refactored handler funcs to have return values instead of writing to conn and to not take conn as a parameterpubsub

2 files changed, 84 insertions, 113 deletions

diff --git a/handlers.go b/handlers.go
index b5987e8..f3ddf25 100644
--- a/handlers.go
+++ b/handlers.go
@@ -9,11 +9,10 @@ import (
 	"time"
 )
 
-func handleGet(conn net.Conn, args []string) {
+func handleGet(args []string)interface{} {
 	if len(args) != 2 {
         err := errors.New("wrong number of arguments for 'GET'")
-        conn.Write(serializeRESP(err))
-		return
+		return err
     }
     
 	key := args[1]
@@ -37,15 +36,13 @@ func handleGet(conn net.Conn, args []string) {
 		return strValue
 	})
 
-
-	conn.Write(serializeRESP(result))
+	return result
 }
 
-func handleExists(conn net.Conn, args []string) {
+func handleExists(args []string)interface{} {
 	if len(args) != 2 {
         err := errors.New("wrong number of arguments for 'EXISTS'")
-        conn.Write(serializeRESP(err))
-		return
+		return err
     }
 
 	key := args[1]
@@ -58,14 +55,13 @@ func handleExists(conn net.Conn, args []string) {
 		}
 	})
 
-	conn.Write(serializeRESP(result))
+	return result
 }
 
-func handleSet(conn net.Conn, args []string) {
+func handleSet(args []string)interface{} {
 	if len(args) != 3 {
         err := errors.New("wrong number of arguments for 'SET'")
-        conn.Write(serializeRESP(err))
-		return
+		return err
     }
 
 	key := args[1]
@@ -75,15 +71,14 @@ func handleSet(conn net.Conn, args []string) {
 		return SimpleString("OK")
 	})
 
-	conn.Write(serializeRESP(result))
+	return result
 }
 
-func handleDel(conn net.Conn, args []string) {
+func handleDel(args []string)interface{} {
 
 	if len(args) < 2 {
         err := errors.New("wrong number of arguments for 'DEL'")
-        conn.Write(serializeRESP(err))
-		return
+		return err
     }
 	keys := args[1:]
 	deletedKeys := db.ExecuteMulti(keys, func(shards []*Shard) interface{}{
@@ -98,16 +93,16 @@ func handleDel(conn net.Conn, args []string) {
 		}
 		return count
 	})
-	conn.Write(serializeRESP(deletedKeys))
+
+	return deletedKeys
 }
 
 
-func handleIncr(conn net.Conn, args []string) {
+func handleIncr(args []string)interface{} {
 
 	if len(args) != 2 {
         err := errors.New("wrong number of arguments for 'INCR'")
-        conn.Write(serializeRESP(err))
-		return
+		return err
     }
 
 	key := args[1]
@@ -136,15 +131,14 @@ func handleIncr(conn net.Conn, args []string) {
 
 	})
 
-	conn.Write(serializeRESP(result))
+	return result
 }
 
-func handleDecr(conn net.Conn, args []string) {
+func handleDecr(args []string)interface{} {
 
 	if len(args) != 2 {
         err := errors.New("wrong number of arguments for 'DECR'")
-        conn.Write(serializeRESP(err))
-		return
+		return err
     }
 
 	key := args[1]
@@ -172,24 +166,17 @@ func handleDecr(conn net.Conn, args []string) {
 		}
 
 	})
-
-	conn.Write(serializeRESP(result))
+	return result
 }
 
 func handlePing(conn net.Conn, args []string) {
-	if len(args) != 1 {
-        err := errors.New("wrong number of arguments for 'PING'")
-        conn.Write(serializeRESP(err))
-		return
-    }
-	conn.Write(serializeRESP(SimpleString("PONG")))
+	conn.Write(serializeRESP(SimpleString("OK")))
 }
 
-func handleFlushall(conn net.Conn, args []string) {
+func handleFlushall(args []string)interface{} {
 	if len(args) != 1 {
         err := errors.New("wrong number of arguments for 'FLUSHALL'")
-        conn.Write(serializeRESP(err))
-		return
+		return err
     }
 	result := db.ExecuteAll(func(shards []*Shard)interface{}{
 		for _, shard := range shards{
@@ -197,14 +184,13 @@ func handleFlushall(conn net.Conn, args []string) {
 		}
 		return SimpleString("OK")
 	})
-	conn.Write(serializeRESP(result))
+	return result
 }
 
-func handleRename(conn net.Conn, args []string){
+func handleRename(args []string)interface{}{
 	if len(args) != 3 {
         err := errors.New("wrong number of arguments for 'RENAME'")
-        conn.Write(serializeRESP(err))
-		return
+		return err
     }
 	keys := args[1:]
 
@@ -220,14 +206,13 @@ func handleRename(conn net.Conn, args []string){
 
 		return SimpleString("OK")
 	})
-	conn.Write(serializeRESP(result))
+	return result
 }
 
-func handleRpush(conn net.Conn, args []string) {
+func handleRpush(args []string)interface{} {
 	if len(args) < 3 {
 		err := errors.New("wrong number of arguments for 'RPUSH'")
-		conn.Write(serializeRESP(err))
-		return
+		return err
 	}
 	key := args[1]
 	newItems := args[2:]
@@ -248,14 +233,13 @@ func handleRpush(conn net.Conn, args []string) {
 		s.data[key] = Item{Value: list}
 		return len(list)
 	})
-	conn.Write(serializeRESP(result))
+	return result
 }
 
-func handleLpush(conn net.Conn, args []string) {
+func handleLpush(args []string)interface{} {
 	if len(args) < 3 {
 		err := errors.New("wrong number of arguments for 'LPUSH'")
-		conn.Write(serializeRESP(err))
-		return
+		return err
 	}
 	key := args[1]
 	newItems := args[2:]
@@ -276,21 +260,20 @@ func handleLpush(conn net.Conn, args []string) {
 		s.data[key] = Item{Value: list}
 		return len(list)
 	})
-	conn.Write(serializeRESP(result))
+
+	return result	
 }
 
-func handleLrange(conn net.Conn, args []string) {
+func handleLrange(args []string)interface{} {
 	if len(args) != 4 {
 		err := errors.New("wrong number of arguments for 'LRANGE'")
-		conn.Write(serializeRESP(err))
-		return
+		return err
 	}
 	start, err1 := strconv.Atoi(args[2])
 	stop, err2 := strconv.Atoi(args[3])
 	if err1 != nil || err2 != nil {
 		err := errors.New("value is not an integer or out of range")
-		conn.Write(serializeRESP(err))
-		return
+		return err
 	}
 	key := args[1]
 
@@ -328,14 +311,13 @@ func handleLrange(conn net.Conn, args []string) {
 		}
 		return typedList[start : stop+1]
 	})
-	conn.Write(serializeRESP(result))
+	return result
 }
 
-func handleLpop(conn net.Conn, args []string) {
+func handleLpop(args []string)interface{} {
 	if len(args) != 2 {
 		err := errors.New("wrong number of arguments for 'LPOP'")
-		conn.Write(serializeRESP(err))
-		return
+		return err
 	}
 	key := args[1]
 
@@ -360,14 +342,13 @@ func handleLpop(conn net.Conn, args []string) {
 		}
 		return newItem
 	})
-	conn.Write(serializeRESP(result))
+	return result
 }
 
-func handleRpop(conn net.Conn, args []string) {
+func handleRpop(args []string)interface{} {
 	if len(args) != 2 {
 		err := errors.New("wrong number of arguments for 'RPOP'")
-		conn.Write(serializeRESP(err))
-		return
+		return err
 	}
 	key := args[1]
 
@@ -392,19 +373,17 @@ func handleRpop(conn net.Conn, args []string) {
 		}
 		return newItem
 	})
-	conn.Write(serializeRESP(result))
+	return result
 }
 
-func handleExpire(conn net.Conn, args []string) {
+func handleExpire(args []string)interface{} {
 	if len(args) != 3 {
-		conn.Write(serializeRESP(errors.New("wrong number of arguments for 'EXPIRE'")))
-		return
+		return errors.New("wrong number of arguments for 'EXPIRE'")
 	}
 	key := args[1]
 	seconds, err := strconv.Atoi(args[2])
 	if err != nil {
-		conn.Write(serializeRESP(errors.New("value is not an integer")))
-		return
+		return errors.New("value is not an integer")
 	}
 
 	result := db.Execute(key, func(s *Shard) interface{} {
@@ -417,14 +396,13 @@ func handleExpire(conn net.Conn, args []string) {
 		s.data[key] = item
 		return 1
 	})
-	conn.Write(serializeRESP(result))
+	return result
 }
 
-func handleHset(conn net.Conn, args []string) {
+func handleHset(args []string)interface{}{
 	if len(args) < 4 || (len(args)-2)%2 != 0 {
 		err := errors.New("wrong number of arguments for 'HSET'")
-		conn.Write(serializeRESP(err))
-		return
+		return err
 	}
 	key := args[1]
 
@@ -448,13 +426,12 @@ func handleHset(conn net.Conn, args []string) {
 		s.data[key] = Item{Value: hash}
 		return count
 	})
-	conn.Write(serializeRESP(result))
+	return result
 }
 
-func handleHget(conn net.Conn, args []string) {
+func handleHget(args []string)interface{} {
 	if len(args) != 3 {
-		conn.Write(serializeRESP(errors.New("wrong number of arguments for 'HGET'")))
-		return
+		return errors.New("wrong number of arguments for 'HGET'")
 	}
 	key := args[1]
 	field := args[2]
@@ -474,13 +451,12 @@ func handleHget(conn net.Conn, args []string) {
 		}
 		return val
 	})
-	conn.Write(serializeRESP(result))
+	return result
 }
 
-func handleHgetall(conn net.Conn, args []string) {
+func handleHgetall(args []string)interface{} {
 	if len(args) != 2 {
-		conn.Write(serializeRESP(errors.New("wrong number of arguments for 'HGETALL'")))
-		return
+		return errors.New("wrong number of arguments for 'HGETALL'")
 	}
 	key := args[1]
 
@@ -495,13 +471,12 @@ func handleHgetall(conn net.Conn, args []string) {
 		}
 		return hash
 	})
-	conn.Write(serializeRESP(result))
+	return result
 }
 
-func handleHkeys(conn net.Conn, args []string) {
+func handleHkeys(args []string)interface{} {
 	if len(args) != 2 {
-		conn.Write(serializeRESP(errors.New("wrong number of arguments for 'HKEYS'")))
-		return
+		return errors.New("wrong number of arguments for 'HKEYS'")
 	}
 	key := args[1]
 
@@ -520,13 +495,12 @@ func handleHkeys(conn net.Conn, args []string) {
 		}
 		return keys
 	})
-	conn.Write(serializeRESP(result))
+	return result
 }
 
-func handleHvalues(conn net.Conn, args []string) {
+func handleHvalues(args []string)interface{} {
 	if len(args) != 2 {
-		conn.Write(serializeRESP(errors.New("wrong number of arguments for 'HVALUES'")))
-		return
+		return errors.New("wrong number of arguments for 'HVALUES'")
 	}
 	key := args[1]
 
@@ -545,13 +519,12 @@ func handleHvalues(conn net.Conn, args []string) {
 		}
 		return values
 	})
-	conn.Write(serializeRESP(result))
+	return result
 }
 
-func handleType(conn net.Conn, args []string) {
+func handleType(args []string)interface{} {
 	if len(args) != 2 {
-		conn.Write(serializeRESP(errors.New("wrong number of arguments for 'TYPE'")))
-		return
+		return errors.New("wrong number of arguments for 'TYPE'")
 	}
 	key := args[1]
 
@@ -571,13 +544,12 @@ func handleType(conn net.Conn, args []string) {
 			return SimpleString("unknown")
 		}
 	})
-	conn.Write(serializeRESP(result))
+	return result
 }
 
-func handleDbsize(conn net.Conn, args []string) {
+func handleDbsize(args []string)interface{} {
 	if len(args) != 1 {
-		conn.Write(serializeRESP(errors.New("wrong number of arguments for 'DBSIZE'")))
-		return
+		return errors.New("wrong number of arguments for 'DBSIZE'")
 	}
 	result := db.ExecuteReadAll(func(shards []*Shard) interface{} {
 		count := 0
@@ -586,21 +558,19 @@ func handleDbsize(conn net.Conn, args []string) {
 		}
 		return count
 	})
-	conn.Write(serializeRESP(result))
+	return result
 }
 
-func handleKeys(conn net.Conn, args []string) {
+func handleKeys(args []string)interface{} {
 	if len(args) < 2 || len(args) > 3 {
-		conn.Write(serializeRESP(errors.New("wrong number of arguments for 'KEYS'")))
-		return
+		return errors.New("wrong number of arguments for 'KEYS'")
 	}
 	pattern := args[1]
 	limit := -1
 	if len(args) == 3 {
 		val, err := strconv.Atoi(args[2])
 		if err != nil {
-			conn.Write(serializeRESP(errors.New("value is not an integer")))
-			return
+			return errors.New("value is not an integer")
 		}
 		limit = val
 	}
@@ -624,20 +594,18 @@ func handleKeys(conn net.Conn, args []string) {
 		}
 		return matches
 	})
-	conn.Write(serializeRESP(result))
+	return result
 }
 
-func handleLrem(conn net.Conn, args []string) {
+func handleLrem(args []string)interface{} {
 	if len(args) != 4 {
-		conn.Write(serializeRESP(errors.New("wrong number of arguments for 'LREM'")))
-		return
+		return errors.New("wrong number of arguments for 'LREM'")
 	}
 	key := args[1]
 	count, err := strconv.Atoi(args[2])
 	toBeRemoved := args[3]
 	if err != nil {
-		conn.Write(serializeRESP(errors.New("value is not an integer")))
-		return
+		return errors.New("value is not an integer")
 	}
 
 	result := db.Execute(key, func(s *Shard) interface{} {
@@ -699,5 +667,5 @@ func handleLrem(conn net.Conn, args []string) {
 		}
 		return counter
 	})
-	conn.Write(serializeRESP(result))
+	return result
 }
\ No newline at end of file
diff --git a/main.go b/main.go
index 80b78cb..570b512 100644
--- a/main.go
+++ b/main.go
@@ -15,16 +15,16 @@ const NumShards = 16
 var db RedisDB
 var hub Hub
 
-type handlerFunc func(net.Conn, []string)
+type baseHandlerFunc func([]string)interface{}
+type connectionHandlerFunc func(net.Conn, []string)
 
-var commandRegistry = map[string]handlerFunc{
+var baseCommandRegistry = map[string]baseHandlerFunc{
 	"GET":      handleGet,
 	"SET":      handleSet,
 	"DEL":      handleDel,
 	"EXISTS":   handleExists,
 	"INCR":     handleIncr,
 	"DECR":     handleDecr,
-	"PING":     handlePing,
 	"RENAME":   handleRename,
 	"FLUSHALL": handleFlushall,
 	"RPUSH":    handleRpush,
@@ -42,9 +42,12 @@ var commandRegistry = map[string]handlerFunc{
 	"DBSIZE":   handleDbsize,
 	"KEYS":     handleKeys,
 	"LREM":     handleLrem,
+}
+var connectionCommandRegistry = map[string]connectionHandlerFunc{
 	"SUBSCRIBE":   handleSubscribe,
 	"UNSUBSCRIBE": handleUnsubscribe,
 	"PUBLISH":     handlePublish,
+	"PING":		   handlePing,
 }
 
 func main() {
@@ -115,8 +118,8 @@ func handleConnection(conn net.Conn) {
 
 		command := strings.ToUpper(args[0])
 
-		if handler, ok := commandRegistry[command]; ok {
-            handler(conn, args)
+		if handler, ok := baseCommandRegistry[command]; ok {
+            conn.Write(serializeRESP(handler(args)))
         } else {
             conn.Write(serializeRESP(errors.New("unknown command")))
         }