428387 - Custom handling of connection failure

Status: RESOLVED FIXED

(Mozilla Labs :: Prism, defect)

Description

[JJ Zhuang]

We have an app with a localhost web service running on port 7633.  If the web service is not running, when Prism starts it will popup an alert saying "can't connect to http://localhost:7633, which is not very user friendly.

What we want to do is to have a callback to a registered fail-to-connect handler (in javascript).  Then the handler can try to start our web service.  If it starts successfully, handler code will return positive and Prism should retry connecting; if failed to start the web service, a negative return from handler will shutdown Prism.

Comment 1

[JJ Zhuang]

Also have a question about this.  What's the best way to run an external program from a javascript in prism?

Comment 2

[Mark Finkle (:mfinkle) (use needinfo?)]

(In reply to comment #1)
> Also have a question about this.  What's the best way to run an external
> program from a javascript in prism?
> 

nsIProcess provides that feature

Comment 3

[JJ Zhuang]

Thanks Mark!

Comment 4

[Matthew Gertner]

Attachment: Rename startup handler to load and add a real startup handler to nsCommandLineHandler.js

I discussed this with Mark and we don't feel like this is a generic use case since most Prism apps won't be using a local server. Instead, you should check whether the local server is reachable at startup and take action as appropriate.

I've added a real startup() handler in this patch that can be used in webapp.js to do the check before the page loads.

Comment 5

[Mark Finkle (:mfinkle) (use needinfo?)]

Comment on attachment 315539 [details] [diff] [review]
Rename startup handler to load and add a real startup handler to nsCommandLineHandler.js

we might need to update some webapp.js scripts, but this is a better scheme.

Comment 6

[JJ Zhuang]

OK sounds good.  Is the startup handler called before or after the window has a chance to load the static splash screen?  It's better if user can see the splash screen while the startup handler is working in the background because it can take a while.  Thanks!

Comment 7

[Matthew Gertner]

Attachment: Add another event after the splashscreen is displayed

Good point, JJ. The startup() function is called before the splashscreen is displayed. This patch adds another event that can be used to do processing after the splashscreen comes up.