[ZOO-Discuss] [ZOO Project Trac] #3: Filling optional default values issue with GIS GRASS integration

[ZOO Project Trac]

#3: Filling optional default values issue with GIS GRASS integration
-------------------+--------------------------------------------------------
Reporter:  soeren  |       Owner:                 
    Type:  defect  |      Status:  new            
Priority:  major   |   Component:  zoo-kernel     
 Version:  1.0     |    Keywords:  optional values
-------------------+--------------------------------------------------------
 By default the zoo kernel fills all optional literal data inputs with
 default values. Thats fine in case default literal values are provided.

 But here is the issue: ''optional literal data inputs are also attached in
 case no default values are available.''

 This results in something like {{{"distance=NULL"}}}, which will in case
 of gis grass modules, abort the processing with an error.

 There may be two solutions:

 1. The zoo kernel do not fill optional literal inputs when no default
 values are supported
 2. The zoo kernel uses the language specific way (None in case of Python)
 to specify missing default literal input values and the GIS GRASS
 integration framework will take care of parameter with attached NULL/None
 values

 Both solutions are ok in case of literal data for me. The second one has
 the advantage, that the input map structure are fully available with
 literal data for service modules. So no new memory must be
 allocated/modified in case the developer decides to modify literal data in
 the input map.

 Optional complex data inputs should IMHO not be filled. GIS GRASS has many
 modules with optional complex data inputs.

-- 
Ticket URL: <http://svn.zoo-project.org/trac/ticket/3>
ZOO Project Trac <http://svn.zoo-project.org/>
Open WPS Platform