send and receive JSON over sockets in server and client application in C

Question

I want to send the data in JSON over sockets in a server-client application written in C.

I am using json-c / libjson library for handling JSON data

Answer 1

1) jobj is a pointer, so when you use

write(fd, jobj, sizeof(jobj))

you're writing a pointer to that object, not that object.

3) Same as before.

Maybe you should try sending it with something like

if (write(fd, jobj, sizeof(*jobj)) == -1)
    /* error handler /*

On the receive side, you should do a for loop, like

for (;;)
{
    r = read(fd, jobj, SIZE);

    if (r == -1)
        /*error handler*/
    if (r == 0)
        break;
}

if you know the maximum SIZE of the json, or combine malloc() and realloc() otherwise

EDIT:

I did this, and now it works fine.

client.c

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

int main()
{
    /* all previous code until
    printf("Size of string- %lu\n", sizeof(json_object_to_json_string(jobj)))*/

    char temp_buff[MAX_SIZE];

    if (strcpy(temp_buff, json_object_to_json_string(jobj)) == NULL)
    {
        perror("strcpy");
        return EXIT_FAILURE;
    }

    if (write(fd, temp_buff, strlen(temp_buff)) == -1)
    {
        perror("write");
        return EXIT_FAILURE;
    }

    printf("Written data\n");
    return EXIT_SUCCESS;
}

server.c

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

int main()
{
    /* all previous code until
    printf("Reading from client\n"); */

    ssize_t r;

    char buff[MAX_SIZE];

    for (;;)
    {
        r = read(connfd, buff, MAX_SIZE);

        if (r == -1)
        {
            perror("read");
            return EXIT_FAILURE;
        }
        if (r == 0)
            break;

        printf("READ: %s\n", buff);
    }

    return EXIT_SUCCESS;
}

MAX_SIZE is a macro that specifies the maximum buffer length, set it as you wish. Please next time paste ALL your code (including the #include ...) and indent it properly.