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Enhancement
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Resolution: Unresolved
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Major
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None
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None
When typing a complex rule in the predicate language, there doesn't appear to be any way to break up a series of predicates across more than one line.
This hard-to-read example works:
regex( "^/foo" ) and regex( value="%q", pattern="p1=([0-9]+)" ) and regex( value="%q", pattern="p2=([a-z]+)" ) -> rewrite( "/bar" )
but this more readable version fails
regex( "^/foo" ) and regex( value="%q", pattern="p1=([0-9]+)" ) and regex( value="%q", pattern="p2=([a-z]+)" ) -> rewrite( "/bar" )
with the following confusing error message:
[ERROR] java.util.NoSuchElementException [ERROR] at java.base/java.util.ArrayDeque.removeFirst(Unknown Source) [ERROR] at java.base/java.util.ArrayDeque.pop(Unknown Source) [ERROR] at io.undertow.server.handlers.builder.PredicatedHandlersParser.collapseOutput(PredicatedHandlersParser.java:425) [ERROR] at io.undertow.server.handlers.builder.PredicatedHandlersParser.handleLineEnd(PredicatedHandlersParser.java:413) [ERROR] at io.undertow.server.handlers.builder.PredicatedHandlersParser.parse(PredicatedHandlersParser.java:353) [ERROR] at io.undertow.server.handlers.builder.PredicatedHandlersParser.parse(PredicatedHandlersParser.java:326) [ERROR] at io.undertow.server.handlers.builder.PredicatedHandlersParser.parse(PredicatedHandlersParser.java:86)
It seems reasonable that if the parser just finished parsing a predicate and the next token encountered is "and", "or", "->" then the parser can assume its still on the same rule regardless of any line breaks.
Trying to use parenthesis also doesn't work. This hard-to-read version of the rule with parenthesis around the predicates works:
( regex( "^/foo" ) and regex( value="%q", pattern="p1=([0-9]+)" ) and regex( value="%q", pattern="p2=([a-z]+)" ) ) -> rewrite( "/bar" )
But adding the line breaks back in like so:
( regex( "^/foo" ) and regex( value="%q", pattern="p1=([0-9]+)" ) and regex( value="%q", pattern="p2=([a-z]+)" ) ) -> rewrite( "/bar" )
gives the following error:
[ERROR] java.lang.IllegalArgumentException: UT000045: Error parsing predicated handler string Invalid expression:
( regex( "^/foo" )
^
[ERROR] at io.undertow.server.handlers.builder.PredicatedHandlersParser.error(PredicatedHandlersParser.java:736)
If there are still open parenthesis in the parsing of predicates, it seems reasonable to have the parser ignore any line breaks until the parentheses block is closed.
