CODEWITHSUNDEEP
phpmysql
leojg
leojg

Reputation: 1186

PHP handle a blob without creating a file

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!

Upvotes: 1

Views: 1549

Answers (2)

dynamic
dynamic

Reputation: 48141

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"; 
}

Upvotes: 2

Oz Solomon
Oz Solomon

Reputation: 3054

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!)

Upvotes: 0

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