Add string length validation, add full UUID support, add test

modernnet.nimble

@@ -1,6 +1,6 @@
 # Package
 
-version     = "2.0.1"
+version     = "2.1.0"
 author      = "Yu-Vitaqua-fer-Chronos"
 description = "ModernNet implements a packet reading and writing system, as well as some useful tools for implementing this into your own project!"
 license     = "Apache-2.0"
@@ -11,4 +11,5 @@ srcDir      = "src"
 
 requires "nim >= 2.0.0"    # May work on earlier versions, only tested on latest stable versions
 requires "zippy >= 0.10.9" # Used for handling compressed MC packets
-requires "regex >= 0.23.0" # Pure Nim regex engine, used for verifying identifiers
+requires "regex >= 0.23.0" # Pure Nim regex engine, used for verifying identifiers
+requires "https://github.com/Yu-Vitaqua-fer-Chronos/uuids >= 0.1.12" # Used for handling UUIDs

src/modernnet/buffer.nim

@@ -47,7 +47,13 @@ func writeVarNum*[R: int32 | int64](b: Buffer, value: R) =
     b.writeNum(cast[uint8]((val and SegmentBits) or ContinueBit))
     val = val shr 7
 
+func writeUUID*(b: Buffer, uuid: UUID) =
+  ## Writes a UUID to a buffer
+  b.writeNum[:int64](uuid.mostSigBits())
+  b.writeNum[:int64](uuid.leastSigBits())
+
 func writeString*(b: Buffer, s: string) =
+  ## Writes a string to a buffer
   b.writeVarNum[:int32](s.len.int32)
   if (b.pos + s.len) > b.buf.len:
     b.buf.setLen(b.pos + s.len)
@@ -109,14 +115,25 @@ func readVarNum*[R: int32 | int64](b: Buffer): R {.raises: [MnEndOfBufferError,
     else:
       {.error: "Deserialisation of `" & $R & "` is not implemented!".}
 
-func readString*(b: Buffer): string {.raises: [MnEndOfBufferError, MnPacketParsingError].} =
+func readUUID*(b: Buffer): UUID =
+  ## Reads a UUID from a buffer
+  initUUID(b.readNum[:int64](), b.readNum[:int64]())
+
+func readString*(b: Buffer, maxLength = 32767): string {.raises: [MnEndOfBufferError, MnPacketParsingError].} =
   ## Reads a string from a buffer
   let length = b.readVarNum[:int32]()
+
+  if length > maxLength * 3:
+    raise newException(MnStringTooLongParsingError, "String is too long!")
+
   result.setLen(length)
 
   let data = b.buf[b.pos..<(b.pos+length)]
   result = cast[string](data)
 
+  if result.len > maxLength:
+    raise newException(MnStringTooLongParsingError, "String is too long!")
+
   b.pos += length
 
 template readIdentifier*(b: Buffer): Identifier =

src/modernnet/exceptions.nim

@@ -26,4 +26,6 @@ type
 
   MnInvalidPositionConstructionError* = object of MnPacketConstructionError
 
+  MnStringTooLongParsingError* = object of MnPacketParsingError
+
   MnConnectionClosedError* = object of MnError

src/modernnet/helpers.nim

@@ -41,7 +41,7 @@ func buildServerListJson*(versionName: string, versionProtocol,
     import modernnet
 
     let sample = @[PlayerSample(name: "VeryRealPlayer",
-      id: "7f81c9a5-4aae-4ace-abd2-1586392441de".UUID)]
+      id: "7f81c9a5-4aae-4ace-abd2-1586392441de".parseUUID())]
 
     let serverList = buildServerListJson("1.19.4", 762, 100,
       sample.len, sample, "Much wow")

src/modernnet/types.nim

@@ -15,10 +15,12 @@
 import std/[
   strformat,     # Used for pretty error printing
   strutils,      # Used for basic text manipulation (`split` for idents)
+  json,          # JSON hooks for UUIDs
   re             # Use this to validate identifiers via regex
 ]
 
 import regex
+import uuids
 
 import "."/[
   exceptions # Imported so we can raise specific errors
@@ -29,8 +31,6 @@ const
   IdentifierValueRegex = re2"[a-z0-9.-_/]"
 
 type
-  UUID* = distinct string ## A distinct string for UUIDs.
-
   Identifier* = object
     ## An MC identifier.
     namespace*, value*: string
@@ -43,8 +43,6 @@ type
     pos: int64
     format: PositionFormat
 
-func `$`*(uuid: UUID): string = uuid.string
-
 proc `$`*(i: Identifier): string =
   ## Get an identifier as a string.
   return i.namespace & ":" & i.value
@@ -116,4 +114,14 @@ proc fromPos*(pos: Position, format = XZY): int64 =
     return ((pos.x.int64 and 0x3FFFFFF) shl 38) or ((pos.y.int64 and 0xFFF) shl 26) or (pos.z.int64 and 0x3FFFFFF)
 
   else:
-    raise newException(MnInvalidPositionConstructionError, "How did you *get* here?")
+    raise newException(MnInvalidPositionConstructionError, "How did you *get* here?")
+
+func fromJsonHook*(uuid: var UUID, node: JsonNode) =
+  ## Converts a UUID from JSON.
+  uuid = node.getStr().parseUUID()
+
+func toJsonHook*(uuid: UUID): JsonNode =
+  ## Converts a UUID to JSON.
+  newJString($uuid)
+
+export UUID, parseUUID, uuids.`$`, mostSigBits, leastSigBits, initUUID

tests/test1.nim

@@ -60,7 +60,18 @@ test "VarNum tests":
   assert buffer.readVarNum[:int64]() == c, "VarLong test 1 failed!"
   assert buffer.readVarNum[:int64]() == d, "VarLong test 2 failed!"
 
-test "String parsing":
+test "UUID parsing/serialising":
+  var buffer = newBuffer()
+
+  var a = parseUUID("7f81c9a5-4aae-4ace-abd2-1586392441de")
+
+  buffer.writeUUID(a)
+
+  buffer.pos = 0
+
+  assert buffer.readUUID() == a, "UUID test failed!"
+
+test "String parsing/serialising":
   var buffer = newBuffer()
 
   var a = "Hello world!"