Added command show limit.

closes #6

README.md

@@ -110,6 +110,12 @@ Displays all values, the keys of which are in the range between "START" and "LIM
  * `LIMIT` - The key or key prefix indicating the end of the range
  * `FORMAT` - Data Display Format (Optional)
 
+> show limit `LIMIT` [`FORMAT`]
+
+Displays all content of the database limited by "LIMIT".
+ * `LIMIT` - Limiting the number of records displayed
+ * `FORMAT` - Data Display Format (Optional)
+
 #### The list of formats available to display
  * `raw` - Raw data without processing (default)
  * `bson` - Attempts to convert the data to be displayed from `bson` to `json`

commands/showCommand.go

@@ -29,6 +29,7 @@ func ShowByPrefix(prefix, format string) string {
 	return showByIterator(
 		dbh.NewIterator(util.BytesPrefix([]byte(prefix)), nil),
 		format,
+		0,
 	)
 }
 
@@ -45,13 +46,31 @@ func ShowByRange(start, limit, format string) string {
 	return showByIterator(
 		dbh.NewIterator(&util.Range{Start: []byte(start), Limit: []byte(limit)}, nil),
 		format,
+		0,
+	)
+}
+
+// ShowLimit It shows all content of the database limited by the limit.
+// Use the field `format` for specifying the display format of data.
+// The list of possible values of format options: raw (default), geohash, bson, int64, float64
+//
+// Returns a string containing information about the result of the operation.
+func ShowLimit(limit int, format string) string {
+	if !isConnected {
+		return AppError(ErrDbDoesNotOpen)
+	}
+
+	return showByIterator(
+		dbh.NewIterator(nil, nil),
+		format,
+		limit,
 	)
 }
 
 // Show by iterator
 //
 // Returns a string containing information about the result of the operation.
-func showByIterator(iter iterator.Iterator, format string) string {
+func showByIterator(iter iterator.Iterator, format string, limit int) string {
 	if iter.Error() != nil {
 		return "Empty result!"
 	}
@@ -62,11 +81,18 @@ func showByIterator(iter iterator.Iterator, format string) string {
 
 	w.Init(writer, 0, 8, 0, '\t', 0)
 	fmt.Fprintln(w, "Key\t| Value")
+
+	count := 0
 	for iter.Next() {
 		key := iter.Key()
 		value := iter.Value()
 
 		fmt.Fprintf(w, "%s\t| %s\n", string(key), cliutil.ToString(format, value))
+
+		count++
+		if limit != 0 && count >= limit {
+			break
+		}
 	}
 
 	w.Flush()

main.go

@@ -85,7 +85,7 @@ func main() {
 		// Command: show
 		case args[0] == "show":
 			if len(args) == 1 {
-				fmt.Println("Bad format. Please use 'show prefix|range'")
+				fmt.Println("Bad format. Please use 'show prefix|range|limit'")
 				break
 			}
 
@@ -118,8 +118,28 @@ func main() {
 
 				fmt.Println(commands.ShowByPrefix(args[2], format))
 				break
+			// Sub-command: limit
+			case "limit":
+				if len(args) < 3 || len(args) > 4 {
+					fmt.Println("Bad format. Please use 'show limit LIMIT [FORMAT]'")
+					break
+				}
+
+				limit, err := strconv.Atoi(args[2])
+				if err != nil {
+					fmt.Println("Bad LIMIT value. LIMIT must be a number")
+					break
+				}
+
+				format := ""
+				if len(args) == 4 {
+					format = args[3]
+				}
+
+				fmt.Println(commands.ShowLimit(limit, format))
+				break
 			default:
-				fmt.Println("Bad format. Please use 'show prefix|range'")
+				fmt.Println("Bad format. Please use 'show prefix|range|limit'")
 			}
 
 			break