How can I tell a browser to refresh from perl?

[Anonymous Monk]

I have a perl text that from time to time rewrites a .html file. How can I get the browser to redisplay the file? It can refresh every N seconds, but I'd like it faster and more efficient (browsers flicker upon refresh). I'm doing this:

system("/usr/bin/osascript reload.scpt");

. . . where reload.scpt is a trivial Applescript:

tell application "Google Chrome"
    reload active tab of window 1
end tell

But it annoys me to have to fork a new process each time. Is there a better way to do it? There used to be interfaces from perl directly to Applescript, but I can't get Mac::OSA::Simple to work these days. Can it be done in some non-applescript way? Or maybe the browser can watch for changes in the file, if I can put it where the browser can get at it?

[haukex]

Hi Anonymous,

Is this HTML file on a web server, or are you accessing it via a file:// URL? If it were on a web server, there would be ways to do it with AJAX requests. If not, and this is all just on a single local machine with a file:// URL, then because I haven't worked on a Mac in a while I can't tell you if there's a better way, perhaps a Monk more versed in that can help (have you tried Mac::AppleScript?). But if it works, maybe it doesn't need fixing ;-)

Regards,
-- Hauke D

[Anonymous Monk]

All on a local machine. And I can't get any perl-to-AppleScript module to work. In any case, Mac::Applescript is no good because it compiles the script every time, and so is less efficient than my current solution! At least Mac::OSA::Simple, if it worked, would execute a precompiled and even preloaded script. I was really hoping for some non-AppleScript solution.

[Corion]

You don't tell us which browser you're using. Maybe WWW::Mechanize::Firefox can help, especially the ->reload method.

[poj]

You could perhaps try adding this meta tag to the html

<meta http-equiv="refresh" content="2"/>
poj

[Anonymous Monk]

As the third sentence of my original post says, I know that I can have the browser periodically refresh. This is not what I'm looking for. The browser will refresh every N seconds (N=2 in your case) with a flicker, but the file updates only every few minutes. I don't want the browser to poll, I want to tell the browser when it's time.

[LanX]

Here a JS solution:

 
setTimeout(
    function () { 
          window.location.reload(true)
                },
    60000);

[Anonymous Monk]

As the third sentence of my original post says, I know that I can have the browser periodically refresh. This is not what I'm looking for. The browser will refresh every N seconds (N=60 in your case, meaning a long wait from when the file updates to when we see it) with a flicker, but the file updates only every few minutes. I don't want the browser to poll, I want to tell the browser when it's time.

[LanX]

> As the third sentence of my original post says,

And as another sentence said

>  Is there a better way to do it? 

JS doesn't spawn a process and doesn't depend on AppleScript or OS or browser at all.

You can also use JS in a hidden iframe checking in short frequency if something changed, before conditionally reloading the parent frame. (Hence no "flickering")

But that's becoming OT here, Google is your friend.

I know newer technologies like WebSockets allow to push content, but IIRC this will need a server keeping the connection alive.

See http://en.wikipedia.org/wiki/Push_technology for various options

[Anonymous Monk]

Can it be done in some non-applescript way? Or maybe the browser can watch for changes in the file, if I can put it where the browser can get at it?

see Server-sent events

[Anonymous Monk]

http://mojolicious.org/perldoc/Mojolicious/Guides/Cookbook#EventSource-web-service, https://developer.mozilla.org/en-US/docs/Web/API/Server-sent_events/Using_server-sent_events