Updating status as page loads...

sid

I have a program here, that is supposed to download a predefined list of images (up to about 1500 at a time - and no, this is not about adult content :-P).
What i would like the script to do, is give the user an update about what it;s doing at any given point. something like:

file_001.jpg ... done
file_002.jpg ... done
file_003.jpg ... done
file_004.jpg ... error
file_005.jpg ... done
file_006.jpg ... done
file_007.jpg ...

you get the idea. the reasoning behind that is, that the page will load forever and a day when it downloads such an amount of data. for 106 files it took 36.7 sec. If that's an average number, 1500 files would take somewhere between 9 and 10 minutes. To prevent the users from getting bored/closing the window, iId like them to see that progress.

I have tried it with [man]flush/man, but the result was no different than laving it out. Here is the procedure of the product class, which will take care of the downloads. it downloads all images that belong to a certain product (up to 32/product - usually around 8) and is invoked for each product in a category (up to 100 products):


<?php

Class ... {

//...

function extract_images() {
	$img = array();
	$img = $this->generate_image_filenames();

	foreach ($img AS $key => $val) {
		$url = BASE_URL . $this->id . $val . ".jpg";
		$file = DIR_CACHE_IMAGES . md5($this->id . $val . CACHE_SALT) . ".jpg";

		is_file($file) ? unlink($file) : false;

		if (!copy($url, $file)) {
			error("image_copy", $url ."/" . $file);
		}
		else {
			print "ok<br/>";
			flush();
		}
	}
}

//...

}

$this->generate_image_filenames() ... returns an array of file names for a product
$url ... the absolute url of the file to be downloaded
$file ... the target, where we want to copy the file to
error() ... logs errors

i wonder if someone has a quick solution for this - javascript i suppose would be one thing to look into (though i'd rather go out of its way).
my favorite solution would be a method i can simply invoke in the else{} path, which adds a string to the displayed info (or replaces the current info) - such as

// snip
		else {
			display_message($url . "... done");
		}
// snip

thanks a bunch in advance!
rock on.

jkurrle

Why not have it post message data to an array, then flush the array to the screen every 100 entries. I would think that would be faster...

sid

as you see, i do try to flush() in the else path, but it just doesn't actually print anything before it's finished processing.

jkurrle

What if, instead, you used implode() to make the array into a variable and tried to print or echo the variable? Would this not do the same thing, but in a different way?

sid

im not sure what you mean, but the issue i am facing is that i want to send data to the browser to be displayed, while the script is still running. the issue is not about which information to show, but the fact that i want to continuously update the information the user sees, so it's obvious that the script is still working. It's likely that this whole thing can take up to 10 minutes on slower servers - even I would be tempted to hit refresh or close the window, if all i see is a blank screen.

Arc

Try this...it is one of the coolest programs I have used...it does downloads and uploads and gives full status on each file, tells download/upload speed, fully customizable, among other things. Works with PHP, ASP.net, etc...

http://www.element-it.com/MultiPowUpload.aspx

sid

thanks a bunch 0 ill look into that. maybe i can get some code from there. the issue is that i am fetching images from another web server and dont actually upload them. but maybe i can poke around this source and find some helpful markers.

still, if anyone has further ideas, i'd be more than happy to hear about them.

Arc

That may not work then if the images are from a remote server...never tried that. Also the product is in flash, but they do sell the source code.

jkurrle

I have nowhere near the coding expertise as you, but I have a question. What happens, when instead of using flush(), you simply do an echo in each iteration of the loop.

Example:
if (test_successful) echo "File $filename successfully downloaded <br />";
else echo "File $filename had errors <br />";

I realize you will have a huge scrolling screen, but I'm curious as to whether it would display or not...

heropage

I guess you need to use ajax to do this.