Do not return error IQ result if the string to validate is
not a valid JID. It is indistinguishable if the error is
caused by the string to check, or if some other involved JID,
like the one in the 'to' attribute, is malformed.
Return the normalized JID in its parts, to make it clear
which parts constitute the JID
Do not use text as child of an IQ child element. Using
text makes it impossible to inject further child elements as
XMPP disallows mixed content.
Add support for base64 encoding.
Always announce the jidprep identity.
0.12013-05-28psa
Initial published version approved by the XMPP Council.
0.0.22013-05-21lance
Incorporated feedback.
0.0.12013-05-08lance
Initial version.
To accurately compare and match JIDs, a normalization step is
required by RFC 7622RFC 7622: Extensible Messaging and Presence Protocol (XMPP): Address Format <http://tools.ietf.org/html/rfc7622>.. This normalization is split into two steps
called 'Preparation' and 'Enforcement' by RFC 8264RFC 8264: PRECIS Framework: Preparation, Enforcement, and Comparison of Internationalized Strings in Application Protocols <http://tools.ietf.org/html/rfc8264>. and maybe
resource-intensive. The protocol defined herein, called "JID Prep"
can be used to ask XMPP entities to perform such a
normalization. Amongst other use-cases, this protocol can be used
for testing purposes, where a test suite checks the conformance of
an normalization implementation of, e.g., an XMPP server
implementation.
Furthermore, in some environments, especially ones like IoT where
devices with constraint resources are used, a client may not have
access to the various Unicode and internationalization libraries
necessary to properly normalize a JID. For those situations, this
protocol can be used by a client to ask a server to normalize a JID
on its behalf.
If a server supports JID Prep queries, it MUST specify the
'urn:xmpp:jidprep:1' feature in its service discovery information
features as specified in Service Discovery (XEP-0030)XEP-0030: Service Discovery <https://xmpp.org/extensions/xep-0030.html>..
...
]]>
To request preparation and enforcement, and thus normalization
and validation, of a string to a JID, the client sends a JID Prep
request to the service. This request is an <iq/> of type 'get',
containing a <jid-validate-request/> element qualified by the
'urn:xmpp:jidprep:1' namespace. This element contains a
<maybe-jid/> child element whose textual content is the string
to normalize to and validate as JID.
Σ@example.com/resource
]]>
If the given string can be enforced to a valid JID, then a
<jid-validate-result/> with a <valid-jid/> child
element is returned. This child element contains the normalized
JID parts. The valid-jid element MUST contain <domainpart/>
and may contain <localpart/> and/or <resourcepart/>
elements. If the JID does not contain a local- or resourcepart,
then the corresponding element is omitted. Those elements contain the
normalized, i.e., PRECIS enforced, strings of the own JID
parts.
σexample.comresource
]]>
If the service is given an invalid JID, a
<jid-validate-result/> IQ result response with an
<invalid-jid/> elmeent is returned.
henryⅣ@example.com
]]>Invalid codepoint 'Ⅳ' in localpart.
]]>
To be able to feed arbitrary strings into the validator, not
being limited by XML 1.0, the protocol supports an optional Base64
encoding of the string to validate. The requestor first encodes the
string to UTF-8, then encodes the UTF-8 byte-sequence using Base64
(RFC 4648RFC 4648: The Base16, Base32, and Base64 Data Encodings <http://tools.ietf.org/html/rfc4648>. § 4) and
places the result into an <base64-maybe-jid/> element. This
element is a put under the <jid-validate-base64-request/> IQ
child element qualified by the 'urn:xmpp:jidprep:1' namespace.
The IQ respones of the service are identical to the ones of the
non-Base64 case.
If supported, service announces 'urn:xmpp:jidprep:base64:1'
feature.
zqNAZXhhbXBsZS5jb20vcmVzb3VyY2U=
]]>
If a client has the ability to perform the normalization process
itself, it SHOULD NOT make use of the protocol defined herein.
Upon a successful response, it is RECOMMENDED that the client
caches the result, mapping the original JID to the normalized
version.
As the process for normalizing and validating a JID can be
resource intensive, there is a possibility for denial of service
attacks. A server MAY rate limit the number of requests to prevent
such attacks. Likewise, the server MAY restrict access to the
service torequests from users that are local to the server or
otherwhise trusted.
This document requires no interaction with the Internet Assigned Numbers Authority (IANA)The Internet Assigned Numbers Authority (IANA) is the central coordinator for the assignment of unique parameter values for Internet protocols, such as port numbers and URI schemes. For further information, see <http://www.iana.org/>..
The XMPP RegistrarThe XMPP Registrar maintains a list of reserved protocol namespaces as well as registries of parameters used in the context of XMPP extension protocols approved by the XMPP Standards Foundation. For further information, see <https://xmpp.org/registrar/>. includes 'urn:xmpp:jidprep:1' in its registry of protocol namespaces (see <https://xmpp.org/registrar/namespaces.html>).
urn:xmpp:jidprep:1
If the protocol defined in this specification undergoes a revision that is not fully backwards-compatible with an older version, the XMPP Registrar shall increment the protocol version number found at the end of the XML namespaces defined herein, as described in Section 4 of XEP-0053.
TODO: Add once the XEP leaves the experimental state.