Pydantic Streamlit

In this example we will demonstrate: Connecting to RSTAB and creating new model Creating a Streamlit app with Pydantic validator class Read the comments for detailed instructions.

from math import inf
from dlubal.api import rstab
from pydantic import BaseModel, Field
import streamlit as st

"""
Cantilever beam design using RSTAB API and Pydantic for input validation.
To run this script install Streamlit and execute the following command in the terminal:
'python -m streamlit run pydantic_streamlit.py'
"""

class CantileverData(BaseModel):
    """
    Pydantic class defining the model parameters.
    This class is used to validate the input parameters for the RSTAB model.
    """
    length: float = Field(None, gt=0, le=10)
    material: str = 'S235'
    section: str = 'IPE 120'


def define_structure(model : CantileverData) -> None:
    """
    Define and return a list of structural objects.
    This function creates a cantilever beam with the specified parameters.
    """
    object_lst = [
        # Define material
        rstab.structure_core.Material(
            no=1,
            name=model.material,
        ),

        # Define section
        rstab.structure_core.Section(
            no=1,
            name=model.section,
            material=1,
        ),

        # Define nodes
        rstab.structure_core.Node(
            no=1,
        ),
        rstab.structure_core.Node(
            no=2,
            coordinate_1=model.length,
        ),

        # Define member
        rstab.structure_core.Member(
            no=1,
            node_start=1,
            node_end=2,
            section_start=1,
        ),

        # Define nodal support at Node 1 (fully fixed)
        rstab.types_for_nodes.NodalSupport(
            no=1,
            nodes=[1],
            spring_x=inf,
            spring_y=inf,
            spring_z=inf,
            rotational_restraint_x=inf,
            rotational_restraint_y=inf,
            rotational_restraint_z=inf,
        ),
    ]
    rstab_app.create_object_list(objs=object_lst)

if __name__ == '__main__':

    # Streamlit app
    st.title("RSTAB API Cantilever Design")
    form = st.form(key='cantilever_form')
    l = form.slider(label='Select length [m] (0, 10>)', min_value=0.00, max_value=15.00)
    mat = form.selectbox('Select material', ['S235', 'S275', 'S355', 'S450'])
    sec = form.selectbox('Select section', ['IPE 100', 'IPE 120','HEA 100', 'HEB 100'])
    submit_button = form.form_submit_button(label='Submit')

    if submit_button:
        try:
            model = CantileverData(length=l, material=mat, section=sec)

            form.write('Parameters OK. Creating cantilever in RSTAB...')
            with rstab.Application() as rstab_app:
                # Step 1: Create a new model
                rstab_app.close_all_models(save_changes=False)
                rstab_app.create_model(name='cantilever')

                # Step 2: Clear existing objects
                rstab_app.delete_all_objects()

                # Step 3: Define and create all objects.
                define_structure(model)
                st.badge("Success", icon=":material/check:", color="green")

        except ValueError as e:
            st.badge("Error", icon="⚠️", color="red")
            st.error(f"Pydantic output: {e}")