Add template of OTP verification page

The presenter does not do anything.

Fixes: pypa#996

tests/unit/test_routes.py

@@ -123,6 +123,7 @@ def add_policy(name, filename):
             domain=warehouse,
         ),
         pretend.call("accounts.login", "/account/login/", domain=warehouse),
+        pretend.call("accounts.two-factor", "/account/two-factor/", domain=warehouse),
         pretend.call("accounts.logout", "/account/logout/", domain=warehouse),
         pretend.call("accounts.register", "/account/register/", domain=warehouse),
         pretend.call(

warehouse/accounts/forms.py

@@ -32,6 +32,11 @@ def validate_username(self, field):
             raise wtforms.validators.ValidationError("No user found with that username")
 
 
+class OtpCodeMixin:
+
+    otp_code = wtforms.StringField(validators=[wtforms.validators.DataRequired()])
+
+
 class NewUsernameMixin:
 
     username = wtforms.StringField(
@@ -219,6 +224,12 @@ def validate_password(self, field):
                 )
 
 
+class TwoFactorForm(OtpCodeMixin, forms.Form):
+    def __init__(self, *args, user_service, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.user_service = user_service
+
+
 class RequestPasswordResetForm(forms.Form):
     username_or_email = wtforms.StringField(
         validators=[wtforms.validators.DataRequired()]

warehouse/accounts/views.py

@@ -30,6 +30,7 @@
     RegistrationForm,
     RequestPasswordResetForm,
     ResetPasswordForm,
+    TwoFactorForm,
 )
 from warehouse.accounts.interfaces import (
     IPasswordBreachedService,
@@ -156,6 +157,45 @@ def login(request, redirect_field_name=REDIRECT_FIELD_NAME, _form_class=LoginFor
     }
 
 
+@view_config(
+    route_name="accounts.two-factor",
+    renderer="accounts/two-factor.html",
+    uses_session=True,
+    require_csrf=True,
+    require_methods=False,
+)
+def two_factor(request, redirect_field_name=REDIRECT_FIELD_NAME,
+               _form_class=TwoFactorForm):
+    if request.authenticated_userid is not None:
+        return HTTPSeeOther(request.route_path("manage.projects"))
+
+    user_service = request.find_service(IUserService, context=None)
+
+    redirect_to = request.POST.get(
+        redirect_field_name, request.GET.get(redirect_field_name)
+    )
+
+    form = _form_class(request.POST, user_service=user_service)
+
+    if request.method == "POST":
+        request.registry.datadog.increment(
+            "warehouse.authentication.two-factor.start",
+            tags=["auth_method:two_factor_form"]
+        )
+        if form.validate():
+            pass  # TODO: replace by call of OTP validation method
+        else:
+            request.registry.datadog.increment(
+                "warehouse.authentication.two-factor.failure",
+                tags=["auth_method:two_factor_form"]
+            )
+
+    return {
+        "form": form,
+        "redirect": {"field": REDIRECT_FIELD_NAME, "data": redirect_to},
+    }
+
+
 @view_config(
     route_name="accounts.logout",
     renderer="accounts/logout.html",
@@ -429,8 +469,8 @@ def _login_user(request, userid):
     # that we create a new session (which will cause it to get a new
     # session identifier).
     if (
-        request.unauthenticated_userid is not None
-        and request.unauthenticated_userid != userid
+            request.unauthenticated_userid is not None
+            and request.unauthenticated_userid != userid
     ):
         # There is already a userid associated with this request and it is
         # a different userid than the one we're trying to remember now. In

warehouse/routes.py

@@ -98,6 +98,7 @@ def includeme(config):
         domain=warehouse,
     )
     config.add_route("accounts.login", "/account/login/", domain=warehouse)
+    config.add_route("accounts.two-factor", "/account/two-factor/", domain=warehouse)
     config.add_route("accounts.logout", "/account/logout/", domain=warehouse)
     config.add_route("accounts.register", "/account/register/", domain=warehouse)
     config.add_route(

warehouse/templates/accounts/two-factor.html

@@ -0,0 +1,67 @@
+{#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+-#}
+{% extends "base.html" %}
+
+{% block title %}Log in{% endblock %}
+
+{% block content %}
+{% if testPyPI %}
+{% set title = "TestPyPI" %}
+{% else %}
+{% set title = "PyPI" %}
+{% endif %}
+
+<section class="horizontal-section">
+    <div class="site-container">
+        <h1 class="page-title">Two-factor authentication</h1>
+
+        <form method="POST" action="{{ request.current_route_path() }}">
+            <input name="csrf_token" type="hidden" value="{{ request.session.get_csrf_token() }}">
+
+            {% if redirect.data %}
+            <input name="{{ redirect.field }}" type="hidden" value="{{ redirect.data }}">
+            {% endif %}
+
+            {% if form.errors.__all__ %}
+            <ul class="form-errors">
+                {% for error in form.errors.__all__ %}
+                <li>{{ error }}</li>
+                {% endfor %}
+            </ul>
+            {% endif %}
+
+            <div class="form-group">
+                <label for="otp_code" class="form-group__label">Authentication code</label>
+                {{ form.otp_code(placeholder="Authentication code", autocorrect="off", autocapitalize="off", spellcheck="false", required="required", class_="form-group__input", tabindex="1", autofocus=true) }}
+                {% if form.otp_code.errors %}
+                <ul class="form-errors">
+                    {% for error in form.otp_code.errors %}
+                    <li>{{ error }}</li>
+                    {% endfor %}
+                </ul>
+                {% endif %}
+            </div>
+
+            <div class="form-group">
+                <div class="split-layout split-layout--table">
+                    <div>
+                        <input type="submit" value="Verify" class="button button--primary" tabindex="3">
+                    </div>
+            <span></span>
+                </div>
+            </div>
+        </form>
+    </div>
+</section>
+{% endblock %}