接收的字节多于发送的 C++

Question

我想通过套接字将文件从 Linux 服务器发送到 Windows 客户端，问题是我收到的字节比发送的多。

服务器代码--------------------------------------------- -

if (resultEnviarLongitud = send(ClientSocket,GotFileSize.c_str(),1024,0)<0){
    cout<<endl<<"Error mandando la longitud! "<<endl;
}
rewind(fs);

while ((len = fread(Buffer,1,1024, fs)) > 0)
{
    if((resultEnviar = send(ClientSocket,Buffer,1024,0)) < 0){
        printf("ERROR: Failed to send file %s.\n", nombreArchivoADescargar.c_str());
        break;
    }
    sumEnviada+=len;
}

send(ClientSocket,"Hi",sizeof(Buffer),0);


cout<<"Bytes enviados: "<<sumEnviada<<endl;
strcpy(data, "");

cout<<endl<<"ARCHIVO MANDADO EXITOSAMENTE!"<<endl;
rutaArchivoADescargar.clear();

客户端代码------------------------------------------

if (resultRecibirLongitud = recv(sock, Buffer, sizeof(Buffer), 0) > 0)
{
    LongitudArchivo = atoi(Buffer);
    cout<<endl<<"Longitud Archivo a Recibir: " <<LongitudArchivo<<endl; 
}

FILE *fp=fopen("imagen.jpg","wb");
if (fp==NULL){
    cout<<"Error al crear archivo."<<endl;
}else{
    bzero(Buffer2, 1024); 
    int fr_block_sz = 0;
    int contador=0;

    //shutdown(sock, SD_SEND); I HAVE TO USE IT?

    while((fr_block_sz = recv(sock, Buffer2, 1024, 0)) >= 0) 
    {
        if (fr_block_sz == 0) break;
        if ( strcmp (Buffer,"Hi") == 0) break;
        int write_sz = fwrite(Buffer2, 1, 1024, fp);
        if(write_sz < fr_block_sz)
        {
            printf("File write failed on server.\n");
        }
        bzero(Buffer2, 1024);
        contador+=fr_block_sz;
        if (contador >= LongitudArchivo)break;
        bzero(Buffer2, 1024); 
    }
    cout<<endl<<"Numero de bytes recibidos: "<<contador<<endl<<endl;
    if(fr_block_sz < 0)
    {
        printf("Error receiving file from client to server.\n");
    }
    printf("Ok received from client!\n");
    fclose(fp); 
}

谢谢，

Answer 1

while ((len = fread(Buffer,1,1024, fs)) > 0)
{
    if((resultEnviar = send(ClientSocket,Buffer,1024,0)) < 0)

您的问题之一是即使您fread 更少的字节，您也总是发送 1024 字节的缓冲区。 （注意 1348656 四舍五入到最接近的 1024 倍数是 1349632。）

因此，在写入方面，您需要以下内容：

while ((len = fread(Buffer,1,1024, fs)) > 0)
{
    if((resultEnviar = send(ClientSocket,Buffer,len,0)) < 0)

在阅读方面你想要这样的东西：

while((fr_block_sz = recv(sock, Buffer2, 1024, 0)) >= 0) 
{
    // ...
    int write_sz = fwrite(Buffer2, 1, fr_block_sz, fp);

您最初的 send 也有问题，因为您总是发送 1024 个字节而没有检查这是 c_str 返回的实际长度。