Mind you that N refreshes to your app can happen from this and those N runs can make the generation that much slower than just waiting for the page to be generated. What is taking so long to generate the page in the first place? Is the server underpowered?


-Waswas

Mind you that N refreshes to your app can happen from this and those N runs can make the generation that much slower than just waiting for the page to be generated.

If a simple probe to tell if it's ready or not makes your app go "much slower", then you haven't quite designed it right. Gotta keep the probe cheap.

-- Randal L. Schwartz, Perl hacker
Be sure to read my standard disclaimer if this is a reply.

my $page = $m->dhandler_arg;
# do sanity checking ...
unless ($m->comp_exists($page)) {
  unless ($m->cache->get($page)) { # see if we're building it already
    $m->cache->set($page,'1','60 sec'); # set a flag to say we're buil
+ding it
    $m->comp("/building_page"); # please wait page
    $m->flush_buffer; # flush the output
    # here we begin building the page
    $m->comp("/build_page", $page);
  }
  $m->comp("/building_page");
  $m->flush_buffer;
}
</%init>
[download]

The building page, would spit up a simple note saying it's processing, and a meta-refresh tag so the client re-requests it in a moment. A little css/javascript can be used to add some animation to keep them amused.

(code above is untested, but should get you going in the right direction)

Thanks, cowboy, this looks great.

I don't follow all of it, though.

Is there an automatic redirect to the finished page? Or is the user just instructed to hit refresh after waiting a bit on the building_page component?

thanks

water

I basically print out a very light 'Loading' type page, which has a meta-refresh tag to tell the client to re-request it in a few seconds.

If it has completed whatever work it needs to do (in my case, execute a heavy database query and collect results, then cache them), it then displays the results (which are now in the cache), if it hasn't completed it, it spits up the 'Loading' page again, set to refresh again.

(update:) The basic logic is as follows:

if (page_is_in_cache) {
  display page.
}
elsif (flag_is_in_cache) {
  page is being rendered, display a 'loading' message with a meta refr
+esh
}
else {
  set_flag_in_cache
  display loading page
  render page
  stuff page in cache
  clear flag in cache
}
[download]