ndn-js
Version:
A JavaScript client library for Named Data Networking
188 lines (161 loc) • 7.43 kB
HTML
<!--
* Copyright (C) 2014-2019 Regents of the University of California.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
* A copy of the GNU Lesser General Public License is in the file COPYING.
-->
<html xmlns = "http://www.w3.org/1999/xhtml">
<meta charset="UTF-8">
<head>
<title>NDN Get File via WebSocket</title>
<script type="text/javascript" src="../../build/ndn.js"></script>
<script type="text/javascript">
hostip = "localhost";
var face = new Face({port:9696,host:hostip,verify:false});
///////////////////////////////////////////////////////////////////////////////////////////////////////////
/*
* Context for calling expressInterest to fetch a big file.
*/
var ContentContext = function ContentContext(face, T0) {
this.T0 = T0;
this.face = face;
this.totalBlocks = 0;
this.firstReceivedSegmentNumber = null;
this.firstReceivedData = null;
};
ContentContext.prototype.expressInterest = function(name) {
var thisContext = this;
this.face.expressInterest
(name,
function(interest, data) { thisContext.onData(interest, data); },
function(interest) { thisContext.onTimeout(interest); });
};
ContentContext.prototype.onTimeout = function(interest) {
var T1 = new Date();
document.getElementById('content').innerHTML += "<p>Interest time out.</p>";
document.getElementById('content').innerHTML += "<p>Time elapsed: " + (T1 - this.T0) + " ms including 4s timeout</p>";
document.getElementById('content').innerHTML += "<p>Total number of blocks: " + this.totalBlocks + "</p>";
};
ContentContext.prototype.onData = function(interest, data) {
if (data.getContent().isNull()) {
console.log("data content is null");
return;
}
// Use the segmentNumber to load multiple segments.
var segmentNumber = data.getName().get(-1).toSegment();
if (this.firstReceivedSegmentNumber == null) {
// This is the first call.
this.firstReceivedSegmentNumber = segmentNumber;
if (segmentNumber != 0) {
// Special case: Save this data packet object for later and request segment zero.
this.firstReceivedData = data;
var componentsForZero = data.getName().components.slice
(0, data.getName().size() - 1);
componentsForZero.push([0]);
this.expressInterest(new Name(componentsForZero));
return;
}
}
// Process received data here...
// Count content length
//nameStr = escape(data.getName().toUri());
this.totalBlocks++;
// Check for the special case if the saved content is for the next segment that we need.
if (this.firstReceivedData != null &&
this.firstReceivedSegmentNumber == segmentNumber + 1) {
// Substitute the saved data send its content and keep going.
data = this.firstReceivedData;
segmentNumber = segmentNumber + 1;
// Clear firstReceivedData to save memory.
this.firstReceivedData = null;
// Process received data here...
// Count content length
//nameStr = escape(data.getName().toUri());
//document.getElementById('content').innerHTML += "<p>Name string: " + nameStr + "</p>";
//document.getElementById('content').innerHTML += "<p>Content buffer length: " + data.getContent().size() + "</p>";
this.totalBlocks++;
}
var finalSegmentNumber = null;
if (data.getMetaInfo() != null && data.getMetaInfo().getFinalBlockId().getValue().size() > 0)
finalSegmentNumber = data.getMetaInfo().getFinalBlockId().toSegment();
if (finalSegmentNumber == null || segmentNumber != finalSegmentNumber) {
// Make a name for the next segment and get it.
//var segmentNumberPlus1 = NumToArray(segmentNumber + 1);
// Make a name for the next segment and get it.
var segmentNumberPlus1 = DataUtils.nonNegativeIntToBigEndian(segmentNumber + 1);
// Put a 0 byte in front.
var nextSegmentNumber = new Uint8Array(segmentNumberPlus1.length + 1);
nextSegmentNumber.set(segmentNumberPlus1, 1);
var components = data.getName().components.slice
(0, data.getName().size() - 1);
components.push(nextSegmentNumber);
this.expressInterest(new Name(components));
}
else {
// Final block received.
// Record stop time
var T1 = new Date();
document.getElementById('content').innerHTML += "<p>Final block received.</p>";
document.getElementById('content').innerHTML += "<p>Time elapsed: " + (T1 - this.T0) + " ms</p>";
document.getElementById('content').innerHTML += "<p>Total number of blocks: " + this.totalBlocks + "</p>";
}
};
/*
* Convert the big endian Uint8Array to an unsigned int.
* Don't check for overflow.
*/
function ArrayToNum(bytes) {
var result = 0;
for (var i = 0; i < bytes.length; ++i) {
result = result * 10;
result += (bytes[i] - 48);
}
return result;
};
/*
* Convert the int value to a new big endian Uint8Array and return.
* If value is 0 or negative, return Uint8Array(0).
*/
function NumToArray(value) {
value = Math.round(value);
if (value <= 0)
return new Uint8Array(0);
numString = value.toString();
var size = numString.length;
var result = new Uint8Array(size);
for (i = 0; i < size; i++) {
result[i] = numString.charCodeAt(i);
}
return result;
};
function run() {
document.getElementById('content').innerHTML += "<p>Started...</p>";
var name = new Name(document.getElementById('interest').value);
var context = new ContentContext(face, new Date());
context.expressInterest(name);
}
</script>
</head>
<body >
<form>
Please Enter an Interest:<br />
<input id="interest" type="text" name="INTEREST" size="50" value="/wentao.shang/choir_jail.png" />
</form>
<button onclick="run()">Fetch Content</button>
<p id="content">Result: <br/></p>
</body>
</html>