The captive_portal() func has a loop, there is no end when the configuration is complete,I think we should break after DNS is turned off,Otherwise, methods after portal.start() cannot be run.

if self.check_valid_wifi():
    print("Connected to WiFi!")
    self.http_server.set_ip(self.local_ip, self.ssid)
    self.dns_server.stop(self.poller)
    break

This is a great project, please forgive my grammar, because English is not my native language

Each restart of the esp8266 that has valid credentials currently rewrites the file.

While this should be fine, it is possible to write a partial file if the write is interrupted.

I wasn't 100% sure if there was a better place, but imagine that the write_creds() in captive_portal.py could do the following?

    def write_creds(self, ssid, password):
        try:
            os.stat(self.CRED_FILE)
        except OSError:
            open(self.CRED_FILE, "wb").write(b",".join([ssid, password]))
            print("Wrote credentials to {:s}".format(self.CRED_FILE))

and the try_connect_from_file() func would need to either remove the else clause if the ssid/password is not present or an `os.remove(self.CRED_FILE) would need to be added

Starting captive portal
Waiting for access point to turn on
AP mode configured: ('192.168.4.1', '255.255.255.0', '192.168.4.1', '192.168.4.1')
HTTP Server listening on ('0.0.0.0', 80)
Configured HTTP server
DNS Server listening on ('0.0.0.0', 53)
Configured DNS server
Sending www.gstatic.com. -> 192.168.4.1
Sending www.google.com. -> 192.168.4.1
Sending www.gstatic.com. -> 192.168.4.1

• Accepting new HTTP connection
  Sending www.google.com. -> 192.168.4.1
  Sending www.gstatic.com. -> 192.168.4.1
• Reading incoming HTTP data
• Accepting new HTTP connection
  Sending www.youtube.com. -> 192.168.4.1
• Sending outgoing HTTP data
  Sending ssl.gstatic.com. -> 192.168.4.1
• Reading incoming HTTP data
• Accepting new HTTP connection
  Sending www.gstatic.com. -> 192.168.4.1
• Sending outgoing HTTP data
• Accepting new HTTP connection
  Sending www.google.com. -> 192.168.4.1
• Reading incoming HTTP data
  Sending spclient.wg.spotify.com. -> 192.168.4.1
• Sending outgoing HTTP data
• Reading incoming HTTP data
• Accepting new HTTP connection
  Sending mtalk.google.com. -> 192.168.4.1
• Sending outgoing HTTP data
  Sending dealer.spotify.com. -> 192.168.4.1
• Reading incoming HTTP data
  Sending dealer.spotify.com. -> 192.168.4.1
• Sending outgoing HTTP data
  Sending 0.client-channel.google.com. -> 192.168.4.1
• Sending outgoing HTTP data
  Sending signaler-pa.clients6.google.com. -> 192.168.4.1
• Sending outgoing HTTP data
  Sending clients4.google.com. -> 192.168.4.1
• Sending outgoing HTTP data
  Sending oauthaccountmanager.googleapis.com. -> 192.168.4.1
  Sending favrohdoy. -> 192.168.4.1
• Accepting new HTTP connection
  Sending yuxjawivfx. -> 192.168.4.1
• Accepting new HTTP connection
  Sending yqncsolbleyg. -> 192.168.4.1
• Reading incoming HTTP data
• Accepting new HTTP connection
• Sending outgoing HTTP data
• Accepting new HTTP connection
  Sending calendar.google.com. -> 192.168.4.1
• Reading incoming HTTP data
• Reading incoming HTTP data
• Reading incoming HTTP data
• Sending outgoing HTTP data
• Sending outgoing HTTP data
• Sending outgoing HTTP data
• Sending outgoing HTTP data
• Accepting new HTTP connection
• Sending outgoing HTTP data
  Traceback (most recent call last):
  File "main.py", line 5, in
  File "captive_portal.py", line 168, in start
  File "captive_portal.py", line 125, in captive_portal
  File "captive_portal.py", line 147, in handle_http
  File "captive_http.py", line 223, in write_to
  OSError: [Errno 104] ECONNRESET

First of all, I really like this. It works nicely with my android phone to get the target device into the desired WiFi. Nice!

But I don't understand how the connection.html is to be served. Once the wifi setup is done the main loop isn't run anymore, no polling takes place and thus the http server will not serve anything afterwards. The readme even states that the AP is stopped once station mode is connected.

But imho the esp supports to run in ap and sta mode at the same time. So it should be possible to keep the AP running and allow for a nice redirect to a page served on sta side.

What am I missing?

The captive_portal() func has a loop that involves a call to check_valid_wifi() that calls a has_creds() function. The has_creds() will never return None once an ssid/password is entered as it is never cleared.

def has_creds(self):
    self.ssid, self.password = self.http_server.saved_credentials <-- HERE
    return None not in [self.ssid, self.password]

I feel like the connect_to_wifi() func might be the best place to negate the cached values as you are already setting the self.ssid/self.password to None anyway?

...
# forget the credentials since they didn't work, and turn off station mode
self.http_server.saved_credentials = [None, None]
self.ssid = self.password = None
self.sta_if.active(False)
...

Hello, I would like to have a captive portal on my ESP32. My intention is in really that when mobile user acess de ESP32 Access Point without password, can open automatically the default browser on the SO (Android/IOS) with the IP of ESP32 device, without user needs to type the ESP32 IP on the browser.

I think that the captive portal will works for this purpose, right?

Ps: Mobile user do not need access the internet via ESP32, just access automatically the ESP32 HTTP page on it.

Thank you!

code:

from captive_portal import CaptivePortal

portal = CaptivePortal()
contents = open("./wifi.creds", "rb").read().split(b",")
print()
print('VVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVV')
print(contents)
portal.start()
print(contents)
print('------------------------------------------')

logs：

# First restart
$l`��rےo��l$ �

VVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVV
[b'MERCURY_6510', b'104104104104']
Trying to load WiFi credentials from ./wifi.creds
Trying to connect to SSID 'MERCURY_6510' with password 104104104104
#6 ets_task(4020f4d8, 28, 3fff9348, 10)
Connection in progress
Connection in progress
Connected to MERCURY_6510
Wrote credentials to ./wifi.creds
[b'MERCURY_6510', b'104104104104']
------------------------------------------
MicroPython v1.12 on 2019-12-20; ESP module with ESP8266
Type "help()" for more information.
>>> 

# Second restart
�$l`�
�l$䌎2#
VVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVV
[b'']
Trying to load WiFi credentials from ./wifi.creds
Invalid credentials file: [b'']
Starting captive portal
Waiting for access point to turn on
#6 ets_task(4020f510, 29, 3fff8bc8, 10)
AP mode configured: ('192.168.4.1', '255.255.255.0', '192.168.4.1', '192.168.4.1')
HTTP Server listening on ('0.0.0.0', 80)
Configured HTTP server

I guess the text was not closed, so it was not saved
this problem can be solved by using with

def write_creds(self, ssid, password):
        with open(self.CRED_FILE, "wb") as fp:
                fp.write(b",".join([ssid, password]))
        #open(self.CRED_FILE, "wb").write(b",".join([ssid, password]))
        print("Wrote credentials to {:s}".format(self.CRED_FILE))

I have written an uasyncio task based on your code along with nano webserver. I am on Ubuntu and my Captive Portal app launches when I connect to ESP Access point. the Index page loads on the captive portal app - but the style sheet doesn't load.

However when I use a browser, I get both the page and style sheet (I have cleared cache to test it).

Do you have any thoughts on this.

Do you have any suggestion for reading material to learn python asyncio/threads?

Special characters are represented as url escape from the html form. For example, ! is changed %21. This change prevents connecting to my wifi. I tried to correct this with urllib.parse.unquote, but that method used a particular string split that is not implemented in micropython, returning a NotImplemented error.