a set of Process Profiles organized in hierarchic levels according to the following rules:

  * *Concept*: The higher level in the hierarchy. *Concepts* are basic text files containing an abstract description of a WPS Service.
  * *Generic*: A *Generic* profile can make reference to *Concepts*. It defines inputs and outputs without data format or maximum size limitation.
  * *Implementation*: An *Implementation* profile can inherit from a
    generic profile and make reference to concepts. It contains all
    the metadata information about a particular WPS Service (see
    :ref:`ZCFG reference <services-zcfg>` for more information).

Both *Generic* and *Implementation* process profiles are created  from :ref:`ZCFG <services-zcfg>` files and stored in the registry sub-directories
according to their level (*Concept*, *Generic* or *Implementation*).

To activate the registry, you have to add a ``registry`` key to the
``[main]`` section of your ``main.cfg`` file, and set its value to the
directory path used to store the profile ZCFG files.


Generic Process Profile
-----------------------

A Generic Process Profile is a ZCFG file located in the ``generic``
sub-directory, it defines `main metadata information
<zcfg-reference.html#main-metadata-information>`__, inputs and outputs
name, basic metadata and multiplicity. It can make reference to a
concept by defining a ``concept`` key in the `main metadata
information <zcfg-reference.html#main-metadata-information>`__ part.

You can find below the `GO.zcfg` file, a typical Generic Process
Profile for Generic Geographic Operation, taking one InputPolygon
input parameter and returning a result named Result, it make reference
to the ``GOC`` concept:

.. code-block:: none
   :linenos:
   
   [GO]
    Title = Geographic Operation
    Abstract = Geographic Operation on exactly one input, returning one output
    concept = GOC
    level = generic
    statusSupported = true
    storeSupported = true
    <DataInputs>
     [InputPolygon]
      Title = the geographic data
      Abstract = the geographic data to run geographipc operation
      minOccurs = 1
      maxOccurs = 1
    </DataInputs>
    <DataOutputs>
     [Result]
      Title = the resulting data
      Abstract = the resulting data after processing the operation
    </DataOutputs>  


.. Note:: if you need to reference more than one concept, you should
    separate their names with a comma (ie. concept = GO,GB),

Process Implementation Profile
------------------------------

A Process Implementation Profile is similar to a `ZCFG file
<zcfg-reference.html>`__ located in the `implementation`
sub-directory, it defines (or inherit from its parent) all the
properties of a `Generic Process Profile <#generic-process-profile>`__
and specify `Data Format <zcfg-reference.html#type-of-data-nodes>`__
for both inputs and outputs. It can make reference to a concept by
defining a ``concept`` key in the `main metadata information
<zcfg-reference.html#main-metadata-information>`__ part.

You can find below the `VectorOperation.zcfg` file, a typical Process
Implementation Profile for Vector Geographic Operation, it inherit
from the `GP generic profile <#generic-process-profile>`__:

.. code-block:: none
   :linenos:
   
   [VectorOperation]
    Title = Vector Geographic Operation
    Abstract = Apply a Vector Geographic Operation on a features collection and return the resulting features collection
    extend = GO
    level = profile
    <DataInputs>
     [InputPolygon]
      Title = the vector data
      Abstract = the vector data to run geographic operation
      <ComplexData>
       <Default>
        mimeType = text/xml
        encoding = UTF-8
        schema = http://fooa/gml/3.1.0/polygon.xsd
       </Default>
       <Supported>
        mimeType = application/json
        encoding = UTF-8
        extension = js
       </Supported>
    </DataInputs>
    <DataOutputs>
     [Result]
      Title = the resulting data
      Abstract = the resulting geographic data after processing the operation
      <ComplexData>
       <Default>
        mimeType = text/xml
        encoding = UTF-8
        schema = http://fooa/gml/3.1.0/polygon.xsd
       </Default>
       <Supported>
        mimeType = application/json
        encoding = UTF-8
        extension = js
       </Supported>
      </ComplexData>
    </DataOutputs>  


ZCFG inheritance
----------------------------------

For the ZCFG files at the service level, you can inherit the metadata
from a Process Implementation Profile available in the registry. As
before, you simply need to add a ``extend`` key refering the ZCFG you
want to inherit from and a ``level`` key taking the `ìmplementation``
value to your main metadata informations.

So, for example, the original `ConvexHull.zcfg
<http://www.zoo-project.org/trac/browser/trunk/zoo-project/zoo-services/ogr/base-vect-ops/cgi-env/ConvexHull.zcfg?rev=491>`__
may be rewritten as:

.. code-block:: none
   :linenos:
   
   [ConvexHull]
    Title = Compute convex hull.
    Abstract = Return a feature collection that represents the convex hull of each geometry from the input collection.
    serviceProvider = ogr_service.zo
    serviceType = C
    extend = VectorOperation
    level = implementation

Now, suppose that your service is able to return the result in KML
format, then you may write the following:

.. code-block:: none
   :linenos:
   
   [ConvexHull]
    Title = Compute convex hull.
    Abstract = Return a feature collection that represents the convex hull of each geometry from the input collection.
    serviceProvider = ogr_service.zo
    serviceType = C
    extend = VectorOperation
    level = implementation
    <DataOutputs>
     [Result]
        <Supported>
         mimeType = application/vnd.google-earth.kml+xml
         encoding = utf-8
        </Supported>
    </DataOutputs>