PHP : 将 blob 转换为图像文件
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Php : Convert a blob into an image file
提问by josh
Is this possible with php and a mysql database to Convert a blob into an image file?
这是否可以使用 php 和 mysql 数据库将 blob 转换为图像文件？
采纳答案by Hyperboreus
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.
如果 BLOB 包含图像的二进制数据（以可识别的格式，例如 tiff、png、jpeg 等），则获取 BLOB 的内容，将其写入文件，然后瞧……您得到了一个图像。
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.
在一些奇怪的操作系统上，你必须给输出文件一个相应的扩展名，这样图像文件才能被识别。
回答by Robert Cesaric
You can use a few different methods depending on what php image library you have installed. Here's a few examples.
根据您安装的 php 图像库，您可以使用几种不同的方法。这里有几个例子。
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.
请注意， echo <img> 只是我在循环访问 MySQL 结果资源时用来显示来自同一个 php 脚本的多个图像的一个技巧。您也可以像@NAVEED 所示通过 header() 输出。
GD:
广东：
$image = imagecreatefromstring($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):
ImageMagick (iMagick):
$image = new Imagick();
$image->readimageblob($blob);
echo '<img src="data:image/png;base64,' . base64_encode($image->getimageblob()) . '" />';
GraphicsMagick (gMagick):
GraphicsMagick (gMagick)：
$image = new Gmagick();
$image->readimageblob($blob);
echo '<img src="data:image/png;base64,' . base64_encode($image->getimageblob()) . '" />';
回答by bonyiii
In my case i had to use base64_decode to convert blob images correctly into file.
就我而言，我必须使用 base64_decode 将 blob 图像正确转换为文件。
$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($image));
}
回答by Naveed
If you are storing images in MySql table Blob field and want to get these images then this article is useful for you:
如果您将图像存储在 MySql 表 Blob 字段中并希望获取这些图像，那么本文对您很有用：
Look at the following part from above article:
看上面文章的以下部分：
<?php
if(isset($_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);
}
?>
