Open WPS Platform

ZCFG : the ZOO Service Configuration File

Authors:Nicolas Bozon, Gérald Fenoy, Jeff McKenna
Last Updated:$Date: 2011-12-07 14:44:57 +0100 (Wed, 07 Dec 2011) $

The ZOO Service configuration file (.zcfg) describes the service and will be parsed by the ZOO Kernel. We will describe here what such a file contains. You can also take a look at the existing examples of ZCFG files in the cgi-env directory of each services available in the ZOO-Project SVN source tree.

A ZOO Configuration file is divided into three distinct sections :

  1. Main Metadata information
  2. List of Inputs metadata information
  3. List of Outputs metadata information

Note

The ZOO Service Configuration File is case sensitive.

Main Metadata Information

The fist part in a ZOO Configuration file contains the metadata information relative to the service. Note that the “name of your service” between brackets on the first line has to be the exact same name as the function you defined in your services provider code. In most cases, this name is also the name of the ZCFG file without the “.zcfg” extension.

You can see below a description of the main metadata information:

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
[Name of your service]
Title = Title of your service
Abstract = Description of your service
processVersion = Version number of your service
storeSupported = true/false
statusSupported = true/false
serviceType = the programming language used to implement the service (C/Fortran/Python/Java/PHP/Javascript)
serviceProvider = name of your services provider (shared library/Python Module/Java Class/PHP Script/JavaScript script)
<MetaData>
  title = Metadata title of your service
</MetaData>

List of Inputs

The list of inputs contains metadata information of each supported input, and they are grouped using a <DataInputs> node.

Each input is defined as :

  • a name (between brackets as for the name of the service before)
  • various medata properties (Title, Abstract, minOccurs and maxOccurs)
  • a Type Of Data node (description)

A typical list of inputs (<DataInputs>) look like the following:

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
<DataInputs>
  [Name of the first input]
    Title = Title of the first input
    Abstract = Abstract describing the first input
    minOccurs = Minimum occurence of the first input
    maxOccurs = Maximum occurence of the first input
    <Type Of Data Node />
  [Name of the second input]
    Title = Title of the second input
    Abstract = Abstract describing the second input
    minOccurs = Minimum occurence of the second input
    maxOccurs = Maximum occurence of the second input
    <Type Of Data Node />
</DataInputs>

Note

you can add <MetaData> node as in the main metadata information.

List of Outputs

The list of outputs is very similar to a list of inputs except it is specified as a <DataOutputs> node.

A typical <DataOutputs> node looks like the following:

1
2
3
4
5
6
<DataOutputs>
  [Name of the output]
    Title = Title of the output
    Abstract = Description of the output
    <Type Of Data Node />
</DataOutputs>

Type Of Data Nodes

In the beginning of this ZCFG introduction, we spoke about “Type Of Data Nodes” to describe the data type of inputs and outputs.

You can define your data as:

Except for LiteralData, each Type Of Data node must have at least one <Default> and one <Supported> node. Even if one of those are empty, it has to be present with an opening and closing tag on two different lines. So, something like the following:

1
2
<Default>
</Default>

Otherwise, ZOO-Kernel won’t be able to parse your ZCFG and will fail to process requests.

LiteralData node

A <LiteralData> node contains:

  • one <Default> node,
  • zero or more <Supported> nodes depending on the existence or the number of supported Units Of Measure (UOM), and
  • a dataType property. The dataType property defines the type of literal data, such as a string, an interger and so on (consult the complete list of supported data types).

<Default> and <Supported> nodes can contain the uom property to define which UOM has to be used for this input value.

For input <LiteralData> nodes, you can add the value property to the <Default> node to define a default value for this input. This means that, when your Service will be run, even if the input wasn’t defined, this default value will be set as the current value for this input.

A typical <LiteralData> node, defining a float data type using meters or degrees for its UOM, looks like the following:

1
2
3
4
5
6
7
8
9
<LiteralData>
  dataType = float
  <Default>
    uom = meters
  </Default>
  <Supported>
    uom = feet
  </Supported>
</LiteralData>

BoundingBoxData node

A <BoundingBoxData> node contains:

  • one <Default> node with a CRS property defining the default Coordinate Reference Systems (CRS), and
  • one or more <Supported> nodes depending on the number of CRS your service supports (note that you can alternatively use a single <Supported> node with a comma-separated list of supported CRS).

A typical <BoundingBoxData> node, for two supported CRS (EPSG:4326 and EPSG:3785), looks like the following:

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
<BoundingBoxData>
  <Default>
    CRS = urn:ogc:def:crs:EPSG:6.6:4326
  </Default>
  <Supported>
    CRS = urn:ogc:def:crs:EPSG:6.6:4326
  </Supported>
  <Supported>
    CRS = urn:ogc:def:crs:EPSG:6.6:3785
  </Supported>
</BoundingBoxData>

ComplexData node

A ComplexData node contains:

  • a <Default> node and
  • one or more <Supported> nodes depending on the number of supported formats. A format is made up of this set of properties : mimeType, encoding and optionaly schema.

For output ComplexData nodes, you can add the extension property to define what extension to use to name the file when storing the result is required. Obviously, you’ll have to add the extension property to each supported format (for the <Default> and <Supported> nodes).

You can also add the asReference property to the <Default> node to define if the output should be stored on server side per default.

Note

the client can always modify this behavior by setting asReference attribute to true or false for this output in the request ResponseDocument parameter.

You can see below a sample ComplexData node for default application/json and text/xml (encoded in UTF-8 or base64) mimeTypes support:

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
<ComplexData>
  <Default>
    mimeType = application/json
    encoding = UTF-8
  </Default>
  <Supported>
    mimeType = text/xml
    encoding = base64
    schema = http://fooa/gml/3.1.0/polygon.xsd
  </Supported>
  <Supported>
    mimeType = text/xml
    encoding = UTF-8
    schema = http://fooa/gml/3.1.0/polygon.xsd
  </Supported>
</ComplexData>