使用node.js保存存储在s3上的图像？

Question

我正在尝试编写一个使用node.js在s3上存储图像的图像服务器.上传图像工作正常,我可以使用s3浏览器客户端正确下载和查看它(我特别使用dragondisk,但我已经成功下载了其他的),但是当我用节点下载它并尝试把它写入磁盘,我无法打开文件(它说它可能已损坏或使用预览无法识别的文件格式).我正在使用amazon sdk进行节点和fs来编写文件.我知道你可以将一个可选的编码传递给fs.writeFile,但我已经尝试了所有这些并且它不起作用.我还尝试在getObject上设置putObject和ResponseContentType上的ContentType,以及在各种组合中设置ContentEncoding和ResponseContentEncoding(以及所有这些内容).结果相同.这是一些代码:

var AWS = require('aws-sdk')
  , gm = require('../lib/gm')
  , uuid = require('node-uui')
  , fs = require('fs');

AWS.config.loadFromPath('./amazonConfig.json');
var s3 = new AWS.S3();

var bucket = 'myBucketName'; // There's other logic here to set the bucket name.

exports.upload = function(req, res) {
    var id = uuid.v4();
    gm.format("/path/to/some/image.jpg", function(format){
        var key = req.params.dir + "/" + id + "/default." + format;
        fs.readFile('/path/to/some/image.jpg', function(err, data){
            if (err) { console.warn(err); }
            else {
                s3.client.putObject({
                    Bucket: bucket,
                    Key: key,
                    Body: data,
                    ContentType: 'image/jpeg'
                    // I've also tried adding ContentEncoding (in various formats) here.
                 }).done(function(response){
                    res.status(200).end(JSON.stringify({ok:1, id: id}));
                }).fail(function(response){
                    res.status(response.httpResponse.statusCode).end(JSON.stringify(({err: response})));
                });
            }
        });
    });
};

exports.get = function(req, res) {
    var key = req.params.dir + "/" + req.params.id + "/default.JPEG";
    s3.client.getObject({
        Bucket: bucket, 
        Key:  key,
        ResponseContentType: 'image/jpeg'
        // Tried ResponseContentEncoding here in base64, binary, and utf8
    }).done(function(response){
        res.status(200).end(JSON.stringify({ok:1, response: response}));
        var filename = '/path/to/new/image/default.JPEG';
        fs.writeFile(filename, response.data.Body, function(err){
            if (err) console.warn(err);
            // This DOES write the file, just not as an image that can be opened.
            // I've tried pretty much every encoding as the optional third parameter
            // and I've matched the encodings to the ResponseContentEncoding and
            // ContentEncoding above (in case it needs to be the same)
        });
    }).fail(function(response){
        res.status(response.httpResponse.statusCode).end(JSON.stringify({err: response}));
    });
};

顺便说一句,我正在使用express进行路由,所以这就是req.params的来源.

Answer 1

对于那些仍在努力解决这个问题的人.这是我用本机aws-sdk的方法.

var AWS = require('aws-sdk');
AWS.config.loadFromPath('./s3_config.json');
var s3Bucket = new AWS.S3( { params: {Bucket: 'myBucket'} } );

在您的路由器方法中: - ContentType应设置为图像文件的内容类型

  buf = new Buffer(req.body.imageBinary.replace(/^data:image\/\w+;base64,/, ""),'base64')
  var data = {
    Key: req.body.userId, 
    Body: buf,
    ContentEncoding: 'base64',
    ContentType: 'image/jpeg'
  };
  s3Bucket.putObject(data, function(err, data){
      if (err) { 
        console.log(err);
        console.log('Error uploading data: ', data); 
      } else {
        console.log('succesfully uploaded the image!');
      }
  });

s3_config.json文件是: -

{
  "accessKeyId":"xxxxxxxxxxxxxxxx",
  "secretAccessKey":"xxxxxxxxxxxxxx",
  "region":"us-east-1"
}

Answer 2

好的,经过重大的试验和错误,我已经想出了如何做到这一点.我最终切换到knox,但据推测,你可以使用与aws-sdk类似的策略.这种解决方案让我说,"必须有一种比这更好的方式",但是我对任何有效的方法感到满意.

var imgData = "";
client.getFile(key, function(err, fileRes){
    fileRes.on('data', function(chunk){
        imgData += chunk.toString('binary');
    }).on('end', function(){
        res.set('Content-Type', pic.mime);
        res.set('Content-Length', fileRes.headers['content-length']);
        res.send(new Buffer(imgData, 'binary'));
    });
});

getFile()将数据块作为缓冲区返回.有人会认为你可以将结果直接输出到前端,但无论出于何种原因,这是我能够使服务正确返回图像的唯一方法.将缓冲区写入二进制字符串感觉是多余的,只是将其写回缓冲区,但是嘿,如果它有效,它就可以工作.如果有人找到更有效的解决方案,我很乐意听到它.