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@ryanramage
Last active December 17, 2015 16:29
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Couchapp Live reload. Simply add <script src="live.js"/> You must have two rewrites defined as follows: { "from": "_db/*" , "to" : "../../*" }, { "from": "_ddoc" , "to" : "" },
(function(){
var currentETag;
onLoad(function pageLoaded() {
console.log('starting live reload');
if (window.EventSource) return eventsource();
else setInterval(polling, 1500);
});
/* Use couchdb eventsource changes feed. Reload page when id matches this ddoc */
function eventsource() {
fetchName(function(err, name){
var ddoc_name = '_design/' + name;
var source = new EventSource("_db/_changes?feed=eventsource&since=now");
var sourceListener = function(e) {
var data = JSON.parse(e.data);
if (data.id !== ddoc_name) return;
window.location.reload();
};
// start listening for events
source.addEventListener('message', sourceListener , false);
});
}
/* Poll for etag changes to the ddoc */
function polling() {
fetchStatus(function(err, etag){
if (!currentETag) currentETag = etag;
else {
if (currentETag !== etag) {
window.location.reload();
}
}
});
}
function fetchStatus(callback) {
var client = new XMLHttpRequest();
client.onreadystatechange = function() {
if (this.readyState == this.DONE) {
callback(null, client.getResponseHeader('ETag').toString());
}
};
client.open("HEAD", '_ddoc');
client.send();
}
function fetchName(callback) {
var client = new XMLHttpRequest();
client.onreadystatechange = function() {
if (this.readyState == this.DONE) {
var data = JSON.parse(this.response);
callback(null, data.name);
}
};
client.open("GET", '_ddoc/_info');
client.send();
}
function onLoad(callback) {
if (document.addEventListener) {
//Standards. Hooray! Assumption here that if standards based,
//it knows about DOMContentLoaded.
document.addEventListener("DOMContentLoaded", callback, false);
window.addEventListener("load", callback, false);
} else if (window.attachEvent) {
window.attachEvent("onload", callback);
testDiv = document.createElement('div');
try {
isTop = window.frameElement === null;
} catch (e) {}
//DOMContentLoaded approximation that uses a doScroll, as found by
//Diego Perini: http://javascript.nwbox.com/IEContentLoaded/,
//but modified by other contributors, including jdalton
if (testDiv.doScroll && isTop && window.external) {
scrollIntervalId = setInterval(function () {
try {
testDiv.doScroll();
callback();
} catch (e) {}
}, 30);
}
}
}
})();
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