Add flask app with auto-reload to render the form template

render/__main__.py

@@ -0,0 +1,60 @@
+"""Web Server Gateway Interface with autoreload to render spawner template.
+
+Usage: `python -m render`
+
+"""
+from pathlib import Path
+from traceback import format_exc
+
+import glicid_spawner
+from flask import Flask, render_template, request
+from glicid_spawner.form import options_attrs, options_form, options_from_form
+from livereload import Server
+
+# Monkeypatch
+USERNAME = 'john-doe'
+glicid_spawner.micromamba.MICROMAMBA_ROOT = (
+    Path(__file__).parent / '..' / 'tests' / 'data' / 'micromamba'
+).resolve()
+glicid_spawner.micromamba.GLOBAL_USER = 'global'
+glicid_spawner.micromamba.GLOBAL_EXCLUDED = 'qux'
+
+# Flask app
+app = Flask(__name__)
+app.debug = True
+
+
+@app.route('/')
+def home():
+    """Form spawner home page."""
+    return render_template(
+        'form.html', spawner_options_form=options_form(USERNAME), options=options_attrs(USERNAME)
+    )
+
+
+@app.route('/submit', methods=['POST'])
+def submit():
+    """Reformat form data and extract spawner options.
+
+    https://jupyterhub.readthedocs.io/en/stable/reference/spawners.html#spawner-options-from-form
+
+    """
+    formdata = dict(request.form.lists())
+
+    # Trying to parse the options from the formdata
+    try:
+        return render_template(
+            'options.html', formdata=formdata, options=options_from_form(formdata)
+        )
+    except Exception:
+        return render_template('options.html', formdata=formdata, err=format_exc())
+
+
+def server_autoreload():
+    """Start auto-reload server."""
+    server = Server(app.wsgi_app)
+    server.serve()
+
+
+if __name__ == '__main__':
+    server_autoreload()