use date(now) equivalent in mapserver

Question

I want to use present year in a CLASS in a map file. I managed to write permanent expressions like:

LAYER
    CLASSITEM "YEAR"
...
    CLASS
        NAME "Previous years"
        EXPRESSION ('[YEAR]'<'2015')

But I failed to construct a working expression, which includes a reference to present time.

There is an example of what I would like to write:

LAYER
CLASSITEM "YEAR"
...
    CLASS
        NAME "Present year" # Year n
        EXPRESSION ('[YEAR]'=='([date format=YYYY]'))
...
    CLASS
        NAME "Previous year" # Year n-1
        EXPRESSION ('[YEAR]'=='([date format=YYYY]'-'1'))
...
    CLASS
        NAME "Archived years" # Years <n-1
        EXPRESSION ('[YEAR]'<'([date format=YYYY]'-'1'))

I adapted [date format=YYYY] expression from a MapServer template page.It didn't work.... But unfortunately I did find no simple examples of templates imported variables direct use in a map file, especially for [date] variables.

Has someone any idea of what it could look like? I'm just looking for reusable examples that I could adapt for my scripts.

Answer 1

I have an example that is working, (in the sense that mapserver does not make a timeout statement).

I have been investigating sources of documentation from Template.General, here I've found the syntax behind structuring the DATE-tag.

@user30184 posted this webpage, a manpage that explains the structure of the C-type syntax that "DATE"-tag is build upon.

Finally I've added a logical expression because the expression is supposed to work within two limitations of time:

("[*NAMEOFCOLUMN*]" gt "DATE format = %Y-%m-%d" && "[*NAMEOFCOLUMN*]" lt "DATE format = %Y-%m-%d")