I there a way to handle a blob(a file saved to mysql) without having to create a file?
I need to retrive a blob from the db, wich can be any kind of file, img, text, video, etc. and be able to show it in html.
So far, what I managed to do is to create a file and work with it. But this has a little problem and it is that i have to delete it after the user stop working with the file. But I can not create a cronjob(or something simillar) to delete these files after some time.
Any Ideas?
Thanks!
You can have a script that prints the content of the file on-the-fly from the database. All you have to do is to store its content-type and retrive the content from the database.
#showFile.php
$contenttype = ... // retrive content type from database
$blob = ... // retrive blob from database
header('Content-type: ' . $contenttype);
echo $blob;
If you don't have MIME type saved in your database, you can try this: Determinate mime type from MySQL column
function mimetype($data)
{
//File signatures with their associated mime type
$Types = array(
"474946383761"=>"image/gif", //GIF87a type gif
"474946383961"=>"image/gif", //GIF89a type gif
"89504E470D0A1A0A"=>"image/png",
"FFD8FFE0"=>"image/jpeg", //JFIF jpeg
"FFD8FFE1"=>"image/jpeg", //EXIF jpeg
"FFD8FFE8"=>"image/jpeg", //SPIFF jpeg
"25504446"=>"application/pdf",
"377ABCAF271C"=>"application/zip", //7-Zip zip file
"504B0304"=>"application/zip", //PK Zip file ( could also match other file types like docx, jar, etc )
);
$Signature = substr($data,0,60); //get first 60 bytes shouldnt need more then that to determine signature
$Signature = array_shift(unpack("H*",$Signature)); //String representation of the hex values
foreach($Types as $MagicNumber => $Mime)
{
if( stripos($Signature,$MagicNumber) === 0 )
return $Mime;
}
//Return octet-stream (binary content type) if no signature is found
return "application/octet-stream";
}
A simple way to show content stored in your DB is to create another PHP script, say show_content.php.
From your HTML you would do something like:
<img src="show_content.php?id=444" />
This will call your script with $_GET['id'] === '444'
In the script, let assume you have a functions called get_blob($id) and get_blob_content_type($id). Your peseudocode in show_content.php would look like:
header('Content-Type: ' . get_blob_content_type($id), true);
echo get_blob($id);
Where get_blob_content_type() returns something like image/jpg and get_blob() returns the actual content.
Bonus concept: If your blobs have associated file names (for example, you stored the blob alongside its original filename, say cat.jpg), you can specify this to the browser, so if the user right-clicks and selects save, they will get the original file name. All you have to do is add the following code before the echo statement:
header('Content-Disposition: inline; filename="' . get_blob_file_name($id) ."');
(make sure you don't have quotes in your filenames!)
header('Content-Length: '.strlen($data)); header("Content-type: image/png"); echo $data;