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Date/Time: Tue, 13 Nov 2018 04:55:53 +0000


DTC with JSON encoding

Support Request:
[2017-12-22 15:06:03]
Jose - Posts: 4
Hello,

Please help me because in the past two days I tried to solve JSON communication (from .NET C#) with DTC but in this moment I feel myself in an infinitive circle.

In SierraChart I set the DTC server encoding to JSON (with authorization is not required).
Related to this "Connection and Logon Sequence" description:
(https://www.sierrachart.com/index.php?page=doc/DTCMessageDocumentation.php#ConnectionLogon)
"If the Client knows the default encoding used by the Server, then it does not need to send an ENCODING_REQUEST message to the Server but it is preferred."
...for me it means I can skip the encoding part and I can step forward (to the point 3.)) to the LOGON_REQUEST.

My LOGON_REQUEST JSON text is this:
{"Type":1,"HeartbeatIntervalInSeconds":5,"TradeMode":1,"ClientName":"Jose"}
Is it okay or something is missing from it?

Originally .NET framework has the "Encoding.BigEndianUnicode" support but the DTC server is waiting for the message in "LittleEndian" encoding. I have found some interesting articles in this topic and if I understand well the differences between LittleEndian and BigEndian depends on my hardware. I have checked my computer architecture and that is LittleEndian (https://msdn.microsoft.com/en-us/library/system.bitconverter.islittleendian.aspx). ...so I think my message encoding is correct.

I sent all JSON messages with this encoding but however anything what I sent to DTC server then I got this error message:
DTC client #1. 127.0.0.1 | Received message with an invalid size (1). | 2017-12-22 14:12:06 *
Can you help me what am I doing wrong?

Thanks in advance!
Jose
[2017-12-23 06:03:53]
DTC Engineering - Posts: 270
Each JSON message needs to be encoded using 8-bit characters and needs to be null-terminated. Big endian and little endian is not relevant here.

Unicode is not supported.

{"Type":1,"HeartbeatIntervalInSeconds":5,"TradeMode":1,"ClientName":"Jose"}
As long as according to the documentation all of the fields which are required or you want to specify are included, then it is OK.
Date Time Of Last Edit: 2017-12-28 02:29:45
[2017-12-28 02:29:02]
DTC Engineering - Posts: 270
We would like to know if post #2 was helpful and resolved the issue?
[2017-12-29 02:42:04]
Jose - Posts: 4
Yes, it was very-very helpful! Thank you so much!!!
...especially these words saved me: needs to be null-terminated
:)

Firstly I tried without ending char, after I used \n and \r\n but these could not help. Somehow I totally forgot the null-terminated string existence. Originally I encoded in UTF-8 but because of the unsuccessful tries I started to play with the different encodings, so this mixed me totally. Now with \0 ending in UTF-8 encoding everything works well! Thank you again!

ps.: Sorry for the late answer, it happened just because of the Christmas holiday :)
I wish you happy holidays and a Perfect New Year!!!
Date Time Of Last Edit: 2017-12-29 02:43:29
[2017-12-29 02:48:59]
DTC Engineering - Posts: 270
This is good.

Happy holidays and new year.
[2017-12-29 02:55:31]
Jose - Posts: 4
Thank you!

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