streamlit-message-passing

Streamlit component for doing message passing between parent window and server via JS

Installation instructions

pip install streamlit-message-passing

Usage instructions

import streamlit as st

from msgpassing import listen_for_parameters

# If parent window is running on http://localhost:8080 ...
data = listen_for_parameters(web_url="http://localhost:8080")

# We can wait until we have these parameters:
if not data:
  st.stop()

st.markdown("Parameters is: ```%s```" % json.dumps(data, indent=2))

On the parent window, you can do something like this:

<iframe src="http://localhost:8501/" frameborder="0"></iframe>
<script>
  document.addEventListener('DOMContentLoaded', function () {
    const messageHandler = (event) => {
      console.debug("Received message from iframe:", event.data, event.origin)

      // Optional: Check if we're receiving messages from our dashboard only
      // We assume that the streamlit app is running on http://localhost:8501
      if (event.origin !== "http://localhost:8501") return;

      if (event.data.type === "ready") {
        // We are ready to send these parameters to streamlit
        const msg = { 
          type: "parameters", 
          foo: "1", 
          bar: 2
        };
        
        console.debug("Sending parameters to iframe:", msg);
        event.source.postMessage(msg, "http://localhost:8501");
      }
    };

    window.addEventListener("message", messageHandler, false);
  });
</script>

See iframe.html for a full example.