I want to create an HTTP post request in C. I have success to send Get Method but, when I try with Post, program is just stopped.
Here the code :
#include<stdio.h>
#include<winsock2.h>
#include <string.h>
#pragma comment(lib,"ws2_32.lib") //Winsock Library
int main(int argc , char *argv[])
{
WSADATA wsa;
SOCKET s;
struct sockaddr_in server;
char *message , server_reply[2000];
int recv_size;
printf("\nInitialising Winsock...");
if (WSAStartup(MAKEWORD(2,2),&wsa) != 0)
{
printf("Failed. Error Code : %d",WSAGetLastError());
return 1;
}
printf("Initialised.\n");
//Create a socket
if((s = socket(AF_INET , SOCK_STREAM , 0 )) == INVALID_SOCKET)
{
printf("Could not create socket : %d" , WSAGetLastError());
}
printf("Socket created.\n");
server.sin_addr.s_addr = inet_addr("127.0.0.1");
server.sin_family = AF_INET;
server.sin_port = htons( 80 );
//Connect to remote server
if (connect(s , (struct sockaddr *)&server , sizeof(server)) < 0)
{
puts("connect error");
return 1;
}
puts("Connected");
// Work well with Get Method
// strcat(message, "GET /voleur/receiver.php?arg1=Hello HTTP/1.1\n");
strcat(message, "POST /voleur/receiver.php HTTP/1.1\n");
strcat(message, "Host: 127.0.0.1\n");
strcat(message, "Connection: close\n");
strcat(message, "Content-Type:application/octet-stream\n");
strcat(message, "Content-Encoding:binary\n");
strcat(message, "Content-Length:16\n");
strcat(message, "Accept-Charset: utf-8\n\n");
if( send(s , message , strlen(message) , 0) < 0)
{
puts("Send failed");
return 1;
}
// My argument
char *data = "arg1=Hello";
send(s , data , strlen(data), 0);
puts("Data Send\n");
//Receive a reply from the server
if((recv_size = recv(s , server_reply , 2000 , 0)) == SOCKET_ERROR)
{
puts("recv failed");
}
puts("Reply received\n");
//Add a NULL terminating character to make it a proper string before printing
server_reply[recv_size] = '\0';
puts(server_reply);
return 0;
}
First:
You should reformat your HTTP header:
strcat(message, "Content-Type:application/octet-stream\n");
strcat(message, "Content-Encoding:binary\n");
strcat(message, "Content-Length:16\n");
should be
strcat(message, "Content-Type: application/octet-stream\n");
strcat(message, "Content-Encoding: binary\n");
strcat(message, "Content-Length: 16\n");
Second:
As far as I can see, your problem lies within the following lines:
strcat(message, "Content-Length: 16\n");
[...]
char *data = "arg1=Hello";
send(s , data , strlen(data), 0);
because you declare there will be 16 bytes of data - but you only send 10 bytes, which will cause the server to wait for the remaining 6 bytes.
Related
I want to send post data to php script, but php never get my post data. Here my code :
#include<stdio.h>
#include<winsock2.h>
#include <string.h>
#pragma comment(lib,"ws2_32.lib") //Winsock Library
int main(int argc , char *argv[])
{
WSADATA wsa;
SOCKET s;
struct sockaddr_in server;
char message[1024] , server_reply[2000];
int recv_size;
printf("\nInitialising Winsock...");
if (WSAStartup(MAKEWORD(2,2),&wsa) != 0)
{
printf("Failed. Error Code : %d",WSAGetLastError());
return 1;
}
printf("Initialised.\n");
//Create a socket
if((s = socket(AF_INET , SOCK_STREAM , 0 )) == INVALID_SOCKET)
{
printf("Could not create socket : %d" , WSAGetLastError());
}
printf("Socket created.\n");
server.sin_addr.s_addr = inet_addr("127.0.0.1");
server.sin_family = AF_INET;
server.sin_port = htons( 80 );
//Connect to remote server
if (connect(s , (struct sockaddr *)&server , sizeof(server)) < 0)
{
puts("connect error");
return 1;
}
puts("Connected");
// Work well with Get Method
// strcat(message, "GET /voleur/receiver.php?arg1=Hello HTTP/1.1\n");
strcpy(message, "POST /voleur/receiver.php HTTP/1.1\r\n");
strcat(message, "Host: 127.0.0.1:80\r\n");
strcat(message, "Content-Type: application/x-www-form-urlencoded\r\n");
strcat(message, "Content-Length: 10\r\n");
strcat(message, "Accept-Charset: utf-8\r\n\r\n");
strcat(message, "arg1=Hello");
if( send(s , message , strlen(message) , 0) < 0)
{
puts("Send failed");
return 1;
}
puts("Data Send\n");
//Receive a reply from the server
if((recv_size = recv(s , server_reply , 2000 , 0)) == SOCKET_ERROR)
{
puts("recv failed");
}
puts("Reply received\n");
//Add a NULL terminating character to make it a proper string before printing
server_reply[recv_size] = '\0';
puts(server_reply);
return 0;
}
This the php script :
<?php
echo "POST DATA : ".json_encode($_POST);
?>
Here the response :
Reply received
HTTP/1.1 200 OK
Date: Fri, 18 Nov 2016 10:34:21 GMT
Server: Apache/2.4.18 (Win32) OpenSSL/1.0.2e PHP/7.0.8
X-Powered-By: PHP/7.0.8
Content-Length: 14
Content-Type: text/html; charset=UTF-8
POST DATA : []
When i try send data throught GET method thats work well, but for POST method, PHP script doesn't receive any data from client.
Thankyou for David Schwartz, this the right code :
#include<stdio.h>
#include<winsock2.h>
#include <string.h>
#pragma comment(lib,"ws2_32.lib") //Winsock Library
int main(int argc , char *argv[])
{
WSADATA wsa;
SOCKET s;
struct sockaddr_in server;
char message[1024] , server_reply[2000];
int recv_size;
printf("\nInitialising Winsock...");
if (WSAStartup(MAKEWORD(2,2),&wsa) != 0)
{
printf("Failed. Error Code : %d",WSAGetLastError());
return 1;
}
printf("Initialised.\n");
//Create a socket
if((s = socket(AF_INET , SOCK_STREAM , 0 )) == INVALID_SOCKET)
{
printf("Could not create socket : %d" , WSAGetLastError());
}
printf("Socket created.\n");
server.sin_addr.s_addr = inet_addr("127.0.0.1");
server.sin_family = AF_INET;
server.sin_port = htons( 80 );
//Connect to remote server
if (connect(s , (struct sockaddr *)&server , sizeof(server)) < 0)
{
puts("connect error");
return 1;
}
puts("Connected");
// Work well with Get Method
// strcat(message, "GET /voleur/receiver.php?arg1=Hello HTTP/1.1\n");
strcpy(message, "POST /voleur/receiver.php HTTP/1.1\r\n");
strcat(message, "Host: 127.0.0.1:80\r\n");
strcat(message, "Content-Type: application/x-www-form-urlencoded\r\n");
strcat(message, "Content-Length: 16\r\n");
strcat(message, "Accept-Charset: utf-8\r\n\r\n");
strcat(message, "arg1=Hello World");
if( send(s , message , strlen(message) , 0) < 0)
{
puts("Send failed");
return 1;
}
puts("Data Send\n");
//Receive a reply from the server
if((recv_size = recv(s , server_reply , 2000 , 0)) == SOCKET_ERROR)
{
puts("recv failed");
}
puts("Reply received\n");
//Add a NULL terminating character to make it a proper string before printing
server_reply[recv_size] = '\0';
puts(server_reply);
return 0;
}
It is a sample code where i have tried to pass a request to server and get me the desired data.
But my connect to remote server code is not working as i thought.
if (connect(s , (struct sockaddr *)&server , sizeof(server)) < 0)
{
puts("connect error");
return 1;
}
puts("Connected");
I don't know why value of the condition is getting below zero.Why connection is not getting done?
Full code:
/*
Create a TCP socket
*/
#include<stdio.h>
#include<winsock2.h>
#pragma comment(lib,"ws2_32.lib") //Winsock Library
int main(int argc , char *argv[])
{
WSADATA wsa;
SOCKET s;
struct sockaddr_in server;
char *message , server_reply[2000];
int recv_size;
printf("\nInitialising Winsock...");
if (WSAStartup(MAKEWORD(2,2),&wsa) != 0)
{
printf("Failed. Error Code : %d",WSAGetLastError());
return 1;
}
printf("Initialised.\n");
//Create a socket
if((s = socket(AF_INET , SOCK_STREAM , 0 )) == INVALID_SOCKET)
{
printf("Could not create socket : %d" , WSAGetLastError());
}
printf("Socket created.\n");
server.sin_addr.s_addr = inet_addr("74.125.235.20");
server.sin_family = AF_INET;
server.sin_port = htons( 80 );
//Connect to remote server
if (connect(s , (struct sockaddr *)&server , sizeof(server)) < 0)
{
puts("connect error");
return 1;
}
puts("Connected");
//Send some data
message = "GET / HTTP/1.1\r\n\r\n";
if( send(s , message , strlen(message) , 0) < 0)
{
puts("Send failed");
return 1;
}
puts("Data Send\n");
//Receive a reply from the server
if((recv_size = recv(s , server_reply , 2000 , 0)) == SOCKET_ERROR)
{
puts("recv failed");
}
puts("Reply received\n");
//Add a NULL terminating character to make it a proper string before printing
server_reply[recv_size] = '\0';
puts(server_reply);
closesocket(s);
WSACleanup();
return 0;
}
You need to initalize the whole sockaddr_in to zero before assigning to it.
memset( &server, 0, sizeof(server) );
server.sin_addr.s_addr = inet_addr("74.125.235.20");
server.sin_family = AF_INET;
server.sin_port = htons( 80 );
I copied your code and tried it out and it seemed to work, maybe you have a firewall that is interfering.
BTW I changed your inet_addr call to
InetPtonA( AF_INET, "74.125.235.20", &server.sin_addr.s_addr );
I am just wondering why this crashes when a client connects?? Its supposed to be a simple TCP server that when the client connects and sends a string, the server responds with the number of A's in the string. The server crashes as soon as the client types a letter in.
#include<io.h>
#include<stdio.h>
#include<winsock2.h>
#pragma comment(lib,"ws2_32.lib") //Winsock Library
int main(int argc , char *argv[])
{
WSADATA wsa;
SOCKET s , new_socket, master;
struct sockaddr_in server , address;
int c, valread;
char *message = "Welcome to Marshall's TCP Server!!";
int MAXRECV = 1024;
char *buffer;
char AmmtA = 'a';
char AmmtB = 'A';
int count = 0, x;
fd_set readfds;
buffer = (char*) malloc((MAXRECV + 1) * sizeof(char));
printf("\nInitialising Winsock...");
if (WSAStartup(MAKEWORD(2,2),&wsa) != 0)
{
printf("Failed. Error Code : %d",WSAGetLastError());
return 1;
}
printf("Initialised.\n");
//Create a socket
if((s = socket(AF_INET , SOCK_STREAM , 0 )) == INVALID_SOCKET)
{
printf("Could not create socket : %d" , WSAGetLastError());
}
printf("Socket created.\n");
//Prepare the sockaddr_in structure
server.sin_family = AF_INET;
server.sin_addr.s_addr = INADDR_ANY;
server.sin_port = htons( 9000 );
//Bind
if( bind(s ,(struct sockaddr *)&server , sizeof(server)) == SOCKET_ERROR)
{
printf("Bind failed with error code : %d" , WSAGetLastError());
exit(EXIT_FAILURE);
}
puts("Bind done");
//Listen to incoming connections
listen(s , 3);
//Accept and incoming connection
puts("Waiting for incoming connections...");
c = sizeof(struct sockaddr_in);
while( (new_socket = accept(s , (struct sockaddr *)&address, &c)) != INVALID_SOCKET )
{
puts("Connection accepted");
send(new_socket , message , strlen(message) , 0);
valread = recv( new_socket , buffer, MAXRECV, 0);
if( valread == SOCKET_ERROR)
{
int error_code = WSAGetLastError();
if(error_code == WSAECONNRESET)
{
//Somebody disconnected , get his details and print
printf("Host disconnected unexpectedly , ip %s , port %d \n" , inet_ntoa(address.sin_addr) , ntohs(address.sin_port));
//Close the socket and mark as 0 in list for reuse
closesocket( s );
}
else
{
printf("recv failed with error code : %d" , error_code);
}
}
if ( valread == 0)
{
//Somebody disconnected , get his details and print
printf("Host disconnected , ip %s , port %d \n" , inet_ntoa(address.sin_addr) , ntohs(address.sin_port));
//Close the socket and mark as 0 in list for reuse
closesocket( s );
}
else
{
for (x = 0; buffer[x] != '\0'; x++) {
if (buffer[x] == AmmtA || buffer[x] == AmmtB)
count++;
}
char feedback[150];
sprintf(feedback, "There is %d A's in your string", count);
feedback[MAXRECV] = '\0';
printf("%s:%d - %s \n" , inet_ntoa(address.sin_addr) , ntohs(address.sin_port), buffer);
send( s , feedback , MAXRECV , 0 );
}
free(buffer);
}
if (new_socket == INVALID_SOCKET)
{
printf("accept failed with error code : %d" , WSAGetLastError());
return 1;
}
closesocket(s);
WSACleanup();
return 0;
}
10057 - WSAENOTCONN - Socket is not connected.
The send call is correct and it uses new_socket. But the recv call uses socket/sd "s". The recv call should also use new_socket.
The error 10057 is returned because s is only bound to the local end point and not connected with the remote end whereas the new socket returned by the accept connected to the remote end.
for (x = 0; buffer[x] != '\0'; x++) {
if (buffer[x] == AmmtA || buffer[x] == AmmtB)
count++;
}
Why are you comparing buffer[x] to 0. There's no special reason any particular entry in the buffer should be zero, and this can easily read off the end of the buffer. Perhaps you think buffer contains a string. But it doesn't. It contains whatever you read from the socket, and it has no special format or terminator.
Fortunately, you do know the number of bytes you read. You stored that in valread, so you want:
for (x = 0; x < valread; x++) {
I have two programs for server and client. My server can connect to multiple client. But the problem right now I am facing is that, I want to display some message from the server side to client side but I am unable to do that. Both the server and client program are provided below. I think the syntax that is preventing me to print the message on the client side is scanfwhich is used the code of client (second line of the while loop). I am not getting any solution for that about how to display the two messages from the server side when the client will get connected.
Problem 1:
Server side messages that I want to display on the client side when client gets connected : (can be found in the new_connection_handler function)
message = "This is connection handler\n";
message = "Type something \n";
Problem 2:
Why I need to use the sleep (2) on the client side? If I do not use the sleep (2), then I cannot receive the data sent by the client on the client side. The data shows when I send something second time from the client side.
Problem 3:
Is it possible to write both the client and server code together and compile and run it using command line arguments?
Server Code:
#include<stdio.h>
#include<string.h> //strlen
#include<stdlib.h> //strlen
#include<sys/socket.h>
#include<arpa/inet.h> //inet_addr
#include<unistd.h> //write
#include<pthread.h> //for thread
#define MAX_CLIENTS 5
//the thread function
void *new_connection_handler(void *);
int main(int argc , char *argv[])
{
int socket_desc , client_sock , c , *new_sock;
struct sockaddr_in server , client;
//Create socket
socket_desc = socket(AF_INET , SOCK_STREAM , 0);
if (socket_desc == -1)
{
printf("Could not create socket");
}
//Prepare the sockaddr_in structure
server.sin_family = AF_INET;
server.sin_addr.s_addr = INADDR_ANY;
server.sin_port = htons( 8888 );
bzero (&server.sin_zero, 8);
//Bind
if( bind(socket_desc,(struct sockaddr *)&server , sizeof(server)) < 0)
{
//print the error message
perror("bind failed. Error");
return 1;
}
//Listen
listen(socket_desc , MAX_CLIENTS);
//Accept and incoming connection
printf("Waiting for incoming connections\n");
c = sizeof(struct sockaddr_in);
while( (client_sock = accept(socket_desc, (struct sockaddr *)&client, (socklen_t*)&c)) )
{
printf("Connection accepted");
pthread_t thread_id;
if( pthread_create( &thread_id , NULL , new_connection_handler , (void*) &client_sock) < 0)
{
perror("could not create thread");
return 1;
}
printf("Handler assigned\n");
}
if (client_sock < 0)
{
perror("accept failed");
return 1;
}
return 0;
}
void *new_connection_handler(void *socket_desc)
{
//Get the socket descriptor
int sock = *(int*)socket_desc;
int read_size;
char *message , client_message[2000];
//Send some messages to the client
message = "This is connection handler\n";
write(sock , message , strlen(message));
message = "Type something \n";
write(sock , message , strlen(message));
//Receive a message from client
while( (read_size = recv(sock , client_message , 2000 , 0)) > 0 )
{
//Send the message back to client
write(sock , client_message , strlen(client_message));
}
if(read_size == 0)
{
printf("Client disconnected\n");
fflush(stdout);
}
else if(read_size == -1)
{
perror("recv failed");
}
//Free the socket pointer
free(socket_desc);
return 0;
}
Client Code:
#include<stdio.h> //printf
#include<string.h> //strlen
#include<sys/socket.h> //socket
#include<arpa/inet.h> //inet_addr
int main(int argc , char *argv[])
{
int sock;
struct sockaddr_in server;
char message[1000] , server_reply[2000];
int len;
//Create socket
sock = socket(AF_INET , SOCK_STREAM , 0);
if (sock == -1)
{
printf("Could not create socket");
}
puts("Socket created");
server.sin_addr.s_addr = inet_addr("127.0.0.1");
server.sin_family = AF_INET;
server.sin_port = htons( 8888 );
//Connect to remote server
if (connect(sock , (struct sockaddr *)&server , sizeof(server)) < 0)
{
perror("connect failed. Error");
return 1;
}
puts("Connected\n");
//keep communicating with server
while(1)
{
printf("Enter message : ");
scanf("%s" , message);
//Send some data
if( send(sock , message , strlen(message) , 0) < 0)
{
puts("Send failed");
return 1;
}
sleep (2);
//Receive a reply from the server
if((len = recv(sock , server_reply , 2000 , 0)) < 0)
{
puts("recv failed");
break;
}
puts("Server reply :");
server_reply [len]='\0';
printf("%s\n", server_reply);
}
close(sock);
return 0;
}
Your frames are out of sync You open your client handling thread with two sends from the server. Without your "sleep", you pick up one, but not the other. your buffer sizes are also not being used correctly, as they're inconsistently being treated as terminated strings when in fact their send length is based on strlen (which is ok, so long as it is consistent).
I think this is what you're trying to do, with a few modifications:
Client Code
#include <stdio.h>
#include <string.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <stdint.h>
int main(int argc , char *argv[])
{
int sock;
struct sockaddr_in server;
char message[1000] , server_reply[2000];
int len;
//Create socket
sock = socket(AF_INET , SOCK_STREAM , 0);
if (sock == -1)
{
printf("Could not create socket");
}
puts("Socket created");
server.sin_addr.s_addr = inet_addr("127.0.0.1");
server.sin_family = AF_INET;
server.sin_port = htons( 8888 );
//Connect to remote server
if (connect(sock , (struct sockaddr *)&server , sizeof(server)) < 0)
{
perror("connect failed. Error");
return 1;
}
puts("Connected\n");
//keep communicating with server
while((len = recv(sock, server_reply, sizeof(server_reply), 0)) > 0)
{
printf("Server reply: %.*s", len, server_reply);
printf("Enter message : ");
if (fgets(message, sizeof(message), stdin) == NULL)
break;
//Send some data
if( send(sock , message , strlen(message) , 0) < 0)
{
puts("Send failed");
return 1;
}
}
close(sock);
return 0;
}
Server Code
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<sys/socket.h>
#include<arpa/inet.h>
#include<unistd.h>
#include<pthread.h>
#include<stdint.h>
#define MAX_CLIENTS 5
//the thread function
void *new_connection_handler(void *);
int main(int argc , char *argv[])
{
int socket_desc , client_sock;
struct sockaddr_in server , client;
socklen_t c = sizeof(client);
//Create socket
socket_desc = socket(AF_INET , SOCK_STREAM , 0);
if (socket_desc == -1)
{
printf("Could not create socket");
}
//Prepare the sockaddr_in structure
server.sin_family = AF_INET;
server.sin_addr.s_addr = INADDR_ANY;
server.sin_port = htons( 8888 );
bzero (&server.sin_zero, 8);
//Bind
if( bind(socket_desc,(struct sockaddr *)&server , sizeof(server)) < 0)
{
//print the error message
perror("bind failed. Error");
return 1;
}
//Listen
listen(socket_desc , MAX_CLIENTS);
//Accept and incoming connection
printf("Waiting for incoming connections\n");
c = sizeof(client);
while( (client_sock = accept(socket_desc, (struct sockaddr *)&client, &c)) )
{
printf("Connection accepted");
pthread_t thread_id;
if( pthread_create( &thread_id , NULL , new_connection_handler , (void*) (intptr_t)client_sock) < 0)
{
perror("could not create thread");
return 1;
}
printf("Handler assigned\n");
}
if (client_sock < 0)
{
perror("accept failed");
return 1;
}
return 0;
}
void *new_connection_handler(void *socket_desc)
{
//Get the socket descriptor
int sock = (intptr_t)socket_desc;
int read_size = 0;
char client_message[2000];
static const char rdy[] = "READY\n";
write(sock, rdy, sizeof(rdy)-1);
//Receive a message from client
while( (read_size = recv(sock , client_message , sizeof(client_message) , 0)) > 0 )
write(sock , client_message , read_size);
if(read_size == 0)
{
printf("Client disconnected\n");
fflush(stdout);
}
else if(read_size == -1)
{
perror("recv failed");
}
return 0;
}
This still needs better join-logic on the client threads, but if you paste and compile each with appropriate flags I think it does what you're trying to achieve.
Best of luck.
Below is my socket client program. I am trying to send some data from client and trying to receive it in the client side. When I run the program, there is no compilation error. But I am unable to receive the sent message correctly in the client side. I think I am doing some error in
server_reply [len]='\0';
printf("%s\n", server_reply);
My original code is written below: (you can find my server program here in this link Multiple client not getting connected and cannot communicate at the same time)
#include<stdio.h> //printf
#include<string.h> //strlen
#include<sys/socket.h> //socket
#include<arpa/inet.h> //inet_addr
int main(int argc , char *argv[])
{
int sock;
struct sockaddr_in server;
char message[1000] , server_reply[2000];
int len;
//Create socket
sock = socket(AF_INET , SOCK_STREAM , 0);
if (sock == -1)
{
printf("Could not create socket");
}
puts("Socket created");
server.sin_addr.s_addr = inet_addr("127.0.0.1");
server.sin_family = AF_INET;
server.sin_port = htons( 8888 );
//Connect to remote server
if (connect(sock , (struct sockaddr *)&server , sizeof(server)) < 0)
{
perror("connect failed. Error");
return 1;
}
puts("Connected\n");
//keep communicating with server
while(1)
{
printf("Enter message : ");
scanf("%s" , message);
//Send some data
if( send(sock , message , strlen(message) , 0) < 0)
{
puts("Send failed");
return 1;
}
//Receive a reply from the server
if(len = (recv(sock , server_reply , 2000 , 0)) < 0)
{
puts("recv failed");
break;
}
puts("Server reply :");
server_reply [len]='\0';
printf("%s\n", server_reply);
}
close(sock);
return 0;
}
This line is wrong.
if (len = (recv(sock , server_reply , 2000 , 0)) < 0)
{
puts("recv failed");
break;
}
Should be:
if ((len = recv(sock , server_reply , 2000 , 0)) < 0)
{
puts("recv failed");
break;
}