add comments and clean client

1 files changed, 119 insertions, 76 deletions

diff --git a/client.c b/client.c
index 4c3573c..f9617cd 100644
--- a/client.c
+++ b/client.c
@@ -9,13 +9,9 @@
 #include <sys/socket.h>
 #include <ctype.h>
 #include <pthread.h>
-
 #include <arpa/inet.h>
-
 #include "protocol.c"
 
-#define MAXDATASIZE 100 // max number of bytes we can get at once 
-
 #define MAX_READ_SIZE 1024
 #define LINE_MAX 1024
 
@@ -43,9 +39,9 @@ int main(int argc, char *argv[])
     int sockfd, numbytesrecv, numbytessent, recvbytes;  
     // char buf[MAXDATASIZE];
     struct addrinfo hints, *servinfo, *p;
-    int rv;
     char s[INET6_ADDRSTRLEN];
 
+    // check arugments
     if (argc != 4) {
         fprintf(stderr,"<server IP> <server port> <listener port>\n");
         exit(1);
@@ -58,11 +54,13 @@ int main(int argc, char *argv[])
     char* tcpPort = argv[2]; // port we use to connect to server's tcp stream
     char* udpPort = argv[3]; // port we use to connect to server's udp info and command
 
-    if ((rv = getaddrinfo(argv[1], tcpPort, &hints, &servinfo)) != 0) {
+    // resolve host
+    int rv;
+    if ((rv = getaddrinfo(argv[1], tcpPort, &hints, &servinfo)) != 0)
+    {
         fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(rv));
         return 1;
     }
-
     // loop through all the results and connect to the first we can
     for(p = servinfo; p != NULL; p = p->ai_next) {
         if ((sockfd = socket(p->ai_family, p->ai_socktype,
@@ -76,34 +74,31 @@ int main(int argc, char *argv[])
             perror("client: connect");
             continue;
         }
-
         break;
     }
-
     if (p == NULL) {
         fprintf(stderr, "client: failed to connect\n");
         return 2;
     }
-
-    inet_ntop(p->ai_family, get_in_addr((struct sockaddr *)p->ai_addr),
-            s, sizeof s);
-    // printf("client: connecting to %s\n", s);
-
+    inet_ntop(p->ai_family, get_in_addr((struct sockaddr *)p->ai_addr), s, sizeof s);
     freeaddrinfo(servinfo); // all done with this structure
 
+    // now that we're connectioned, let's do the handshake
     uint16_t num_stations = handle_handshake(sockfd, udpPort);
 
+    // handle_handshake will end the program on fail
+    // so if we're here, num_stations is correct
     fflush(stdout);
     printf("Welcome to Snowcast! The server has %u stations.\n", num_stations);
     fflush(stdout);
 
+    // start the thread to accept command lines
     pthread_t command_line_thread;
     pthread_create(&command_line_thread, NULL, command_line_routine, (void*)sockfd);
 
-    // CONSIDER: could recieve the welcome message here
-    // int recvbytes;
+    // this while loop hangs on recv and runs when there is new data 
     while (1) {
-        // recv the first byte of the message to get it's type
+        // get the type of the incoming reply
         uint8_t reply_type = -1;
         // print size of utin8
         if (recv(sockfd, &reply_type, 1, 0) == -1) {
@@ -114,35 +109,38 @@ int main(int argc, char *argv[])
             exit(1);
         }
 
-        if (reply_type == 2) { // we have a second welcome message
+        if (reply_type == WELCOME) {
             fprintf(stderr, "WECLOME reply received twice. Exiting.\n");
             close(sockfd);
             exit(1);
         }
 
-        if (reply_type == 3) { // we have an announce message
-
+        if (reply_type == ANNOUNCE) {
             if (!station_is_set) {
                 fprintf(stderr, "ANNOUNCE reply received before SETSTATION command. Exiting.\n");
                 close(sockfd);
                 exit(1);
             }
 
-            // get the string size
+            // get the string size for the songname
             u_int8_t string_size = -1;
             if (recv(sockfd, &string_size, 1, 0) == -1) {
                 perror("recv in announce");
                 exit(1);
             }
+
+            // read the songname
             char *song_name = malloc(string_size);
             if(song_name == NULL) { perror("malloc in song name"); }
-            
             int bytes_to_read = string_size;
             if (recv_all(sockfd, song_name, &bytes_to_read) == -1) {
                 perror("recv_all in announce");
                 exit(1);
             }
+            remove_timeout(sockfd); // have received all, so can remove timeout
+            if (l) printf("received ANNOUNCE reply.\n");
 
+            // print the songname
             if (!waiting) printf("\n"); // note: this is worth the lines for a clean cmd prompt
             waiting = 0;
             fflush(stdout);
@@ -151,7 +149,9 @@ int main(int argc, char *argv[])
             fflush(stdout);
             free(song_name);
             continue;
-        } else if (reply_type == 4) { // we have an invalid command message
+        } 
+
+        if (reply_type == INVALID) { // we have an invalid command message
             // get the string size
             u_int8_t string_size = -1;
             if (recv(sockfd, &string_size, 1, 0) == -1) {
@@ -170,10 +170,15 @@ int main(int argc, char *argv[])
             fflush(stdout);
             free(message);
             close(sockfd);
+
+            // close the program on all INVALID COMMANDS
             exit(1);
         }
-        else if (reply_type == 6) { // we are getting STATIONINFO
-            // get the string size
+
+        if (reply_type == STATIONINFO) { // we are getting STATIONINFO
+            if (l) printf("received STATIONINFO reply.\n");
+
+            // get the string size, which can be farily long (uint32_t)
             uint32_t buf_string_size = -1;
             int bytes_to_read = sizeof(uint32_t);
             if (recv_all(sockfd, &buf_string_size, &bytes_to_read) == -1) {
@@ -182,7 +187,8 @@ int main(int argc, char *argv[])
             }
 
             uint32_t string_size = ntohl(buf_string_size);
-            printf("string size: %d\n", string_size);
+
+            // recieve the message
             char *info = malloc(string_size);
             if(info == NULL) { perror("malloc in info"); }
             bytes_to_read = string_size;
@@ -190,9 +196,9 @@ int main(int argc, char *argv[])
                 perror("recv_all 2 in stationinfo");
                 exit(1);
             }
-            remove_timeout(sockfd);
-            if (l) printf("received STATIONINFO reply.\n");
+            remove_timeout(sockfd); // remove the timeout, now that we have the data
 
+            // print the info
             fflush(stdout);
             printf("Station Information:\n%s\n", info);
             printf("snowcast_control> ");
@@ -201,32 +207,43 @@ int main(int argc, char *argv[])
             free(info);
             continue;
         }
-        else if (reply_type == 7) { // we are getting StationShutdown
+
+        if (reply_type == STATIONSHUTDOWN) { // we are getting StationShutdown
             if (l) printf("received STATIONSHUTDOWN reply.\n");
-            if (!waiting) printf("\n"); // note: this is worth the lines for a clean cmd prompt
+
+            if (!waiting) printf("\n"); // note: this is worth the lines for a clean cmd prompt :)
             waiting = 0;
-            remove_timeout(sockfd);
+
+            // station no longer set
+            station_is_set = 0;
             fflush(stdout);
             printf("This station has shut down. Please select a different station.\n");
             printf("snowcast_control> ");
             fflush(stdout);
             continue;
         }
-        else if (reply_type == 8) { // we are getting NewStation
+
+        if (reply_type == NEWSTATION) { // we are getting NewStation
+            if (l) printf("received NEWSTATION reply.\n");
+
+            // get station number
             uint16_t station_number = -1;
             if (recv(sockfd, &station_number, 2, 0) == -1) {
                 perror("recv in new station");
                 exit(1);
             }
             station_number = ntohs(station_number);
-            if (l) printf("received NEWSTATION reply.\n");
+
+            // print
             fflush(stdout);
-            printf("\nThere is now a new station @ index %d.\n", station_number);
+            printf("\nThere is now a new station @ index %u.\n", station_number);
             printf("snowcast_control> ");
             fflush(stdout);
+
             continue;
         }
 
+        // if we're here, lost conneciton to the server -> end the program
         printf("\nsocket to server HUNGUP. Exiting.\n");
         close(sockfd);
         exit(1);
@@ -235,105 +252,131 @@ int main(int argc, char *argv[])
 }
 
 void *command_line_routine(void* args) {
+    // unpack sockfd as arg
     int sockfd = (int) args;
 
+    // buffer for input
     char input[LINE_MAX];
 
     printf("Enter a number to change to it's station. Enter q to end stream.\n");
     printf("snowcast_control> ");
     fflush(stdout);
     while (1) {
+        memset(input, 0, LINE_MAX);
 	    char *line = fgets(input, LINE_MAX, stdin);
 
+        // nothing was typed
         if (line == NULL) {
             continue;
-        } else if (strncmp("q\n", input, LINE_MAX) == 0) {
+        } 
+        
+        // q command: exit the program
+        if (strncmp("q\n", input, LINE_MAX) == 0) {
             // end code if type in q
             exiting = 1;
             printf("Exiting.\n");
             close(sockfd);
             exit(0);
-        } else if (strncmp("l\n", input, LINE_MAX) == 0) {
+        }
+        
+        // l command: STATIONINFO command (EXTRA CREDIT)
+        if (strncmp("l\n", input, LINE_MAX) == 0) {
             // send the command to list stations
             if (l) printf("sending LISTSTATIONS command. waiting for STATIONINFO reply.\n");
-            apply_timeout(sockfd);
+            apply_timeout(sockfd); // apply a timeout, will be released when we get the reply
             int list_station_reply_type = 5;
             if (send(sockfd, &list_station_reply_type, 1, 0) == -1) {
                 perror("send");
                 exit(1);
             }
-        } else if (strncmp("log\n", input, LINE_MAX) == 0) {
+            continue;
+        }
+
+        // log command: toggle logging
+        if (strncmp("log\n", input, LINE_MAX) == 0)
+        {
             l = !l;
             printf("LOGGING is now %s!\n", l ? "on" : "off");
             printf("snowcast_control> ");
             fflush(stdout);
+            continue;
         }
-        else {
-            // convert input to an int
-            int inputInt = atoi(input);
-            if (input[0] != '0'  && inputInt == 0) {
-                printf("unknown command: %si", input);
-                printf("snowcast_control> ");
-                fflush(stdout);
-                continue;
-            }
-            // printf("Changing to station %d.\n", inputInt);
-
-            // set waiting so no new line on announce
-            waiting = 1;
-            // send the command to change the station
-            apply_timeout(sockfd);
-            struct SetStation setStation;
-            setStation.commandType = 1;
-            setStation.stationNumber = htons(inputInt);
-            int bytes_to_send = sizeof(struct SetStation);
-            // apply_timeout(sockfd);
-            if (send_all(sockfd, &setStation, &bytes_to_send) == -1) {
-                perror("send_all");
-                exit(1);
-            }
-            if (!station_is_set) {
-                station_is_set = 1;
-            }
+
+        // check if this could be a station number
+        int inputInt = atoi(input);
+        if (input[0] != '0' && inputInt == 0) {
+            // if we're in here, it's ~likely~ not a number (ik it's not perfect, sorry :/)
+            printf("unknown command: %si", input);
+            printf("snowcast_control> ");
+            fflush(stdout);
+            continue;
         }
+
+        // if we're here, it was a valid number, 
+        // & we need to send SETSTATION command.
+        if (l) printf("sending SETSTATION command.\n");
+        waiting = 1; // just for clean cmd
+
+        // setup struct
+        struct SetStation setStation;
+        setStation.commandType = SETSTATION;
+        setStation.stationNumber = htons(inputInt);
+        // send it
+        apply_timeout(sockfd); // apply timeout, will be released when we get ANNOUNCE reply
+        int bytes_to_send = sizeof(struct SetStation);
+        if (send_all(sockfd, &setStation, &bytes_to_send) == -1) {
+            perror("send_all");
+            exit(1);
+        }
+
+        if (!station_is_set) station_is_set = 1; // update, if needed
+        if (l) printf("waiting for ANNOUNCE reply...\n");
     }
     return (NULL);
 }
 
 uint16_t handle_handshake(int sockfd, char* udp_port) {
-    apply_timeout(sockfd); // apply timeout for handshake
+    if (l) printf("found server, sending HELLO command.\n");
 
-    if (l) printf("found server, sending HELLO command. waiting for ANNOUNCE reply.\n");
+    apply_timeout(sockfd); // apply timeout for handshake
 
+    // after we find connection, we need to send HELLO command
     struct Hello hello;
-    hello.commandType = 0;
+    hello.commandType = HELLO;
     // convert updPort to an int
     int udp_port_int = atoi(udp_port);
     hello.udpPort = htons(udp_port_int);
-    if (send(sockfd, &hello, sizeof(struct Hello), 0) == -1) {
+    int hello_len = sizeof(struct Hello);
+    if (send_all(sockfd, &hello, &hello_len) == -1) {
         perror("send");
         exit(1);
     }
 
-     // recv the first byte of the message to get it's type
+    if (l) printf("waiting for WELCOME reply...\n");
+
+    // read WELCOME reply type
     uint8_t reply_type = -1;
     // print size of utin8
-    if (recv(sockfd, &reply_type, 1, 0) == -1) {
+    if (recv(sockfd, &reply_type, 1, 0) == -1) { // only one byte, so can use recv
         perror("recv in handshake");
         exit(1);
     }
 
-    // recv the message, check for errors too
+    if (reply_type != WELCOME) {
+        fprintf(stderr, "first reply is not WELCOME. Exiting.\n");
+        close(sockfd);
+        exit(1);
+    }
+
+    // get the number of stations
     int16_t num_stations = -1;
     int bytes_to_read = sizeof(uint16_t);
     if (recv_all(sockfd, &num_stations, &bytes_to_read) == -1) {
         perror("recv_all in handshake");
         exit(1);
     }
-
     if (l) printf("received ANNOUNCE reply.\n");
 
-    // remove timeout since we no longer are "waiting" for an immediate reply
-    remove_timeout(sockfd);
-    return ntohs(num_stations);
+    remove_timeout(sockfd); // remove timeout since we no longer are "waiting" for an immediate reply
+    return ntohs(num_stations); // return the num_stations to be printed
 }
\ No newline at end of file