NodeJS编写base64图像文件 [英] NodeJS write base64 image-file

问题描述

我的NodeJS服务器收到一个以base64编码的图片.

My NodeJS-Server receives a picture base64 encoded.

data:image/jpeg;base64,/9j/4QCcRXhpZgAASUkqAAgAAAA ... CiiigD//Z

接收到的数据应另存为jpg.因此，我使用了缓冲区和FileSystemWriter:

The received data should be saved as jpg. Therefore I use a Buffer and the FileSystemWriter:

var imageBuffer = new Buffer(data, 'base64'); //console = <Buffer 75 ab 5a 8a ...
fs.writeFile("test.jpg", imageBuffer, function(err) { //... });

fs.writeFile没有调用错误. jpeg文件已保存，但无法打开. 图像查看器说:

the fs.writeFile doesn't call an error. A jpeg-file is saved, but I can't open it. Image-Viewer says:

File is damaged or too big.

原始文件大6kb，新文件7kb.

The original file is 6kb large and the new file 7kb.

推荐答案

您必须从中剥离url元信息，即data:image/jpeg部分. (重申@CBroe所说的)这是一个小功能，可以从输入字符串中返回正确的信息.

You have to strip the url meta information from it, the data:image/jpeg part. (Reiterating what @CBroe said) Here is a small function to return the correct information from the input string.

var data = 'data:image/jpeg;base64,iVBORw0KGgoAAAANSUhEUgAAA..kJggg==';

function decodeBase64Image(dataString) {
  var matches = dataString.match(/^data:([A-Za-z-+\/]+);base64,(.+)$/),
    response = {};

  if (matches.length !== 3) {
    return new Error('Invalid input string');
  }

  response.type = matches[1];
  response.data = new Buffer(matches[2], 'base64');

  return response;
}

var imageBuffer = decodeBase64Image(data);
console.log(imageBuffer);
// { type: 'image/jpeg',
//   data: <Buffer 89 50 4e 47 0d 0a 1a 0a 00 00 00 0d 49 48 44 52 00 00 00 b4 00 00 00 2b 08 06 00 00 00 d1 fd a2 a4 00 00 00 04 67 41 4d 41 00 00 af c8 37 05 8a e9 00 00 ...> }

然后您可以使用上述方法保存缓冲区.

Then you can save the buffer using your above method.

fs.writeFile('test.jpg', imageBuffer.data, function(err) { ... });

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