WebAPI/WebMMS

Overview

On the surface, MMS messages are very similar to multipart HTML emails. One part is responsible for the layout of the message, though MMS uses SMIL rather than HTML. The other parts are attachments, such as text, picture, video, and sound files. Much like in multipart emails, the attachments have "file names" and are referred to by those from the presentation part.

The API proposal below exposes the SMIL document as a DOM tree and the attachments as Blobs (or, rather, an extension thereof, akin to how File is an extension of Blob). On a User Agent capable of rendring SMIL, the web application may simply render the DOM right away. On other User Agents, it may use XSLT or some other method to convert SMIL to HTML.

To read the attachments, the web application may use the FileReader API. However, it's not that useful or efficient to have image/audio/video data in memory (e.g. as a typed array). For display purposes the web application just needs a URI that resolves to the data, so that it can point to it in a <video>, <audio>, <img> element. In the simplest case this could be a data: URI, but for large data it might just want to stream the data directly from a file on the disk. (This would be a generally useful feature to provide for all blobs, e.g. when storing multimedia data in IndexedDB.)

API

MmsManager

 /**
  * TODO should we merge with this with SmsManager? There are good reasons for and against it.
  * Pro: One API to rule them all, less API clutter, easier to write integrated SMS/MMS app
  *      (which is what everybody wants anyway) 
  * Con: MMS is vastly more complex than SMS, both in terms of API as in terms of implementation
  *      and storing; implementations need to be acutely aware of MMS and how to deal with them.
  */
 interface MmsManager
 {
   DOMRequest   send(MmsMessage message);
   DOMRequest[] send(MmsMessage message[]);
   DOMRequest   delete(long id);
   DOMRequest   delete(MmsMessage message);
   DOMRequest   getMessage(long id);
   DOMRequest   getMessages(SMSFilter filter, bool reverse);
   
   /**
    * Fetch a message's data. Only applicable if message.delivery == "unfetched"
    */
   DOMRequest   fetchMessage(MmsMessage message);
   
   /**
    * Forward a message to a different number.
    */
   DOMRequest   forwardMessage(MmsMessage message, recipient);
   
   /**
    * Cancel a message's delivery with the MMSC.
    */
   DOMRequest   cancelMessage(MmsMessage message);
 }

MmsMessage

 /**
  * MmsMessage constructor.
  */
 MmsMessage MmsMessage(
   DOMString receiver,
   Document document
 )
 
 [Constructor]
 interface MmsMessage
 {
   /**
    * Cf. SmsMessage
    */
   readonly attribute long                 id;
   
   /**
    * Like SmsMessage::delivery, but with an additional possible value: "unfetched"
    */
   readonly attribute DOMString            delivery;
   
   /**
    * Cf. SmsMessage
    */
   readonly attribute DOMString            sender;
   
   /**
    * TODO Should this be plural? (AFAIK MMS supports group messaging.)
    */
   readonly attribute DOMString            receiver;
   
   /**
    * Cf. SmsMessage
    */
   readonly attribute Date                 timestamp;
   
   /**
    * DOM document object representing the SMIL document.
    */
   readonly attribute Document             contentDocument;
   
   /**
    * Object containing all other parts.
    */
   readonly attribute MmsAttachmentStorage attachments;     
 }

MmsAttachment

 /**
  * This object implements a mapping to look up attachments by their name.
  *
  *   var text = message.attachments["text.txt"];
  *   message.attachments["movie.mov"] = new MmsAttachment([data], {type: "application/video"});
  *   delete message.attachments["picture.png"];
  */
 interface MmsAttachmentStorage
 {
   getter MmsAttachment getAttachment(DOMString name);
   setter creator void setAttachment(DOMString name, MmsAttachment attachment);
   deleter void deleteAttachment(DOMString name);
 }
 
 /**
  * MmsAttachment constructor (cf. Blob constructor)
  */
 MmsAttachment MmsAttachment(
   [optional] Array parts,
   [optional] BlobPropertyBag properties
 );
 
 /**
  * MMS attachments extend the DOM Blob type, akin to how File extends Blob.
  */
 [Constructor]
 interface MmsAttachment : Blob
 {
   /**
    * Name of the attachment as it is referenced within the SMIL document (cf. File::name)
    */
   readonly attribute DOMString name;
   
   /**
    * An absolute URI under which User Agent makes the attachment available for download.
    * This is provided so that the data does not have to be loaded into memory first, but
    * can directly be linked to from an <img>, <video>, or <audio> element.
    */
   readonly attribute DOMString uri;
   
   /**
    * Inherited from Blob. See https://developer.mozilla.org/en/DOM/Blob
    */
   readonly attribute unsigned long long size;
   readonly attribute DOMString type;
 }

Example

Receiving an MMS

 navigator.mms.onreceived = function (event) {
   var message = event.message;
   if (message.delivery == "unfetched") {
     message.fetch().onsuccess(function (event) {
       handleNewMessage(event.target.result);
     });
   } else {
     handleNewMessage(message);
   }
 }
 
 function handleNewMessage(message) {
   var pars = message.contentDocument.querySelectorAll("par");
   for (var i = 0; i < pars.length; i++) {
     //TODO
   }
 }

Sending an MMS

 var smil = "<smil><body><par><video src="lolcat.mov"/></par></body></smil>";
 var parser = new DOMParser();
 var doc = parser.parseFromString(smil, "application/smil");  
 
 var message = new MmsMessage(recipient, doc);
 message.attachments["lolcat.mov"] = new MmsAttchment("lolcat.mov", "application/video", videoData);
 
 navigator.mms.send(message);