XEP-0329: File Information Sharing

4.1 Traversing Files¶

If a requesting entity wishes to know what files are being shared by an offering entity, it can do so by sending the following query:

<iq type='get'
    from='juliet@capulet.com/chamber'
    to='romeo@montague.net/home'
    id='1234'>
  <query xmlns="urn:xmpp:fis:0" />
</iq>

If the offering entity wishes to share files with the requesting entity, it may respond with a list of shared folders. It MUST not include any files in this response.

<iq type='result'
    from='romeo@montague.net/home'
    to='juliet@capulet.com/chamber'
    id='1234'>
  <query xmlns="urn:xmpp:fis:0">
    <directory name='documents'/>
    <directory name='pics'/>
    <directory name='audio'/>
  </query>
</iq>

if the offering entity has no files to offer

<iq type='result'
    from='romeo@montague.net/home'
    to='juliet@capulet.com/chamber'
    id='1234'>
  <query xmlns="urn:xmpp:fis:0" />
</iq>

Requesting the list of files and directories within a directory.

<iq type='get'
    from='juliet@capulet.com/chamber'
    to='romeo@montague.net/home'
    id='1235'>
  <query xmlns="urn:xmpp:fis:0" node="documents" />
</iq>

When replying with a list of files, the offering entity can choose to either reply with verbose information on the file using the file attributes defined by Jingle File Transfer (XEP-0234) [1] or it may reply only with the 'name' attribute, which is required and MUST be included in every response.

It is RECOMENDED, when the list files to be sent is small, that a verbose response be made (in order to avoid going back and forth requesting information), and that a non-verbose reponse be made otherwise. This recomendation is made to save bandwidth.

<iq type='result'
    from='romeo@montague.net/home'
    to='juliet@capulet.com/chamber'
    id='1235'>
  <query xmlns="urn:xmpp:fis:0" node="documents">
    <file xmlns='urn:xmpp:jingle:apps:file-transfer:4'>
      <name>test.txt</name>
      <date>1969-07-21T02:56:15Z</date>
      <desc>This is a test. If this were a real file...</desc>
      <range/>
      <size>1022</size>
      <hash xmlns='urn:xmpp:hashes:1' algo='sha-1'>552da749930852c69ae5d2141d3766b1</hash>
    </file>
    <file xmlns='urn:xmpp:jingle:apps:file-transfer:4'>
      <name>test2.txt</name>
    </file>
    <directory name="secret docs" />
  </query>
</iq>

If the requesting entity wants to get detailed information about a file. It can do so by providing its full path.

<iq type='get'
    from='juliet@capulet.com/chamber'
    to='romeo@montague.net/home'
    id='1236'>
  <query xmlns="urn:xmpp:fis:0" node="documents/test2.txt" />
</iq>

<iq type='result'
    from='romeo@montague.net/home'
    to='juliet@capulet.com/chamber'
    id='1236'>
  <query xmlns="urn:xmpp:fis:0">
    <file xmlns='urn:xmpp:jingle:apps:file-transfer:4'>
      <name>test2.txt</name>
      <size>1000</size>
    </file>
  </query>
</iq>

5.1 Using Result Set Management¶

Result Set Management (XEP-0059) [4] defines a way of limiting the results of a request. There are some considerations to use result sets along with this extension.

First, it is defined that the requesting entity is the one that sets the limit of the number of items that can be replied. So it is up to the requesting entity to choose a sensible number.

Second, since this protocol defines a way of handling the directory tree structure by allowing file tags to be children of a directory tags, it becomes difficult to define items for Result Set Management. Therefore, when responding to a request, the offering entity MUST NOT send directory tags with files as their children.

5.2 Out of Band Transfer¶

One obvious way to overcome the limitations of sending large stanzas in-band, is to transfer that information out of band. Out-of-Band Stream Data (XEP-0265) [5] could be used for that purpose. It is hereby RECOMMENDED its implementation when the offering entity has a massive amount of files that would not be practical to advertise in-band.

It is further recommended that when using XEP-0265, the entire directory structure, along with all the files in the shared folder and subfolders, be exchanged in one single reply. Also, all the files attributes should be included. This is to avoid wasting bandwidth initiating out of band streams going back and forth.

6.1 File identification¶

As it was previously discussed, when requesting detailed information about a file, only the "name" attribute is required, but it is strongly RECOMMENDED that the hash attribute be included, in order to reduce the chances of sending the wrong file. When requesting the file to be transferred using Jingle File Transfer (XEP-0234) [1], the information that must be provided has to identify the file uniquely. It is then RECOMMENDED that when requesting a file, the full path of the file in the shared folder be included in the "name" attribute.

<iq type='get'
    from='juliet@capulet.com/chamber'
    to='romeo@montague.net/home'
    id='1237'>
  <jingle xmlns='urn:xmpp:jingle:1'
          action='session-initiate'
          initiator='juliet@capulet.com/chamber'
          sid='uj3b2'>
    <content creator='initiator' name='a-file-request' senders='responder'>
      <description xmlns='urn:xmpp:jingle:apps:file-transfer:4'>
        <file>
          <name>pics/test4.png</name>
          <size>10740</size>
        </file>
      </description>
    </content>
  </jingle>
</iq>

6.2 File Sharing in MUCs¶

For the most part, discovering files in a MUC is exactly the same as what has been described in this document. However, it is RECOMMENDED that a participant in a MUC should have a single shared folder associated with the entire room, as opposed to advertise different files to different participants of the room. This is to reduce the complexity of the client software. Also, due to volatile nature of the participants in a room, keeping track of permissions is more trouble than what it is worth.

Copyright

This XMPP Extension Protocol is copyright © 1999 – 2024 by the XMPP Standards Foundation (XSF).

Permissions

Permission is hereby granted, free of charge, to any person obtaining a copy of this specification (the "Specification"), to make use of the Specification without restriction, including without limitation the rights to implement the Specification in a software program, deploy the Specification in a network service, and copy, modify, merge, publish, translate, distribute, sublicense, or sell copies of the Specification, and to permit persons to whom the Specification is furnished to do so, subject to the condition that the foregoing copyright notice and this permission notice shall be included in all copies or substantial portions of the Specification. Unless separate permission is granted, modified works that are redistributed shall not contain misleading information regarding the authors, title, number, or publisher of the Specification, and shall not claim endorsement of the modified works by the authors, any organization or project to which the authors belong, or the XMPP Standards Foundation.

Disclaimer of Warranty

## NOTE WELL: This Specification is provided on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, express or implied, including, without limitation, any warranties or conditions of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A PARTICULAR PURPOSE. ##

Limitation of Liability

In no event and under no legal theory, whether in tort (including negligence), contract, or otherwise, unless required by applicable law (such as deliberate and grossly negligent acts) or agreed to in writing, shall the XMPP Standards Foundation or any author of this Specification be liable for damages, including any direct, indirect, special, incidental, or consequential damages of any character arising from, out of, or in connection with the Specification or the implementation, deployment, or other use of the Specification (including but not limited to damages for loss of goodwill, work stoppage, computer failure or malfunction, or any and all other commercial damages or losses), even if the XMPP Standards Foundation or such author has been advised of the possibility of such damages.

IPR Conformance

This XMPP Extension Protocol has been contributed in full conformance with the XSF's Intellectual Property Rights Policy (a copy of which can be found at <https://xmpp.org/about/xsf/ipr-policy> or obtained by writing to XMPP Standards Foundation, P.O. Box 787, Parker, CO 80134 USA).

Visual Presentation

The HTML representation (you are looking at) is maintained by the XSF. It is based on the YAML CSS Framework, which is licensed under the terms of the CC-BY-SA 2.0 license.

1. XEP-0234: Jingle File Transfer <https://xmpp.org/extensions/xep-0234.html>.

2. XEP-0096: SI File Transfer <https://xmpp.org/extensions/xep-0096.html>.

3. XEP-0135: File Sharing <https://xmpp.org/extensions/xep-0135.html>.

4. XEP-0059: Result Set Management <https://xmpp.org/extensions/xep-0059.html>.

5. XEP-0265: Out-of-Band Stream Data <https://xmpp.org/extensions/xep-0265.html>.