Replace SessionState with Streamlit built-in

[yorickvanzweeden]

Proposed changes:

• Replace SessionState with Streamlit's st.session_state

Why?

1. The original gist (on which SessionState is based) recommends it
2. SessionState contains an import (import streamlit.report_thread as ReportThread) that does not work in Streamlit 1.4.0 (released 2 days ago)
3. SessionState only supports a single session. Using the demo from two different browsers results in unexpected behaviour. (Try running two queries from two tabs, one of the tabs will copy the question from the other tab)

Status (please check what you already did):

• First draft (up for discussions & feedback)
• Final code
• Added tests
• Updated documentation

[ZanSara]

Hey @yorickvanzweeden, thank you for this contribution! Do you think there's any work left to be done or is it ready for review? If it's ready, I'm going to test it out and if it's all good we might merge it today. Let me know 🙂

[yorickvanzweeden]

Hey @yorickvanzweeden, thank you for this contribution! Do you think there's any work left to be done or is it ready for review? If it's ready, I'm going to test it out and if it's all good we might merge it today. Let me know slightly_smiling_face

Hi @ZanSara , it should work already :)

[ZanSara]

Hey @yorickvanzweeden, I gave it a try very superficially and there is something wrong with the state management. Once I get answers for a question, if I click "Evaluation mode" all the answers disappear. See the attached GIF. Can you verify if it happens on your side as well?

My setup was pretty simple, I just checked out your branch, commented out the image directives in docker-compose.yml and then executed docker-compose up. Let me know if you can reproduce it.

[yorickvanzweeden]

Hi @ZanSara, I can confirm it on my side too. I will have a look at it

[yorickvanzweeden]

@ZanSara, I was writing a default state (No results) on every Streamlit refresh. The bug is fixed and I rechecked the code. I don't expect any different behaviour, as all other changes in webapp.py are read/set statements.

[ZanSara]

Nice, I re-tested and it looks good now! Thank you very much for this contribution 🙂