Lightstreamer Connect fail on DEMO account

[swingwin]

I can't connect to the DEMO stream ("https://demo-apd.marketdatasystems.com") since December 2021 with a C# .NET application using the IG API
On the other hand the connection to a LIVE stream ("https://apd.marketdatasystems.com") works

It seems that the problem comes from the "DotNetClient_N2.dll" library.
Has anyone encountered the same problem ?

 

Edited January 22, 2022 by swingwin

[teebeast]

I fixed this issue in my Fork and reworked some things that where outdated. Look at this Issue #12 and Issue #18  for more information about the changes in my fork.

I asked if I should pull request my work, but i got no answer.

[swingwin]

@(teebeast) :

Thanks for your help.
I tried with your Fork but here is the message I get:

 

[Tartempion]

Hello Swingwin, I have the same problem with my own LabVIEW software which does not use the dotnet library from IG. After reading your message I tried my software on the DEMO stream and I see the same problem as you. (I rarely use the demo stream). Do you know what needs to be changed very concretely in the subscription procedure? I don’t program with C#. Everything is at the socket. Did you read somewhere a message from IG that informed about the modification of the parameters for the DEMO stream subscription requests? It scares me if one day they do the same with the PROD stream ahah. Anyway, it's nice to meet you again. We should stay in touch!

[swingwin]

Hello Tartempion, thanks for your answer and for your tests
It's also a pleasure to see you again.

I asked the support of IG France about this problem, but after consulting their technical service, they tell me that nothing has been changed on their side to access the DEMO stream.
The problem still exists despite the advice provided by Teebeast.
But I realize that the problem does not exist when using the IGLabs companion to access the stream.
The java example provided in IGLabs also works.
This problem is very disturbing.
Especially since I haven't changed anything in my apps for months, and everything was working fine until mid-December 2021.  

 

 

[Funky_Gibbon]

btw, I'm in issue #12 as Slashernator

[Funky_Gibbon]

Hi, I have this problem too.
This is the stack trace.  Looks like the backend has changed.

[jlz]

Hi, the .net example is far from ideal. I ended developing my own library. An example of how to use the LightStreamer client with it is at:

https://github.com/AnAlgoTrader/IG.Csharp.Api.Client/issues/2

It does not use the DotNetClient_N2.dll where the main problem seems to be at.

Edited February 4, 2022 by jlz

[Funky_Gibbon]

Hi, thanks for this.  Have you tried against the demo lightstreamer subscription?
Just asking as my prod one is fine, we're just finding that the demo one fails.

Cheers😊

[jlz]

Hi, it does work fine.

I left the example at:

https://github.com/AnAlgoTrader/IG.Csharp.Api.Client/blob/master/Playground/Program.cs

Edited February 5, 2022 by jlz

[Funky_Gibbon]

Excellent.  Thanks for trying.  I'm going to alter my trading algo to use this library.
Wondered if the old one uses .net 2.1 which is now out of support?
 

[Funky_Gibbon]

Hi, Unfortunately my project uses .Net framework 4.5 and I can't attach this library as the error is telling me they're incompatible.
I've tried all sorts but not strong enough to understand the issue other than rewriting the using statements?

Any ideas?

 

[jlz]

I have changed the type to .net standard 2.0. That should let you load it with both 4.5 and .net core. Pull the latest and rebuild the project.

If you have any other issues with the library please log an issue on Github, I don't get notifications from this forum if I don't log in. Github will send me an email with your issue.

[TommyT]

Hi Swingwin (and other contributors),

I too had a similar problem with the DEMO stream, however my timings were different. I had no issues in December but started to get the same issues as you in early Jan. At the same time as I had connection issues with DEMO, the streaming companion on demo worked fine, and the same code DotNetClient_N2 connect to LIVE stream worked fine

There are other posts on the forum where others state it has happened to them, but during different periods. Given it seems to affect different people at different times, and those people seem to be using it then it suddenly stops for a while, I am beginning to wonder if this is down to the stated data limit.

“40 concurrent subscriptions”.

I wonder if, when an application has the stream up and is killed during testing/debugging, does it leave the subscription count incremented? This would seem to explain why different people get it at different times. If then at some point the count is reset access comes back – which it seems to. And this would also explain why it mostly happens with DEMO. (I have had it happen on LIVE too when I have had to use LIVE when DEMO was not available)

A natural counter to this would be that if this is the case it should block the companion connection too. However, I used F12 dev tool on the browser to look at the mechanism for connecting the companion.

From what I can tell there is a slight difference in the login request headers in the PUT to /gateway/deal/session

The c# code I have adds X-IG-API-KEY and VERSION as default headers, and Content-Type as custom to that request particular, whereas the companion uses

      req.headers = {

            "X-IG-API-KEY": credentials.apiKey,

            "Content-Type": "application/json; charset=UTF-8",

            "Accept": "application/json; charset=UTF-8"

        }; 

Not sure what “Accept” is doing.

Regards Tom

[Funky_Gibbon]

Hi Tom,

Thanks for this, very detailed.  I've just tried lots of GO's on the streaming companion, actually 5 and had the error message.
"Login failed: 403 (Forbidden) error.public-api.exceeded-api-key-allowance"

So likely this is the cause.  Still not sure how a concurrent subscription happens with only one link.  I'll send this to IG.

[Funky_Gibbon]

Funnily enough my demo account is working.  I'm going to try and use the new library I'm not really a coder although I roughly know what I'm doing and its a little different but here goes

[jlz]

7 hours ago, TommyT said:

 

Not sure what “Accept” is doing.

 

The Accept header is just to force the server to send you a specific format, a json format in this case.

It is sent as a header because many servers would use xmls as the standard if nothing is specified.

https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Accept

 

Edited February 8, 2022 by jlz

[TommyT]

On 08/02/2022 at 12:48, Funky_Gibbon said:

Hi Tom,

Thanks for this, very detailed.  I've just tried lots of GO's on the streaming companion, actually 5 and had the error message.
"Login failed: 403 (Forbidden) error.public-api.exceeded-api-key-allowance"

So likely this is the cause.  Still not sure how a concurrent subscription happens with only one link.  I'll send this to IG.

Hi Funky,

I was using the LS dot net Client dll. it supports calls to "connect" and "disconnect" which is pretty opaque. I did not/could not find the level of detail you found (error.public-api.exceeded-api-key-allowance) . It seems to confirm it, though am not sure how the streaming companion escapes this limit even though it uses the same API key and account

regards Tom 

[Funky_Gibbon]

Hi Tom,
Using the LS dot net client, I couldn't retrieve a detailed error.  Only using the streaming companion gave this info.  However, I'm converting to use the other method from Algo Trader.

Cheers, Ad

[swingwin]

As the Teebeast fork does not fix the problem for me,
As I didn't test the Jlz solution,
As the java example works in LIVE and in DEMO,
As the IGlabs companion works LIVE and in DEMO,
As my application (few thousands lines of code) use C#.NET,
I will interface the JAVA lightstreamer library with C#.NET using the IKVM.NET tool.
I will specify here as soon as it works and fixes the problem.

[Funky_Gibbon]

Just to let you all know that my DEMO account was working last week and now it's not again.

[swingwin]

I have not made any progress with IKVM since 17 February.

With the LightStreamer .NET library, always the same problem: connection in LIVE OK but connection in DEMO impossible.

I tried @jlz solution, but same problem

[teebeast]

Which version of LightStreamer .NET library do you use? I tested the NuGet-Package Lightstreamer.DotNetStandard.Client version 5.0.5 and I had no problems with my demo account. Do not use any newer version because its not compatible with IG.

[Funky_Gibbon]

I just rewrote my entire program to use IG.Csharp.Api.Client in WPF forms.  The whole thing is more stable than before with messages that show what's happening with the lightstreamer client.
Fascinating how it pauses from time to time.