- html - 出于某种原因,IE8 对我的 Sass 文件中继承的 html5 CSS 不友好?
- JMeter 在响应断言中使用 span 标签的问题
- html - 在 :hover and :active? 上具有不同效果的 CSS 动画
- html - 相对于居中的 html 内容固定的 CSS 重复背景?
我想编写一个客户端/服务器应用程序,客户端和服务器可以在其中交换消息。
Client site communication:
send
recv
send
recv
Server site communication:
recv
send
recv
send
但是,我有一个问题,因为只有一条消息是发送/接收。之后,套接字关闭,不再发送消息。出了什么问题以及如何解决这个问题?谢谢你。
#undef UNICODE
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <winsock2.h>
#include <ws2tcpip.h>
#include <stdlib.h>
#include <stdio.h>
#pragma comment (lib, "Ws2_32.lib")
#define DEFAULT_PORT "27501"
#define SIZE 1024
int SendAllToClient(SOCKET ClientSocket, char *buffer)
{
int iSendResult;
int total = 0, len = 1024;
int bytesleft = 1024;
while( total < len )
{
iSendResult = send( ClientSocket, buffer, 1024, NULL);
if (iSendResult == SOCKET_ERROR)
{
printf("send failed with error: %d\n", WSAGetLastError());
closesocket(ClientSocket);
WSACleanup();
return 1;
}
total += iSendResult;
bytesleft -= iSendResult;
}
printf("Bytes sent: %d\n", iSendResult);
return total<len?- 1: 1;
}
char *ReadFromClient(SOCKET ConnectSocket)
{
int iResult;
char *buffer = new char[1024];
memset(buffer, 0, 1024);
do
{
iResult = recv(ConnectSocket, buffer, 1024, 0);
if ( iResult > 0 )
printf("Bytes received: %d\n", iResult);
else if ( iResult == 0 )
printf("Connection closed\n");
else
printf("recv failed with error: %d\n", WSAGetLastError());
}
while( iResult > 0 );
return buffer;
}
int main(int argc , char *argv[])
{
WSADATA wsaData;
char *buffer;
SOCKET ListenSocket = INVALID_SOCKET;
SOCKET ClientSocket = INVALID_SOCKET;
struct addrinfo *result = NULL;
struct addrinfo hints;
int sessionID;
int iResult;
// Datagram d1,d2,d3;
// Initialize Winsock
iResult = WSAStartup(MAKEWORD(2,2), &wsaData);
if (iResult != 0)
{
printf("WSAStartup failed with error: %d\n", iResult);
return 1;
}
ZeroMemory(&hints, sizeof(hints));
hints.ai_family = AF_INET;
hints.ai_socktype = SOCK_STREAM;
hints.ai_protocol = IPPROTO_TCP;
hints.ai_flags = AI_PASSIVE;
// Resolve the server address and port
iResult = getaddrinfo(NULL, DEFAULT_PORT, &hints, &result);
if ( iResult != 0 )
{
printf("getaddrinfo failed with error: %d\n", iResult);
WSACleanup();
return 1;
}
// Create a SOCKET for connecting to server
ListenSocket = socket(result->ai_family, result->ai_socktype, result->ai_protocol);
if (ListenSocket == INVALID_SOCKET)
{
printf("socket failed with error: %d\n", WSAGetLastError());
freeaddrinfo(result);
WSACleanup();
return 1;
}
// Setup the TCP listening socket
iResult = bind( ListenSocket, result->ai_addr, (int)result->ai_addrlen);
if (iResult == SOCKET_ERROR)
{
printf("bind failed with error: %d\n", WSAGetLastError());
freeaddrinfo(result);
closesocket(ListenSocket);
WSACleanup();
return 1;
}
freeaddrinfo(result);
iResult = listen(ListenSocket, SOMAXCONN);
if (iResult == SOCKET_ERROR)
{
printf("listen failed with error: %d\n", WSAGetLastError());
closesocket(ListenSocket);
WSACleanup();
return 1;
}
printf("Server is listening on localhost:%s ...\n", DEFAULT_PORT);
// Accept a client socket
SOCKADDR_IN addr;
int addrlen = sizeof(addr);
ClientSocket = accept(ListenSocket, (SOCKADDR*)&addr, &addrlen);
if (ClientSocket == INVALID_SOCKET)
{
printf("accept failed with error: %d\n", WSAGetLastError());
closesocket(ListenSocket);
WSACleanup();
return 1;
}
char *ip = inet_ntoa(addr.sin_addr);
int port = addr.sin_port;
printf("\nClient %s:%d connected to server\n", ip, port);
// No longer need server socket
closesocket(ListenSocket);
// shutdown the connection since we're done
iResult = shutdown(ClientSocket, SD_SEND);
if (iResult == SOCKET_ERROR)
{
printf("shutdown failed with error: %d\n", WSAGetLastError());
closesocket(ClientSocket);
WSACleanup();
return 1;
}
//read
buffer = ReadFromClient(ClientSocket);
printf("FROM CLIENT: %s\n", buffer);
//send
memset(buffer, 0, 1024);
memcpy(buffer, "Hi client, how are you?", strlen("Hi client, how are you?"));
SendAllToClient(ClientSocket, buffer);
//read
//send
// cleanup
closesocket(ClientSocket);
WSACleanup();
return 0;
}
客户端代码:
#undef UNICODE
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <winsock2.h>
#include <ws2tcpip.h>
#include <stdlib.h>
#include <stdio.h>
#pragma comment (lib, "Ws2_32.lib")
#define DEFAULT_PORT "27501"
#define SIZE 1024
int SendAllToServer(SOCKET ServerSocket, char *buffer)
{
int iSendResult;
int total = 0, len = 1024;
int bytesleft = 1024;
while( total < len )
{
iSendResult = send( ServerSocket, buffer, 1024, NULL);
if (iSendResult == SOCKET_ERROR)
{
printf("send failed with error: %d\n", WSAGetLastError());
closesocket(ServerSocket);
WSACleanup();
return 1;
}
total += iSendResult;
bytesleft -= iSendResult;
}
printf("Bytes sent: %d\n", iSendResult);
return total<len?- 1: 1;
}
char *ReadFromServer(SOCKET ConnectSocket)
{
int iResult;
char *buffer = new char[1024];
memset(buffer, 0, 1024);
do {
iResult = recv(ConnectSocket, buffer, 1024, 0);
if ( iResult > 0 )
printf("Bytes received: %d\n", iResult);
else if ( iResult == 0 )
printf("Connection closed\n");
else
printf("recv failed with error: %d\n", WSAGetLastError());
} while( iResult > 0 );
return buffer;
}
int main(int argc , char *argv[])
{
WSADATA wsaData;
SOCKET ConnectSocket = INVALID_SOCKET;
struct addrinfo *result = NULL,
*ptr = NULL,
hints;
char* buffer;
int sessionID;
int iResult;
// Datagram d1,d2;
// Initialize Winsock
iResult = WSAStartup(MAKEWORD(2,2), &wsaData);
if (iResult != 0) {
printf("WSAStartup failed with error: %d\n", iResult);
return 1;
}
ZeroMemory( &hints, sizeof(hints) );
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
hints.ai_protocol = IPPROTO_TCP;
// Resolve the server address and port
iResult = getaddrinfo("127.0.0.1", DEFAULT_PORT, &hints, &result);
if ( iResult != 0 ) {
printf("getaddrinfo failed with error: %d\n", iResult);
WSACleanup();
return 1;
}
// Attempt to connect to an address until one succeeds
for(ptr=result; ptr != NULL ;ptr=ptr->ai_next) {
// Create a SOCKET for connecting to server
ConnectSocket = socket(ptr->ai_family, ptr->ai_socktype,
ptr->ai_protocol);
if (ConnectSocket == INVALID_SOCKET) {
printf("socket failed with error: %d\n", WSAGetLastError());
WSACleanup();
return 1;
}
// Connect to server.
iResult = connect( ConnectSocket, ptr->ai_addr, (int)ptr->ai_addrlen);
if (iResult == SOCKET_ERROR) {
closesocket(ConnectSocket);
ConnectSocket = INVALID_SOCKET;
continue;
}
break;
}
freeaddrinfo(result);
if (ConnectSocket == INVALID_SOCKET) {
printf("Unable to connect to server!\n");
WSACleanup();
return 1;
}
//send
buffer = new char[1024];
memset(buffer, 0, 1024);
memcpy(buffer, "Hi server", strlen("Hi server"));
SendAllToServer(ConnectSocket, buffer);
//read
memset(buffer, 0, 1024);
buffer = ReadFromServer(ConnectSocket);
printf("FROM SERVER: %s\n", buffer);
//send
//read
// cleanup
closesocket(ConnectSocket);
WSACleanup();
return 0;
}
编辑
#include "data_types.h"
#undef UNICODE
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <winsock2.h>
#include <ws2tcpip.h>
#include <stdlib.h>
#include <stdio.h>
#include <string>
#include <iostream>
#pragma comment (lib, "Ws2_32.lib")
#define DEFAULT_PORT "27015"
#define SIZE 1024
int SendAllToClient(SOCKET ClientSocket)
{
char *buffer = new char[SIZE];
int iSendResult;
memset(buffer, 0, SIZE);
int total = 0, len = SIZE;
int bytesleft = SIZE;
while( total < len )
{
iSendResult = send( ClientSocket, buffer + total, bytesleft, NULL);
if (iSendResult == SOCKET_ERROR)
{
printf("send failed with error: %d\n", WSAGetLastError());
closesocket(ClientSocket);
WSACleanup();
return 1;
}
total += iSendResult;
bytesleft -= iSendResult;
}
printf("Bytes sent: %d\n", iSendResult);
delete buffer;
return total<len?- 1: 1;
}
char* ReadFromClient(SOCKET ClientSocket)
{
std::string data = "";
char *all = NULL;
char buffer[1];
int total = 0, len = SIZE;
int bytesleft = SIZE;
int iResult;
memset(buffer, 0, 1);
while(total < len)
{
if ((iResult = recv(ClientSocket, buffer, 1, 0)) == 0)
{
if (errno != 0)
{
// cleanup
closesocket(ClientSocket);
WSACleanup();
exit(1);
}
}
data = data + std::string(buffer);
total += iResult;
bytesleft -= iResult;
memset(buffer, 0, 1);
}
all = new char[data.length() + 1];
strcpy(all, data.c_str());
return all;
}
int main(int argc , char *argv[])
{
WSADATA wsaData;
char *buffer;
SOCKET ListenSocket = INVALID_SOCKET;
SOCKET ClientSocket = INVALID_SOCKET;
struct addrinfo *result = NULL;
struct addrinfo hints;
int sessionID;
int iResult;
// Datagram d1,d2,d3;
// Initialize Winsock
iResult = WSAStartup(MAKEWORD(2,2), &wsaData);
if (iResult != 0)
{
printf("WSAStartup failed with error: %d\n", iResult);
return 1;
}
ZeroMemory(&hints, sizeof(hints));
hints.ai_family = AF_INET;
hints.ai_socktype = SOCK_STREAM;
hints.ai_protocol = IPPROTO_TCP;
hints.ai_flags = AI_PASSIVE;
// Resolve the server address and port
iResult = getaddrinfo(NULL, DEFAULT_PORT, &hints, &result);
if ( iResult != 0 )
{
printf("getaddrinfo failed with error: %d\n", iResult);
WSACleanup();
return 1;
}
// Create a SOCKET for connecting to server
ListenSocket = socket(result->ai_family, result->ai_socktype, result->ai_protocol);
if (ListenSocket == INVALID_SOCKET)
{
printf("socket failed with error: %d\n", WSAGetLastError());
freeaddrinfo(result);
WSACleanup();
return 1;
}
// Setup the TCP listening socket
iResult = bind( ListenSocket, result->ai_addr, (int)result->ai_addrlen);
if (iResult == SOCKET_ERROR)
{
printf("bind failed with error: %d\n", WSAGetLastError());
freeaddrinfo(result);
closesocket(ListenSocket);
WSACleanup();
return 1;
}
freeaddrinfo(result);
iResult = listen(ListenSocket, SOMAXCONN);
if (iResult == SOCKET_ERROR)
{
printf("listen failed with error: %d\n", WSAGetLastError());
closesocket(ListenSocket);
WSACleanup();
return 1;
}
printf("Server is listening on localhost:%s ...\n", DEFAULT_PORT);
// Accept a client socket
SOCKADDR_IN addr;
int addrlen = sizeof(addr);
ClientSocket = accept(ListenSocket, (SOCKADDR*)&addr, &addrlen);
if (ClientSocket == INVALID_SOCKET)
{
printf("accept failed with error: %d\n", WSAGetLastError());
closesocket(ListenSocket);
WSACleanup();
return 1;
}
char *ip = inet_ntoa(addr.sin_addr);
int port = addr.sin_port;
printf("\nClient %s:%d connected to server\n", ip, port);
// No longer need server socket
closesocket(ListenSocket);
// shutdown the connection since we're done
iResult = shutdown(ClientSocket, SD_SEND);
if (iResult == SOCKET_ERROR)
{
printf("shutdown failed with error: %d\n", WSAGetLastError());
closesocket(ClientSocket);
WSACleanup();
return 1;
}
//read
buffer = new char[1024];
memset(buffer, 0, 1024);
buffer = ReadFromClient(ClientSocket);
printf("FROM CLIENT: %s\n", buffer);
//send
memset(buffer, 0, 1024);
memcpy(buffer, "Hi client, how are you?", strlen("Hi client, how are you?"));
// Send an initial buffer
iResult = send( ClientSocket, buffer, (int)strlen(buffer), 0 );
if (iResult == SOCKET_ERROR) {
wprintf(L"send failed with error: %d\n", WSAGetLastError());
closesocket(ClientSocket);
WSACleanup();
return 1;
}
//read
//send
// cleanup
closesocket(ClientSocket);
WSACleanup();
return 0;
}
客户
#include "data_types.h"
#undef UNICODE
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <winsock2.h>
#include <ws2tcpip.h>
#include <stdlib.h>
#include <stdio.h>
#include <string>
#include <iostream>
#pragma comment (lib, "Ws2_32.lib")
#define DEFAULT_PORT "27015"
#define SIZE 1024
int SendAllToServer(SOCKET ClientSocket)
{
char *buffer = new char[SIZE];
memset(buffer, 0, SIZE);
int total = 0, len = SIZE;
int bytesleft = SIZE, iSendResult;
while( total < len )
{
iSendResult = send( ClientSocket, buffer + total, bytesleft, NULL);
if (iSendResult == SOCKET_ERROR)
{
printf("send failed with error: %d\n", WSAGetLastError());
closesocket(ClientSocket);
WSACleanup();
return 1;
}
total += iSendResult;
bytesleft -= iSendResult;
}
printf("Bytes sent: %d\n", iSendResult);
delete buffer;
return total<len?- 1: 1;
}
char *ReadFromServer(SOCKET ClientSocket)
{
std::string data = "";
char *all = NULL;
char buffer[1];
int total = 0, len = SIZE;
int bytesleft = SIZE;
int iResult;
memset(buffer, 0, 1);
while(total < len)
{
if ((iResult = recv(ClientSocket, buffer, 1, 0)) == 0)
{
if (errno != 0)
{
// cleanup
closesocket(ClientSocket);
WSACleanup();
exit(1);
}
}
data = data + std::string(buffer);
total += iResult;
bytesleft -= iResult;
memset(buffer, 0, 1);
}
all = new char[data.length() + 1];
strcpy(all, data.c_str());
return all;
}
int main(int argc , char *argv[])
{
WSADATA wsaData;
SOCKET ConnectSocket = INVALID_SOCKET;
struct addrinfo *result = NULL,
*ptr = NULL,
hints;
char* buffer;
int sessionID;
int iResult;
// Datagram d1,d2;
// Initialize Winsock
iResult = WSAStartup(MAKEWORD(2,2), &wsaData);
if (iResult != 0) {
printf("WSAStartup failed with error: %d\n", iResult);
return 1;
}
ZeroMemory( &hints, sizeof(hints) );
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
hints.ai_protocol = IPPROTO_TCP;
// Resolve the server address and port
iResult = getaddrinfo("127.0.0.1", DEFAULT_PORT, &hints, &result);
if ( iResult != 0 ) {
printf("getaddrinfo failed with error: %d\n", iResult);
WSACleanup();
return 1;
}
// Attempt to connect to an address until one succeeds
for(ptr=result; ptr != NULL ;ptr=ptr->ai_next) {
// Create a SOCKET for connecting to server
ConnectSocket = socket(ptr->ai_family, ptr->ai_socktype,
ptr->ai_protocol);
if (ConnectSocket == INVALID_SOCKET) {
printf("socket failed with error: %d\n", WSAGetLastError());
WSACleanup();
return 1;
}
// Connect to server.
iResult = connect( ConnectSocket, ptr->ai_addr, (int)ptr->ai_addrlen);
if (iResult == SOCKET_ERROR) {
closesocket(ConnectSocket);
ConnectSocket = INVALID_SOCKET;
continue;
}
break;
}
freeaddrinfo(result);
if (ConnectSocket == INVALID_SOCKET) {
printf("Unable to connect to server!\n");
WSACleanup();
return 1;
}
//send
buffer = new char[1024];
memset(buffer, 0, 1024);
memcpy(buffer, "Hi server, how are you?", strlen("Hi server, how are you?"));
// Send an initial buffer
iResult = send( ConnectSocket, buffer, (int)strlen(buffer), 0 );
if (iResult == SOCKET_ERROR) {
closesocket(ConnectSocket);
WSACleanup();
return 1;
}
//read
memset(buffer, 0, 1024);
// Receive until the peer closes the connection
do {
iResult = recv(ConnectSocket, buffer, 1024, 0);
if ( iResult > 0 )
wprintf(L"Bytes received: %d\n", iResult);
else if ( iResult == 0 )
wprintf(L"Connection closed\n");
else
wprintf(L"recv failed with error: %d\n", WSAGetLastError());
} while( iResult > 0 );
printf("FROM SERVER: %s\n", buffer);
//send
//read
// cleanup
closesocket(ConnectSocket);
WSACleanup();
return 0;
}
最佳答案
首要问题:
iSendResult = send( ClientSocket, buffer, 1024, NULL);
那个 1024 应该是
bytesleft
.如果您已经读取了 512 个字节,则不想再读取 512 个字节。
buffer
应该是
buffer + total
.如果您已经发送了 512 个字节,您不想再次发送相同的 512 个字节,您想发送其他 512 个字节。
ReadFromServer
功能完全被破坏并且不遵循正确的逻辑。它只会返回 fatal error ,甚至不会尝试准确读取 1,024 个字节。它最多只能读取 1,024 个字节,然后,无论它实际读取了多少字节,都会尝试再次读取 1,024 个字节——并在同一地址覆盖它已经读取的消息的任何部分!
buffer = ReadFromServer(ConnectSocket);
printf("FROM SERVER: %s\n", buffer);
不要这样做。假设服务器是恶意的,并向您发送了 1,024 个字节,这些字节不是合法的 C 样式字符串。将其传递给
printf
通过
%s
可能导致客户端崩溃或行为不端。始终将接收自网络的数据视为不受信任且可能具有恶意。尽管您的代码在不修复此问题的情况下也可以工作,但有一天这样做会以某种可怕的方式咬住您,并且养成这不是一个好习惯。
delete[]
完成后的缓冲区。但是你为什么要返回一个原始指针呢?您可以返回
std::string
, 一个
std::vector
,或许多其他更好的机制,可以避免泄漏风险并使拷贝安全。
关于c++ - Winsock2,客户端-服务器通信——轮流发送/接收,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/62475005/
我正在使用 voip 推送通知制作 ios 应用程序。 我想从 Node js 发送 voip 推送通知,但不是很好。 我阅读了本教程 CallKit iOS Swift Tutorial for V
我编写了一个服务器,当浏览器尝试连接到某些站点时,它会检查黑名单并发回 404,但是当我调用 send() 时没有错误,但消息不会出现在网络上浏览器,除非我关闭连接? 有什么建议吗? 接受来自浏览器的
#include int main() { char c = getchar(); //EOF (ctrl + d ) while( ( c = getchar() ) != '?'
我正在尝试使用MailMessage对象通过PowerShell发送电子邮件。该脚本使用Import-CSV来使用文件,然后在电子邮件正文中使用ConvertTo-HTML。由于我要发送的电子邮件客户
我需要创建一个脚本,每 30 秒对网络流量进行一次采样并存储发送/接收的字节。该数据随后用于绘制图形。我编写了一个在 Windows 2012 上完美运行的程序,但我意识到某些 cmdlet 在以前的
我正在运行“autoit3.chm”文件。当它运行时,我想发送一个向下键箭头,但它不起作用: $file = FileGetShortName("C:\Users\PHSD100-SIC\Deskto
当我使用网络浏览器测试我的程序时,我可以很好地写入套接字/FD,所以我决定循环它并在连接中途切断连接,我发现了一个问题。 send() 能够在套接字不可用时关闭整个程序。我认为问题在于该程序陷入了第
我正在运行“autoit3.chm”文件。当它运行时,我想发送一个向下键箭头,但它不起作用: $file = FileGetShortName("C:\Users\PHSD100-SIC\Deskto
所以我试图向自己发送数据并接收数据然后打印它,现在我已经测试了一段时间,我注意到它没有发送任何东西,事实上,也许它是,但我没有正确接收它,我需要这方面的帮助。 这就是我用来发送数据的
问题:开发人员创建自己的序列化格式有多常见?具体来说,我使用 java 本质上将对象作为一个巨大的字符串发送,并用标记来分隔变量。 我的逻辑:我选择这个是因为它几乎消除了语言依赖性(忽略java的修改
我必须在 Linux 上编写一个应用程序,该应用程序需要与具有自定义以太网类型的设备进行通信。甚至在如何编写这样的应用程序中也有很多解决方案。一个缺点是需要 root 访问权限(AFAIK)。之后释放
我有一个包含三个单选按钮选项的表单。我需要将表单数据提交到另一个文件,但由于某种原因,发送的数据包含所选单选按钮的值“on”,而不是 value 属性的值。 我尝试通过 post() 函数手动操作和发
基本上我想实现这样的目标: Process 1 Thread 1 Receive X from process 2 Thread 2 Receive Y from proces
我目前正在 Google App Engine 上开发一个系统,对它还很陌生,我正在使用 Java 平台进行开发。我在 servlet 之间发送 session 对象时遇到问题。我已经在 appeng
当我尝试将“this”(触发的元素)作为参数发送给函数时,函数收到“Object[Document build.php]”作为参数,而不是触发的元素。请让我知道我的错误: function set(a
我正在寻找让我的应用响应联系人 > 发送的魔法咒语。我希望能够接收联系人的 URI 以便检索联系人。谁有 list 过滤器/代码 fragment 吗? 最佳答案 我没有睾丸,但您可以尝试基于 ACT
关于我心爱的套接字的另一个问题。我先解释一下我的情况。之后我会告诉你是什么困扰着我。 我有一个客户端和一个服务器。这两个应用程序都是用 C++ 编写的,实现了 winsock2。连接通过 TCP 和
我看到了这篇文章 http://www.eskimo.com/~scs/cclass/int/sx5.html 但这部分让我感到困惑:如果我们已经使用 send_array 或 send_array_
我对这行代码有疑问。我必须将一个数据包带到一个端口并重新发送到接口(interface)(例如:eth0)。我的程序成功地从端口获取数据包,但是当我重新发送(使用 send())到接口(interfa
我正在尝试编写一个 X11 输入驱动程序,它可以使用我的 Android 手机上的触摸屏来移动和单击鼠标。我可以正常移动鼠标,但我无法让应用程序正确识别点击。我当前的代码位于 https://gist
我是一名优秀的程序员,十分优秀!