How can I know an image downloaded?

[paulsr]

Folks:

I've seen this question in other forum posts, but I can't find an answer...

If I download an image with something like:

Code: Select all

put url t_img_url into url ("binfile:" & t_location)

... is there any easy way to know that it worked?

If the remote file does not exist, the web server generates a 404 page and sends that instead. So whether the image downloads, or a 404 page downloads, the local file is created, and the command appears to have been successful.

I can't find anything that generates an error.

Do I have to inspect the local file to see if it's an html 404 page?

TIA for any help...

--paul

[dunbarx]

Hi.

I don't use this sort of thing, but in general, as these things go, don't you think that checking the result of the url command is the same as checking the result? By that I mean, literally, the result, as if you clicked "Cancel" in an "Ask" dialog.

No shame in checking the success of your query with standard tools.

Craig Newman

[paulsr]

Thanks Craig, but "the result" is always blank, because even if a 404 page is downloaded, LiveCode doesn't see it as an error, because something was downloaded even if it wasn't the image I wanted.

--paul

[Klaus]

Hi Paul,

why not download into a variable first, check this and then save to disk on success?

Code: Select all

...
put url t_img_url into tImageVariable

## Network problem?
if the result <> empty then
  ## error
  exit HANDLERNAME
end if

## check content of variable:
if tImageVariable contains "404" then
  ## or maybe ... contains "</html>"?

  ## error
  exit HANDLERNAME
end if
## Finally:
put tImageVariable into url ("binfile:" & t_location)
...

Best

Klaus

[dunbarx]

I was being obtuse, as usual, in trying to relate the standard checking of the "result" to checking the result of your url query. I just meant to say that you should check your, er, results.

[paulsr]

Thanks Klaus. I guess the answer is "yes" ... I do have to check the file to see if it contains "404".

Or, as you say "</html>".

I guess to be sure, I shd also check for "</HTML>" and "404". It's possible a binary image file could contain the sequence "404".

--paul

[Klaus]

Hi Paul,

Or, as you say "</html>".
I guess to be sure, I shd also check for "</HTML>" and "404". It's possible a binary image file could contain the sequence "404".
--paul

sure, just look for something that looks like HTML code and is definitively NOT in the binary data of an image.


Best

Klaus

[Mag]

Hi all! Interesting discussion, and if I would like to just know if a particular file exist, before to use the "load URL" or "put URL" commands?

[Thierry]

Hi all! if I would like to just know if a particular file exist?

You can check in the Dictionnary:

there is and/or exists

Oups sorry; this applies only on local files
I was too fast reading your post

Thierry

[Simon]

To find if files exists in an online folder you need to run a php script:

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<?php
$path = ".";
$dh = opendir($path);
$i=1;
while (($file = readdir($dh)) !== false) {
    if($file != "." && $file != ".." && $file != "index.php" && $file != ".htaccess" && $file != "error_log" && $file != "cgi-bin") {
        echo "<a href='$path/$file'>$file</a><br /><br />";
        $i++;
    }
}
closedir($dh);
?> 

Just use the "put url.../myList.php" to get a listing of all the files in the directory.
This is a simple php script and only returns the filenames, google "index of files in directory php" to get many more with tons of features.

Simon

[Mag]

Thank you Simon! This will be very useful to avoid to get wrong remote files due to "404" forwards.

PS
Thierry, no problem, actually my post was not very clear, in every way thank you for your replay!