I have a application which is generating images with file_get_contents and file_put_contents method from a dynamic image source. After creating the image the image is uploaded to a directory on my server. The problem I face is every time the image is generated and I refresh the page I see the old image appear. It shows the new image when I clear the cache.
How could I solve the issue?
<?php
$imagename = "img".$id.".png";
$host = $_SERVER['DOCUMENT_ROOT'];
$path = $host.'/url/path/img/'.$imagename;
if(file_exists($path)) {
//echo 'File already exists in that directory';
unlink($path);
$filehandler = file_get_contents($imgurl);
file_put_contents($path, $filehandler);
}
else {
$filehandler = file_get_contents($imgurl);
file_put_contents($path, $filehandler);
}
It would always be better to use version as query Param to all images, js and css files. Using timestamp will not be as good since it will not be shown from cache if image is not updated. So in order to avoid additional overhead use version of images
That is,
Initially
<img src="image.png?v1" />
Till now next updation occurs this should be the URL
Once it is updated, it should change to
<img src="image.png?v2" />
As the other answers already stated, simplest solution is to add a parameter to the image URL. To still leverage browser caching when the image is unchanged, you should not use a random value.
My recommendation is to use the modification time of the image file, e.g.
<img src="image.png?<?php filemtime('image.png'); ?>" />
This has the advantage, that you don't need to keep track of versions to increment a number or similar.
This can be solved by adding random parameters to the image src, as shown here. For example, turn this:
<img src="image.png" />
Into this:
<img src="image.jpg?1222259157.415">
In the second src, the numbers after the question mark are the current timestamp. This is demonstrated in this answer, which sets the timestamp in JavaScript and appends it to the src using Date.now().
Website I'm developing is showing products on sale and a lot of them are being updated and imported from XML (imported/updated 2x a day).
The problem is with getting product images. Some of them do not display even if url is provided.
Some XML contain from tens of items to hundreds of them.
The code loops through each item, gets all the data and then the image.
Example code regarding getting the image :
if (#file_get_contents($i->image)) {
$name = uniqid(rand(), true) . '.jpg';
$img = $name;
$url = $i->image;
$destinationPath = public_path() . '/img/upload/Items/'.$name;
#file_put_contents($destinationPath, #file_get_contents($url));
} else {
// do something else if there is no image
}
Is my approach wrong here ?
Remote server can't keep up with file requests ? And before each request need some pause ?
If items are updated 2x daily I shouldn't bother with saving images locally and give img src the external url from XML ?
Better use cURL() ?
If approach is accepted what improvement in needs ?
Thank you.
I'm building a web based system, which will host loads and loads of highres images, and they will be available for sale. Of course I will never display the highres image, instead when browsing people will only see a low resolution, watermarked image. Currently the workflow is as follows:
PHP script handles the highres image upload, when image is uploaded, it's automatically re-sized to a low res image and to a thumbnail image as well and both of the files are saved on the server, (no watermark is added).
When people are browsing, the page displays the thumbnail of the image, on click, it enlarges and displays the lowres image with watermark as well. At the time being I apply the watermark on the fly whenever the lowres image is opened.
My question is, what is the correct way:
1) Should I save a 2nd copy of the lowres image with thumbnail, only when it's access for the first time? I mean if somebody access the image, I add the watermark on the fly, then display the image & store it on the server. Next time the same image is accessed if a watermarked copy exist just display the wm copy, otherwise apply watermark on the fly. (in case watermark.png is changed, just delete the watermarked images and they will be recreated as accessed).
2) Should I keep applying watermarks on the fly like I'm doing now.
My biggest question is how big is the difference between a PHP file_exists(), and adding a watermark to an image, something like:
$image = new Imagick();
$image->readImage($workfolder.$event . DIRECTORY_SEPARATOR . $cat . DIRECTORY_SEPARATOR .$mit);
$watermark = new Imagick();
$watermark->readImage($workfolder.$event . DIRECTORY_SEPARATOR . "hires" . DIRECTORY_SEPARATOR ."WATERMARK.PNG");
$image->compositeImage($watermark, imagick::COMPOSITE_OVER, 0, 0);
All lowres images are 1024x1024, JPG with a quality setting of 45%, and all unnecessary filters removed, so the file size of a lowres image is about 40Kb-80Kb.
It is somehow related to this question, just the scale and the scenarios is a bit different.
I'm on a dedicated server (Xeon E3-1245v2) cpu, 32 GB ram, 2 TB storage), the site does not have a big traffic overall, but it has HUGE spikes from time to time. When images are released we get a few thousand hits per hours with people browsing trough the images, downloading, purchasing, etc. So while on normal usage I'm sure that generating on the fly is the right approach, I'm a bit worried about the spike period.
Need to mention that I'm using ImageMagick library for image processing, not GD.
Thanks for your input.
UPDATE
None of the answers where a full complete solution, but that is good since I never looked for that. It was a hard decision which one to accept and whom to accord the bounty.
#Ambroise-Maupate solution is good, but yet it's relay on the PHP to do the job.
#Hugo Delsing propose to use the web server for serving cached files, lowering the calls to PHP script, which will mean less resources used, on the other hand it's not really storage friendly.
I will use a mixed-merge solution of the 2 answers, relaying on a CRON job to remove the garbage.
Thanks for the directions.
Personally I would create a static/cookieless subdomain in a CDN kinda way to handle these kind of images. The main reasons are:
Images are only created once
Only accessed images are created
Once created, an image is served from cache and is a lot faster.
The first step would be to create a website on a subdomain that points to an empty folder. Use the settings for IIS/Apache or whatever to disable sessions for this new website. Also set some long caching headers on the site, because the content shouldn't change
The second step would be to create an .htaccess file containing the following.
RewriteEngine on
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^(.*) /create.php?path=$1 [L]
This will make sure that if somebody would access an existing image, it will show the image directly without PHP interfering. Every non-existing request will be handled by the create.php script, which is the next thing you should add.
<?php
function NotFound()
{
if (!headers_sent()) {
$protocol = (isset($_SERVER['SERVER_PROTOCOL']) ? $_SERVER['SERVER_PROTOCOL'] : 'HTTP/1.0');
header($protocol . ' 404 Not Found');
echo '<h1>Not Found</h1>';
exit;
}
}
$p = $_GET['path'];
//has path
if (strlen($p)<=1)
NotFound();
$clean = explode('?', $p);
$clean = explode('#', $clean[0]);
$params = explode('/', substr($clean[0], 1)); //drop first /
//I use a check for two, because I dont allow images in the root folder
//I also use the path to determine how it should look
//EG: thumb/125/90/imagecode.jpg
if (count($params)<2)
NotFound();
$type = $params[0];
//I use the type to handle different methods. For this example I only used the full sized image
//You could use the same to handle thumbnails or cropped/watermarked
switch ($type) {
//case "crop":if (Crop($params)) return; else break;
//case "thumb":if (Thumb($params)) return; else break;
case "image":if (Image($params)) return; else break;
}
NotFound();
?>
<?php
/*
Just some example to show how you could create a responds
Since you already know how to create thumbs, I'm not going into details
Array
(
[0] => image
[1] => imagecode.JPG
)
*/
function Image($params) {
$tmp = explode('.', $params[1]);
if (count($tmp)!=2)
return false;
$code = $tmp[0];
//WARNING!! SQL INJECTION
//USE PROPER DB METHODS TO GET REALPATH, THIS IS JUST EXAMPLE
$query = "SELECT realpath FROM images WHERE Code='".$code."'";
//exec query here to $row
$realpath = $row['realpath'];
$f = file_get_contents($realpath);
if (strlen($f)<=0)
return false;
//create folder structure
#mkdir($params[0]);
//if you had more folders, continue creating the structure
//#mkdir($params[0].'/'.$params[1]);
//store the image, so a second request won't access this script
file_put_contents($params[0].'/'.$params[1], $f);
//you could directly optimize the image for web to make it even better
//optimizeImage($params[0].'/'.$params[1]);
//now serve the file to the browser, because even the first request needs to show the image
$finfo = finfo_open(FILEINFO_MIME_TYPE);
header('Content-Type: '.finfo_file($finfo, $params[0].'/'.$params[1]));
echo $f;
return true;
}
?>
I would suggest you to create watermarked images on-the-fly and to cache them at the same time as everybody suggested.
Then you could create a garbage-collector PHP script that will be executed every days (using cron). This script will browse your cache folder to read every image access time. This can done using fileatime() PHP method. Then when a cached wm image has not been accessed within 24 or 48 hours, just delete it.
With this method, you can handle spike periods as images are cached at the first request. AND you will save your HDD space as your garbage-collector script will delete unused images for you.
This method will only work if your server partition has atime updates enabled.
See http://php.net/manual/en/function.fileatime.php
For most scenarios, lazily applying the watermark would probably make most sense (generate the watermarked image on the fly when requested then cache the result) however if you have big spikes in demand you are creating a mechanism to DOS yourself: create the watermarked version on upload.
Considering your HDD storage capacity and Pikes.
I would only create a watermarked image if it is viewed.(so yes on the fly) In that way you dont use to much space with a bunch a files that are or might not be viewed.
I would not watermark thumbnails i would rather make a filter that fake watermark and protect from being saved. That filter would apply to all thumbnails without creating a second image.
In this way all your thumbbails are watermarked (Fake with onther element on top).
Then if one of these thumbnails is viewed it generate a watermarked image (only once) since after its generated you load the new watermarked image.
This would be the most efficient way to deal with your HDD storage and Pikes.
The other option would be to upgrade your hosting services. Godaddy offer unlimited storage and bandwith for about 50$ a year.
I can't get the cycle2 pager to work and I've checked the various questions and answers on this topic. I'm beginning to think it may have to do with my setup: the user clicks one of several buttons and that brings up one or more thumbnail images from a mysql database. Each thumbnail is related via the database to one or more larger images that I'd like to play in a slideshow. An ajax call sends the info about which thumb was clicked and a server page retrieves the larger images from a directory and displays them all in a div on the calling page as follows:
<?php
$thumb_path = $_POST['thumb_path'];
ob_start();
echo basename($thumb_path, ".png");
$thumb_name = ob_get_contents();
ob_end_clean();
$dir = "pathTo/$thumb_name/*.png";
$images = glob( $dir );
foreach( $images as $image ):
echo "<img src='" . $image . "' />";
endforeach;
?>
So far, so good as all the larger images are displayed (statically, all at once) in the div. The problem comes when I try to wrap the php script above in any of the cycle2 pagers (I'd like to use the one that automatically creates thumbnails for navigating the larger images, but none work). What happens is that all the larger images are loaded on top of each other without any navigation controls (thumbnails, dots, numbers etc. as the case may be). The larger images do play if I set the
data-cycle-timeout
parameter to something other than zero, but I'd like to set it to zero and let the users navigate the larger images themselves.
I'm a total noob at web programming and it's taken a while to get this stuff to work, chiefly by studying code snippets I've found on the web. I hope any solution doesn't involve a major redesign.
Thanks in advance for any help.
I've built a gallery using ci where the image that is uploaded is kept its same size as long as its within 3000x5000 px range. Upon displaying them and since i haven't cropped thumbnails , how can I re size them when needed so say i want to re-size a list of them as 150x150 how would i go about this?
i followed the guide
http://ellislab.com/codeigniter/user-guide/libraries/image_lib.html
Problem is when loading the library it wants me to specify each images complete config information.
So say I loaded the variable into a controller to be displayed in a view, and when loading it would look like this:
foreach($gallery as $img)
{
echo "<div>";
echo "<img src='" . $this->img_lib->resize($img->imagepath, 150, 150) . "'>";
echo "</div>";
}
ps: does the image gets saved when its resized? because i dont want that.
better solution: http://www.matmoo.com/digital-dribble/codeigniter/image_moo/
I know how to do it outside of ci. Essentially the img "src" needs to equal a php script OR be intercepted by htaccess which then redirects it to a php script.
You could try something like this:
foreach($gallery as $img)
{
echo "<div>";
echo "<img src='/imageResize.php?path=" . $img->imagepath . "'>";
echo "</div>";
}
File: imageResize.php
$path = $_REQUEST['path'];
$this->img_lib->resize($path, 150, 150);
Depending on the folder structure of your site it would be better to just pass the filename rather than the full path. Even better is to use .htaccess (which I do in our CMS) to intercept the image and resize/crop on the fly. e.g. <img src="/path/to/image.jpg?w=150&h=150" />
Does that help provide some direction?
On your other question, a physical file isn't saved on the server unless you specify it to do so.
The answer from #SaRiD is on the right track. However, it doesn't necessarily have to be outside of CI. You can point the image source to a controller method that takes care of the resizing and serve the image.
You also need to use the correct headers to identify the image resource to the browser, within this method.
You state that you do not want to save the thumbnail. This obviously depend on the need of the application. You can set it in a way that it serves the previously cropped and saved thumbnails to the browser if that exists (from a previous request), rather than creating and serving thumbnails each time - it will save you some CPU cycles.