在下载的同时从 UnityWebRequest 获取数据？

我有这段代码可以进行 REST 调用：

public IEnumerator GetCooroutine(string route)
{
    string finalURL = URL + route;
    UnityWebRequest www = UnityWebRequest.Get(finalURL);
    yield return www.SendWebRequest();

    if (www.isNetworkError || www.isHttpError) {
        Debug.Log(www.error);
    }
    else {
        Debug.Log("GET succesfull. Response: " + www.downloadHandler.text);
    }
}

我需要在接收时访问请求的数据或正文，并将其用于其他用途。我不想等到它完成接收它们才访问它们。

如果我使用yield，代码等待直到send完成它的执行，我不希望这样。

这是可以做到的UnityWebRequest但你必须执行额外的工作。秘诀就是使用DownloadHandlerScript with UnityWebRequest.

创建一个单独的类并使其派生自DownloadHandlerScript代替MonoBehaviour。在下面的例子中，我将其称为CustomWebRequest。覆盖bool ReceiveData(byte[] data, int dataLength), void CompleteContent()和void ReceiveContentLength(int contentLength)里面有函数。

这是一个例子CustomWebRequest class:

public class CustomWebRequest : DownloadHandlerScript
{
    // Standard scripted download handler - will allocate memory on each ReceiveData callback
    public CustomWebRequest()
        : base()
    {
    }

    // Pre-allocated scripted download handler
    // Will reuse the supplied byte array to deliver data.
    // Eliminates memory allocation.
    public CustomWebRequest(byte[] buffer)
        : base(buffer)
    {
    }

    // Required by DownloadHandler base class. Called when you address the 'bytes' property.
    protected override byte[] GetData() { return null; }

    // Called once per frame when data has been received from the network.
    protected override bool ReceiveData(byte[] byteFromServer, int dataLength)
    {
        if (byteFromServer == null || byteFromServer.Length < 1)
        {
            Debug.Log("CustomWebRequest :: ReceiveData - received a null/empty buffer");
            return false;
        }

        //Do something with or Process byteFromServer here


        return true;
    }

    // Called when all data has been received from the server and delivered via ReceiveData
    protected override void CompleteContent()
    {
        Debug.Log("CustomWebRequest :: CompleteContent - DOWNLOAD COMPLETE!");
    }

    // Called when a Content-Length header is received from the server.
    protected override void ReceiveContentLength(int contentLength)
    {
        Debug.Log(string.Format("CustomWebRequest :: ReceiveContentLength - length {0}", contentLength));
    }
}

要使用它来开始下载，只需创建新的实例UnityWebRequest并使用CustomWebRequest as the downloadHandler在致电之前SendWebRequest功能。不需要协程，你甚至不需要产生任何东西。操作方法如下：

UnityWebRequest webRequest;
//Pre-allocate memory so that this is not done each time data is received
byte[] bytes = new byte[2000];

void Start()
{
    string url = "http://yourUrl/mjpg/video.mjpg";
    webRequest = new UnityWebRequest(url);
    webRequest.downloadHandler = new CustomWebRequest(bytes);
    webRequest.SendWebRequest();
}

就是这样。

• 当 Unity 第一次发出请求时，ReceiveContentLength(int contentLength)叫做。您可以使用contentLength参数来确定您将从该请求收到的总字节数。

• The ReceiveData每次收到新数据时都会调用该函数 通过该函数，您可以从以下位置访问当前数据byteFromServer参数及其长度dataLength范围。

• 当 Unity 完成接收数据后，CompleteContent函数是 叫。