[Mozilla Enterprise] Problem with custom protocol handler in autoconfig file and ESR 68

Tue Oct 22 12:28:23 UTC 2019

Thanks - that workaround appears to work fine for me as well

James Pearson

Mike Kaply wrote:
> 
> It's definitely a bug. It appears to be a timing issue with messing with protocol handlers too early.
> 
> Getting someone to look at it might be tricky since it's not necessarily a supported mechanism. But here's a workaround to just do it later in the startup process that works for me:
> 
> Components.utils.import("resource://gre/modules/Services.jsm");
> 
> Services.obs.addObserver(function observer(subject, topic, data) {
>    // DO ANYTHING YOU NEED TO DO LATER IN STARTUP LIKE PROTOCOL HANDLERS
>    Services.obs.removeObserver(observer, topic);
> }, "final-ui-startup");
> 
> I am going to see if I can figure out what caused it though.
> 
> Mike
> 
> 
> 
> On Mon, Oct 21, 2019 at 8:34 AM Mike Kaply <mkaply at mozilla.com<mailto:mkaply at mozilla.com>> wrote:
> I'm definitely investigating it as a bug.
> 
> Mike
> 
> On Fri, Oct 18, 2019 at 4:16 PM James Pearson <james-p at moving-picture.com<mailto:james-p at moving-picture.com>> wrote:
> I actually meant: "I can sort-of work around this problem ..."
> 
> But I would still like to know if this a bug or something that can be fixed in the autoconfig file
> 
> Thanks
> 
> James Pearson
> ________________________________________
> From: Enterprise [enterprise-bounces at mozilla.org<mailto:enterprise-bounces at mozilla.org>] on behalf of James Pearson [james-p at moving-picture.com<mailto:james-p at moving-picture.com>]
> Sent: 16 October 2019 14:41
> To: Mike Kaply
> Cc: enterprise at mozilla.org<mailto:enterprise at mozilla.org>
> Subject: Re: [Mozilla Enterprise] Problem with custom protocol handler in autoconfig file and ESR 68
> 
> I can't sort-of work around this problem by checking for a custom pref
> in the autoconfig file - and don't set up the custom protocol handler if
> this pref doesn't exist, but set this custom pref. On subsequent runs of
> Firefox, as the custom pref exists and is set, the custom protocol
> handler is set up
> 
> This does mean that the custom protocol handler doesn't work on the
> first run, but all works as expected on subsequent runs ...
> 
> Is this a bug I should report - or is it something that should be
> 'fixed' (somehow?) in the autoconfig file ?
> 
> Thanks
> 
> James Pearson
> 
> James Pearson wrote:
>>
>> pdfjs.disabled is set to false
>>
>> Thanks
>>
>> James Pearson
>>
>> Mike Kaply wrote:
>>>
>>> That's quite strange.
>>>
>>> Are you sure you're not somehow accidentally turning it off?
>>>
>>> What do you see for the value of pdfjs.disabled when you go to
>>> about:config?
>>>
>>> Mike
>>>
>>> On Tue, Oct 15, 2019 at 10:25 AM James Pearson
>>> <james-p at moving-picture.com<mailto:james-p at moving-picture.com><mailto:james-p at moving-picture.com<mailto:james-p at moving-picture.com>>> wrote:
>>> This is really aimed at Mike Kaply ...
>>>
>>> Many years ago on this list, Mike provided the 'magic' to add a custom
>>> protocol handler in an autoconfig cfg file - the archives of this list
>>> don't go back to 2014, so I can't link to the original thread - but what
>>> is needed is something like this:
>>>
>>> const Cc = Components.classes;
>>> const Ci = Components.interfaces;
>>> var extProtocolSvc =
>>> Cc["@mozilla.org/uriloader/external-protocol-service;1<http://mozilla.org/uriloader/external-protocol-service;1><http://mozilla.org/uriloader/external-protocol-service;1>"].getService(Ci.nsIExternalProtocolService);
>>>
>>> var handlerSvc =
>>> Cc["@mozilla.org/uriloader/handler-service;1<http://mozilla.org/uriloader/handler-service;1><http://mozilla.org/uriloader/handler-service;1>"].getService(Ci.nsIHandlerService);
>>>
>>>
>>> var handlerInfo = extProtocolSvc.getProtocolHandlerInfo("yourprotocol");
>>>
>>> var file =
>>> Cc["@mozilla.org/file/local;1<http://mozilla.org/file/local;1><http://mozilla.org/file/local;1>"].createInstance(Ci.nsIFile);
>>>
>>> // This should be the path to the .app file on Mac or the EXE on Windows
>>> file.initWithPath("/Applications/Preview.app");
>>> var localHandlerApp =
>>> Cc["@mozilla.org/uriloader/local-handler-app;1<http://mozilla.org/uriloader/local-handler-app;1><http://mozilla.org/uriloader/local-handler-app;1>"].createInstance(Ci.nsILocalHandlerApp);
>>>
>>> localHandlerApp.executable = file;
>>> // The name that will be shown in preferences.
>>> // Not used on Mac
>>> localHandlerApp.name = "Preview";
>>> handlerInfo.possibleApplicationHandlers.appendElement(localHandlerApp,
>>> false);
>>> handlerInfo.preferredAction = Ci.nsIHandlerInfo.useHelperApp;
>>> handlerInfo.preferredApplicationHandler = localHandlerApp;
>>> handlerInfo.alwaysAskBeforeHandling = false;
>>> handlerSvc.store(handlerInfo);
>>>
>>> This has worked fine ever since for us - and works with ESR 68 -
>>> however, it appears to 'break' the built-in PDF viewer
>>>
>>> If I create a new profile with a custom protocol handler defined in the
>>> autoconfig (as above), then the built-in PDF viewer isn't used - you're
>>> given the option to open the PDF file in an external viewer instead
>>>
>>> Looking at the Preference Setting for PDF, it is set to 'Always ask' -
>>> changing this to 'Preview in Firefox' just brings up a Save dialog when
>>> clicking on a link to a PDF file
>>>
>>> (The custom protocol handler works fine)
>>>
>>> However, if I create a new profile with an autoconfig that doesn't have
>>> a custom handler defined, start Firefox with that new profile, then quit
>>> Firefox. Then restart Firefox (using the same profile), but this time
>>> using an autoconfig that has the custom handler defined, then the
>>> built-in PDF viewer works as expected ... as does the custom protocol
>>> handler
>>> git push
> 
>>> i.e. defining a custom protocol handler on the first run of Firefox
>>> appears to interfere with/break the built-it PDF viewer
>>>
>>> This is with Firefox ESR 68.1 on Linux
>>>
>>> Any idea what I can do to prevent this happening ?
>>>
>>> Thanks
>>>
>>> James Pearson
>>> _______________________________________________
>>> Enterprise mailing list
>>> Enterprise at mozilla.org<mailto:Enterprise at mozilla.org><mailto:Enterprise at mozilla.org<mailto:Enterprise at mozilla.org>>
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>>>
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>>>
>>
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