Simple Python script to fetch the Fronius Load Management status from web interface and post it to Home Assistant

fronius_load_management_status.py

#!/usr/bin/env python3

import requests
import http.client as http_client
import logging

import hashlib
import os
import re
import threading
import time

# from enum import Enum

from requests.auth import AuthBase
from requests.compat import  urlparse
from requests.cookies import extract_cookies_to_jar
from requests.utils import parse_dict_header

MAX_GPIOS = 4

# FIXME: Not sure if this is all values yet
# class LoadStatusReason(Enum):
#     PSTR_EMRS_REASON_0 = "disabled by config"
#     PSTR_EMRS_REASON_1 = "PSTR_EMRS_REASON_1"
#     PSTR_EMRS_REASON_2 = "PSTR_EMRS_REASON_2"
#     PSTR_EMRS_REASON_3 = "minimum consecutive ON-time running"
#     PSTR_EMRS_REASON_4 = "power crosses low-limit"
#     PSTR_EMRS_REASON_5 = "power crosses high-limit"
#     PSTR_EMRS_REASON_6 = "intended runtime requires activation"

# Copied from the requests lib because Fronius uses x-www-authenticate as the header rather than www-authenticate
class HTTPFroniusDigestAuth(AuthBase):
    """Attaches HTTP Digest Authentication to the given Request object."""

    def __init__(self, username, password):
        self.username = username
        self.password = password
        # Keep state in per-thread local storage
        self._thread_local = threading.local()

    def init_per_thread_state(self):
        # Ensure state is initialized just once per-thread
        if not hasattr(self._thread_local, "init"):
            self._thread_local.init = True
            self._thread_local.last_nonce = ""
            self._thread_local.nonce_count = 0
            self._thread_local.chal = {}
            self._thread_local.pos = None
            self._thread_local.num_401_calls = None

    def build_digest_header(self, method, url):
        """
        :rtype: str
        """

        realm = self._thread_local.chal["realm"]
        nonce = self._thread_local.chal["nonce"]
        qop = self._thread_local.chal.get("qop")
        algorithm = self._thread_local.chal.get("algorithm")
        opaque = self._thread_local.chal.get("opaque")
        hash_utf8 = None

        if algorithm is None:
            _algorithm = "MD5"
        else:
            _algorithm = algorithm.upper()
        # lambdas assume digest modules are imported at the top level
        if _algorithm == "MD5" or _algorithm == "MD5-SESS":

            def md5_utf8(x):
                if isinstance(x, str):
                    x = x.encode("utf-8")
                return hashlib.md5(x).hexdigest()

            hash_utf8 = md5_utf8
        elif _algorithm == "SHA":

            def sha_utf8(x):
                if isinstance(x, str):
                    x = x.encode("utf-8")
                return hashlib.sha1(x).hexdigest()

            hash_utf8 = sha_utf8
        elif _algorithm == "SHA-256":

            def sha256_utf8(x):
                if isinstance(x, str):
                    x = x.encode("utf-8")
                return hashlib.sha256(x).hexdigest()

            hash_utf8 = sha256_utf8
        elif _algorithm == "SHA-512":

            def sha512_utf8(x):
                if isinstance(x, str):
                    x = x.encode("utf-8")
                return hashlib.sha512(x).hexdigest()

            hash_utf8 = sha512_utf8

        KD = lambda s, d: hash_utf8(f"{s}:{d}")  # noqa:E731

        if hash_utf8 is None:
            return None

        # XXX not implemented yet
        entdig = None
        p_parsed = urlparse(url)
        #: path is request-uri defined in RFC 2616 which should not be empty
        path = p_parsed.path or "/"
        if p_parsed.query:
            path += f"?{p_parsed.query}"

        A1 = f"{self.username}:{realm}:{self.password}"
        A2 = f"{method}:{path}"

        HA1 = hash_utf8(A1)
        HA2 = hash_utf8(A2)

        if nonce == self._thread_local.last_nonce:
            self._thread_local.nonce_count += 1
        else:
            self._thread_local.nonce_count = 1
        ncvalue = f"{self._thread_local.nonce_count:08x}"
        s = str(self._thread_local.nonce_count).encode("utf-8")
        s += nonce.encode("utf-8")
        s += time.ctime().encode("utf-8")
        s += os.urandom(8)

        cnonce = hashlib.sha1(s).hexdigest()[:16]
        if _algorithm == "MD5-SESS":
            HA1 = hash_utf8(f"{HA1}:{nonce}:{cnonce}")

        if not qop:
            respdig = KD(HA1, f"{nonce}:{HA2}")
        elif qop == "auth" or "auth" in qop.split(","):
            noncebit = f"{nonce}:{ncvalue}:{cnonce}:auth:{HA2}"
            respdig = KD(HA1, noncebit)
        else:
            # XXX handle auth-int.
            return None

        self._thread_local.last_nonce = nonce

        # XXX should the partial digests be encoded too?
        base = (
            f'username="{self.username}", realm="{realm}", nonce="{nonce}", '
            f'uri="{path}", response="{respdig}"'
        )
        if opaque:
            base += f', opaque="{opaque}"'
        if algorithm:
            base += f', algorithm="{algorithm}"'
        if entdig:
            base += f', digest="{entdig}"'
        if qop:
            base += f', qop="auth", nc={ncvalue}, cnonce="{cnonce}"'

        return f"Digest {base}"

    def handle_redirect(self, r, **kwargs):
        """Reset num_401_calls counter on redirects."""
        if r.is_redirect:
            self._thread_local.num_401_calls = 1

    def handle_401(self, r, **kwargs):
        """
        Takes the given response and tries digest-auth, if needed.

        :rtype: requests.Response
        """

        # If response is not 4xx, do not auth
        # See https://github.com/psf/requests/issues/3772
        if not 400 <= r.status_code < 500:
            self._thread_local.num_401_calls = 1
            return r

        if self._thread_local.pos is not None:
            # Rewind the file position indicator of the body to where
            # it was to resend the request.
            r.request.body.seek(self._thread_local.pos)
        s_auth = r.headers.get("x-www-authenticate", "")

        if "digest" in s_auth.lower() and self._thread_local.num_401_calls < 2:

            self._thread_local.num_401_calls += 1
            pat = re.compile(r"digest ", flags=re.IGNORECASE)
            self._thread_local.chal = parse_dict_header(pat.sub("", s_auth, count=1))

            # Consume content and release the original connection
            # to allow our new request to reuse the same one.
            r.content
            r.close()
            prep = r.request.copy()
            extract_cookies_to_jar(prep._cookies, r.request, r.raw)
            prep.prepare_cookies(prep._cookies)

            prep.headers["Authorization"] = self.build_digest_header(
                prep.method, prep.url
            )
            _r = r.connection.send(prep, **kwargs)
            _r.history.append(r)
            _r.request = prep

            return _r

        self._thread_local.num_401_calls = 1
        return r

    def __call__(self, r):
        # Initialize per-thread state, if needed
        self.init_per_thread_state()
        # If we have a saved nonce, skip the 401
        if self._thread_local.last_nonce:
            r.headers["Authorization"] = self.build_digest_header(r.method, r.url)
        try:
            self._thread_local.pos = r.body.tell()
        except AttributeError:
            # In the case of HTTPDigestAuth being reused and the body of
            # the previous request was a file-like object, pos has the
            # file position of the previous body. Ensure it's set to
            # None.
            self._thread_local.pos = None
        r.register_hook("response", self.handle_401)
        r.register_hook("response", self.handle_redirect)
        self._thread_local.num_401_calls = 1

        return r

    def __eq__(self, other):
        return all(
            [
                self.username == getattr(other, "username", None),
                self.password == getattr(other, "password", None),
            ]
        )

    def __ne__(self, other):
        return not self == other

def main():
    # other interesting path is /config/emrs/ which returns the load management config

    # Debug logging
    http_client.HTTPConnection.debuglevel = 1
    logging.basicConfig()
    logging.getLogger().setLevel(logging.DEBUG)
    requests_log = logging.getLogger("requests.packages.urllib3")
    requests_log.setLevel(logging.DEBUG)
    requests_log.propagate = True

    r = requests.get("http://INVERTER_IP/status/emrs/", auth=HTTPFroniusDigestAuth('admin', 'INVERTER_ADMIN_PASSWORD'))

    gpios = r.json()['Body']['Data']['emrs']['gpios']
    for i in range(1, MAX_GPIOS+1):
        pin_name = format(f'pin{i}')
        pin = gpios[pin_name]
        # reason = LoadStatusReason[pin['reason']]
        # state = "on" if pin['state'] else "off"
        # print(f'Pin {i} is {state} because {reason.value}')

        headers = {
            "Authorization": "Bearer HOME_ASSISTANT_API_TOKEN",
            "Content-Type": "application/json",
        }

        r = requests.post(format(f'http://HOME_ASSISTANT_SERVER:8123/api/states/sensor.fronius_load_management_{pin_name}'), headers=headers, json={
            "state": pin['reason']
        })

        print(r.text)


if __name__ == '__main__':
    main()