xeps/inbox/user-invite.xml

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<!DOCTYPE xep SYSTEM 'xep.dtd' [
  <!ENTITY % ents SYSTEM 'xep.ent'>
%ents;
]>
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<xep>
<header>
  <title>Easy User Onboarding</title>
  <abstract>This document defines a protocol and URI scheme for user invitation in order to allow a third party to register on a server. The goal of this is to make onboarding for XMPP IM newcomers as easy as possible.</abstract>
  &LEGALNOTICE;
  <number>xxxx</number>
  <status>ProtoXEP</status>
  <type>Standards Track</type>
  <sig>Standards</sig>
  <approver>Council</approver>
  <dependencies>
    <spec>XMPP Core</spec>
    <spec>XEP-0001</spec>
    <spec>XEP-0050</spec>
    <spec>XEP-0082</spec>
    <spec>XEP-0077</spec>
    <spec>XEP-0147</spec>
    <spec>XEP-0379</spec>
  </dependencies>
  <supersedes/>
  <supersededby/>
  <shortname>N/A</shortname>
  <author>
    <firstname>Marc</firstname>
    <surname>Schink</surname>
  </author>
  <revision>
    <version>0.0.1</version>
    <date>2018-01-10</date>
    <initials>ms</initials>
    <remark><p>First submission.</p></remark>
  </revision>
</header>
<section1 topic='Introduction' anchor='intro'>
  <p>Romeo is an active XMPP IM (Instant Messaging) user or the operator of
    an XMPP server. He convinces Juliet (who may not have an XMPP account yet)
    to install a client but she may still need to choose an XMPP server,
    create an account, and add Romeo as a contact.
    This specification defines two ways for Romeo to simplify this process for Juliet:</p>
  <section2 topic='User Invitation'>
    <p>If Romeo is an XMPP user, he can create an out-of-band link (URI)
      which allows Juliet to:</p>
    <ol>
      <li>Download an XMPP client (if needed).</li>
      <li>Optionally register an account with Romeo's server (if permitted by
	the server rules), or with a public server.</li>
      <li>Establish a mutual presence subscription between Romeo and Juliet.</li>
    </ol>
    <p>The process is designed to automatically skip steps that Juliet already
      completed, to make the overall experience as smooth as possible.</p>
  </section2>
  <section2 topic='Account Creation'>
    <p>If Romeo is an administrator of an XMPP server, he can create an
      out-of-band link (URI) which allows Juliet to:</p>
    <ol>
      <li>Download an XMPP client (if needed).</li>
      <li>Register an account on Romeo's server with a user name defined by
	Romeo and a password not known to Romeo.</li>
      <li>Establish a mutual presence subscription between Romeo and Juliet.</li>
    </ol>
  </section2>
</section1>
<section1 topic='Requirements' anchor='reqs'>
  <p>This specification makes use of XMPP URIs. The basic URI scheme for XMPP
    is defined in &rfc5122; and extended in &xep0147; and &xep0379;.
    Furthermore, this heavily builds upon the blocks provided in
    <cite>XEP-0379</cite> for landing page and roster subscription.
  </p>
  <p>
    To create out-of-band invitation links, Romeo's server needs to implement
    the &xep0050; commands specified in the following section, and his client
    must be able to execute them.
  </p>
  <p>
    Furthermore, Romeo's server SHOULD provide a HTTPS service hosting the
    landing page.
  </p>
</section1>
<section1 topic='Discovery' anchor='discover'>
  <p>Romeo can query his server for the availability of "User Invitation" and
  "Account Creation" commands:</p>
  <example caption="Discover available ad-hoc commands"><![CDATA[
<iq type='get' from='romeo@example.com' to='example.com' id='disco'>
  <query xmlns='http://jabber.org/protocol/disco#items'
         node='http://jabber.org/protocol/commands'/>
</iq>
]]></example>
  <p>TODO: use appropriate node namespace.</p>
  <example caption="Discovery result for available ad-hoc commands"><![CDATA[
<iq type='result' to='romeo@example.com' from='example.com' id='disco'>
  <query xmlns='http://jabber.org/protocol/disco#items'
         node='http://jabber.org/protocol/commands'>
    <item jid='example.com'
          node='invite'
          name='Invite user'/>
    <item jid='example.com'
          node='create-account'
          name='Create account'/>
  </query>
</iq>
]]></example>
  <p>When performing the account creation, Juliet's client needs to ensure
    that the server supports the extended IBR protocol with a &lt;preauth&gt;
    token: TODO</p>
</section1>
<section1 topic='Glossary' anchor='glossary'>
  <p>OPTIONAL.</p>
</section1>
<section1 topic='Use Cases' anchor='usecases'>
  <section2 topic='Creating a User Invitation' anchor='create-invitation'>
    <p>A user can execute the 'invite' command to obtain a new invitation link
      with a unique invitation token.</p>
    <example caption="Exceute user invitation command"><![CDATA[
<iq type='set' from='romeo@example.com' to='example.com' id='exec1'>
  <command xmlns='http://jabber.org/protocol/commands'
           node='invite'
           action='execute'/>
</iq>
]]></example>
    <example caption="User invitation finished"><![CDATA[
<iq type='result' to='romeo@example.com' from='example.com' id='exec2'>
  <command xmlns='http://jabber.org/protocol/commands'
           node='invite'
           status='completed'>
    <x xmlns='jabber:x:data' type='result'>
      <item>
        <field var='uri'>
          <value>xmpp:inviter@example.com?roster;preauth=TOKEN;ibr=y</value>
        </field>
        <field var='landing-url'>
          <value>https://example.com/invite/#TOKEN</value>
        </field>
        <field var='expire'>
          <value>2017-11-06T02:56:15Z</value>
        </field>
      </item>
    </x>
  </command>
</iq>
]]></example>
    <p>The token should be unique, sufficiently
    long and generated by a strong random number generator.</p>
  <p>A server MUST provide the <strong>uri</strong> field which contains an
    XMPP URI of the following format:</p>
  <code>xmpp:inviter@example.com?roster;preauth=TOKEN;ibr=y</code>
  <p>The <strong>ibr</strong> query component in the XMPP URI indicates that
    the invitee is allowed to create an account on Romeo's server, using the
    'preauth' token.
    If the server does not support or allow in-band registration for invited
    users, the server MUST omit the <strong>ibr</strong> query component.</p>
  <p>Additionally, the server SHOULD provide the <strong>landing-url</strong>
    field which contains an HTTPS URL of a web-based landing page as described
    in &xep0379; § 3.3. The URL format may differ from the example shown here
    depending on where the landing page is hosted.</p>
  <p>If the server omits the <strong>landing-page</strong> field, Romeo's
    client SHOULD generate an appropriate landing page URL hosted by the
    client developer or a trusted third party.</p>
  <p>A server MAY provide a field which provides the expiration date of the
    generated token. The expiration date MUST conform to the DateTime profile
    specified in &xep0082;. If the field is not provided, the token does not
    expire.</p>
  <p>Romeo's client should provide adequate means to export the
    <strong>landing-page</strong> URL, possibly accompanied with a short
    description and the <strong>expire</strong> information, so that Romeo can
    share it with Juliet by other means than XMPP, like e-mail or a QR code.</p>
  </section2>
  <section2 topic='Redeeming a User Invitation' anchor='redeem-invitation'>
    <p></p>
  </section2>
  <section2 topic='Account Creation' anchor='account-creation'>
    <example caption="Exceute account creation command"><![CDATA[
<iq type='set' from='romeo@example.com' to='example.com' id='exec1'>
  <command xmlns='http://jabber.org/protocol/commands'
           node='create-account'
           action='execute'/>
</iq>
]]></example>
    <example caption="Service returns form for account creation"><![CDATA[
<iq type='result' to='romeo@example.com' from='example.com' id='exec1'>
  <command xmlns='http://jabber.org/protocol/commands'
           sessionid='config:20020923T213616Z-700'
           node='create-account'
           status='executing'>
    <actions execute='complete'>
      <complete/>
    </actions>
    <x xmlns='jabber:x:data' type='form'>
      <field var='username' label='Username' type='text-single'/>
      <field var='roster-subscription' label='Roster subscription' type='boolean'/>
    </x>
  </command>
</iq>
]]></example>
    <p>A server MAY require a username to be specified for account creation.
      In this case, the server MUST add the &lt;required/&gt; element to the
      username field.
      The username MUST be a valid localpart as defined in &rfc6122; §2.3.</p>
    <example caption="Account creation with specified username"><![CDATA[
<iq type='set' from='romeo@example.com' to='example.com' id='exec2'>
  <command xmlns='http://jabber.org/protocol/commands'
           sessionid='config:20020923T213616Z-700'
           node='create-account'>
    <x xmlns='jabber:x:data' type='submit'>
      <field var='username'>
        <value>juliet</value>
      </field>
    </x>
  </command>
</iq>
]]></example>
    <example caption="Account creation finished"><![CDATA[
<iq type='result' to='romeo@example.com' from='example.com' id='exec2'>
  <command xmlns='http://jabber.org/protocol/commands'
           sessionid='config:20020923T213616Z-700'
           node='create-account'
           status='completed'>
    <x xmlns='jabber:x:data' type='result'>
      <item>
        <field var='uri'>
          <value>xmpp:juliet@example.com?register;preauth=TOKEN</value>
        </field>
        <field var='landing-url'>
          <value>https://example.com/invite/#TOKEN</value>
        </field>
        <field var='expire'>
          <value>2017-11-06T02:56:15Z</value>
        </field>
      </item>
    </x>
  </command>
</iq>
]]></example>
    <p>The server's response for account creation is the same as for user
      invitation except for the format of the <strong>uri</strong> field which
      contains an XMPP URI of the following format:</p>
    <code>xmpp:juliet@example.com?register;preauth=TOKEN</code>
    <p>If no username was specified during the account creation process, the
      local part of the JID in the XMPP URI is omitted by the server which
      results in the following format:</p>
    <code>xmpp:example.com?register;preauth=TOKEN</code>
  </section2>
  <section2 topic='Extension of In-Band Registration'>
    <p>In order to allow invited users to register on a server, in-band
      registration as defined in &xep0077; needs to be extended.
      The invited user MUST send the following extended stanza in order to
      register an account with a token.</p>
    <example caption="Retrieving registration fields"><![CDATA[
<iq type='get' id='reg1' to='example.com'>
  <query xmlns='jabber:iq:register'>
    <preauth xmlns='urn:xmpp:invite:0'/>
  </query>
</iq>
]]></example>
    <example caption="Receiving registration fields"><![CDATA[
<iq type='result' to='romeo@example.com' from='example.com' id='reg1'>
  <query xmlns='jabber:iq:register'>
    <username/>
    <password/>
    <token/>
  </query>
</iq>
]]></example>
    <example caption='Registration process aborted (invalid token)'><![CDATA[
<iq type='error' from='example.com' id='reg1'>
  <query xmlns='jabber:iq:register'>
    <username>juliet</username>
    <password>m1cro$oft</password>
    <token>TOKEN</token>
  </query>
  <error type='cancel'>
    <invalid-token xmlns='urn:xmpp:invite:0'/>
  </error>
</iq>
]]></example>
    <example caption='Registration process aborted (token expired)'><![CDATA[
<iq type='error' from='example.com' id='reg1'>
  <query xmlns='jabber:iq:register'>
    <username>juliet</username>
    <password>m1cro$oft</password>
    <token>TOKEN</token>
  </query>
  <error type='cancel'>
    <token-expired xmlns='urn:xmpp:invite:0'/>
  </error>
</iq>
]]></example>
    <p>After the invitee has successfully registered on the inviter's server
      and roster subscription is enabled for account creation, the server MUST
      use roster pushes as defined in &rfc6121; §2.1.6 in order to inform the
      inviter about the invitee's new account without the need to reconnect.</p>
    <example caption="Push roster item of invitee to inviter"><![CDATA[
<iq type='set' from='romeo@example.com' id='push'>
  <query xmlns='jabber:iq:roster'>
    <item subscription='both' jid='juliet@example.com'/>
  </query>
</iq>
]]></example>
  </section2>
</section1>
<section1 topic='Business Rules' anchor='rules'>
  <section2 topic='Fallback to Client-Side PARS'>
    <p>If the inviter's server does not support user invitation, the client
      application SHOULD silently fall back to &xep0379; for a good user
      experience.</p>
  </section2>
  <section2 topic='Account Creation'>
    <p>If a username was specified during the account creation process, the
      server SHOULD NOT create an account on the server until the invitee
      actually registers it with the corresponding token.
      The server MUST reserve the username at least until the corresponding
      token expires.</p>
  </section2>
</section1>
<section1 topic='Implementation Notes' anchor='impl'>
  <section2 topic='XMPP Server Suggestion for Invitees'>
    <p>If the invitee opens the invitation URI and chooses to create a new
      account, the client MUST use the inviter's server as default if the
      server advertises in-band registration support via the
      <strong>ibr=y</strong> query compontent.</p>
  </section2>
</section1>
<section1 topic='Accessibility Considerations' anchor='access'>
  <p>OPTIONAL.</p>
</section1>
<section1 topic='Internationalization Considerations' anchor='i18n'>
  <p>OPTIONAL.</p>
</section1>
<section1 topic='Security Considerations' anchor='security'>
  <p>See security considerations in &xep0379;.</p>
</section1>
<section1 topic='IANA Considerations' anchor='iana'>
  <p>This document requires no interaction with &IANA;.</p>
</section1>
<section1 topic='XMPP Registrar Considerations' anchor='registrar'>
    <p>As authorized by &xep0147;, the XMPP Registrar maintains a registry of
      queries and key-value pairs for use in XMPP URIs (see &QUERYTYPES;).</p>
    <p>The key-value parameter <strong>preauth</strong> is added to the
      <strong>register</strong> query action as defined in &xep0077;</p>
    <code><![CDATA[
<querytype>
  <name>register</name>
    ...
    <key>
      <name>preauth</name>
      <desc>the token used to allow one-time in-band registration on the inviter's server</desc>
    </key>
</querytype>
]]></code>

    <p>In addition to the <strong>preauth</strong> key-value parameter define
      in &xep0379;, the <strong>ibr</strong> parameter is added to the
      <strong>roster</strong> query action.</p>
    <code><![CDATA[
<querytype>
  <name>roster</name>
    ...
    <key>
      <name>ibr</name>
      <value>y</value>
      <desc>the parameter to indicate that the token allows the invitee to create an account on the inviter's server via in-band registration</desc>
    </key>
</querytype>
]]></code>
</section1>
<section1 topic='XML Schema' anchor='schema'>
  <p>REQUIRED for protocol specifications.</p>
</section1>
</xep>