First draft.
Gathering information on many implementations has always been a chore, there exist various lists or comparisons for XMPP clients, servers and libraries, but these are often out of date, inaccurate, incomplete, or generally unmaintained.
+This specification aims at solving this problem by putting the work of publishing and keeping up to date said information onto the maintainers of the software. Given many already do maintain this kind of list, the inconvenience should be minimal.
+The information listed SHOULD include, but isn’t limited to, the project name, homepage, description, logo, screenshots if relevant, specifications supported (RFCs and XEPs). A full list of supported properties is described in RDF format at http://usefulinc.com/ns/doap#.
+A central point should be defined to gather the list of implementations publishing their information, this specifications proposes xmpp.org for this purpose.
+Creating, publishing and maintaining a project description should be as easy as possible for producers.
+Fetching, parsing and using a project description should be as easy as possible for consumers.
+These two requirements have oriented the choice of technologies towards being as restrictive as possible:
+A user might want to know which compliance suite level a given client supports before choosing it.
+A sysadmin might want to know which compliance suite level a given server supports before choosing it.
+An XMPP service might want to propose clients based on their advertised support of what they consider a modern client.
+A specification author might want to know the list of projects implementing this specification, their support level and version.
+An XMPP enthousiast website might want to automatically update their XMPP comparison page with up to date information.
+This specification won’t list every property one could add to their DOAP file, that is the role of the DOAP specification, so it will start with examples.
+Here is a minimal DOAP file, containing the same data as the XMPP Software Listing:
+But a lot more information can be added:
+It is recommended to start from such an example and tweak it to correspond to your project.
+As per the requirements, and as you may have seen in the previous example, we want to know the implementation status of each relevant XMPP specification, which isn’t covered by the DOAP specification.
+In order to support that, the https://linkmauve.fr/ns/xmpp-doap# namespace defines the <SupportedXep/> element, which sports a few properties:
+| Property | +Description | +Required | +
|---|---|---|
| xep | +The URL to the XEP document. | +Required | +
| status | +The support status by this project, can be 'complete', 'partial', 'planned', 'deprecated', 'removed' or 'wontfix'. | +Required | +
| version | +XEP version implemented by this software. | +Optional | +
| since | +Software version this support first appeared in. | +Optional | +
| note | +Any implementation note the project deems relevant. | +Optional | +
A project SHOULD publish the information it deems relevant in the format defined in this specification.
+A project MAY maintain this information in another serialisation (JSON-LD, Turtle…), but MUST submit it in RDF/XML serialisation.
+Once satisfied with it, a project SHOULD submit their DOAP file to xmpp.org following this process.
+xmpp.org SHOULD cache and host the given files on the behalf of projects, so that if their website goes down for whichever reason other consumers can keep working as usual.
+Projects with an existing internationalization process are encouraged to use it to translate user-facing strings in the DOAP file.
+This document introduces no additional security considerations above and beyond those defined in the documents on which it depends.
+This document requires no interaction with &IANA;.
+This document requires no interaction with the ®ISTRAR;.
+https://schema.org/ was also considered, given the considerable overlap in features with DOAP, but it didn’t contain many properties useful for software projects. Parts of its properties are reused in this specification, where DOAP was lacking (namely for the logo, screenshot and documentation properties).
+AppStream was also considered, but it lacks the extensibility and existing tooling of RDF, while being limited to being a description for software installers instead of a generic software description.
+A aesgcm URL MUST never be linkified and clients MUST NOT offer another direct way for users to open them in a browser as this could leak the anchor with the encryption key to the server operator. This is also the reason the aesgcm URL was choosen in the first place to prevent users from accidentally opening a HTTP URL in the browser.
The aesgcm scheme is not registered at the IANA, and it probably shouldn’t be as it is mostly a hack in order to work around the limitations of &xep0384; version 0.3.0 with regards to the extensibility, as this extension could only encrypt the <body/> of a message.
Fix incorrect max sequence number in the text; it was given as one less than two to the power of 15, but in reality it is one less than two to the power of 16, which is clear from the context).
Each chunk of data is included as the XML character data of the <data/> element after being encoded as Base64 as specified in Section 4 of &rfc4648;. Each block MUST be a valid base64 block with padding at the end if needed.
-The <data/> element MUST possess a 'seq' attribute; this is a 16-bit unsigned integer that acts as a counter for data chunks sent in a particular direction within this session. The 'seq' value starts at 0 (zero) for each sender and MUST be incremented for each packet sent by that entity. Thus, the second chunk sent has a 'seq' value of 1, the third chunk has a 'seq' value of 2, and so on. The counter loops at maximum, so that after value 65535 (215 - 1) the 'seq' MUST start again at 0.
+The <data/> element MUST possess a 'seq' attribute; this is a 16-bit unsigned integer that acts as a counter for data chunks sent in a particular direction within this session. The 'seq' value starts at 0 (zero) for each sender and MUST be incremented for each packet sent by that entity. Thus, the second chunk sent has a 'seq' value of 1, the third chunk has a 'seq' value of 2, and so on. The counter loops at maximum, so that after value 65535 (216 - 1) the 'seq' MUST start again at 0.
The <data/> element MUST also possess a 'sid' attribute that ties the data chunk to this particular IBB session.
In the case of IQ stanzas, if the packet can be processed then the recipient MUST reply with an IQ stanza of type "result".