使用Node.js将Base64图像转换为原始二进制文件 [英] Convert Base64 image to raw binary with Node.js

问题描述

我发现的帖子与我要查找的内容很接近，但是我无法成功实现我想要的内容.这是一般流程:

I have found posts that are close to what I'm looking for, but I have not been able to successfully implement what I want. Here is the general flow:

1. 提交包含其余场地数据的照片，作为base64数据
2. 带状数据前缀(如果存在)，所以我只有图像base64数据

---

var base64data = venue.image.replace(/^data:image\/png;base64,|^data:image\/jpeg;base64,|^data:image\/jpg;base64,|^data:image\/bmp;base64,/, '');

---

1. 通过MongoDB将Base64数据存储在GridFS中(我正在使用 gridfstore )
2. 然后，我想根据要求通过URL检索图像作为原始图像文件.

---

// generic images route
server.get(version+'/images/:id', function(req, res) {
  gridfstore.read( req.params.id, function(error,data) {
    res.writeHead(200, {
      'Content-Type': 'image/jpeg',
      'Content-Length': data.buffer.length
    });

    res.end(data.buffer);
  });
});

基本上，此方法返回GridFS中存储的Base64字节.我尝试了其他方法，但是它们不返回原始图像.

Basically, this method returns the Base64 bytes stored in GridFS. I have tried other methods but they don't return the raw image.

我想使用如下URL提取图片:

I'd like to pull up the image using URLs like this:

http://[localhost]/1/images/11dbcef0-257b-11e3-97d7-cbbea10abbcb

这是浏览器跟踪的屏幕截图:

Here is a screenshot of the browser trace:

推荐答案

您可以从MongoDB中获取字符串，创建新的缓冲区实例，并在执行此操作时指定编码.结果缓冲区将以二进制数据存储.

You can take the string from MongoDB, create a new buffer instance, and specify an encoding when doing so. The resultant buffer will be in binary data.

var b64str = /* whatever you fetched from the database */;
var buf = new Buffer(b64str, 'base64');

因此在您的实现中:

server.get(version+'/images/:id', function(req, res) {
  gridfstore.read(req.params.id, function(err, data) {
    var img = new Buffer(data.buffer, 'base64');

    res.writeHead(200, {
      'Content-Type': 'image/jpeg',
      'Content-Length': img.length
    });
    res.end(img); 

  });
});

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