server-client-network/Client.c

#include <sys/socket.h>
#include <stdio.h>
#include <sys/socket.h>
#include <netinet/in.h>
#define __USE_MISC
#include <arpa/inet.h>
#include <string.h>
#include <unistd.h>
#include "Stream.h"
#include "Client.h"

void clientInitDefaults(Client* c)
{
    c->port = -1;
    c->socket = -1;
}

int clientInit(Client* c, char* ip, short port)
{
    c->port = port;
    
    c->socket = socket(AF_INET, SOCK_STREAM, 0);
    if(c->socket == -1)
    {
        perror("Cannot create socket");
        clientRemove(c);
        return -1;
    }

    struct sockaddr_in socketData;
    memset(&socketData, 0, sizeof(struct sockaddr_in));
    socketData.sin_family = AF_INET;
    socketData.sin_port = htons(port);
    if(inet_aton(ip, &socketData.sin_addr) == 0)
    {
        printf("'%s' is not a valid ip\n", ip);
        clientRemove(c);
        return -1;
    }

    if(connect(c->socket, (struct sockaddr*) &socketData, sizeof(struct sockaddr_in)) == 0)
    {
        printf("Connection with server (%s) established\n", inet_ntoa(socketData.sin_addr));
        Stream in;
        streamInit(&in);
        if(clientReceive(c, &in) == -1)
        {
            printf("Server did not respond");
            clientRemove(c);
            return -1;
        }
        else
        {
            char answer;
            if(streamGetChar(&in, &answer) == -1)
            {
                printf("Server sent an invalid response");
                clientRemove(c);
                return -1;
            }
            else if(answer > 0)
            {
                printf("Successfully received server response\n");
                char welcome[100];
                streamGetChars(&in, welcome, 100);
                printf("%s\n", welcome);
            }
            else
            {
                char error[100];
                streamGetChars(&in, error, 100);
                printf("%s\n", error);
                clientRemove(c);
                return -1;
            }
        }
    }
    else
    {
        perror("No server is available");
        clientRemove(c);
        return -1;
    }

    return 0;
}

int clientReceive(Client* c, Stream* in)
{
    int size = recv(c->socket, in->data, in->size, 0);
    if(size > 0)
    {
        in->size = size;
        return 0;
    }
    return -1;
}

void clientRemove(Client* c)
{
    c->port = -1;
    
    if(c->socket != -1)
    {
        if(close(c->socket) != 0)
        {
            perror("Cannot close client socket");
        }
        else
        {
            printf("socket closed\n");
        }
    }
}

void clearInput()
{
    int c = getchar();  
    while(c != EOF && c != '\n')
    {
        c = getchar(); 
    }
}

int readInt()
{
    int type;
    while(scanf("%d", &type) == 0)
    {
        printf("Not a number\n");
        clearInput();
    }
    clearInput();
    return type;
}

void clientWaitForData(Client* c)
{
    while(1)
    {
        printf("Choose a package: ");
        int type = readInt();
        
        if(type == -1)
        {
            break;
        }
        else if(type >= 0 && type < 4)
        {
            Stream out;
            streamInit(&out);
            streamWriteChar(&out, type);
            
            switch(type)
            {
                case 0:
                    printf("first number: ");
                    streamWriteInt(&out, readInt());
                    printf("second number: ");
                    streamWriteInt(&out, readInt());
                    break;
                case 1:
                    printf("text: ");
                    char buffer[128];
                    fgets(buffer, 128, stdin);
                    if(strlen(buffer) == 127 && buffer[126] != '\n')
                    {
                        clearInput();
                    }
                    streamWriteChars(&out, buffer);
                    break;
                case 2:
                    // empty
                    break;
            }
            
            if(clientSendData(c, &out) == -1)
            {
                break;
            }
        }
        else
        {
            printf("%d is not a valid package number\n", type);
        }
    }
}

int clientSendData(Client* c, Stream* s)
{
    if(send(c->socket, s->data, s->index, MSG_NOSIGNAL) == -1)
    {
        perror("Cannot send data");
        return -1;
    }
    return 0;
}