Php : Convert a blob into an image file

问题:

Is this possible with php and a mysql database to Convert a blob into an image file?

回答1:

If the BLOB contains the binary data of an image (in a recognizable format like e.g. tiff, png, jpeg, etc), take the content of the BLOB, write it to a file, and voilà... you got an image.

On some strange operation systems you have to give the output file a correspondig extension, so that the image file can be recognised as such.

回答2:

You can use a few different methods depending on what php image library you have installed. Here's a few examples.

Note, the echo <img> is just a trick I use to display multiple images from the same php script when looping through a MySQL result resource. You could just as well output via header() as @NAVEED had shown.

GD:

$image = imagecreatefromstring($blob); 

ob_start(); //You could also just output the $image via header() and bypass this buffer capture.
imagejpeg($image, null, 80);
$data = ob_get_contents();
ob_end_clean();
echo '<img src="data:image/jpg;base64,' .  base64_encode($data)  . '" />';

ImageMagick (iMagick):

$image = new Imagick();
$image->readimageblob($blob);
echo '<img src="data:image/png;base64,' .  base64_encode($image->getimageblob())  . '" />';

GraphicsMagick (gMagick):

$image = new Gmagick();
$image->readimageblob($blob);
echo '<img src="data:image/png;base64,' .  base64_encode($image->getimageblob())  . '" />';

回答3:

In my case i had to use base64_decode to convert blob images correctly into file.

$path = "/tmp/images";
$sql = "SELECT image_name, image_content FROM images";

$result = mysql_query($sql, $db_con);
if (!$result) {
   $message  = 'Invalid query: ' . mysql_error() . "\n";
   $message .= 'Whole query: ' . $sql;
   die($message);
}

while($row = mysql_fetch_array($result, MYSQL_ASSOC)) {
   $image = $row["image_contents"];
   $name = $row["image_name"];

   // option 1
   $file = fopen($path."/".$name,"w");
   echo "File name: ".$path."$name\n";
   fwrite($file, base64_decode($image));
   fclose($file);

   // option 2 (oneliner)
   // file_put_contents($path."/".$name, base64_decode($image));
}

回答4:

If you are storing images in MySql table Blob field and want to get these images then this article is useful for you:

• Tutorial on how to store images in Mysql BLOB field

Look at the following part from above article:

<?php
if(isset($_REQUEST['id']))
{
   // get the file with the id from database
      include “dbconfig.php”;
      $dbconn = mysql_connect($dbhost, $dbusr, $dbpass) or die(”Error Occurred-”.mysql_error());
      mysql_select_db($dbname, $dbconn) or die(”Unable to select database”);

      $id    = $_ REQUEST ['id'];
      $query = “SELECT `img_name`, `img_type`, `img_size`, `img_data`
                       FROM img_tbl WHERE id = ‘$id’”;

      $result = mysql_query($query) or die(mysql_error());
      list($name, $type, $size, $content) = mysql_fetch_array($result);

      header(”Content-length: $size”);
      header(”Content-type: $type”);
      print $content;

      mysql_close($dbconn);
}
?>