Inter Widget Communication with Drag&Drop

Enables the inter widget communication and drag and drop between widgets within a widget container.

How to start

• See two widgets in action here: https://graasp.epfl.ch/#url=iwc
• Source code of these widgets: src.xml and dest.xml

Description

Widgets are often rendered as iframes inside a widget container. The library allows a widget to broadcast messages to other widgets open on the page. In addition, an object can be brought from one widget to another with drag and drop.

Example 1: send data from one widget to another

// require the iwc library in both src and dest widgets
<script type="text/javascript" src="http://graasp.epfl.ch/gadget/libs/iwc.min.js"></script>

// ------- Source gadget --------
// send some data
iwc.publish({
  event: "select",
  type: "json",
  message: {
    data: "some text"
  }
})

// ------- Destination gadget --------
// start listenning on incoming events
iwc.connect(function (envelope, message) {
  var data = message.data
  console.log(data)
}

Example 2: drag&drop from one widget to another

// require the iwc library in both src and dest widgets
<script type="text/javascript" src="http://graasp.epfl.ch/gadget/libs/iwc.min.js"></script>

// ------- Source gadget --------
// 'dragme' - id of the DOM node that can be dragged
iwc.draggable('dragme', {
  // function should return the data that you want to transfer
  dragstart: function () {
    return "my data"
  }
})

// ------- Destination gadget --------
// 'droparea' - id of the DOM node that accepts draged elements
iwc.droppable('droparea', {
  drop: function (data) {
    // data - that was passed during the drop
  }
})

APIs

Inter Widget Communication

// start listenning on incoming events
iwc.connect(function (envelope, message) {
  // envelope - contains extra info about the event  
  // message - object passed from one widget to another
})

// broadcasts event to other widgets
iwc.publish({
  event: "select",       // type of event: select, click, etc.
  type: "json",
  message: {             // message object passed
    data: "some text"
  }
})

Drag and drop

// turns a DOM element into a draggable object
iwc.draggable(elemId, opts)

opts.dragstart = function (drag) {
  // drag - object on which dragstart is executed
  return {data: "data"} // this data passed to droppable object
}

// turns a DOM element into a droppable object
iwc.droppable(elemId, opts)

opts.drop = function (data, drop, drag) {
  // data - that was passed to droppable object
  // drop - object on where the drop occured
  // drag - object that was dropped
}

opts.dragover = function (drop) {
  // drop - object on where the drop occured
}

Thanks

The initial code of inter-widget communication is based on the openapp library by Erik Isaksson and Matthias Palmér.

MIT License

Copyright (c) 2013 Evgeny Bogdanov

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.