Hi,
I am creating a protocol with javascript for my xulrunner app. How do I go about returning a file not found error from my protocol so that it is displayed as a standard message in the browser control (as a alert or page depending on the prefs)? I've tried "moz-neterror:page?e=error&u=url&d=desc" from netError.xhtml but that gives a message saying that the protocol does not exist.

I've also tried throwing an error msg from javascript but that does not return a standard 404 or simillar page.

Help is appreciated thank you.
James


----------------------------------------------
James Newell
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Spoke too soon again.
Googling firefox + neterror returned about:neterror, which returned "about:neterror?e=netTimeout&u=blank&c=UTF-8&d=Insertmessagehere"

And then I also found the error names and descriptions in the netError.xhtml file.


    <div id="errorContainer">
      <div id="errorTitlesContainer">
        <h1 id="et_generic">&generic.title;</h1>
        <h1 id="et_dnsNotFound">&dnsNotFound.title;</h1>
        <h1 id="et_fileNotFound">&fileNotFound.title;</h1>
        <h1 id="et_malformedURI">&malformedURI.title;</h1>
        <h1 id="et_protocolNotFound">&protocolNotFound.title;</h1>
        <h1 id="et_connectionFailure">&connectionFailure.title;</h1>
        <h1 id="et_netTimeout">&netTimeout.title;</h1>


        <h1 id="et_redirectLoop">&redirectLoop.title;</h1>
        <h1 id="et_unknownSocketType">&unknownSocketType.title;</h1>
        <h1 id="et_netReset">&netReset.title;</h1>
        <h1 id="et_netOffline">&netOffline.title;</h1>
        <h1 id="et_netInterrupt">&netInterrupt.title;</h1>
        <h1 id="et_deniedPortAccess">&deniedPortAccess.title;</h1>
        <h1 id="et_proxyResolveFailure">&proxyResolveFailure.title;</h1>
        <h1 id="et_proxyConnectFailure">&proxyConnectFailure.title;</h1>
      </div>


      <div id="errorDescriptionsContainer">
        <div id="ed_generic">&generic.longDesc;</div>
        <div id="ed_dnsNotFound">&dnsNotFound.longDesc;</div>
        <div id="ed_fileNotFound">&fileNotFound.longDesc;</div>
        <div id="ed_malformedURI">&malformedURI.longDesc;</div>
        <div id="ed_protocolNotFound">&protocolNotFound.longDesc;</div>
        <div id="ed_connectionFailure">&connectionFailure.longDesc;</div>
        <div id="ed_netTimeout">&netTimeout.longDesc;</div>
        <div id="ed_redirectLoop">&redirectLoop.longDesc;</div>


        <div id="ed_unknownSocketType">&unknownSocketType.longDesc;</div>
        <div id="ed_netReset">&netReset.longDesc;</div>
        <div id="ed_netOffline">&netOffline.longDesc;</div>
        <div id="ed_netInterrupt">&netInterrupt.longDesc;</div>
        <div id="ed_deniedPortAccess">&deniedPortAccess.longDesc;</div>
        <div id="ed_proxyResolveFailure">&proxyResolveFailure.longDesc;</div>
        <div id="ed_proxyConnectFailure">&proxyConnectFailure.longDesc;</div>
      </div>
    </div>

Sorry,
James


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James Newell wrote:
> I am creating a protocol with javascript for my xulrunner app. How do I go about returning a file not found error from my protocol so that it is displayed as a standard message in the browser control (as a alert or page depending on the prefs)? I've tried "moz-neterror:page?e=error&u=url&d=desc" from netError.xhtml but that gives a message saying that the protocol does not exist.

Throwing from asyncOpen should work, as should calling OnStopRequest with the 
correct error code.

-Boris

Me again.

For some reason (js security?) no arguments are working and only the generic error message is being displayed with my about:neterror?e=... method.

In regard to Boris' suggested method:
I'm guessing that to throw from asyncOpen or call OnStopRequest, that I have to create a nsIStreamListener listener object and pass it to asyncOpen.
The thing is that I don't have a channel. I mean that under certain circumstances when a particular file is determined not exist, I have no URI to pass to create newChannel.
 If i'm wrong would u be able to provide a quick sample.
Thanks heaps,
James


Boris Zbarsky wrote:
>Throwing from asyncOpen should work, as should calling OnStopRequest 
with the 
correct error code.





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James Newell wrote:
> I'm guessing that to throw from asyncOpen

Yes.  From your protocol handler's asyncOpen.

> The thing is that I don't have a channel.

Thowing from newChannel is also fine.

> I mean that under certain circumstances when a particular file is determined not exist, I have no URI to pass to create newChannel.

Throwing from newURI is also possible...

Put another way, you're implementing a protocol handler, right?  Gecko is what 
calls newURI, newChannel, asyncOpen on your code.  What are you returning to 
Gecko from those methods?

-Boris

Boris Zbarsky wrote:
> Thowing from newChannel is also fine.
> [...]
> Throwing from newURI is also possible...

You won't get an error page if you throw from newURI and IIRC not if you 
throw from newChannel either.

Christian Biesinger wrote:
> You won't get an error page if you throw from newURI and IIRC not if you 
> throw from newChannel either.

For now.  But we're planning to fix at least the latter, last I checked.  And in 
both cases you _will_ get the appropriate error notification.

-Boris

Thanks guys,

I threw just a string. I'm guessing that i'm supposed to throw some specific error. I did try googling a Components.interfaces error to throw for file not found but couldn't find one. Is there a list somewhere? Or what status do I pass onStopRequest?

Yes I was returning a file channel from my protocol, instead of the javascript channel in the example (http://nexgenmedia.net/docs/protocol/) used.

I need to view example code or tutorial of a nsIChannel implemented in javascript. I looked at lots of the cpp ones but could not find where they made callbacks to the listener to return data etc.

Thanks for all the help,
Very appreciated!

James
 


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James Newell wrote:
> I threw just a string. I'm guessing that i'm supposed to throw some specific
> error.

Yes, you are.  Depending on what sort of error you're reporting, of course.  See 
nsDocShell::DisplayLoadError for the list of errors we know how to report.

You probably want NS_ERROR_FILE_NOT_FOUND which I believe is 0x80520012.

-Boris

James Newell wrote:
> I threw just a string. I'm guessing that i'm supposed to throw some specific error.

Components.results.NS_ERROR_FILE_NOT_FOUND might also work.

-Boris

Throwing the error from the newChannel function works, however it comes
up as a message box regardless of the setting
pref("browser.xul.error_pages.enabled", true); whilst other protocols
adhere to this setting.

Do you know if placing this in one of those methods that you have
previously stipulated make it work?

James.

Boris Zbarsky wrote:
> James Newell wrote:
> > I threw just a string. I'm guessing that i'm supposed to throw some specific error.
>
> Components.results.NS_ERROR_FILE_NOT_FOUND might also work.
> 
> -Boris

James Newell wrote:
> Throwing the error from the newChannel function works, however it comes
> up as a message box regardless of the setting
> pref("browser.xul.error_pages.enabled", true); whilst other protocols
> adhere to this setting.

Yeah.   Like biesi said, newChannel errors can't use error pages at the moment, 
so they get an error dialog.  You'd have to throw this from asyncOpen, I think, 
to get an error page.  Or pass it to onStopRequest.  Either one would work, but 
asyncOpen is probably easier.

-Boris

It works!

Do you know where I can learn more about passing data to
nsIStreamListener?

Thanks for all the help its very appreciated!
James

James Newell wrote:
> Do you know where I can learn more about passing data to
> nsIStreamListener?

The only available documentation is probably the IDL file for it...

Ok now I'm getting the error:

[Exception... "Component returned failure code: 0x80004001
(NS_ERROR_NOT_IMPLEME
NTED) [nsIStreamListener.onDataAvailable]"  nsresult: "0x80004001
(NS_ERROR_NOT_
IMPLEMENTED)"  location: "JS frame ::
file:///C:/Documents%20and%20Settings/Admi
nistrator/Desktop/ePaedia/AppDir/Contents/components/protocol-ePaedia.js
:: anon
ymous :: line 317"  data: no]

while passing a stream to the object listener from asyncOpen

Dumping the listner object reveals it is indeed a nsIStreamListener and
onStartRequest calls correctly



Any clues?

James Newell wrote:
> while passing a stream to the object listener from asyncOpen

Er...  You're not supposed to do that.  That's why it's _async_Open.  All the 
callbacks need to be async.

-Boris

How do I do it then?

Boris Zbarsky wrote:
> James Newell wrote:
> > while passing a stream to the object listener from asyncOpen
>
> Er...  You're not supposed to do that.  That's why it's _async_Open.  All the
> callbacks need to be async.
> 
> -Boris

James Newell wrote:
> How do I do it then?

Async.  Like post an event or set a timer or whatever.  When that fires, call 
onStartRequest/onStopRequest.

But seriously, if you know in asyncOpen you have a problem, just throw from 
asyncOpen.

-Boris

> Boris Zbarsky wrote:
>> James Newell wrote:
>>> while passing a stream to the object listener from asyncOpen
>> Er...  You're not supposed to do that.  That's why it's _async_Open.  All the
>> callbacks need to be async.
>>
>> -Boris
> 

I've got the error business sorted and I know what Async means just not
how to implement it. What about onDataAvailiable, the doco for
nsIStreamListner, the listener object passed to asyncOpen supposedly
implements this function. If i dont use that then how do I pass the
data to the listener?

I know that this code
(http://www.mozdev.org/source/browse/archangel/src/archangel-protocol.js?rev=1.3&content-type=text/x-cvsweb-markup)
isn't async but it supposedly works and they seem to use
onDataAvailiable.

    this.streamListener.onStartRequest (this, this.context);

    var len = str.length;
    this.stringStream.setData (str, len);
    this.streamListener.onDataAvailable (this, this.context,
                                         this.stringStream, 0, len);
    this.streamListener.onStopRequest (this, this.context,
                                       Components.results.NS_OK);

???

Boris Zbarsky wrote:
> James Newell wrote:
> > How do I do it then?
>
> Async.  Like post an event or set a timer or whatever.  When that fires, call
> onStartRequest/onStopRequest.
>
> But seriously, if you know in asyncOpen you have a problem, just throw from
> asyncOpen.
> 
> -Boris
>

James Newell wrote:
> I've got the error business sorted and I know what Async means just not
> how to implement it. What about onDataAvailiable, the doco for
> nsIStreamListner, the listener object passed to asyncOpen supposedly
> implements this function.

Yes....  That's correct...  Who's calling asyncOpen?  What object are they 
passing in as the nsIStreamListener?

> I know that this code
> (http://www.mozdev.org/source/browse/archangel/src/archangel-protocol.js?rev=1.3&content-type=text/x-cvsweb-markup)
> isn't async but it supposedly works

Fun.  It's not guaranteed to work, and is allowed to crash given what they're 
doing.  And it's _definitely_ guaranteed to not work in some cases.

-Boris

James Newell wrote:
> I've got the error business sorted and I know what Async means just not
> how to implement it.

I would probably use an nsITimer with a short timeout (1 msec or 
something) and call the callback functions from there.

On trunk you could also post an nsIRunnable to the current thread (which 
you can get from the nsIThreadManager), but on branch this isn't scriptable.

-christian

Isnt it the docshell/browser element calling asyncOpen from the channel
I return from my protocol handler? They are passing [xpconnect wrapped
nsIStreamListner] which I assume is the correct object. The funny thing
is when i removed a argument, it gave an error saying not enough
arguments for the onDataAvailiable function and when i alert the
listener.onDataAvailiable as a variable i get function() { native code
} or similar.

Boris Zbarsky wrote:
> James Newell wrote:
> > I've got the error business sorted and I know what Async means just not
> > how to implement it. What about onDataAvailiable, the doco for
> > nsIStreamListner, the listener object passed to asyncOpen supposedly
> > implements this function.
>
> Yes....  That's correct...  Who's calling asyncOpen?  What object are they
> passing in as the nsIStreamListener?
>
> > I know that this code
> > (http://www.mozdev.org/source/browse/archangel/src/archangel-protocol.js?rev=1.3&content-type=text/x-cvsweb-markup)
> > isn't async but it supposedly works
>
> Fun.  It's not guaranteed to work, and is allowed to crash given what they're
> doing.  And it's _definitely_ guaranteed to not work in some cases.
> 
> -Boris

James Newell wrote:
> Isnt it the docshell/browser element calling asyncOpen from the channel
> I return from my protocol handler?

In some cases yes.  OK.

> They are passing [xpconnect wrapped
> nsIStreamListner] which I assume is the correct object.

Ok....  But calling onDataAvailable on it throws NOT_IMPLEMENTED?  I assume you 
did call OnStartRequest, right?

> The funny thing is when i removed a argument, it gave an error saying not enough
> arguments for the onDataAvailiable function

Sure.  XPConnect enforces the arg count.

> and when i alert the
> listener.onDataAvailiable as a variable i get function() { native code
> } or similar.

Right.

-Boris

Ok I've pretty much got it working with a channel and stream listener
interface that wraps an existing mozilla one. The last problem is that
images etc relative to the current document uri are not resolving.

In the newURI method of the protocol handler i have been experimenting
with resolving from the base uri but when I resolve the uri (e.g
"flashfile" from the base "protocol://host/path") the original spec
(i.e. "flashfile") is being returned and not resolved.

Is there an easy way of doing this with XPCOM?

Thanks,
James

James Newell wrote:
> In the newURI method of the protocol handler i have been experimenting
> with resolving from the base uri but when I resolve the uri (e.g
> "flashfile" from the base "protocol://host/path") the original spec
> (i.e. "flashfile") is being returned and not resolved.

What's the code you use?

> Is there an easy way of doing this with XPCOM?

Sure... nsIURI has methods to resolve relative URIs.  They should be working. 
What sort of nsIURI are you using?  What protocol handler flags does your 
protocol handler have?

-Boris

Flags are:

	protocolFlags: nsIProtocolHandler.URI_STD,

Code is:

	newURI: function(spec, charset, baseURI) {

		//Create a new URI object
		var objURI =
Components.classes[@mozilla.org/network/simple-uri;1].createInstance(Components.interfaces.nsIURI);

		//Use the specified uri
		if (baseURI) {
			objURI.spec = baseURI.resolve(spec)
		} else {
			objURI.spec = spec;
		}

		//Return the new uri
		return objURI;

	},

I also tried using "@mozilla.org/network/standard-url;1" but I kept
getting an exception trying to set the spec

Thanks

James Newell wrote:
> Flags are:
> 		//Create a new URI object
> 		var objURI =
> Components.classes[@mozilla.org/network/simple-uri;1].createInstance(Components.interfaces.nsIURI);

Simple URIs do not support relative URIs.  If you have a concept of relative 
URIs, you need to use "@mozilla.org/network/standard-url;1".

> I also tried using "@mozilla.org/network/standard-url;1" but I kept
> getting an exception trying to set the spec

What sort of exception?  What was your spec string?

-Boris

The code I used was basically the same...

		//Create a new URI object
		var objURI =
Components.classes["@mozilla.org/network/standard-url;1"].createInstance(Components.interfaces.nsIURL);


		if (baseURI) {
			dump("Resolved URI: " + baseURI.resolve(spec) + "\n");
			aURL.spec = baseURI.resolve(spec)
		} else {
			objURI.spec = spec;
		}

		//Return the new uri
		return objURI;

I also saw the init method used but it seems to be undefined on my url?

James Newell wrote:
> I also saw the init method used but it seems to be undefined on my url?

Ah.  Yeah, you have to call init().  It's on nsIStandardURL, so you'll need to 
QI your URI to that.

-Boris

The error i get is:

Error: [Exception... "Component returned failure code: 0x804b000a
[nsIStandardURL.init]"  nsresult: "0x804b000a (<unknown>)"  location:
"JS frame ::
file:///C:/Documents%20and%20Settings/Administrator/Desktop/ePaedia/Application/Windows/components/epaedia-protocolHandler.js
:: anonymous :: line 132"  data: no]
Source File:
file:///C:/Documents%20and%20Settings/Administrator/Desktop/ePaedia/Application/Windows/components/epaedia-protocolHandler.js
Line: 132

My code is:

	newURI: function(spec, charset, baseURI) {

		//Create a new URI object
		var objURI =
Components.classes["@mozilla.org/network/standard-url;1"].createInstance(Components.interfaces.nsIStandardURL);


		objURI.init(Components.interfaces.nsIStandardURL.URLTYPE_STANDARD,
-1, spec, charset, baseURI);

		//Return the new uri
		return objURI;

	},

the uri that is supposed to load is "epaedia://Life and
Times/intro.html" and within that page is a flash file,
"flash/intro.swf" that needs the uri to be resolved.


Boris Zbarsky wrote:
> James Newell wrote:
> > I also saw the init method used but it seems to be undefined on my url?
>
> Ah.  Yeah, you have to call init().  It's on nsIStandardURL, so you'll need to
> QI your URI to that.
> 
> -Boris

Also is there a description of the difference between the constants?
they aren't immediately clear to me on xul planet.
Thanks

James Newell wrote:
> Error: [Exception... "Component returned failure code: 0x804b000a

http://twpol.dyndns.org/mozilla/misc/nserror?0x804b000a

That's NS_ERROR_MALFORMED_URI.

> 		objURI.init(Components.interfaces.nsIStandardURL.URLTYPE_STANDARD,
> -1, spec, charset, baseURI);

OK, that pretty much looks right...

> the uri that is supposed to load is "epaedia://Life and
> Times/intro.html"

Spaces are not allowed in hostnames, which is presumably why you get the result 
you get.

If you don't really have a hostname, you probably want URLTYPE_NO_AUTHORITY 
instead of URLTYPE_STANDARD, and something like:

   epaedia:///Life and Times/intro.html

(note the three slashes).  That's how file:// works, for example.

-Boris

James Newell wrote:
> Also is there a description of the difference between the constants?

Yeah, we should really write much better API docs for those....

Cross-posting to .network -- these are the nsIStandardURL constants.

-Boris