1 files changed, 54 insertions, 0 deletions
diff --git a/helper/protocol.nim b/helper/protocol.nim
new file mode 100755
index 0000000..c7e097a
--- /dev/null
+++ b/helper/protocol.nim
@@ -0,0 +1,54 @@
+import json
+
+type
+  Message* = object
+    cmd*: string
+    args*: string
+
+  MessageParsingError* = object of Exception
+
+proc parseMessage*(data: string): Message {.raises: [MessageParsingError, KeyError].} =
+  var dataJson: JsonNode
+  try:
+    dataJson = parseJson(data)
+  except JsonParsingError:
+    raise newException(MessageParsingError, "Invalid JSON: " &
+                       getCurrentExceptionMsg())
+  except:
+    raise newException(MessageParsingError, "Unknown error: " &
+                       getCurrentExceptionMsg())
+
+  if not dataJson.hasKey("cmd"):
+    raise newException(MessageParsingError, "Cmd field missing")
+  result.cmd = dataJson["cmd"].getStr()
+  if result.cmd.len == 0:
+    raise newException(MessageParsingError, "Cmd field is empty")
+
+  if not dataJson.hasKey("args"):
+    raise newException(MessageParsingError, "Args field missing")
+  result.args = dataJson["args"].getStr()
+  if result.args.len == 0:
+    raise newException(MessageParsingError, "Args field is empty")
+
+proc createMessage*(cmd, args: string): string =
+  result = $(%{
+    "cmd": %cmd,
+    "args": %args
+  }) & "\c\l"
+
+when isMainModule:
+  block:
+    let data = """{"cmd": "status", "args": "verbose"}"""
+    let parsed = parseMessage(data)
+    doAssert parsed.cmd == "status"
+    doAssert parsed.args == "verbose"
+
+  # Test failure
+  block:
+    try:
+      let parsed = parseMessage("asdasd")
+    except MessageParsingError:
+      doAssert true
+    except:
+      doAssert false
+