Question

我在通过套接字发送/接收文件时遇到问题。例如 - 在小视频（440 Mb）中，整个视频都存在干扰（绿色噪声）。 Bug sreenshot

为什么会这样？

// server side
bool ClientThread::GetFile(char* path, LPDWORD fileSize, LPDWORD bytes)
{
    FileInfo* fileInfo = new FileInfo();
    if (!m_client->SyncGetRequest(fileInfo))
    {
        delete fileInfo;
        return false;
    }

    *fileSize = fileInfo->parts * fileInfo->partSize + fileInfo->remain;

    HANDLE hFile = CreateFile(path, GENERIC_READ | GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
    if (hFile == INVALID_HANDLE_VALUE)
    {
        printf("Creating file is failed!\n");
        delete fileInfo;
        return false;
    }
    HANDLE hMap = CreateFileMapping(hFile, NULL, PAGE_READWRITE, 0, *fileSize, 0);
    if (!hMap)
    {
        printf("Creating file mapping is failed!\n");
        CloseHandle(hFile);
        delete fileInfo;
        return false;
    }

    void* ptr = MapViewOfFile(hMap, FILE_MAP_READ | FILE_MAP_WRITE, 0, 0, *fileSize);
    if (!ptr)
    {
        printf("Map View of file has been failed!\n");
        CloseHandle(hMap);
        CloseHandle(hFile);
        delete fileInfo;
        return false;
    }

    for (int i = 0; i < fileInfo->parts; i++)
    {
        int received = m_client->SyncGetRequest((byte*)((DWORD)ptr + i * fileInfo->partSize), fileInfo->partSize);
        if (received != fileInfo->partSize)
            printf("WARNING! Byte mismatch detected! Part: %d\n", i + 1);

        if (received <= 0)
        {
            printf("File receiving is failed! Part: %d\n", i + 1);

            UnmapViewOfFile(ptr);
            CloseHandle(hMap);
            CloseHandle(hFile);

            delete fileInfo;
            return false;
        }
        *bytes += received;
    }

    if (fileInfo->remain > 0)
    {
        int received = m_client->SyncGetRequest((byte*)((DWORD)ptr + fileInfo->parts * fileInfo->partSize), fileInfo->remain);
        *bytes += received;
    }
    UnmapViewOfFile(ptr);

    CloseHandle(hMap);
    CloseHandle(hFile);
    delete fileInfo;
    printf("File successfully received!\n");
    return true;
}
// client side
void Client::SendFile(HANDLE hFile)
{
    DWORD partSize = 4096;
    DWORD size = GetFileSize(hFile, NULL);

    int parts = size / partSize;
    int remain = size - parts * partSize;

    FileInfo fInfo = { parts, partSize, remain };

    if (!SyncSendRequest(&fInfo))
        return;

    HANDLE hMap = CreateFileMapping(hFile, NULL, PAGE_READONLY, 0, 0, 0);
    if (hMap)
    {
        void* ptr = MapViewOfFile(hMap, FILE_MAP_READ, 0, 0, 0);
        if (ptr)
        {
            for (int i = 0; i < parts; i++)
            {
                if (!SyncSendRequest((byte*)((DWORD)ptr + i * partSize), partSize))
                {
                    printf("Error sending file! Part: %d\n", i + 1);
                    break;
                }
            }

            if (remain > 0)
            {
                SyncSendRequest((byte*)((DWORD)ptr + parts * partSize), remain);
            }

            UnmapViewOfFile(ptr);
        }
        CloseHandle(hMap);
    }

    printf("File is sent!\n");
}

SyncSendData执行send / recv响应/从服务器（1字节）

SyncGetData执行recv并从/向服务器发送响应（1个字节）

接收文件的大小与原始文件的大小相匹配。

Answer 1

事实证明问题不在于传输协议。但是从屏幕截图中可以看出，您正在使用Windows媒体播放器窗口来运行视频。

尝试安装一些视频编解码器，然后查看视频是否正常播放。

检查文件有效性的另一种简单方法是在双方执行校验和。（他们应该是平等的。）

问候。

通过套接字发送文件

1 个答案: