使用node.js在Azure文件存储中上载文件

Question

我们正在尝试创建一个Web服务,使用node.js服务将文件上载到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);
}

});

}

以下是我们上传文件的客户端.

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");
    }
}

它显示错误

请求'POST/api/files_stage /'已超时.这可能是由于脚本无法写入响应,或者无法及时从异步调用返回而导致的.

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 });
    }

但面对这个问题

{"error":"函数createFileFromStream的参数流应该是一个对象"}

我是node.js的新手.请帮我解决这个问题.

Answer 1

这里有几个问题.让我们逐一介绍它们.

1.在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.

这样做的原因是Azure移动服务有两个主体解析器,无论如何都可以确保为您解析请求主体.因此,虽然您可以通过指定不常见的内容类型来遍历Express正文解析器,但您仍然会通过天真地假设它是UTF-8字符串来点击Azure主体解析器,这会破坏您的数据流.

因此,唯一的选择是通过指定无法处理的内容类型跳过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解析器一起播放.

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);

同

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. createFileFromStream您尝试使用的Azure存储api功能需要一个流.

同时,手动解析请求主体时可以获得的最佳结果是字节数组.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来构建来自字节数组的可读流,并且您必须组装适合Azure存储API的自己的流.一些胶带和stream@0.0.1应该没问题.

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"
}

如果在服务的package.json中指定它们不起作用,您可以随时转到此链接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的默认上载限制,请为您的服务指定MS_MaxRequestBodySizeKB.

请记住,因为您将数据作为Base64编码传输,您必须考虑到这种开销.因此,要支持上传大小为20Mb的文件,您必须设置MS_MaxRequestBodySizeKB为大约20*1024*4/3 = 27307.