Python client for lightstreamer

Mickael

Hi,
I'm having trouble maintaining the streaming connection with IG as well.
It cuts automatically after roughly an hour or so, and I don't know how to test if the connection is active or not.
Any help with that would be greatly appreciated.

Thanks in advance.

Gianluca Finocchiaro

Hi Mickael,

could you please send us the client side log snippet that puts in evidence the cut?

Thanks, Gianluca

femi

Hi,

I am trying to connect to IG streaming api with lightstreamer with Python. I am using the the light streamer stock list demo implementation on Github with the parameters modified for IG index. I appear to be getting a server error, When i use the same details on IG streaming companion, i was able to connect to the server successfully, which makes me suspect that this is not a server issue.

see my debug logs below

urllib3.connectionpool - DEBUG - Starting new HTTPS connection (1): demo-api.ig.com
urllib3.connectionpool - DEBUG - https://demo-api.ig.com:443 "POST /gateway/deal/session HTTP/1.1" 200 359

root - DEBUG - Opening a new session to <https://demo-apd.marketdatasystems.com>

root - DEBUG - Making a request to <https://demo-apd.marketdatasystems.com/lightstreamer/create_session.txt> with body <b'LS_op2=create&LS_cid=mgQkwtwdysogQz2BJ4Ji+kOj2Bg&LS_user=*****&LS_password=CST-*****XST-*****'>
root - ERROR - -2

Server response error:
%sA system error occurred.

Any assistance would be appreciated

Gianluca Finocchiaro

Hi Femi,

consider that the Python demo is just an example of how to implement the Network Protocol, so it is possible that some corner case has not been taken into consideration.

Anyway, we'll be going into a debug session to check what goes wrong when connecting with IG and get back to you with more information.

Thanks,
Gianluca

Gianluca Finocchiaro

Thank you very much Femi for your cooperation in analyzing this issue.

After having fixed a bug in the demo source code on a logging instruction, and tried to establish a session with IG by using similar JavaScript code, we have concluded that something unexpected is happing to your account.

In fact, the negative code error sent back by the server (-2) indicates that the specific Metadata Adapter implementation has refused the user connection, as you can see from the documentation.

Please let us know if your issue will be resolved.

Thanks and Regards,
Gianluca

femi

Thanks a lot Gialunca. I found out the issue was a bug in my own code that generated the tokens for the request. really appreciate your help.

Gianluca Finocchiaro

Hi femi,

thank you for this feedback.

femi

Hi Gialunca,

I had an application running this morning, and i noticed that occasionally, the lightstreamer server "Freezes" i.e stops sending back messages, causing a TimeoutError. I can attempt to automatically reconnect back to the server in such cases, but i wanted to get your thoughts, if there is already a way to do this?

Thanks,
Femi

Gianluca Finocchiaro

Hi Femi,

I confirm that the demo currently does not provide any reconnection mechanism. Therefore, for the moment you should extend the demo with automatic retries.

Regards,
Gianluca

newguy

I wonder if someone can answer a very simple and very early question for me, before I start re-learning my forgotten coding skills. I can see that people are somehow using python to connect to IG. I notice that lightstreamer doesn't seem to have a linux version, so I'm wondering if the python is running on linux. I really can't face windows.

Giuseppe Corti

Server-side Lightstreamer can work on both Linux and Windows systems, and in any other system for which a jvm implementation is available.

On the client-side, we have several client libraries specific to various systems and technologies.
While for Python I confirm that it is available for different OS, including Linux.

newguy

Giuseppe Corti On the client-side, we have several client libraries specific to various systems and technologies.
While for Python I confirm that it is available for different OS, including Linux.

Oh? I'm confused, I must have missed it. If there is a .deb that I can install, or if it's in a repository, could you please post a link? My intention is to use python on a linux mint system to connect to IG, who seem to require lightstreamer for streaming data.

Giuseppe Corti

For the Python language, we do not have an official client library, but you can refer to this project on GitHub, as a starting point for your client-side developments:
https://github.com/Lightstreamer/Lightstreamer-example-StockList-client-python

Hope that helps.
Giuseppe

newguy

Yes, thank you. But this implies that you have an official client library for, perhaps, C/C++? Where's that?

Giuseppe Corti

There are several client libraries available for various technologies: Javascript (Web and NodeJS), JVM (Java Se, Android), Apple (iOS, macOS, tvOS, watchOS), .NET (.NET PCL, Unity).
You can find them by looking inside our distribution (https://lightstreamer.com/download/#ls71).
But to find out which of these and which versions are supported by IG, you should check their streaming API page.

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