Dev : Tips : Disable XUL cache: Difference between revisions

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(redirect to devmo, all the up-to-date info is there minus the overlay reload thing, which sounds kinda iffy)
 
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{{extdev}}
See [http://developer.mozilla.org/en/docs/Setting_up_extension_development_environment Setting up extension development environment] at [http://developer.mozilla.org MDC].


'''nglayout.debug.disable_xul_cache''' is a preference useful for extension developers. Basically when it is set to '''false''' (which is default), Mozilla caches chrome XUL and JavaScript (and more) in a file named XUL.mfl or similarly. This means you have to restart Mozilla to test your changes to chrome files.
[[Category:Redirects]]
 
If you develop and extension you should disable the XUL cache by [[Editing configuration|setting]] this pref to '''true''', although it will make Mozilla slower at startup and when opening new windows.
 
==Getting rid of JARs==
However even when '''nglayout.debug.disable_xul_cache''' is set to '''true''', Mozilla forbids rewriting *.jar files containing installed extensions. To overcome this and to avoid having to repackage after making any changes, you can do one of the following:
* Use the [[Getting_started_with_extension_development#reg-em|new features of Firefox/Thunderbird 1.5's Extension Manager]] ('''recommended''').
* [[#Changing install.rdf|Package your extension to use plain directories]] instead of a single JAR before installing (you should use this if you have to develop using Firefox/Thunderbird 1.0 or older).
* Unarchive the JAR file you want to edit and make it permanent by [[#Editing chrome.rdf|updating chrome.rdf]] to point to the unpacked files instead of the JAR (after installing).
* Use installed-chrome.txt to add your files to chrome, see [http://xulplanet.com/tutorials/xulapp/newpackage.html] and [http://www.mozilla.org/docs/tutorials/tinderstatus/] ''(not sure if it works in Firefox. Definitely not with 1.5)''
 
The following sections provide detailed instructions
 
===Changing install.rdf===
: ''Note: this tip is most useful for developing extensions in the Mozilla Suite or Firefox/Thunderbird 1.0 or older. If you develop for Firefox/Thunderbird 1.5 or if you are new to extension development, you really ought to consider using the [[Getting_started_with_extension_development#reg-em|new features of Extension Manager]] instead.''
 
An easy way to make Firefox/Thunderbird read your extension's chrome files from a plain directory instead of a JAR file is to create and install an XPI that doesn't use a JAR file. There are a few differences from the regular [[Packaging extensions|packaging technique]]:
* Put your chrome files in a directory instead of a JAR:<br/> Instead of putting your chrome files into <tt>myextension.xpi/chrome/myextension.jar</tt> you should put them into a directory called <tt>myextension.xpi/chrome/myextension/</tt>
* Replace the following line in [[install.rdf]]:<br /><tt><Description about="urn:mozilla:extension:file:myextension.jar"></tt><br />with<br /><tt><Description about="urn:mozilla:extension:file:myextension"></tt>
* Change the install.js:<br />For Mozilla Suite there might be additional modifications in the install.js file necessary which reflect the install.rdf file changes which is replaced by the .js file.
 
An [http://cgi29.plala.or.jp/~mozzarel/addon/obsolete/phoenix_firebird_firefox/non-jarred/ example]
of this technique is available.  Also, myk is planning to update his [http://www.mozilla.org/docs/tutorials/tinderstatus/ tinderstatus extension]
to demonstrate this technique.
 
Please note, that it's recommended to package chrome files in a JAR when doing a public release - for better startup performance.
 
===Editing chrome.rdf===
We assume that the extension is installed in profile in this section.
 
'''''Important!! Backup your profile before editing chrome.rdf!'''''
<ol><li>Unpack the JAR file you have, say <tt>[profile]\extensions\{YOUR-EXTENSION'S-GUID}\chrome\my-ext.jar</tt> to the same directory. You will get (at least) <tt>[profile]\extensions\{YOUR-EXTENSION'S-GUID}\chrome\content</tt> directory.</li>
<li>In <tt>[profile]\chrome\chrome.rdf</tt> look for '''my-ext.jar!''' and delete it. For example replace this line
<pre>c:baseURL="jar:file:///D:/Firefox/Profiles/default/extensions/{GUID}/chrome/my-ext.jar!/content/my-ext/"</pre>
with this:
<pre>c:baseURL="file:///D:/Firefox/Profiles/default/extensions/{GUID}/chrome/content/my-ext/"</pre>
Note, that you should also delete '''jar:''' at the beginning of the path.</li></ol>
 
==The overlay problem==
There is still another issue to be solved: a Javascript that's called from the overlay.
The steps above help you test scripts that are not part of the overlay, like your settings dialog. But they can't help you test the overlay scripts because Firefox caches those.
 
The solution is to have the overlay script load its code from an external [[File IO|file]], which is reloaded and re-evaluated constantly.
Here's an example:
 
<pre>
var TheExt = {
 
//aFuncCall is a string to be evaluated as a function call
inject : function (aFuncCall) {
                var codeFileName =  "injected.js";
 
// Get profile directory
var file = Components.classes["@mozilla.org/file/directory_service;1"].
createInstance(Components.interfaces.nsIProperties).
get("ProfD", Components.interfaces.nsIFile);
 
// Get the file with the code
file.append(codeFileName);
if (!file.exists()) {
dump ("Error: " + file.path + "does not exist.\n");
return;
}
 
// Read the file into code
var code = "";
var fstream = Components.classes["@mozilla.org/network/file-input-stream;1"]
.createInstance(Components.interfaces.nsIFileInputStream);
var sstream = Components.classes["@mozilla.org/scriptableinputstream;1"]
.createInstance(Components.interfaces.nsIScriptableInputStream);
fstream.init(file, 1, 0, false);
sstream.init(fstream);
code += sstream.read(-1);
sstream.close();
fstream.close();
// Run the code
eval(code);
eval(aFuncCall);
},
doAction : function() {
this.inject("doAction()");
}
}
 
dump ("Testing the extension.\n");
TheExt.doAction();
</pre>
 
The file injected.js simply looks like this:
<pre>
function doAction() {
dump ("Action!\n")
}
</pre>
 
You can add as many functions as you want. inject() evaluates all the functions in the file, but only executes the aFuncCall parameter.
 
[[Category:Development]]

Latest revision as of 19:53, 23 May 2007