Attempt to provide sensible errors on network issues

Currently the add-on works fine if all is well, however various things
can go wrong which makes the add-on bail out with no proper error.

And since the cause of network errors could be anywhere, we do not want
the end-user to have to dig deep into Kodi logs to find probable
suspects.

So we do want to return the exact error message (i.e. Connection
refused, No route to host, etc.) so the user can relate it to other
possible problems. (WIFI issues, Internet down or unreliable, etc.)

resources/language/resource.language.en_gb/strings.po

@@ -653,6 +653,14 @@ msgctxt "#30962"
 msgid "There is a problem with this VRT NU %s stream and Kodi %s does not support the alternative stream. Please upgrade to a newer Kodi version or try to play this program from the VRT NU website. Please report this problem at https://www.vrt.be/vrtnu/help/"
 msgstr ""
 
+msgctxt "#30963"
+msgid "Unable to open URL"
+msgstr ""
+
+msgctxt "#30964"
+msgid "There is a problem connecting to the Internet. This could be related to Kodi, your network, your ISP or VRT NU.\n\nError: {error}"
+msgstr ""
+
 msgctxt "#30965"
 msgid "Using a SOCKS proxy requires the PySocks library (script.module.pysocks) installed."
 msgstr ""

resources/language/resource.language.nl_nl/strings.po

@@ -545,6 +545,14 @@ msgctxt "#30962"
 msgid "There is a problem with this VRT NU %s stream and Kodi %s does not support the alternative stream. Please upgrade to a newer Kodi version or try to play this program from the VRT NU website. Please report this problem at https://www.vrt.be/vrtnu/help/"
 msgstr "Er is een probleem met deze VRT NU %s-stream en Kodi %s ondersteunt de alternatieve stream niet. Schakel over op een nieuwere versie van Kodi of probeer dit programma af te spelen vanaf de VRT NU-website. Meld dit probleem op https://www.vrt.be/vrtnu/help/"
 
+msgctxt "#30963"
+msgid "Unable to open URL"
+msgstr "Probleem bij het openen van een URL"
+
+msgctxt "#30964"
+msgid "There is a problem connecting to the Internet. This could be related to Kodi, your network, your ISP or VRT NU.\n\nError: {error}"
+msgstr "Er is een fout opgetreden met het Internet gebruik. Dit kan liggen aan Kodi, aan jouw netwerk, aan jouw ISP of aan VRT NU.\n\nFout: {error}"
+
 msgctxt "#30965"
 msgid "Using a SOCKS proxy requires the PySocks library (script.module.pysocks) installed."
 msgstr "Het gebruik van SOCKS proxies vereist dat de PySocks library (script.module.pysocks) geïnstalleerd is."

resources/lib/tokenresolver.py

@@ -10,11 +10,12 @@
 
 try:  # Python 3
     import http.cookiejar as cookielib
-    from urllib.parse import urlencode, unquote
-    from urllib.request import build_opener, install_opener, ProxyHandler, HTTPCookieProcessor, HTTPErrorProcessor, urlopen, Request
+    from urllib.error import URLError
+    from urllib.parse import unquote, urlencode
+    from urllib.request import HTTPCookieProcessor, HTTPErrorProcessor, ProxyHandler, Request, build_opener, install_opener, urlopen
 except ImportError:  # Python 2
     from urllib import urlencode
-    from urllib2 import build_opener, install_opener, ProxyHandler, HTTPCookieProcessor, HTTPErrorProcessor, unquote, urlopen, Request
+    from urllib2 import HTTPCookieProcessor, HTTPErrorProcessor, ProxyHandler, Request, URLError, build_opener, install_opener, unquote, urlopen
     import cookielib
 
 
@@ -231,9 +232,17 @@ def _get_new_user_xvrttoken(self):
         cookiejar = cookielib.CookieJar()
         opener = build_opener(HTTPCookieProcessor(cookiejar), ProxyHandler(self._proxies))
         self._kodi.log_notice('URL get: ' + unquote(self._USER_TOKEN_GATEWAY_URL), 'Verbose')
-        opener.open(self._USER_TOKEN_GATEWAY_URL)
+        try:
+            opener.open(self._USER_TOKEN_GATEWAY_URL)
+        except URLError as e:
+            self._kodi.show_ok_dialog(heading=self._kodi.localize(30963), message=self._kodi.localize(30964, error=e, url=unquote(self._USER_TOKEN_GATEWAY_URL)))
+            raise
         self._kodi.log_notice('URL post: ' + unquote(self._VRT_LOGIN_URL), 'Verbose')
-        opener.open(self._VRT_LOGIN_URL, data=data)
+        try:
+            opener.open(self._VRT_LOGIN_URL, data=data)
+        except URLError as e:
+            self._kodi.show_ok_dialog(heading=self._kodi.localize(30963), message=self._kodi.localize(30964, error=e, url=unquote(self._VRT_LOGIN_URL)))
+            raise
         xvrttoken = TokenResolver._create_token_dictionary(cookiejar)
         refreshtoken = TokenResolver._create_token_dictionary(cookiejar, cookie_name='vrtlogin-rt')
         if xvrttoken is not None:
@@ -253,7 +262,11 @@ def _get_fresh_token(self, refresh_token, token_name, token_variant=None):
         opener = build_opener(HTTPCookieProcessor(cookiejar), ProxyHandler(self._proxies))
         self._kodi.log_notice('URL get: ' + refresh_url, 'Verbose')
         req = Request(refresh_url, headers=headers)
-        opener.open(req)
+        try:
+            opener.open(req)
+        except URLError as e:
+            self._kodi.show_ok_dialog(heading=self._kodi.localize(30963), message=self._kodi.localize(30964, error=e, url=req.full_url))
+            raise
         token = TokenResolver._create_token_dictionary(cookiejar, token_name)
         self._set_cached_token(token, token_variant)
         return list(token.values())[0]
@@ -273,34 +286,46 @@ def _handle_login_error(self, logon_json, cred):
 
     def _get_roaming_xvrttoken(self, xvrttoken):
         ''' Get new 'roaming' X-VRT-Token from VRT NU website '''
-        roaming_xvrttoken = None
         cookie_value = 'X-VRT-Token=' + xvrttoken.get('X-VRT-Token')
         headers = {'Cookie': cookie_value}
         opener = build_opener(NoRedirection, ProxyHandler(self._proxies))
         self._kodi.log_notice('URL get: ' + unquote(self._ROAMING_TOKEN_GATEWAY_URL), 'Verbose')
         req = Request(self._ROAMING_TOKEN_GATEWAY_URL, headers=headers)
-        req_info = opener.open(req).info()
+        try:
+            req_info = opener.open(req).info()
+        except URLError as e:
+            self._kodi.show_ok_dialog(heading=self._kodi.localize(30963), message=self._kodi.localize(30964, error=e, url=req.full_url))
+            raise
         try:  # Python 3
             cookie_value += '; state=' + req_info.get('Set-Cookie').split('state=')[1].split('; ')[0]
             url = req_info.get('Location')
         except AttributeError:  # Python 2
             cookie_value += '; state=' + req_info.getheader('Set-Cookie').split('state=')[1].split('; ')[0]
             url = req_info.getheader('Location')
         self._kodi.log_notice('URL get: ' + unquote(url), 'Verbose')
-        try:  # Python 3
-            url = opener.open(url).info().get('Location')
-        except AttributeError:  # Python 2
-            url = opener.open(url).info().getheader('Location')
+        try:
+            try:  # Python 3
+                url = opener.open(url).info().get('Location')
+            except AttributeError:  # Python 2
+                url = opener.open(url).info().getheader('Location')
+        except URLError as e:
+            self._kodi.show_ok_dialog(heading=self._kodi.localize(30963), message=self._kodi.localize(30964, error=e, url=url))
+            raise
+        if url is None:
+            return None
+
         headers = {'Cookie': cookie_value}
-        if url is not None:
-            self._kodi.log_notice('URL get: ' + unquote(url), 'Verbose')
-            req = Request(url, headers=headers)
+        self._kodi.log_notice('URL get: ' + unquote(url), 'Verbose')
+        req = Request(url, headers=headers)
+        try:
             try:  # Python 3
                 setcookie_header = opener.open(req).info().get('Set-Cookie')
             except AttributeError:  # Python 2
                 setcookie_header = opener.open(req).info().getheader('Set-Cookie')
-            roaming_xvrttoken = TokenResolver._create_token_dictionary(setcookie_header)
-        return roaming_xvrttoken
+        except URLError as e:
+            self._kodi.show_ok_dialog(heading=self._kodi.localize(30963), message=self._kodi.localize(30964, error=e, url=req.full_url))
+            raise
+        return TokenResolver._create_token_dictionary(setcookie_header)
 
     @staticmethod
     def _create_token_dictionary(cookie_data, cookie_name='X-VRT-Token'):