Warn the user if is using an old app version.

[Closes #4636]

4 files changed, 64 insertions, 1 deletions

diff --git a/src/leap/bitmask/backend.py b/src/leap/bitmask/backend.py
index 8a289a79..705a85be 100644
--- a/src/leap/bitmask/backend.py
+++ b/src/leap/bitmask/backend.py
@@ -194,6 +194,8 @@ class Signaler(QtCore.QObject):
 
     prov_problem_with_provider = QtCore.Signal(object)
 
+    prov_unsupported_client = QtCore.Signal(object)
+
     # These will exist both in the backend and the front end.
     # The frontend might choose to not "interpret" all the signals
     # from the backend, but the backend needs to have all the signals
@@ -205,6 +207,7 @@ class Signaler(QtCore.QObject):
     PROV_CHECK_CA_FINGERPRINT_KEY = "prov_check_ca_fingerprint"
     PROV_CHECK_API_CERTIFICATE_KEY = "prov_check_api_certificate"
     PROV_PROV_PROBLEM_WITH_PROVIER_KEY = "prov_problem_with_provider"
+    PROV_UNSUPPORTED_CLIENT = "prov_unsupported_client"
 
     def __init__(self):
         """
@@ -220,7 +223,8 @@ class Signaler(QtCore.QObject):
             self.PROV_DOWNLOAD_CA_CERT_KEY,
             self.PROV_CHECK_CA_FINGERPRINT_KEY,
             self.PROV_CHECK_API_CERTIFICATE_KEY,
-            self.PROV_PROV_PROBLEM_WITH_PROVIER_KEY
+            self.PROV_PROV_PROBLEM_WITH_PROVIER_KEY,
+            self.PROV_UNSUPPORTED_CLIENT
         ]
 
         for sig in signals:
@@ -243,6 +247,11 @@ class Signaler(QtCore.QObject):
         # will do zmq.send_multipart, and the frontend version will be
         # similar to this
         log.msg("Signaling %s :: %s" % (key, data))
+
+        # for some reason emitting 'None' gives a segmentation fault.
+        if data is None:
+            data = ''
+
         try:
             self._signals[key].emit(data)
         except KeyError:
diff --git a/src/leap/bitmask/gui/mainwindow.py b/src/leap/bitmask/gui/mainwindow.py
index f954006d..69cb4169 100644
--- a/src/leap/bitmask/gui/mainwindow.py
+++ b/src/leap/bitmask/gui/mainwindow.py
@@ -380,6 +380,9 @@ class MainWindow(QtGui.QMainWindow):
             partial(self._login_widget.set_status,
                     self.tr("Unable to login: Problem with provider")))
 
+        self._backend.signaler.prov_unsupported_client.connect(
+            self._needs_update)
+
     def _backend_disconnect(self):
         """
         Helper to disconnect from backend signals.
@@ -856,6 +859,18 @@ class MainWindow(QtGui.QMainWindow):
                     "<a href='https://leap.se'>More about LEAP"
                     "</a>") % (VERSION, VERSION_HASH[:10], greet))
 
+    def _needs_update(self):
+        """
+        Display a warning dialog to inform the user that the app needs update.
+        """
+        url = "https://dl.bitmask.net/"
+        msg = self.tr(
+            "The current client version is not supported "
+            "by this provider.<br>"
+            "Please update to latest version.<br><br>"
+            "You can get the latest version from {0}").format(url)
+        QtGui.QMessageBox.warning(self, self.tr("Update Needed"), msg)
+
     def changeEvent(self, e):
         """
         Reimplements the changeEvent method to minimize to tray
diff --git a/src/leap/bitmask/provider/__init__.py b/src/leap/bitmask/provider/__init__.py
index 53587d65..68f3ded0 100644
--- a/src/leap/bitmask/provider/__init__.py
+++ b/src/leap/bitmask/provider/__init__.py
@@ -18,6 +18,10 @@
 Module initialization for leap.bitmask.provider
 """
 import os
+
+from distutils.version import LooseVersion
+
+from leap.bitmask import __version__ as BITMASK_VERSION
 from leap.common.check import leap_assert
 
 
@@ -32,3 +36,21 @@ def get_provider_path(domain):
     """
     leap_assert(domain is not None, "get_provider_path: We need a domain")
     return os.path.join("leap", "providers", domain, "provider.json")
+
+
+class SupportedClient(object):
+    """
+    Class responsible of checking for client compatibility.
+    """
+
+    @classmethod
+    def supports(self, minimum_version):
+        """
+        :param minimum_version: the version number of the client that
+                                we need to check.
+        :type minimum_version: str
+
+        :returns: True if that version is supported or False otherwise.
+        :return type: bool
+        """
+        return LooseVersion(minimum_version) <= LooseVersion(BITMASK_VERSION)
diff --git a/src/leap/bitmask/provider/providerbootstrapper.py b/src/leap/bitmask/provider/providerbootstrapper.py
index 947ba0c9..695b1593 100644
--- a/src/leap/bitmask/provider/providerbootstrapper.py
+++ b/src/leap/bitmask/provider/providerbootstrapper.py
@@ -30,6 +30,7 @@ from leap.bitmask import util
 from leap.bitmask.util.constants import REQUEST_TIMEOUT
 from leap.bitmask.services.abstractbootstrapper import AbstractBootstrapper
 from leap.bitmask.provider.supportedapis import SupportedAPIs
+from leap.bitmask.provider import SupportedClient
 from leap.common import ca_bundle
 from leap.common.certs import get_digest
 from leap.common.files import check_and_fix_urw_only, get_mtime, mkdir_p
@@ -45,6 +46,14 @@ class UnsupportedProviderAPI(Exception):
     pass
 
 
+class UnsupportedClientVersionError(Exception):
+    """
+    Raised when attempting to use a provider with an older
+    client than supported.
+    """
+    pass
+
+
 class WrongFingerprint(Exception):
     """
     Raised when a fingerprint comparison does not match.
@@ -59,6 +68,8 @@ class ProviderBootstrapper(AbstractBootstrapper):
     If a check fails, the subsequent checks are not executed
     """
 
+    MIN_CLIENT_VERSION = 'x-minimum-client-version'
+
     def __init__(self, signaler=None, bypass_checks=False):
         """
         Constructor for provider bootstrapper object
@@ -187,6 +198,8 @@ class ProviderBootstrapper(AbstractBootstrapper):
         res.raise_for_status()
         logger.debug("Request status code: {0}".format(res.status_code))
 
+        min_client_version = res.headers.get(self.MIN_CLIENT_VERSION, '0')
+
         # Not modified
         if res.status_code == 304:
             logger.debug("Provider definition has not been modified")
@@ -194,6 +207,10 @@ class ProviderBootstrapper(AbstractBootstrapper):
         # end refactor, more or less...
         # XXX Watch out, have to check the supported api yet.
         else:
+            if not SupportedClient.supports(min_client_version):
+                self._signaler.signal(self._signaler.PROV_UNSUPPORTED_CLIENT)
+                raise UnsupportedClientVersionError()
+
             provider_definition, mtime = get_content(res)
 
             provider_config = ProviderConfig()