android - 如何在 python Flask 服务器端接收从 android 客户端上传的文件

Question

以下是android端的java代码。它将文件从智能手机上传到 Flask 服务器(基于 Flask 框架构建的 Web 服务器)。在 Flask 服务器端，如何正确接收文件？我为此工作了好几天，但无法弄清楚如何正确地做到这一点。 request.headers 为我提供了正确解析的 header 数据，但 request.data 或 request.stream 无法为我提供预期的数据。任何帮助将不胜感激!

public void doUpload(String filename)
{
    HttpURLConnection conn = null;
    DataOutputStream os = null;
    DataInputStream inputStream = null;

    String urlServer = "http://216.96.***.***:8000/upload";

    String lineEnd = "\r\n";
    String twoHyphens = "--";
    String boundary =  "*****";
    int bytesRead, bytesAvailable, bufferSize, bytesUploaded = 0;
    byte[] buffer;
    int maxBufferSize = 2*1024*1024;

    String uploadname = filename.substring(23);

    try
    {
        FileInputStream fis = new FileInputStream(new File(filename) );

        URL url = new URL(urlServer);
        conn = (HttpURLConnection) url.openConnection();
        conn.setChunkedStreamingMode(maxBufferSize);

        // POST settings.
        conn.setDoInput(true);
        conn.setDoOutput(true);
        conn.setUseCaches(false);
        conn.setRequestMethod("POST");
        conn.setRequestProperty("Connection", "Keep-Alive");
        conn.setRequestProperty("Content-Type", "multipart/form-data; boundary="+boundary);
        conn.addRequestProperty("username", Username);
        conn.addRequestProperty("password", Password);
        conn.connect();

        os = new DataOutputStream(conn.getOutputStream());
        os.writeBytes(twoHyphens + boundary + lineEnd);
        os.writeBytes("Content-Disposition: form-data; name=\"uploadedfile\";filename=\"" + uploadname +"\"" + lineEnd);
        os.writeBytes(lineEnd);

        bytesAvailable = fis.available();
        System.out.println("available: " + String.valueOf(bytesAvailable));
        bufferSize = Math.min(bytesAvailable, maxBufferSize);
        buffer = new byte[bufferSize];

        bytesRead = fis.read(buffer, 0, bufferSize);
        bytesUploaded += bytesRead;
        while (bytesRead > 0)
        {
            os.write(buffer, 0, bufferSize);
            bytesAvailable = fis.available();
            bufferSize = Math.min(bytesAvailable, maxBufferSize);
            buffer = new byte[bufferSize];
            bytesRead = fis.read(buffer, 0, bufferSize);
            bytesUploaded += bytesRead;
        }
        System.out.println("uploaded: "+String.valueOf(bytesUploaded));
        os.writeBytes(lineEnd);
        os.writeBytes(twoHyphens + boundary + twoHyphens + lineEnd);

        // Responses from the server (code and message)
        conn.setConnectTimeout(2000); // allow 2 seconds timeout.
        int rcode = conn.getResponseCode();
        if (rcode == 200) Toast.makeText(getApplicationContext(), "Success!!", Toast.LENGTH_LONG).show();
        else Toast.makeText(getApplicationContext(), "Failed!!", Toast.LENGTH_LONG).show();
        fis.close();
        os.flush();
        os.close();
        Toast.makeText(getApplicationContext(), "Record Uploaded!", Toast.LENGTH_LONG).show();
    }
    catch (Exception ex)
    {
        //ex.printStackTrace();
        //return false;
    }
}
}

我的服务器端代码:

@app.route('/cell_upload', methods=['GET', 'POST'])
def cell_upload():
    """Uploads a new file for the user from cellphone."""
    if request.method == 'POST':
        int_message = 1
        print "Data uploading"
        print request.headers
        logdata = request.stream.readline()
        while(logdata):
            print "uploading"
            print logdata
            logdata = request.stream.readline()
        print "Uploading done"
        return Response(str(int_message), mimetype='text/plain')
    int_message = 0
    return Response(str(int_message), mimetype='text/plain')

Answer 1

我不确定你的确切问题是什么，但我能够通过使用从 this SO question 中获取的 java(客户端)代码来解决问题并按如下方式稍微修改您的 flask 代码:

if request.method == 'POST':
        int_message = 1
        print "Data uploading"
        print request.headers
        for v in request.values:
          print v
        #logdata = request.stream.readline()
        #while(logdata):
        #    print "uploading"
        #    print logdata
        #    logdata = request.stream.readline()
        print "Uploading done"
        return Response(str(int_message), mimetype='text/plain')

我不认为这是“最终答案”，但希望它能帮助您朝着正确的方向前进。