Find and remove file from cache - firefox-addon

Question

I have this css which applies background-image: path/to/desktop/build1.png.
So whatever is build1.png on desktop will be the background image. However, in my addon, after I dynamically delete build1.png and replace it with another image that I rename build1.png, the background-image does not update. I tried ctrl+f5 and it didn't work. So I'm thinking after I dynamically replace the image on the desktop I should delete it from cache.
Test case, copy paste to scratchpad with environment browser and hit run, it opens a new tab with a gui for the test case. Hit "Release Img" then hit "applyCss" then hit "Aurora Img" and watch how the background of the div doesn't change.
Here is youtube video demo of this testcase demo'ing the issue: https://www.youtube.com/watch?v=mbGJxHtstrw
var tab = gBrowser.loadOneTab('data:text/html,<div class="profilist-icon-build-1">backround of this span is of icon on desktop</div><input type="button" value="applyCss"><input type="button" value="removeCss"> Change File on Desktop to: <input type="button" value="Release Img"><input type="button" value="Beta Img"><input type="button" value="Aurora Img"><input type="button" value="Nightly Img">', {inBackground:false});
//start - listen for loadOneTab to finish loading per https://gist.github.com/Noitidart/0f076070bc77abd5e406
var mobs = new window.MutationObserver(function(mutations) {
mutations.forEach(function(mutation) {
if (mutation.attributeName == 'progress' && tab.getAttribute('progress') == '') {
//alert('tab done loading');
init();
mobs.disconnect();
}
});
});
mobs.observe(tab, {attributes: true});
//end - listen for loadOneTab to finish loading per https://gist.github.com/Noitidart/0f076070bc77abd5e406
function init() {
//run on load of the loadOneTab
var win = tab.linkedBrowser.contentWindow;
var doc = win.document;
var btns = doc.querySelectorAll('input[type=button]');
Array.prototype.forEach.call(btns, function(b) {
b.addEventListener('click', handleBtnClick, false);
});
}
Cu.import('resource://gre/modules/Services.jsm');
Cu.import('resource://gre/modules/osfile.jsm');
var sss = Cc['#mozilla.org/content/style-sheet-service;1'].getService(Ci.nsIStyleSheetService);
var cssBuildIconsStr = '.profilist-icon-build-1 { background-image: url("' + OS.Path.toFileURI(OS.Path.join(OS.Constants.Path.desktopDir, 'build1.png')) + '"); ';
var newURIParam = {
aURL: 'data:text/css,' + encodeURIComponent(cssBuildIconsStr),
aOriginCharset: null,
aBaseURI: null
};
var cssBuildIconsURI = Services.io.newURI(newURIParam.aURL, newURIParam.aOriginCharset, newURIParam.aBaseURI);
function handleBtnClick(e) {
var targ = e.target;
var doc = e.target.ownerDocument;
var win = doc.defaultView;
switch(targ.value) {
case 'applyCss':
if (sss.sheetRegistered(cssBuildIconsURI, sss.AUTHOR_SHEET)) {
win.alert('ERROR: Sheet is already registered! Will not re-register...');
} else {
sss.loadAndRegisterSheet(cssBuildIconsURI, sss.AUTHOR_SHEET);
win.alert('REGISTERED')
}
break;
case 'removeCss':
if (sss.sheetRegistered(cssBuildIconsURI, sss.AUTHOR_SHEET)) {
sss.unregisterSheet(cssBuildIconsURI, sss.AUTHOR_SHEET);
win.alert('UNregged');
} else {
win.alert('ERROR: Sheet is not registered! Nothing to unregister...');
}
break;
case 'Release Img':
xhr('https://raw.githubusercontent.com/Noitidart/Profilist/%2321/bullet_release.png', function(d){saveToDiskAsBuild1(d, win)});
break;
case 'Beta Img':
xhr('https://raw.githubusercontent.com/Noitidart/Profilist/%2321/bullet_beta.png', function(d){saveToDiskAsBuild1(d, win)});
break;
case 'Aurora Img':
xhr('https://raw.githubusercontent.com/Noitidart/Profilist/%2321/bullet_aurora.png', function(d){saveToDiskAsBuild1(d, win)});
break;
case 'Nightly Img':
xhr('https://raw.githubusercontent.com/Noitidart/Profilist/%2321/bullet_nightly.png', function(d){saveToDiskAsBuild1(d, win)});
break;
default:
win.alert('unknown button clicked, value = "' + targ.value + '"');
}
}
function xhr(url, cb) {
let xhr = Cc["#mozilla.org/xmlextras/xmlhttprequest;1"].createInstance(Ci.nsIXMLHttpRequest);
let handler = ev => {
evf(m => xhr.removeEventListener(m, handler, !1));
switch (ev.type) {
case 'load':
if (xhr.status == 200) {
cb(xhr.response);
break;
}
default:
Services.prompt.alert(null, 'XHR Error', 'Error Fetching Package: ' + xhr.statusText + ' [' + ev.type + ':' + xhr.status + ']');
break;
}
};
let evf = f => ['load', 'error', 'abort'].forEach(f);
evf(m => xhr.addEventListener(m, handler, false));
xhr.mozBackgroundRequest = true;
xhr.open('GET', url, true);
xhr.channel.loadFlags |= Ci.nsIRequest.LOAD_ANONYMOUS | Ci.nsIRequest.LOAD_BYPASS_CACHE | Ci.nsIRequest.INHIBIT_PERSISTENT_CACHING;
xhr.responseType = "arraybuffer"; //dont set it, so it returns string, you dont want arraybuffer. you only want this if your url is to a zip file or some file you want to download and make a nsIArrayBufferInputStream out of it or something
xhr.send(null);
}
function saveToDiskAsBuild1(data, win) {
var file = OS.Path.join(OS.Constants.Path.desktopDir, 'build1.png');
var promised = OS.File.writeAtomic(file, new Uint8Array(data));
promised.then(
function() {
win.alert('succesfully saved image to desktop')
},
function(ex) {
win.alert('FAILED in saving image to desktop')
}
);
}