iOS Question iMQTT - Error decompressing data

Mike1970 · Jun 14, 2022

Hi everyone i'm trying to use MQTT for the first time.
I follwed this example.

It connects succesfully but unfortuntely when I receive a message this error shows up

B4X:

Error occurred on line: 96 (B4XPage_Details)
Error decompressing data
Stack Trace: (
  CoreFoundation       5198FB57-5645-3B34-A49F-F32B52256CF3 + 627356
  libobjc.A.dylib      objc_exception_throw + 60
  CoreFoundation       5198FB57-5645-3B34-A49F-F32B52256CF3 + 983952
  Potty                -[B4ICompressedStreams DecompressBytes::] + 336
  Potty                -[B4ISerializator ReadObject::] + 96
  CoreFoundation       5198FB57-5645-3B34-A49F-F32B52256CF3 + 138020
  CoreFoundation       5198FB57-5645-3B34-A49F-F32B52256CF3 + 259600
  Potty                +[B4I runDynamicMethod:method:throwErrorIfMissing:args:] + 1300
  Potty                -[B4IShell runMethod:] + 416
  Potty                -[B4IShell raiseEventImpl:method:args::] + 1488
 Potty                -[B4IShellBI raiseEvent:event:params:] + 1580
 Potty                +[B4IObjectWrapper raiseEvent:::] + 268
 Potty                -[MQTTClient handleMessage:onTopic:retained:] + 232
 Potty                -[MQTTSessionManager newMessage:data:onTopic:qos:retained:mid:] + 144
 Potty                -[MQTTSession handlePublish:] + 996
 Potty                -[MQTTSession decoder:newMessage:] + 2204
 Potty                -[MQTTDecoder stream:handleEvent:] + 2260
 CoreFoundation       5198FB57-5645-3B34-A49F-F32B52256CF3 + 1065248
 CoreFoundation       5198FB57-5645-3B34-A49F-F32B52256CF3 + 1169356
 CoreFoundation       5198FB57-5645-3B34-A49F-F32B52256CF3 + 1113748

The sub is

B4X:

Private Sub mqtt_MessageArrived (Topic As String, Payload() As Byte)
    Log(Topic)
    Dim obj As Object = serializator.ConvertBytesToObject(Payload)
    'Log(obj)
End Sub

The data sent is something like this:
{"temperature":34.32,"moisture":100,"waterLevel":0,"lux":500,"uuid":"aadasdada-asdsad-asdasd-asdassd"}

N.B.
Assume that the problem is App-side because from terminal i receive data correctly... and also if a do something like:

B4X:

Private Sub mqtt_MessageArrived (Topic As String, Payload() As Byte)
    Log(Topic)
    For Each b In Payload
        Log(Chr(b))
    Next
End Sub

it print all correct characters

Thanks in advance

Erel · Jun 15, 2022

The error is not related to MQTT.

You can only deserialize a message with B4XSerializator if it was previously serialized with B4XSerializator.

B4X:

Dim s As String = BytesToString(Payload, 0, Payload.Length, "utf8")
Dim obj As Map = s.As(JSON).ToMap 'json library
Log(obj)

Erel · Jun 15, 2022

The error is not related to MQTT.

You can only deserialize a message with B4XSerializator if it was previously serialized with B4XSerializator.

B4X:

Dim s As String = BytesToString(Payload, 0, Payload.Length, "utf8")
Dim obj As Map = s.As(JSON).ToMap 'json library
Log(obj)

Mike1970 · Jun 15, 2022

Oh

Erel said:
You can only deserialize a message with B4XSerializator if it was previously serialized with B4XSerializator.

Oh ok thanks Erel for the clarification

iOS Question iMQTT - Error decompressing data

Mike1970

Well-Known Member

Erel

Erel

B4X founder

Mike1970

Well-Known Member

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iOS Question iMQTT - Error decompressing data

Mike1970

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Erel

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