ina260-zmq-publisher/src/publisher.c

//  Weather update server
//  Binds PUB socket to tcp://*:5556
//  Publishes random weather updates

#include <zmq.h>
#include <assert.h>
#include <time.h>
#include <dirent.h>

#include "utils.h"

// Global:
char *__logdir;
char *__key;
char *__interface;
int __loginterval;
int __port;

void publish(void *publisher, char *filepath, char* client, long int interval);

int main (int argc, char *argv [])
{
    if(argc != 6){
        printf("Usage: %s <abslogdir> <loginterval> <port> <key> <interface>",argv[0]);
        exit(1);
    }

    //----- Init global variables
    __logdir=argv[1];
    __loginterval=atoi(argv[2]);
    __port=atoi(argv[3]);
    __key=argv[4];
    __interface=argv[5];

    //----- Prepare our context and publisher
    void *context = zmq_ctx_new ();
    void *publisher = zmq_socket (context, ZMQ_PUB);
    char bindto[30];
    sprintf(bindto,"tcp://%s:%d",__interface,__port);
    int rc = zmq_connect (publisher, bindto);
    if(rc!=0){
        printf("Failed to bind zmq on %s\n",bindto);
        exit(1);
    }

    //----- Start publisher
    struct dirent *de;  // Pointer for directory entry
    while(1){
        int interval=INTERVAL(__loginterval);
        int interval_next=INTERVAL_NEXT(__loginterval);
        DIR *dr = opendir(__logdir);
        while ((de = readdir(dr)) != NULL){
            if(strcmp(de->d_name,".") && strcmp(de->d_name,"..")){
                char *client=de->d_name;
                char logfile[255];
                char logfile_next[255];
                sprintf(logfile,"%s/%s/%ld",__logdir,client,interval);
                sprintf(logfile_next,"%s/%s/%ld",__logdir,client,interval_next);
                // As long as next logfile is not available, we should wait
                // for sending the current one
                printf("Waiting for %s...%s\n",client,logfile_next);
                while(!FILE_EXISTS(logfile_next)){
                    sleep(1);
                }
                // Send current one
                if(FILE_EXISTS(logfile)){
                    publish(publisher,logfile,client,interval);
                    //remove(logfile);
                }
            }
        }
        closedir(dr);
    }

    zmq_close (publisher);
    zmq_ctx_destroy (context);

    return 0;
}

void publish(void *publisher, char *filepath, char* client, long int interval){
    printf("Publish!\n");
    char buffer[ZMQ_MSG_SIZE];
    sprintf(buffer,"%s\n%s\n%s\n%ld\n",ZMQ_TOKEN,__key,client,interval);
    int msglen=strlen(buffer);

    FILE *fptr;
    char * line = NULL;
    size_t len = 0;
    ssize_t read;
    fptr=fopen(filepath,"r");
    while ((read = getline(&line, &len, fptr)) != -1) {
        if((read+msglen) <ZMQ_MSG_SIZE){
            strcat(buffer,line);
            msglen+=read;
        } else {
            zmq_send (publisher, buffer, ZMQ_MSG_SIZE, 0);
            sprintf(buffer,"%s\n%s\n%s\n%ld\n",ZMQ_TOKEN,__key,client,interval);
            strcat(buffer,line);
            msglen=strlen(buffer);
        }
    }
    fclose(fptr);
    zmq_send (publisher, buffer, ZMQ_MSG_SIZE, 0);
}