Allows to test some file variables to decide to execute command set.

parameters

filter: the selector
- a string
  considered as the extension of the file to match with (equals), or the mimetype to match with (equals or starts with)
- a string array, as a list of file extensions or mimetypes to match with
- a json object, as an conditional expression (logical and combination)
  - property as a variable
    - extension: extension of current file
    - mimetype: mimetype of current file
    - name: name of current file
    - basename: name (without extension) of current file
    - path: relative to san path of the current file
    - length: length of current file (bytes)
    - lastmodified: last modified timestamp (unix epoch time) of current file
    - width: pixel width of current file
    - height: pixel height of current file
    - xdpi: horizontal density in dots per inch of current file
    - ydpi: vertical density in dots per inch of current file
    - original.extension: extension of original file
    - original.mimetype: mimetype of original file
    - original.name: name of original file
    - original.basename: name (without extension) of original file
    - original.path: relative to san path of the original file
    - original.length: length of original file (bytes)
    - original.lastmodified: last modified timestamp (unix epoch time)
    - original.width: pixel width of original file
    - original.height: pixel height of original file
    - original.xdpi: horizontal density in dots per inch of original file
    - original.ydpi: vertical density in dots per inch of original file
      
      Value is the test to be performed, as
      - a simple value, to check if the variable is equal to
        Example:
        
        "filter": { "extension":"jpg" }
      - an object, as logical and combination, where property name is an operator and value is the value to used with the operator, or an array of values (logical or combination)
      - an array, as logical or combination of all items
        Example 1:
        
        { "filter": { "extension":["jpg","png"] } }
        
        Example 2:
        
        { "filter": { "mimetype":["application/pdf",{"startswith":"image/"}] } }
  - property as a logical operator
    - or: the value must be an array of conditions
      
      example:
      { "filter": { "or": [ {"path": {"ct":"/asset/"}}, {"path": {"ct":"/legacy/"}} ] ] } }
    - and: The value must be an array of conditions.
      
      example:
      { "filter": { "and": [ {"extension":"jpg"}, {"length":{"<":"2MiB"}} ] ] } }
    - not: the value must be an object (conditional expression)
      
      example:
      { "filter": { "not": { "extension": ["zip","mp4"] ] } } }
- an array, as a combination table of the above types
  Example:
```
{
   "filter": [
       {
           "extension":"jpg"
       },
       {
           "extension":"png",
           "length":{"<":"2MiB"}
       }
   ]
}
```
if: action to do if file matches selector
else: action to do if file doen’t match selector

Action can be:

null: means cancel transform execution (do not return any image)
json object or json array: a command set to apply
empty json object or empty json array: continue process

JSON object properties

filter: the file selector
if: action to do file matches the selector
else: action to do file doesn’t match the selector

simplified syntax parameters

Not supported.

array type parameters

[filter]: if matches the filter, continue, else cancel

[filter, action]: if matches the filter, do the action, else cancel

[filter,actionIf,actionElse]: if matches the filter, do the actionIf, else do actionElse

string type parameter