flask render template

A Flask app needs to put the current date on a html page. The render_template() can help with that.

Firstly create an index.html under /templates directory. The render_template() seems to pick up html files from the /templates directory automatically without extra config.

Use the double braces {{}} to include any data that needs to be on the page.

<html>

{{date}}. Hello.

</html>

Then on the Flask app.

from flask import Flask, render_template

from datetime import date

app = Flask(__name__)

@app.route('/', methods = ['GET'])

def hello():

return render_template('index.html', date = str(date.today()))

When there is a strucutre of data to be consumed, can also use the tojson filter to convert data (with many fields) into json. Then consume data in the subsequent javascript.

var a = {{ data|tojson }};

</script>

Sometimes it needs if-else and loop logic in the html page.

{% if show_result%}

{% for name, description in results %}

<tr>

<td>{{ description }}</td>

</tr>

{% endfor %}

</table>

{% endif %}

Then render_template('index.html', show_result = True, results = zip(names, descriptions)) will send through the variables.