使用 node.js 在 Azure 文件存储中上传文件

Question

我们正在尝试创建一个 Web 服务，以使用 node.js 服务将文件上传到 Azure 文件存储。

下面是 node.js 服务器代码。

exports.post = function(request, response){
var shareName = request.headers.sharename;
var dirPath = request.headers.directorypath;
var fileName = request.headers.filename;

var body;
var length;

request.on("data", function(chunk){
    body += chunk;
    console.log("Get data");
});


request.on("end", function(){
    try{
        console.log("end");
        var data = body;
        length = data.length;

console.log(body); // This giving the result as undefined
console.log(length);

        fileService.createFileFromStream(shareName, dirPath, fileName, body, length, function(error, result, resp) {
            if (!error) {
                // file uploaded
                response.send(statusCodes.OK, "File Uploaded");
            }else{
                response.send(statusCodes.OK, "Error!");
            }
        });

    }catch (er) {
response.statusCode = 400;
return res.end('error: ' + er.message);
}

});

}

下面是我们客户端上传文件。

private static void sendPOST() throws IOException {
    URL obj = new URL("https://crowdtest-fileservice.azure-mobile.net/api/files_stage/");
    HttpURLConnection con = (HttpURLConnection) obj.openConnection();
    con.setRequestMethod("POST");
    con.setRequestProperty("sharename", "newamactashare");
    con.setRequestProperty("directorypath", "MaheshApp/TestLibrary/");
    con.setRequestProperty("filename", "temp.txt");


    Path path = Paths.get("C:/Users/uma.maheshwaran/Desktop/Temp.txt");
    byte[] data = Files.readAllBytes(path);

    // For POST only - START
    con.setDoOutput(true);
    OutputStream os = con.getOutputStream();
    os.write(data);
    os.flush();
    os.close();
    // For POST only - END

    int responseCode = con.getResponseCode();
    System.out.println("POST Response Code :: " + responseCode);

    if (responseCode == HttpURLConnection.HTTP_OK) { // success
        BufferedReader in = new BufferedReader(new InputStreamReader(con.getInputStream()));
        String inputLine;
        StringBuffer response = new StringBuffer();

        while ((inputLine = in.readLine()) != null) {
            response.append(inputLine);
            System.out.println(inputLine);
        }
        in.close();

        // print result
        System.out.println(response.toString());
    } else {
        BufferedReader br = new BufferedReader(new InputStreamReader(con.getErrorStream()));
        String line = "";
        while ((line = br.readLine()) != null) {
            System.out.println(line);
        }
        System.out.println("POST request not worked");
    }
}

显示错误

The request 'POST /api/files_stage/' has timed out. This could be caused by a script that fails to write to the response, or otherwise fails to return from an asynchronous call in a timely manner.

更新：

我也试过下面的代码。

  var body = new Object();
  body = request.body;
  var length = body.length;

  console.log(request.body);
  console.log(body);
  console.log(length);

    try {
        fileService.createFileFromStream(shareName, dirPath, fileName, body, length, function(error, result, resp) {
            if (!error) {
                // file uploaded
                response.send(statusCodes.OK, "File Uploaded");
            }else{
                response.send(statusCodes.OK, "Error!");
            }
        });
    } catch (ex) {
            response.send(500, { error: ex.message });
    }

但面临问题

{"error":"Parameter stream for function createFileFromStream should be an object"}

我是 node.js 的新手。请帮我解决这个问题。

Answer 1

当请求到达exports.post中定义的函数时，整个请求已经存在，所以不需要缓冲。您可以按照以下代码编写一些内容来简化它。

exports.post = function(request, response){
    var shareName = request.headers.sharename;
    var dirPath = request.headers.directorypath;
    var fileName = request.headers.filename;

    var body = request.body;
    var length = body.length;

    console.log(length);

    try {
        fileService.createFileFromText(shareName, dirPath, fileName, body, function(error, result, resp) {
            if (!error) {
                // file uploaded
                response.send(statusCodes.OK, "File Uploaded");
            } else {
                response.send(statusCodes.OK, "Error!");
            }
        });
    } catch (ex) {
        response.send(500, { error: ex.message });
    }
}

Answer 2

我发现最简单的方法是使用 pkgcloud，它抽象了云提供商之间的差异，还为上传和下载文件提供了一个干净的界面。它使用流，因此实现也具有内存效率。

var pkgcloud = require('pkgcloud')
var fs = require('fs')
var client = pkgcloud.storage.createClient({
  provider: 'azure',
  storageAccount: 'your-storage-account',
  storageAccessKey: 'your-access-key'
});

var readStream = fs.createReadStream('a-file.txt');
var writeStream = client.upload({
  container: 'your-storage-container',
  remote: 'remote-file-name.txt'
});

writeStream.on('error', function (err) {
  // handle your error case
});

writeStream.on('success', function (file) {
  // success, file will be a File model
});

readStream.pipe(writeStream);

Answer 3

我们可以利用 SO 上线程的这个答案，它创建一个自定义中间件来将上传文件内容放入缓冲区数组，然后我们可以使用 createFileFromText() 来存储文件在 Azure 存储中。

这是代码片段：

function rawBody(req, res, next) {
    var chunks = [];

    req.on('data', function (chunk) {
        chunks.push(chunk);
    });

    req.on('end', function () {
        var buffer = Buffer.concat(chunks);

        req.bodyLength = buffer.length;
        req.rawBody = buffer;
        next();
    });

    req.on('error', function (err) {
        console.log(err);
        res.status(500);
    });
}
router.post('/upload', rawBody,function (req, res){

    fileService.createShareIfNotExists('taskshare', function (error, result, response) {
        if (!error) {
            // if result = true, share was created.
            // if result = false, share already existed.
            fileService.createDirectoryIfNotExists('taskshare', 'taskdirectory', function (error, result, response) {
                if (!error) {
                    // if result = true, share was created.
                    // if result = false, share already existed.
                    try {
                        fileService.createFileFromText('taskshare', 'taskdirectory', 'test.txt', req.rawBody, function (error, result, resp) {
                            if (!error) {
                                // file uploaded
                                res.send(200, "File Uploaded");
                            } else {
                                res.send(200, "Error!");
                            }
                        });
                    } catch (ex) {
                        res.send(500, { error: ex.message });
                    }

                }
            });
        }
    });

})
router.get('/getfile', function (req, res){
    fileService.createReadStream('taskshare', 'taskdirectory', 'test.txt').pipe(res);
})

Answer 4

这里有几个问题。让我们一一回顾。

1.在您的 Java 客户端中，您不能只将二进制数据转储到 Azure 移动服务连接中。

这是因为 Azure 移动服务有两个正文解析器，可确保无论如何都会为您解析请求正文。因此，虽然您可以通过指定不常见的内容类型来绕过 Express 主体解析器，但您仍然会遇到 Azure 主体解析器，它会天真地假设它是 UTF-8 字符串，从而弄乱您的数据流。

因此，唯一的选择是通过指定它无法处理的内容类型来跳过 Express 解析器，然后通过使用 Base64 编码对二进制数据进行编码来与 Azure 解析器一起使用。

所以，在Java客户端替换

Path path = Paths.get("C:/Users/uma.maheshwaran/Desktop/Temp.txt");
byte[] data = Files.readAllBytes(path);

和

con.setRequestProperty("content-type", "binary");    
Path path = Paths.get("C:/Users/uma.maheshwaran/Desktop/Temp.txt");
byte[] data = Files.readAllBytes(path);
data = Base64.getEncoder().encode(data);

如果您不在 Java 8 上，请将 java.util.Base64 编码器替换为您有权访问的任何其他 Base64 编码器。

2。您尝试使用的 createFileFromStream Azure 存储 api 函数需要流。

同时，手动解析请求体时，你能得到的最好的是一个字节数组。不幸的是，Azure 移动服务使用 NodeJS 版本 0.8，这意味着没有简单的方法从字节数组构建可读流，您将不得不 assemble 适合 Azure 存储的自己的流 api .一些胶带和 stream@0.0.1 应该就可以了。

var base64 = require('base64-js'),
    Stream = require('stream'),
    fileService = require('azure-storage')
        .createFileService('yourStorageAccount', 'yourStoragePassword');

exports.post = function (req, res) {
    var data = base64.toByteArray(req.body),
        buffer = new Buffer(data),
        stream = new Stream();
        stream['_ended'] = false;
        stream['pause'] = function() {
            stream['_paused'] = true;
        };
        stream['resume'] = function() {
            if(stream['_paused'] && !stream['_ended']) {
                stream.emit('data', buffer);
                stream['_ended'] = true;
                stream.emit('end');
            }
        }; 
    try {
        fileService.createFileFromStream(req.headers.sharename, req.headers.directorypath, 
            req.headers.filename, stream, data.length, function (error, result, resp) {
                res.statusCode = error ? 500 : 200;
                res.end();
            }
        );
    } catch (e) {
        res.statusCode = 500;
        res.end();
    }
};

这些是此示例所需的依赖项。

"dependencies": {   
    "azure-storage": "^0.7.0",
    "base64-js": "^0.0.8",
    "stream": "0.0.1"
}

如果在您的服务 package.json 中指定它们不起作用，您可以随时转到此 link 并通过控制台手动安装它们。

cd site\wwwroot
npm install azure-storage
npm install base64-js
npm install stream@0.0.1

3。要增加 1Mb 的默认上传限制，请为您的服务指定 MS_MaxRequestBodySizeKB。

请记住，由于您将数据传输为 Base64 编码，因此您必须考虑此开销。因此，要支持上传最大 20Mb 的文件，您必须将 MS_MaxRequestBodySizeKB 设置为大约 20 * 1024 * 4 / 3 = 27307。

Answer 5

有几件事：

1. createFileFromText 可以处理纯文本。但是对于那些二进制内容它会失败，因为它使用 UTF-8 编码。

您可能想在以下位置参考 blob 的类似问题：Saving blob (might be data!) returned by AJAX call to Azure Blob Storage creates corrupt image

2。 createFileFromStream 或 createWriteStreamToExistingFile \ createWriteStreamToNewFile Azure 存储 API 可能是可以提供帮助的功能。

请注意，这些 API 是针对流的。您需要将请求正文中的 buffer/string 转换为流。可以参考How to wrap a buffer as a stream2 Readable stream?

对于createFileFromStream：

fileService.createFileFromStream(req.headers.sharename, 
  req.headers.directorypath, 
  req.headers.filename, 
  requestStream, 
  data.length, 
  function (error, result, resp) {
    res.statusCode = error ? 500 : 200;
    res.end();
  }
);

对于createWriteStreamToNewFile：

var writeStream = fileService.createWriteStreamToNewFile(req.headers.sharename, 
  req.headers.directorypath, 
  req.headers.filename, 
  data.length);

requestStream.pipe(writeStream);

3。您的代码中存在多个问题

console.log(body); // This giving the result as undefined

原因是你定义了var body而它是undefined。代码 body += chunk 仍然会使 body 未定义。

fileService.createFileFromStream(shareName, dirPath, fileName, body, length, function(error, result, resp) {
  if (!error) {
    // file uploaded
    response.send(statusCodes.OK, "File Uploaded");
  }else{
    response.send(statusCodes.OK, "Error!");
  }
});

当createFileFromStream发生错误时，也可能是网络传输错误，您可能还想return错误代码而不是statusCodes.OK。

使用 node.js 在 Azure 文件存储中上传文件

Uploading a file in Azure File Storage using node.js

node.js

azure

azure-storage

azure-mobile-services

azure-storage-files