php - 如何从base64数据字符串保存PNG图片服务器端(How to save a PNG image server-side, from a base64 data string)

Question

I'm using Nihilogic's "Canvas2Image" JavaScript tool to convert canvas drawings to PNG images.(我正在使用Nihilogic的“ Canvas2Image” JavaScript工具将画布图形转换为PNG图像。)

What I need now is to turn those base64 strings that this tool generates, into actual PNG files on the server, using PHP.(现在，我需要使用PHP将此工具生成的base64字符串转换为服务器上的实际PNG文件。) In short, what I'm currently doing is to generate a file on the client side using Canvas2Image, then retrieve the base64-encoded data and send it to the server using AJAX:(简而言之，我当前正在做的是使用Canvas2Image在客户端生成一个文件，然后检索base64编码的数据，并使用AJAX将其发送到服务器：) // Generate the image file var image = Canvas2Image.saveAsPNG(canvas, true); image.id = "canvasimage"; canvas.parentNode.replaceChild(image, canvas); var url = 'hidden.php', data = $('#canvasimage').attr('src'); $.ajax({ type: "POST", url: url, dataType: 'text', data: { base64data : data } }); At this point, "hidden.php" receives a data block that looks like data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAABE...(此时，“ hidden.php”收到的数据块看起来像data：image / png; base64，iVBORw0KGgoAAAANSUhEUgAABE ...) From this point on, I'm pretty much stumped.(从这一点开始，我很困惑。) From what I've read, I believe that I'm supposed to use PHP's imagecreatefromstring function, but I'm not sure how to actually create an actual PNG image from the base64-encoded string and store it on my server.(通过阅读，我相信应该使用PHP的imagecreatefromstring函数，但是我不确定如何从base64编码的字符串实际创建实际的PNG图像并将其存储在服务器上。) Please aid!(请帮忙！)   ask by Andrei Oniga translate from so

Answer 1

You need to extract the base64 image data from that string, decode it and then you can save it to disk, you don't need GD since it already is a png.(您需要从该字符串中提取base64图像数据，对其进行解码，然后可以将其保存到磁盘，因为它已经是png，所以不需要GD。)

$data = 'data:image/png;base64,AAAFBfj42Pj4'; list($type, $data) = explode(';', $data); list(, $data) = explode(',', $data); $data = base64_decode($data); file_put_contents('/tmp/image.png', $data); And as a one-liner:(作为单线：) $data = base64_decode(preg_replace('#^data:image/w+;base64,#i', '', $data)); An efficient method for extracting, decoding, and checking for errors is:(提取，解码和检查错误的有效方法是：) if (preg_match('/^data:image/(w+);base64,/', $data, $type)) { $data = substr($data, strpos($data, ',') + 1); $type = strtolower($type[1]); // jpg, png, gif if (!in_array($type, [ 'jpg', 'jpeg', 'gif', 'png' ])) { throw new Exception('invalid image type'); } $data = base64_decode($data); if ($data === false) { throw new Exception('base64_decode failed'); } } else { throw new Exception('did not match data URI with image data'); } file_put_contents("img.{$type}", $data);