Agent fetches serialized task data from prologue web server and successfully parses it.

src/common/serialize.nim

@@ -3,28 +3,18 @@ import ./types
 
 type 
     Packer* = ref object 
-        headerStream: StringStream
-        payloadStream: StringStream 
+        stream: StringStream
 
 proc initTaskPacker*(): Packer = 
     result = new Packer 
-    result.headerStream = newStringStream()
-    result.payloadStream = newStringStream() 
+    result.stream = newStringStream()
 
-proc addToHeader*[T: uint8 | uint16 | uint32 | uint64](packer: Packer, value: T): Packer {.discardable.} =
-    packer.headerStream.write(value)
+proc add*[T: uint8 | uint16 | uint32 | uint64](packer: Packer, value: T): Packer {.discardable.} =
+    packer.stream.write(value)
     return packer 
 
-proc addToPayload*[T: uint8 | uint16 | uint32 | uint64](packer: Packer, value: T): Packer {.discardable.} =
-    packer.payloadStream.write(value)
-    return packer 
-
-proc addDataToHeader*(packer: Packer, data: openArray[byte]): Packer {.discardable.} = 
-    packer.headerStream.writeData(data[0].unsafeAddr, data.len)
-    return packer
-
-proc addDataToPayload*(packer: Packer, data: openArray[byte]): Packer {.discardable.} = 
-    packer.payloadStream.writeData(data[0].unsafeAddr, data.len)
+proc addData*(packer: Packer, data: openArray[byte]): Packer {.discardable.} = 
+    packer.stream.writeData(data[0].unsafeAddr, data.len)
     return packer
 
 proc addArgument*(packer: Packer, arg: TaskArg): Packer {.discardable.} = 
@@ -33,34 +23,79 @@ proc addArgument*(packer: Packer, arg: TaskArg): Packer {.discardable.} =
         # Optional argument was passed as "", ignore
         return
 
-    packer.addToPayload(arg.argType)
+    packer.add(arg.argType)
 
     case arg.argType: 
     of cast[uint8](STRING), cast[uint8](BINARY): 
         # Add length for variable-length data types
-        packer.addToPayload(cast[uint32](arg.data.len)) 
-        packer.addDataToPayload(arg.data)
+        packer.add(cast[uint32](arg.data.len)) 
+        packer.addData(arg.data)
     else: 
-        packer.addDataToPayload(arg.data)
+        packer.addData(arg.data)
     return packer
 
-proc packPayload*(packer: Packer): seq[byte] = 
-    packer.payloadStream.setPosition(0) 
-    let data = packer.payloadStream.readAll() 
+proc pack*(packer: Packer): seq[byte] = 
+    packer.stream.setPosition(0) 
+    let data = packer.stream.readAll() 
     
     result = newSeq[byte](data.len)
     for i, c in data:
         result[i] = byte(c.ord)
     
-    packer.payloadStream.setPosition(0) 
+    packer.stream.setPosition(0) 
 
-proc packHeader*(packer: Packer): seq[byte] = 
-    packer.headerStream.setPosition(0) 
-    let data = packer.headerStream.readAll() 
+proc reset*(packer: Packer): Packer {.discardable.}  = 
+    packer.stream.close()
+    packer.stream = newStringStream()
+    return packer
+
+type 
+    Unpacker* = ref object 
+        stream: StringStream
+        position: int 
+
+proc initUnpacker*(data: string): Unpacker = 
+    result = new Unpacker
+    result.stream = newStringStream(data)
+    result.position = 0
+
+proc getUint8*(unpacker: Unpacker): uint8 =
+    result = unpacker.stream.readUint8()
+    unpacker.position += 1
+
+proc getUint16*(unpacker: Unpacker): uint16 =
+    result = unpacker.stream.readUint16()
+    unpacker.position += 2
+
+proc getUint32*(unpacker: Unpacker): uint32 =
+    result = unpacker.stream.readUint32()
+    unpacker.position += 4
+
+proc getUint64*(unpacker: Unpacker): uint64 =
+    result = unpacker.stream.readUint64()
+    unpacker.position += 8
+
+proc getBytes*(unpacker: Unpacker, length: int): seq[byte] = 
+    result = newSeq[byte](length)
+    let bytesRead = unpacker.stream.readData(result[0].addr, length)
+    unpacker.position += bytesRead
     
-    # Convert string to seq[byte]
-    result = newSeq[byte](data.len)
-    for i, c in data:
-        result[i] = byte(c.ord)
+    if bytesRead != length:
+        raise newException(IOError, "Not enough data to read")
+
+proc getArgument*(unpacker: Unpacker): TaskArg = 
+    result.argType = unpacker.getUint8()
     
-    packer.headerStream.setPosition(0) 
+    case result.argType:
+    of cast[uint8](STRING), cast[uint8](BINARY):
+        # Variable-length fields are prefixed with the content-length
+        let length = unpacker.getUint32()
+        result.data = unpacker.getBytes(int(length))
+    of cast[uint8](INT):
+        result.data = unpacker.getBytes(4)
+    of cast[uint8](LONG):
+        result.data = unpacker.getBytes(8)
+    of cast[uint8](BOOL):
+        result.data = unpacker.getBytes(1)
+    else: 
+        discard