webui: Implement login support (password authentication)

4 files changed, 105 insertions, 0 deletions

diff --git a/fg21sim/webui/handlers/__init__.py b/fg21sim/webui/handlers/__init__.py
new file mode 100644
index 0000000..f97ef07
--- /dev/null
+++ b/fg21sim/webui/handlers/__init__.py
@@ -0,0 +1,5 @@
+# Copyright (c) 2016 Weitian LI <liweitianux@live.com>
+# MIT license
+
+from .index import IndexHandler
+from .login import LoginHandler
diff --git a/fg21sim/webui/handlers/base.py b/fg21sim/webui/handlers/base.py
new file mode 100644
index 0000000..5a6e3a9
--- /dev/null
+++ b/fg21sim/webui/handlers/base.py
@@ -0,0 +1,30 @@
+# Copyright (c) 2016 Weitian LI <liweitianux@live.com>
+# MIT license
+
+"""
+Base handler for other handlers
+"""
+
+
+import tornado.web
+from tornado.options import options
+
+
+class BaseRequestHandler(tornado.web.RequestHandler):
+    def get_current_user(self):
+        """
+        Override the ``get_current_user()`` method to implement user
+        authentication.
+
+        Determine the current user based on the value of a cookie.
+
+        References
+        ----------
+        - Tornado: Authentication and security
+          http://www.tornadoweb.org/en/stable/guide/security.html
+        """
+        if (options.password is None) or (options.password == ""):
+            # Password not set, then all accesses are allowed
+            return True
+        else:
+            return self.get_secure_cookie("user")
diff --git a/fg21sim/webui/handlers/login.py b/fg21sim/webui/handlers/login.py
new file mode 100644
index 0000000..4529005
--- /dev/null
+++ b/fg21sim/webui/handlers/login.py
@@ -0,0 +1,40 @@
+# Copyright (c) 2016 Weitian LI <liweitianux@live.com>
+# MIT license
+
+"""
+Login handler
+"""
+
+from tornado.options import options
+from tornado.escape import xhtml_escape
+
+from .base import BaseRequestHandler
+
+
+class LoginHandler(BaseRequestHandler):
+    """
+    Login page handler of the Web UI.
+
+    NOTE
+    ----
+    Only check the password to authenticate the access, therefore, the
+    default username "FG21SIM" is used.
+    """
+    def get(self):
+        if (options.password is None) or (options.password == ""):
+            # Password is not set, just allow
+            self.redirect(self.reverse_url("index"))
+        elif self.current_user:
+            # Already authenticated
+            self.redirect(self.reverse_url("index"))
+        else:
+            self.render("login.html", error="")
+
+    def post(self):
+        password = xhtml_escape(self.get_argument("password"))
+        if password == options.password:
+            self.set_secure_cookie("user", "FG21SIM")
+            self.redirect(self.reverse_url("index"))
+        else:
+            # Password incorrect
+            self.render("login.html", error="Incorrect password!")
diff --git a/fg21sim/webui/templates/login.html b/fg21sim/webui/templates/login.html
new file mode 100644
index 0000000..51d4cd1
--- /dev/null
+++ b/fg21sim/webui/templates/login.html
@@ -0,0 +1,30 @@
+{#
+ # Copyright (c) 2016 Weitian LI <liweitianux@live.com>
+ # MIT license
+ #
+ # Login page for the Web UI of "fg21sim"
+ #}
+
+{% extends "base.html" %}
+
+{% block subtitle %}Login |{% end %}
+
+{% block main %}
+<section id="login">
+  <h2><span class="fa fa-key" aria-hidden="true"></span> Login</h2>
+  <hr />
+
+  <form action="/login" method="post">
+    {% module xsrf_form_html() %}
+    <fieldset>
+      <label for="password">Password:
+        {% if (error != "") %}
+        <span class="label label-warning">{{ error }}</span>
+        {% end %}
+      </label>
+      <input class="form-control" type="password" id="password" name="password" required />
+      <button type="submit">Login</button>
+    </fieldset>
+  </form>
+</section>
+{% end %}