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Checking if File exists on remote server

 
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Checking if File exists on remote server, Checking if File exists on remote server
morkman
post 18 May, 2005 - 08:16 AM
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I am currently working on a site that will need to include an image from a remotes server.

It is a jobsite in the UK JobXpresso. So I am looking at checking for the image first and then displaying if it exists.

Cheers
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skyhawk133
post 18 May, 2005 - 08:44 AM
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I'm thinking the quickest solution for this is to use the fopen() function... The file_exists() function doesn't support remote URL's, however, fopen() does. You can do something like this

CODE

<?
// Set the URL you want to connect to
$url = "http://url.to/file.jpg";

// Check to see if the file exists by trying to open it for read only
if (fopen($url, "r")) {

 echo "File Exists";

} else {

 echo "Can't Connect to File";

}

?>


QUOTE
If the open fails, the function returns FALSE and an error of level E_WARNING is generated. You may use @ to suppress this warning.
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morkman
post 18 May, 2005 - 08:58 AM
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I have tried fopen, however to load the image (or should I say when it checks to see if the image is there) it takes some serious time.

Basically it is going to be for this page
http://www.jobxpresso.com/agentslist.php

so next to the agent there will be a logo of them. mmm, I will carry on searching, but if you do come up with something else let me know.

Thank you very much for your time.
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skyhawk133
post 18 May, 2005 - 02:10 PM
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I was looking yesterday and did find some information on fopen and setting the timeout to like 1 or 2 seconds so it doesn't hold up pages. I think you can also control how many bytes to return with fopen or some similar function, you could pull back 1 byte and then it wouldn't bother downloading the entire thing, just 1 byte to check if it existed.

Search for "file" at php.net and it'll give you all the different File IO functions on the left.

Oh, and welcome to dream.in.code!!!
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cyberscribe
post 18 May, 2005 - 10:53 PM
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If these people are signing up for accounts you can have them upload an image or provide a link to an external image, like we do here for avatars. Then, at time of entry you check the URL or file is valid. From then on, you're golden -- just using <img = to do the work.
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72dpi
post 24 May, 2005 - 12:58 AM
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I currently use this:
CODE

<?php
// url to your images folder (no trailing slash)
$url = "http://www.your.com/imagefolder";
// check if image exists ($thumbnail is our image variable)
if(file_exists("$url/$thumbnail"))
{
// If yes, print out the image
echo "<img src=\"$url/$thumbnail\" alt=\"$thumbnail\" width=\"75\" height=\"100\" />";
}
// if no, give an alternative image
else
{
echo "<img src=\"$url/noimage.gif\" alt=\"$thumbnail\" width=\"75\" height=\"100\" />";
}
?>


It works nice, but same deal, i don't know about speeds from.
I don't know the difference betweeen fopen & this tho.... I am a bit of a newb. blink.gif
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BooleanOperator
post 15 Sep, 2006 - 02:28 PM
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QUOTE(cyberscribe @ 18 May, 2005 - 11:53 PM) *

If these people are signing up for accounts you can have them upload an image or provide a link to an external image, like we do here for avatars. Then, at time of entry you check the URL or file is valid. From then on, you're golden -- just using <img = to do the work.


Hate to drag up an old thread but ....

That doesnt solve the issue if the file has been removed after setup.

Possible Directions:
1. doing this at every request is a significant slow down.
2. doing it incrementally and placing the data of the remote existance locally then at reuqest time check how long since last check, and if needed check again.

I found this thread looking for a good way to check the existance of a remote api.
Still looking, will report back with results later tonight.

This post has been edited by BooleanOperator: 15 Sep, 2006 - 02:29 PM
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BooleanOperator
post 15 Sep, 2006 - 03:17 PM
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The following example from php.net solved my issue with sending a small request:

http://www.php.net/manual/en/function.fsockopen.php#39948
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suleiman
post 24 Mar, 2007 - 07:58 PM
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I am using the following code:

CODE
$url = "/wp-content/avatars";
$thumbnail = '/' . get_the_author_ID() . '.jpg';
if(file_exists("$url/$thumbnail")) {
echo "<img src=\"$url/$thumbnail\" alt=\"$thumbnail\" float=\"left\" width=\"75\" height=\"100\" />";
}
else {
echo "<img src=\"$url/default.jpg\" alt=\"$thumbnail\" width=\"75\" height=\"100\" />";
}}


and it's not working. and it's driving me nuts.

If i set the else code to the same as the if code then the url loads up fine, which means that the php code knows the image is there. What am i doing wrong?

[mod edit] Code tags are there for a reason....use them.
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suleiman
post 24 Mar, 2007 - 08:13 PM
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So I've had a bit of success replacing "file_exists" with if(fopen("$url$thumbnail", "r")) {

but the problem now is that the fopen command is executing all of the code both within the if brackets and the else brackets. So what I get is output that looks like this:

Warning: fopen() [function.fopen]: HTTP request failed! HTTP/1.1 404 Not Found in /home/..../public_html/wp-content/.../author_profile2.php on line 100

and then the image of my default.jpg file.

If i can only get rid of this fopen error then i'm home free!

EDIT: problem fixed. To those of you that are still mucking about with the same issues, when using file_exists you need to be passing a $path variable that looks like this: "home/.../public_html/...." when using fopen you need a $url variable that, not surprisingly, is actually a url.



This post has been edited by suleiman: 24 Mar, 2007 - 09:04 PM
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Styx
post 25 Mar, 2007 - 01:06 AM
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Something you should note about using file_exists is that you don't put leading slashes when using directories.

Also, in your original script, for your path you put /dir/dir, then for your image you put / . id . jpg, then in file_exists you put $url/$thumbnail, which would resolve to /dir/dir//id.jpg

Other than that, it would work just fine the way it was.

Using fopen is another option, as you found, but not one that requires an actual url. Read more about fopen here.

This post has been edited by Styx: 25 Mar, 2007 - 01:08 AM
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