To accommodate IRIs in the current structure, conforming
implementations MUST map IRIs to URIs as specified in Section 3.1 of
[RFC3987], with the following clarifications:
* in step 1, generate a UCS character sequence from the original
IRI format normalizing according to the NFC as specified in
Variant b (normalization according to NFC);
* perform step 2 using the output from step 1.
Implementations MUST NOT convert the ireg-name component before
performing step 2.
Before URIs may be compared, conforming implementations MUST perform
a combination of the syntax-based and scheme-based normalization
techniques described in [RFC3987]. Specifically, conforming
implementations MUST prepare URIs for comparison as follows:
* Step 1: Where IRIs allow the usage of IDNs, those names MUST be
converted to ASCII Compatible Encoding as specified in Section
* Step 2: The scheme and host are normalized to lowercase, as
described in Section 220.127.116.11 of [RFC3987].
* Step 3: Perform percent-encoding normalization, as specified in
Section 18.104.22.168 of [RFC3987].
* Step 4: Perform path segment normalization, as specified in
Section 22.214.171.124 of [RFC3987].
* Step 5: If recognized, the implementation MUST perform scheme-
based normalization as specified in Section 5.3.3 of [RFC3987].
Conforming implementations MUST recognize and perform scheme-based
normalization for the following schemes: ldap, http, https, and ftp.
If the scheme is not recognized, step 5 is omitted.
When comparing URIs for equivalence, conforming implementations shall
perform a case-sensitive exact match.
Implementations should convert URIs to Unicode before display.
Specifically, conforming implementations should perform the
conversion operation specified in Section 3.2 of [RFC3987].