API queries using a "matches" regular expression filter--need to determine what regex syntax works and what doesn't #5
Description
When using the "matches" filter type in an API query, like this:
http://libuiapp01.library.unt.edu/catalog/api/v1/marc/?010a[matches]=^[0-9]{0,3}$
it isn't always clear what regex syntax is supported. The regular expression is sent to Solr, so ostensibly it should support the same syntax, but sometimes things don't quite work the way I expect. I suspect part of this may be related to issue #3, where things aren't being escaped properly (or are being escaped too many times) before they're sent to Solr. For instance:
http://libuiapp01.library.unt.edu/catalog/api/v1/marc/?010a[matches]=^\d
matches where there is a literal "d" character at the beginning of an 010 subfield a, rather than either matching a digit like [0-9] or throwing an error (or not matching anything).
(This is on my to-do list to look into, but I don't really have many other concrete examples, so I need to get some concrete examples.)