The matching semantics for URI templates are an addition to the RFC that specifies their expansion algorithm. Unfortunately, the nature of the expansion algorithm makes round-trip expansion and parsing of URIs inconsistent unless the following rules are followed:
- All parameters, excepting query string parameters, are required.
- Query string parameters cannot do positional matching. E.g. ?one&two&three will always fail. You must use named parameters in a query string.
- Query string parameters with an explode modifier (e.g. {?list*}) are greedy and so will parse differently than they expand.
For these reasons, using explode modified querystring params is strongly discouraged. The RFC sets aside parenthesis for implementation extensions, so the tentative plan is to extend the grammar to allow specifying that a querystring param should be parsed as a list:
/urlpath{?param1,param2,listParam(sep=,),param3}