ns_parsefieldvalue - Parse the content of an HTTP request or reply header field into its components
This function parses the provided field value (from an HTTP request or reply header field) into its parts and returns these in the form of a list of Tcl dicts or a single Tcl dict, when -single was specified. The syntax for the contents of these header fields is specified in RFC 7230 section 3.2.6.
Per default, the command assumes a comma separated list of elements, where every element might consist of multiple parts separated by a semicolon. When the -lower is specified, the keys of the returned dicts are converted to lowercase. When the -single is specified, only the first element of the (potentially) comma separated list of elements is returned. When -strict is specified, then the command is expected to parse the full string, otherwise it will just parse as far as possible (when e.g. -single is used.
The following examples are from RFC 7239:
% ns_parsefieldvalue -lower {For="[2001:db8:cafe::17]:4711"}
{for {[2001:db8:cafe::17]:4711}}
% ns_parsefieldvalue {for=192.0.2.43, for=198.51.100.17}
{for 192.0.2.43} {for 198.51.100.17}
% ns_parsefieldvalue {for=192.0.2.60;proto=http;by=203.0.113.43}
{for 192.0.2.60 proto http by 203.0.113.43}