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improvements in networking code

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This commit is contained in:
VaclavT
2021-12-19 13:35:19 +01:00
parent 8ea91f255b
commit 2a138d0c81
2 changed files with 60 additions and 36 deletions
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86
clib/tcpnet.cpp
View File

@@ -1,18 +1,17 @@
#include <stdio.h>
#include <stdlib.h>
#include <cstdio>
#include <cstdlib>
#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <cstring>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <cerrno>
#include "tcpnet.h"
#define TCPNET_BUFFER_SIZE 131072
#define TCPNET_BUFFER_SIZE 16384
void error(const char *msg) {
@@ -21,23 +20,21 @@ void error(const char *msg) {
}
// TODO do it as RAII
TcpNet::TcpNet() {}
TcpNet::TcpNet() = default;
int TcpNet::server(int portno, std::function<std::pair<bool, std::string>(std::string)> process_request) const {
int TcpNet::server(int portno, const std::function<std::pair<bool, std::string>(std::string)>& process_request) const {
int sockfd, newsockfd;
socklen_t clilen;
char buffer[TCPNET_BUFFER_SIZE];
struct sockaddr_in serv_addr, cli_addr;
int n;
sockfd = socket(AF_INET, SOCK_STREAM, 0);
if (sockfd < 0)
error("ERROR opening socket");
bzero((char *) &serv_addr, sizeof(serv_addr));
memset((char *) &serv_addr, 0, sizeof(serv_addr));
serv_addr.sin_family = AF_INET;
serv_addr.sin_addr.s_addr = INADDR_ANY;
serv_addr.sin_port = htons(portno);
@@ -65,19 +62,17 @@ int TcpNet::server(int portno, std::function<std::pair<bool, std::string>(std::s
error("ERROR on accept");
while (true) {
bzero(buffer,TCPNET_BUFFER_SIZE);
n = read(newsockfd,buffer,TCPNET_BUFFER_SIZE - 1);
if (n == 0) break; // nothing to read from client anymore
if (n < 0) error("ERROR reading from socket");
std::string request = read_from_socket(newsockfd);
if (request.empty()) break;
std::string request{buffer};
std::pair<bool, std::string> response = process_request(request);
shutdown = response.first;
std::string response_str = response.second;
n = write(newsockfd, response_str.c_str(), response_str.size());
if (n < 0)
auto response_len = response_str.size();
auto n = write(newsockfd, response_str.c_str(), response_len);
if (n < 0 || response_len != n)
error("ERROR writing to socket");
requests_processed++;
@@ -93,24 +88,22 @@ int TcpNet::server(int portno, std::function<std::pair<bool, std::string>(std::s
std::vector<std::string> TcpNet::client(const std::string &address, int portno, const std::vector<std::string> &requests) const {
int sockfd, n;
int sockfd;
struct sockaddr_in serv_addr;
struct hostent *server;
std::vector<std::string> responses;
char buffer[TCPNET_BUFFER_SIZE];
sockfd = socket(AF_INET, SOCK_STREAM, 0);
if (sockfd < 0)
error("ERROR opening socket");
server = gethostbyname(address.c_str());
if (server == NULL) {
fprintf(stderr,"ERROR, no such host\n");
fprintf(stderr, "ERROR, no such host\n");
exit(0);
}
bzero((char *) &serv_addr, sizeof(serv_addr));
memset((char *) &serv_addr, 0, sizeof(serv_addr));
serv_addr.sin_family = AF_INET;
bcopy((char *)server->h_addr, (char *)&serv_addr.sin_addr.s_addr, server->h_length);
serv_addr.sin_port = htons(portno);
@@ -121,16 +114,10 @@ std::vector<std::string> TcpNet::client(const std::string &address, int portno,
responses.reserve(requests.size());
for(const auto &req : requests) {
n = write(sockfd, req.c_str(), strlen(req.c_str()));
if (n < 0)
error("ERROR writing to socket");
bzero(buffer, TCPNET_BUFFER_SIZE);
n = read(sockfd,buffer, TCPNET_BUFFER_SIZE - 1);
if (n < 0)
error("ERROR reading from socket");
write_to_socket(sockfd, req);
responses.push_back(std::string(buffer));
std::string response = read_from_socket(sockfd);
responses.push_back(response);
}
close(sockfd);
@@ -144,4 +131,39 @@ std::string TcpNet::client(const std::string &address, int portno, const std::st
auto response = client(address, portno, c);
return response[0];
}
std::string TcpNet::read_from_socket(int sockfd) {
char buffer[TCPNET_BUFFER_SIZE];
std::string request;
long n;
do {
memset(buffer, 0, TCPNET_BUFFER_SIZE);
n = read(sockfd, buffer, TCPNET_BUFFER_SIZE - 1);
if (n == 0) break; // nothing to read from client anymore
if (n < 0) {
if (errno == ECONNRESET) break; // connection reset by peer
std::string err_desc{"ERROR reading from socket "};
err_desc.append(strerror(errno));
error(err_desc.c_str());
}
std::string part{buffer};
request.append(part);
} while (n == TCPNET_BUFFER_SIZE - 1); // TODO what if data exactly of this size
return request;
}
void TcpNet::write_to_socket(int sockfd, const std::string &str) {
const char * buffer = str.c_str();
int pos = 0;
long n;
do {
n = write(sockfd, buffer + pos, (int)(str.length() - pos));
if (n < 0)
error("ERROR writing to socket");
} while (pos + n < str.length());
}

10
clib/tcpnet.h
View File

@@ -10,11 +10,13 @@ public:
TcpNet();
// starts listening on port
int server(int port, std::function<std::pair<bool, std::string>(std::string)> process_request) const;
int server(int port, const std::function<std::pair<bool, std::string>(std::string)>& process_request) const;
// writes request to server on address:port and returns response
std::string client(const std::string &address, int portno, const std::string &request) const;
std::vector<std::string> client(const std::string &address, int portno, const std::vector<std::string> &requests) const;
[[nodiscard]] std::string client(const std::string &address, int portno, const std::string &request) const;
[[nodiscard]] std::vector<std::string> client(const std::string &address, int portno, const std::vector<std::string> &requests) const;
private:
static std::string read_from_socket(int sockfd) ;
static void write_to_socket(int sockfd, const std::string &str) ;
};