In Python, how to open a string representing HTML in the browser?

Question

I'd like to view a Django template in the browser. This particular template is called in render_to_string, but is not connected to a view, so I can't just runserver and navigate to the URL at my localhost.

My idea was to simply call render_to_string in the Django shell and somehow pass the resulting string to a web browser such as Chrome to view it. However, as far as I can tell the webbrowser module only accepts url arguments and can't be used to render strings representing HTML.

Any idea how I could achieve this?

Why can't you create a view for this? – Michael Mior Apr 03 '18 at 21:03 — Michael Mior, Apr 03 '18 at 21:03

Marat · Accepted Answer · 2022-09-16T13:44:21.367

4

Use Data URL:

import base64

html = b"..."

url = "text/html;base64," + base64.b64encode(html)
webbrowser.open(url)

edited Sep 16 '22 at 13:44

answered Apr 03 '18 at 21:19

Marat

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I'm having a bit of trouble reproducing this snippet; it seems like [`base64.encode()`](https://docs.python.org/3.6/library/base64.html#base64.encode) expects two arguments, `input` and `output`. Did you mean `b64encode()`? Also the latter returns a byte string, which can't simply be 'added' to a regular string in Python 3. – Kurt Peek Apr 03 '18 at 21:54
Sorry, I was writing from memory and of course I've mistaken. It should be `b64encode` instead, I updated the answer – Marat Apr 03 '18 at 22:16
On Windows you may well get the error "ValueError: startfile: filepath too long for Windows". See my solution below... Also although explained, this answer still reads incorrectly. I think the penultimate line should be: `url = "text/html;base64," + base64.b64encode(r.text.encode()).decode()` – Peter F Sep 14 '22 at 13:32
@PeterF `html` is supposed to be a byte-like string. This answer comes from the time when Python2 was dominant and strings were bytes; I guess it's time to update the answer – Marat Sep 14 '22 at 17:59

score 0 · Answer 2 · answered Apr 03 '18 at 21:16

0

you could convert the html string to url:

https://docs.python.org/2/howto/urllib2.html

answered Apr 03 '18 at 21:16

optimus_prime

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score 0 · Answer 3 · answered Apr 03 '18 at 21:38

Following Launch HTML code in browser (that is generated by BeautifulSoup) straight from Python, I wrote a test case in which I write the HTML to a temporary file and use the file:// prefix to turn that into a url accepted by webbrowser.open():

import tempfile
import webbrowser
from django.test import SimpleTestCase
from django.template.loader import render_to_string


class ViewEmailTemplate(SimpleTestCase):
    def test_view_email_template(self):
        html = render_to_string('ebay/activate_to_family.html')
        fh, path = tempfile.mkstemp(suffix='.html')
        url = 'file://' + path

        with open(path, 'w') as fp:
            fp.write(html)
        webbrowser.open(url)

(Unfortunately, I found that the page does not contain images referenced by Django's static tag, but that's a separate issue).

score 0 · Answer 4 · answered Sep 14 '22 at 13:38

0

Here's a more concise solution which gets around the possible ValueError: startfile: filepath too long for Windows error in the solution by @marat:

from pathlib import Path

Path("temp.html").write_text(html, encoding='utf-8')
webbrowser.open("temp.html")
Path("temp.html").unlink()

answered Sep 14 '22 at 13:38

Peter F

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If you want to store it in the filesystem, I guess [`tempfile.NamedTemporaryFile](https://docs.python.org/3/library/tempfile.html#tempfile.NamedTemporaryFile) could simplify this a bit – Marat Sep 14 '22 at 17:56
Nice! Thanks for sharing that... I learned something new :) – Peter F Sep 16 '22 at 07:18

In Python, how to open a string representing HTML in the browser?

4 Answers4