`MainPanel`¶

Primary HTMX swap region for AppShell document/fragment dual paths.


Import	`from hedron import MainPanel`
Distribution	`hedron`
Backend activity	No
Normal render mode	`RenderMode.FRAGMENT`

Live demo¶

DemoCode

Docs simulation — not a running Hedron server. Interactive demos show a “Simulated HTMX” trace when applicable.

HomeOverview metrics stay in MainPanel.

Minimal runnable app.py that reproduces this demo (real Hedron, not the docs simulator):

app.py

import os

from hedron import AppShell, Hedron, Nav, NavLink, Page, html, swap

app = Hedron(
    title="AppShell demo",
    security="standard",
    explorer="off",
    session_secret=os.environ.get("HEDRON_SESSION_SECRET", "dev-only"),
)

panel = app.region("comp-main-panel")


def panel_body(name: str, detail: str):
    return html.div(html.strong(name), html.span(detail))


@app.page("/")
def home() -> Page:
    return Page(
        AppShell(
            nav=Nav(
                NavLink("Home", "/home", target=panel.selector, swap="innerHTML", active=True),
                NavLink("Reports", "/reports", target=panel.selector, swap="innerHTML"),
                NavLink("Settings", "/settings", target=panel.selector, swap="innerHTML"),
            ),
            body=panel_body("Home", "Overview metrics stay in MainPanel."),
            panel_id=panel.id,
        ),
        title="AppShell",
    )


@app.view("/home", fragment_regions=(panel,))
def home_frag():
    return swap(panel_body("Home", "Overview metrics stay in MainPanel."))


@app.view("/reports", fragment_regions=(panel,))
def reports_frag():
    return swap(panel_body("Reports", "Reports fragment swapped into the panel."))


@app.view("/settings", fragment_regions=(panel,))
def settings_frag():
    return swap(panel_body("Settings", "Settings fragment; side nav stays put."))

Basic use¶

from hedron import Heading, MainPanel, Text
component = MainPanel(Heading('Dashboard', level=1), Text('Overview'), id='main-panel')

Compose under Page for full documents, or return from a fragment route for HTMX swaps.

How it works¶

MainPanel is the body region AppShell composes for full-document and fragment responses. Keep navigable content here so shell chrome remains stable across swaps.

This component can initiate or represent a backend interaction. The live documentation intercepts that interaction with JavaScript and shows the same pending, success, or replacement states without making a real request. In an application, keep the URL, authorization, validation, and returned fragment on the server; JavaScript is only progressive enhancement.

Constructor and parameters¶

MainPanel(*nodes, *, id='main-panel', class_=None)

Parameter	Type	Meaning
`id`	`str`	Stable region id targeted by NavLink/HtmxLink swaps.
`class_`	`str \| None`	Optional CSS classes.

Composition and backend behavior¶

Keep MainPanel at the smallest semantic boundary. Fragment routes should return only the replaced region and preserve stable target IDs across success, validation, empty, loading, and error responses.

Mutating flows must use POST, validate CSRF, authorize on the server, re-validate typed input, and return a bounded fragment. GET remains safe and repeatable; native submit should still work without HTMX.

Accessibility¶

Authorize the panel id in fragment_regions / InteractionPolicy for HTMX targets.

Security¶

Escaping and SafeUrl / TrustedHtml are framework concerns; authorization and data exposure remain application code. Redact secrets before rendering.

Common mistakes¶

Do not nest multiple competing main panels on one page.
Do not copy docs-preview JavaScript into an application server.

Testing¶

from hedron import RenderMode, render

result = render(component, mode=RenderMode.FRAGMENT)
assert result.html
assert not result.diagnostics

All component demos · Built-in API · Testing

MainPanel¶