循环函数非常耗时

Question

i have php function that parses a xml url and gives me an array.this functions uses a perticular id and gives all information related to that id which is passed in the form. now i have 20 different ids and i am passing these id's in this form using foreach loop like below

<?php 
    $relatedSlides = $result['RelatedSlideshows'];
    if(!empty($relatedSlides)){
        $k=1;
        foreach($relatedSlides as $Related){
            RelatedSlides($Related);
            if($k%6==0){
                echo '</tr><tr>';
            }
            $k++;
        }
    }
?>

This is the foreach loop. $relatedSlides is an array of all slide id's. Now I am writing the function that parses the information about a particular id.

function RelatedSlides($slideId){
    $secret_key = 'my api key';
    $ts=time();
    $hash=sha1($secret_key.$ts);
    $key = 'my secret key';
    $url = 'http://www.slideshare.net/api/2/get_slideshow?api_key='.$key.'&ts='.$ts.'& hash='.$hash.'&slideshow_id='.$slideId.'&detailed=1';
    echo $url;
    $ch=curl_init() or die (curl_error());
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 30);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($ch, CURLOPT_USERAGENT, 'Mozilla Firefox');
    $query = curl_exec($ch);
    $errorCode = curl_errno($ch); 
    curl_close($ch);
    $array = (array) simplexml_load_string($query);
    //echo '<pre>';
    //print_r($array);
    //return $array;
    echo "<font size=\"18\">return code is ".$errorCode."</font>";
    echo '<td valign="top"><div id="slide_thumb"><a href="viewslide.php?slideId='.$array['ID'].'&title='.$array['StrippedTitle'].'"><img src=" '.$array['ThumbnailURL'].'" width="100" height="100"/></a></div><div id="slide_thum_des"><strong>Views:</strong>'.$array['NumViews'].'<br /><ahref="'.$array['DownloadUrl'].'">'.$array['Title'].'....</a></div></td>';
}

When I call this function my connection times out every time. The function is absolutely correct. It gives all data about a particular id but when I run it in a foreach loop for many id's, "connection has been reset" or "connection timed out" displays.

Answer 1

You could try a couple of things:

1. Setup your curl handler outside of the RelateSlides() function. This way you don't have to keep building and tearing down the $ch resource every iteration.

2. Check the slideshare.net api and see if there are params you can pass to pull down smaller files.

3. As Luke wisely mentioned, you could make the page asyncronous, meaning you can render the page with 6 tiles, then have each tile make an ajax call for the slide you want. This way at least the user gets to see something while the tiles load, as opposed to being 'hung up' while you pull all the images at once.

4. I trust slideshare has a pretty robust cdn hosting these images, you may want to see if they have servers closer to your web server.

Quick question, is the curl option how slideshare.net suggested you go about pulling images? Chances are you could just create an image tag with a link directly to their api:

 echo '<img src="http://www.slideshare.net/api/2/get_slideshow?api_key='.$key.'&ts='.$ts.'& hash='.$hash.'&slideshow_id='.$slideId.'&detailed=1' />';

If you are doing the curl option for extended data, you may want to consider caching the extended data so you don't have to keep making the extraneous simplexml_load_string call.