java - 如何从 Eclipse 插件提供 Flash 策略文件？

标签 java flash actionscript eclipse-plugin cross-domain-policy

我有一个 Eclipse 插件，需要打开一对到本地计算机上运行的 Flash 应用程序的套接字。 Flash 需要一个策略文件(XML blob)来授予访问相关端口的权限。 Flash 更喜欢通过端口 843 获取此策略文件，Java 将端口 < 1024 视为特权端口，Mac OS X 和 Linux 类似地限制对端口 < 1024 的访问。我不想以 root 权限运行我的 Eclipse 插件，因此提供服务端口 843 上的策略文件不是一个选项。根据 Adob​​e 文档，如果 Flash 无法在端口 843 上获取策略文件，它将转而请求其尝试连接的端口上的策略文件。 ActionScript 代码如下所示:

/**
  * Connecting to some port to communicate with the debugger. We initiate the
  * connection because Flex doesn't allow us to listen to any ports.
  */
private function initSockets():void
{
    requestSocket = new Socket();
    requestSocket.addEventListener(Event.CONNECT, requestConnected);
    requestSocket.addEventListener(Event.CLOSE, closed);
    requestSocket.addEventListener(ProgressEvent.SOCKET_DATA, processRequestData);
    requestSocket.addEventListener(IOErrorEvent.IO_ERROR, ioError);
    requestSocket.addEventListener(SecurityErrorEvent.SECURITY_ERROR, securityError);
    requestSocket.connect("localhost", SCConstants.DEBUG_LESSON_REQUEST_PORT);

    eventSocket = new Socket();
    eventSocket.addEventListener(Event.CONNECT, eventConnected);
    eventSocket.addEventListener(Event.CLOSE, closed);
    eventSocket.addEventListener(ProgressEvent.SOCKET_DATA, processEventData);
    eventSocket.addEventListener(IOErrorEvent.IO_ERROR, ioError);
    eventSocket.addEventListener(SecurityErrorEvent.SECURITY_ERROR, securityError);
    eventSocket.connect("localhost", SCConstants.DEBUG_LESSON_EVENT_PORT);
}

在 Eclipse 插件方面，我继承了一些在 OS X 上大部分时间都可以运行的代码，但有时在 Windows 上会失败。在 Wi-Fi 而不是有线以太网上运行也往往会失败，尽管我不知道为什么这很重要。

public Boolean connect() throws DebugException {
    try {
        try {
            // connection code
            fRequestServerSocket = new ServerSocket(requestPort);
            fRequestServerSocket.setSoTimeout(ACCEPT_TIMEOUT);
            fEventServerSocket = new ServerSocket(eventPort);
            fEventServerSocket.setSoTimeout(ACCEPT_TIMEOUT);

            TWBLogger.logInfo("Open socket request server:" + fRequestServerSocket);
            TWBLogger.logInfo("Open socket event server:" + fEventServerSocket);

            String policy = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n" +
                "<cross-domain-policy>\n" +
                "<allow-access-from domain=\"*\" to-ports=\"5000,5001\" secure=\"false\" />\n" +
                "</cross-domain-policy>\0";

            // Because of the Flash security policy the first thing
            // that will accept on the socket will be the Flash Player 
            // trying to verify us. The Flash player will request security 
            // policy file with the following string: <policy-file-request/>\0
            // We will serve back the above policy file and then close the socket
            // The next thing to accept is our process in the VM.
            fRequestSocket = fRequestServerSocket.accept();

            fRequestWriter = new PrintWriter(fRequestSocket.getOutputStream());
            fRequestReader = new BufferedReader(new InputStreamReader(fRequestSocket.getInputStream()));

            // Wait some time before giving flash the policy file. Otherwise they don't get it. ;(
            // 3 is too much ... ;(
            Thread.sleep(100);

            fRequestWriter.print(policy);
            fRequestWriter.flush();
            fRequestSocket.close();

            // this should be the real connection
            fRequestSocket = fRequestServerSocket.accept();
            TWBLogger.logInfo("Open socket request:" + fRequestSocket);

            fRequestWriter = new PrintWriter(fRequestSocket.getOutputStream());
            fRequestReader = new BufferedReader(new InputStreamReader(fRequestSocket.getInputStream()));

            // the same situation for the EventSocket 
            fEventSocket = fEventServerSocket.accept();
            fEventReader = new BufferedReader(new InputStreamReader(fEventSocket.getInputStream()));
            TWBLogger.logInfo("Open socket event:" + fEventSocket);
        } catch (SocketTimeoutException e) {
            TWBLogger.logWaring("Connection to the Client Timed out.");
            cleanSockets();
            return false;
            requestFailed("Connection to the VM timed out. Please close any other running lessons that you debug and try again", e);
        } catch (SocketSecurityException e) {
            requestFailed("Security error occured when connecting to the VM", e);
        } catch (Exception e) {
            if (!fTerminated)
            requestFailed("Error occured when connecting to the VM. Please close any other running lessons that you debug.", e);
        } 
    } catch (DebugException e) {
        // close the sockets so that we can debug another application
        cleanSockets();
        throw e;
    }

    // our VM is single threaded
    fThread = new TWBThread(this);
    fThreads = new IThread[] {fThread};

    // start listening for events from the VM
    fEventDispatch = new EventDispatchJob();
    fEventDispatch.schedule();

    // start listening for breakpoints
    IBreakpointManager breakpointManager = getBreakpointManager();
    breakpointManager.addBreakpointListener(this);

    breakpointManager.addBreakpointManagerListener(this);
    return true;
}

这段代码看起来有问题。它不会等待来自 Flash 的消息，而是将策略响应塞入端口。正如我所说，它在大多数情况下都有效，但有时会失败，并且似乎不符合 Adob​​e 的文档。

我尝试监听每个端口上的请求数据包并发送特定于端口的响应。我在环回接口(interface) (Mac OS X) 上使用 WireShark 观察套接字流量。我看到传入的策略请求和发送的响应，但 Flash 仍然在两个端口上给我带来安全沙箱违规。

我还尝试在上面所示的 initSockets 开头添加此行:

Security.loadPolicyFile("xmlsocket://localhost:5002");

然后我在插件中添加了代码以监听端口 5002 并发送以下主策略文件内容:

private final static String FLASH_POLICY_RESPONSE = 
    "<?xml version=\"1.0\"?>\n" +
    "<!DOCTYPE cross-domain-policy SYSTEM \"/xml/dtds/cross-domain-policy.dtd\">\n" +
    "<cross-domain-policy>\n" +
    "<site-control permitted-cross-domain-policies=\"master-only\"/>\n" +
    "<allow-access-from domain=\"*\" to-ports=\"5000,5001\"/>\n" +
    "</cross-domain-policy>\0";

我再次看到请求进来并且响应出去，但是Flash似乎没有响应它。我没有收到安全沙箱违规错误，但端口上也没有流量。

谁能告诉我在 Java 和 Flash 之间打开套接字的正确方法吗？

最佳答案

我找到了解决这个问题的方法。我很早就犯了一个错误，使用 BufferedReader.readLine 来读取策略请求。这是不合适的，因为策略请求是以空值终止的，而不是以新行终止的。这很令人困惑，因为当底层流关闭时它确实会返回。因此，我收到了请求并发送了响应，但响应是在 ActionScript 代码已经确定请求失败之后发送的。

在 Java 端，我使用以下代码在端口上建立通信:

// Create server sockets.
fRequestServerSocket = new ServerSocket(REQUEST_PORT);
fRequestServerSocket.setSoTimeout(ACCEPT_TIMEOUT);
TWBLogger.logInfo("Open socket request server:" + fRequestServerSocket);

fEventServerSocket = new ServerSocket(EVENT_PORT);
fEventServerSocket.setSoTimeout(ACCEPT_TIMEOUT);
TWBLogger.logInfo("Open socket event server:" + fEventServerSocket);

// Serve up the Flash policy file.
serveFlashPolicy();

// Connect request socket.
fRequestSocket = fRequestServerSocket.accept();
TWBLogger.logInfo("Open socket request:" + fRequestSocket);

fRequestWriter = new PrintWriter(fRequestSocket.getOutputStream());
fRequestReader = new BufferedReader(new InputStreamReader(fRequestSocket.getInputStream()));

// Connect event socket.
fEventSocket = fEventServerSocket.accept();
TWBLogger.logInfo("Open socket event:" + fEventSocket);

fEventReader = new BufferedReader(new InputStreamReader(fEventSocket.getInputStream()));

提供策略文件的处理方式如下:

private void serveFlashPolicy() {
    ServerSocket serverSocket = null;
    Socket socket = null;
    TWBLogger.logInfo("Waiting for flash policy request on port " + FLASH_POLICY_PORT);
    try {
        serverSocket = new ServerSocket(FLASH_POLICY_PORT);
        serverSocket.setSoTimeout(ACCEPT_TIMEOUT);

        socket = serverSocket.accept();

        PrintWriter writer = new PrintWriter(socket.getOutputStream());
        BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));

        StringBuilder request = new StringBuilder();
        int c;
        while (0 < (c = reader.read())) {
            request.append((char) c);
        }

        String policyRequest = request.toString();
        if (policyRequest.startsWith(FLASH_POLICY_REQUEST)) {
            writer.print(FLASH_POLICY_RESPONSE);
            writer.print("\0");
            writer.flush();
        }
    } catch (IOException e) {
        TWBLogger.logWaring("IOException on port " + FLASH_POLICY_PORT + ": " + e.toString());
        e.printStackTrace();
    } finally {
        if (null != socket) {
            try {
                socket.close();
            } catch (Exception e) {
                // Ignore
            }
        }

        if (null != serverSocket) {
            try {
                serverSocket.close();
            } catch (Exception e) {
                // Ignore
            }
        }
    }

    TWBLogger.logInfo("Flash policy complete on port " + FLASH_POLICY_PORT);
}

Flash 政策响应如下所示:

private final static String FLASH_POLICY_RESPONSE = 
    "<?xml version=\"1.0\"?>\n" +
    "<!DOCTYPE cross-domain-policy SYSTEM \"/xml/dtds/cross-domain-policy.dtd\">\n" +
    "<cross-domain-policy>\n" +
    "<allow-access-from domain=\"*\" to-ports=\"5000,5001\"/>\n" +
    "</cross-domain-policy>";

我之前发送的 site-control 标记仅允许在从端口 843 提供服务的主策略文件中使用。

关于java - 如何从 Eclipse 插件提供 Flash 策略文件？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/13772889/

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