Changing Web Server Configuration

[avogadro5]

Using LabVIEW 2023 or 2025 Q3, Windows.

I have an app laid out like this at runtime:

This app publishes an image of a front panel using this feature. The niwebserver.conf specifies a port of 8000 using "Listen 8000."

My issue is I need to run multiple copies of "Server.exe" and they should each use a different port so multiple images are published. If I simply run multiple copies with "AllowMultipleInstances=True," only one will be reachable because they are trying to use the same port.

I confirmed this port property returns port 8000 if the server is enabled via property node or ini file first. When I try writing 8001 to it, the webpage is briefly visible at 8001 and not 8000, but the application crashes after a few seconds. If the server is disabled via property node or ini file before changing the port, the property appears to do nothing and reads back 0.

I tried using the configure method to point to a different config file per exe instance (and deleted the niwebserver.conf in the app directory so it isn't discovered automatically), but this node hangs forever even if the server is not enabled when it runs.

I tried commenting out the "Listen 8000" line in the conf file, but this causes errors on the port write node and doesn't seem to work.

The only way to modify the port successfully seems to be modifying "niwebserver.conf" in the same folder as the application before running. I need to be able to launch multiple copies in the same folder (due to the app not being designed to work in a different folder) with different ports. I could have multiple exes with different names/ini files but they all look at this same conf file and I can't change which config file, and if I modify the port at runtime the app crashes.

Anyone run into this or have more ideas to try?

[BertMcMahan]

I didn't download your example but is it crashing with ONE instance running or is the SECOND instance crashing?

If the latter, maybe you should set them all to start at 8000, then change ALL of them instead of trying to only change the second one.

[avogadro5]

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@BertMcMahan wrote:

I didn't download your example but is it crashing with ONE instance running or is the SECOND instance crashing?

If the latter, maybe you should set them all to start at 8000, then change ALL of them instead of trying to only change the second one.

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Just 1. If I can configure that 1 instance port using anything that isn't global to the folder containing the app, that is probably generalizable to solve my problem.

[avogadro5]

Played with it some more and found that it only happens if a browser is already connected on the original port like in the gif I posted. So my workaround is to make the starting port from the config file one that no one will be trying, so in practice that initial connection will never happen.