30
Copyright © 2007 Open Geospatial Consortium, Inc. All Rights Reserved.
EXAMPLE: A DescribeProcess operation response for WPS can look like this encoded in XML:
examples\40_wpsDescribeProcess_response.xml
9.3.3 DescribeProcess exceptions
When a WPS server encounters an error while performing a DescribeProcess operation, it shall return an exception report message as specified in Subclause 8 of [OGC 06-121r3].
The allowed standard exception codes shall include those listed in Table 38. For each listed exceptionCode, the contents of the
―locator‖ parameter value shall be as specified in the right column of Table 38.
NOTE To reduce the need for readers to refer to other documents, all the values listed below are
copied from Table 25 in Subclause 8.3 of [OGC 06-121r3].
Table 38 — Exception codes for DescribeProcess operation
exceptionCode value Meaning of code
“locator” value
MissingParameterValue Operation request does not include a parameter value, and this server did not declare a default
value for that parameter Name of missing
parameter InvalidParameterValue
Operation request contains an invalid parameter value
Name of parameter with invalid value
NoApplicableCode No other exceptionCode specified by this service
and server applies to this exception Omit ―locator‖
parameter or specify the vendor
specific exception code
10 Execute operation mandatory
10.1 Introduction
The mandatory Execute operation allows WPS clients to run a specified process implemented by a server, using the input parameter values provided and returning the
output values produced. Inputs can be included directly in the Execute request, or reference web accessible resources. The outputs can be returned in the form of an XML
response document, either embedded within the response document or stored as web accessible resources. If the outputs are stored, the Execute response shall consist of a
XML document that includes a URL for each stored output, which the client can use to retrieve those outputs. Alternatively, for a single output, the server can be directed to
return that output in its raw form without being wrapped in an XML reponse document.
Normally, the response document is returned only after process execution is completed. However, a client can instruct the server to return the Execute response document
immediately following acceptance by the server of the Execute request. In this case, the Execute response includes a URL from which the response document can later be
retrieved during and after process execution. The server can be instructed to provide
Copyright © 2007 Open Geospatial Consortium, Inc. All Rights Reserved.
31 regular updates to a measure of the amount of processing remaining if the process is not
complete. This allows the client to determine the process status by polling this URL. An example of how this works is shown in the UML activity diagram shown in Figure 2.
Figure 2 — Activity diagram when client requests storage of results
10.2 Execute operation request
10.2.1 Execute request parameters
A request to perform the Execute operation shall include the parameters listed and defined in Table 39 through Table 48. These tables specify the UML model data type,
source of values, and multiplicity of each listed parameter in the operation request, plus the meaning to servers when each optional parameter is included. Although some values
li
sted in the ―Name‖ columns appear to contain spaces, they shall not contain spaces. Client
WPS HTTP
server FTP
server Execute Request
Execute Response Copy of Execute Response process pending
Updated Execute Response process started
Show me the latest Execute Response latest Execute Response
Updated Execute Response process completed Outputs
Send me the outputs Outputs
