I know there are docs and posts about this topic, and I have tried to make them work, but I kept on getting exceptions like (Service Manager::GetSerice returned failure code....)
I was able to create an xpcom component alright, but I would like to have it have a custom interface that defines get(namespace, data), set(namespace, data).
After reading "passing/getting data from/to custom xpcom service", I got confused and stuck on: 1. Do I still need to create an IDL, and compile it into xpt? (I think~ I need) 2. If so, since I might be passing complex js objects into the XPCOM to store, what variable type should I define? (Since I didn't see any type for js objects, void?) 3. Should I do var myService = Components.classes["@my.com/myService;1"] .getService(Components.interfaces.nsISupports); or var myService = Components.classes["@my.com/myService;1"] .getService(); Well, both of them are giving me the same errors. (I am on firefox 2.0.0.4 ubuntu)
Can someone please show me some working code or examples of how to store and retrieve js objects from XPCOM component?
Lei Sun wrote: > 1. Do I still need to create an IDL, and compile it into xpt? (I think~ > I need) > 2. If so, since I might be passing complex js objects into the XPCOM > to store, what variable type should I define? (Since I didn't see any > type for js objects, void?)
You don't need IDL. You will have to use the wrappedJSObject trick, though.
> 3. Should I do > var myService = Components.classes["@my.com/myService;1"] > .getService(Components.interfaces.nsISupports); > or > var myService = Components.classes["@my.com/myService;1"] > .getService();
Either one should work.
> Well, both of them are giving me the same errors. (I am on firefox > 2.0.0.4 ubuntu)
You could try shutting down firefox and deleting compreg.dat and xpti.dat as described here:
> 3. Should I do > var myService = Components.classes["@my.com/myService;1"] > .getService(Components.interfaces.nsISupports); > or > var myService = Components.classes["@my.com/myService;1"] > .getService(); > Well, both of them are giving me the same errors. (I am on firefox > 2.0.0.4 ubuntu)
It worked after I removed the compreg.dat and xpti.dat in the profile dir, and restarted the application.
Then my follow up question is:
Say, we are using reference to refer to this component. Are we able to alter this component's inner implementations? (Please see the code below)
in component's code: function Test() { // you can cheat and use this // while testing without // writing your own interface this.wrappedJSObject = this;
}
// This is the implementation of your component. Test.prototype = { // for nsISupports QueryInterface: function(aIID) { // add any other interfaces you support here if (!aIID.equals(nsISupports)) throw Components.results.NS_ERROR_NO_INTERFACE; return this; },
hello: function() { return {a: 'hello'}; }
}
in calling code: var s = Components.classes["@my.com/myService;1"] .getService().wrappedJSObject; s.hello = function() { // do something really bad, like stealing people's passwords... // --- evil implementation
}
So if I do a
var s = Components.classes["@my.com/myService;1"] .getService().wrappedJSObject;
again, Would that still have the evil implementation from the last block of code? If so, How long will it last? Until the next application restart? And how do I protect the component from being evil used like this?
Lei
On 6/25/07, Nickolay Ponomarev <asquee...@gmail.com> wrote:
> On 6/25/07, Lei Sun <lei....@gmail.com> wrote: > > 3. Should I do > > var myService = Components.classes["@my.com/myService;1"] > > .getService(Components.interfaces.nsISupports); > > or > > var myService = Components.classes["@my.com/myService;1"] > > .getService(); > > Well, both of them are giving me the same errors. (I am on firefox > > 2.0.0.4 ubuntu)
> On 6/25/07, Nickolay Ponomarev <asquee...@gmail.com> wrote: > > On 6/25/07, Lei Sun <lei....@gmail.com> wrote: > > > 3. Should I do > > > var myService = Components.classes["@my.com/myService;1"] > > > .getService(Components.interfaces.nsISupports); > > > or > > > var myService = Components.classes["@my.com/myService;1"] > > > .getService(); > > > Well, both of them are giving me the same errors. (I am on firefox > > > 2.0.0.4 ubuntu)
I think it's important to point out that the attack Lei describes can only be achieve from other privileged code; i.e., user-installed code, not arbitrary web sites. A user would have to install code specifically targeted at the custom XPCOM service in question.
----- Original Message ---- From: Nickolay Ponomarev <asquee...@gmail.com> To: Lei Sun <lei....@gmail.com>
Cc: dev-extensi...@lists.mozilla.org Sent: Monday, June 25, 2007 3:01:27 PM Subject: Re: Share global data in Firefox through javascript implemented XPCOM
On 6/25/07, Lei Sun <lei....@gmail.com> wrote: > Say, we are using reference to refer to this component. Are we able to > alter this component's inner implementations? (Please see the code > below)
> in component's code: > function Test() { > this.wrappedJSObject = this; > }
> in calling code: > var s = Components.classes["@my.com/myService;1"] > .getService().wrappedJSObject; > s.hello = function() { > // do something really bad, like stealing people's passwords... // > --- evil implementation > }
> So if I do a
> var s = Components.classes["@my.com/myService;1"] > .getService().wrappedJSObject;
> again, Would that still have the evil implementation from the last > block of code?
Yes.
> If so, How long will it last? Until the next > application restart?
Yes.
> And how do I protect the component from being > evil used like this?
By avoiding the wrappedJSObject thing and exposing your component's functionality via IDL interfaces instead.
Nickolay
> On 6/25/07, Nickolay Ponomarev <asquee...@gmail.com> wrote: > > On 6/25/07, Lei Sun <lei....@gmail.com> wrote: > > > 3. Should I do > > > var myService = Components.classes["@my.com/myService;1"] > > > .getService(Components.interfaces.nsISupports); > > > or > > > var myService = Components.classes["@my.com/myService;1"] > > > .getService(); > > > Well, both of them are giving me the same errors. (I am on firefox > > > 2.0.0.4 ubuntu)
The intension for this extension is actually to make user to install local script easier? and I am trying to figure out a way, so that they won't be stepping on each other, and I can have a guaranteed way to get all of them fresh without restarting firefox.
You might consider loading the local scripts with nsIScriptLoader since this creates a unique, separated namespace where variables and functions cannot step on each other.
----- Original Message ---- From: Lei Sun <lei....@gmail.com> To: dev-extensi...@lists.mozilla.org Sent: Tuesday, June 26, 2007 1:53:12 AM Subject: Re: Share global data in Firefox through javascript implemented XPCOM
Hi Nick,
I tried to define void, but it didn't work.
Hi Eric,
The intension for this extension is actually to make user to install local script easier? and I am trying to figure out a way, so that they won't be stepping on each other, and I can have a guaranteed way to get all of them fresh without restarting firefox.
Lei
On 6/25/07, Lei Sun <lei....@gmail.com> wrote: > Hi Nickolay,
Lei Sun wrote: > 2. If so, since I might be passing complex js objects into the XPCOM > to store, what variable type should I define?
You can't really do this, because the Object prototype for your custom js objects is defined on your current window, which will go away when the window is closed. If your objects have a consistent interface then you can of course create them in your XPCOM component and retrieve them from your UI code.
