Chapter 21: User Notifications (v0.21)

app/main/forms.py

@@ -41,3 +41,9 @@ class SearchForm(FlaskForm):
         if 'meta' not in kwargs:
             kwargs['meta'] = {'csrf': False}
         super(SearchForm, self).__init__(*args, **kwargs)
+
+
+class MessageForm(FlaskForm):
+    message = TextAreaField(_l('Message'), validators=[
+        DataRequired(), Length(min=1, max=140)])
+    submit = SubmitField(_l('Submit'))

app/main/routes.py

@@ -5,8 +5,9 @@ from flask_login import current_user, login_required
 from flask_babel import _, get_locale
 from langdetect import detect, LangDetectException
 from app import db
-from app.main.forms import EditProfileForm, EmptyForm, PostForm, SearchForm
+from app.main.forms import EditProfileForm, EmptyForm, PostForm, SearchForm, \
-from app.models import User, Post
+    MessageForm
+from app.models import User, Post, Message, Notification
 from app.translate import translate
 from app.main import bp
 
@@ -170,3 +171,52 @@ def search():
         if page > 1 else None
     return render_template('search.html', title=_('Search'), posts=posts,
                            next_url=next_url, prev_url=prev_url)
+
+
+@bp.route('/send_message/<recipient>', methods=['GET', 'POST'])
+@login_required
+def send_message(recipient):
+    user = User.query.filter_by(username=recipient).first_or_404()
+    form = MessageForm()
+    if form.validate_on_submit():
+        msg = Message(author=current_user, recipient=user,
+                      body=form.message.data)
+        db.session.add(msg)
+        user.add_notification('unread_message_count', user.new_messages())
+        db.session.commit()
+        flash(_('Your message has been sent.'))
+        return redirect(url_for('main.user', username=recipient))
+    return render_template('send_message.html', title=_('Send Message'),
+                           form=form, recipient=recipient)
+
+
+@bp.route('/messages')
+@login_required
+def messages():
+    current_user.last_message_read_time = datetime.utcnow()
+    current_user.add_notification('unread_message_count', 0)
+    db.session.commit()
+    page = request.args.get('page', 1, type=int)
+    messages = current_user.messages_received.order_by(
+        Message.timestamp.desc()).paginate(
+            page=page, per_page=current_app.config['POSTS_PER_PAGE'],
+            error_out=False)
+    next_url = url_for('main.messages', page=messages.next_num) \
+        if messages.has_next else None
+    prev_url = url_for('main.messages', page=messages.prev_num) \
+        if messages.has_prev else None
+    return render_template('messages.html', messages=messages.items,
+                           next_url=next_url, prev_url=prev_url)
+
+
+@bp.route('/notifications')
+@login_required
+def notifications():
+    since = request.args.get('since', 0.0, type=float)
+    notifications = current_user.notifications.filter(
+        Notification.timestamp > since).order_by(Notification.timestamp.asc())
+    return jsonify([{
+        'name': n.name,
+        'data': n.get_data(),
+        'timestamp': n.timestamp
+    } for n in notifications])

app/models.py

@@ -1,5 +1,6 @@
 from datetime import datetime
 from hashlib import md5
+import json
 from time import time
 from flask import current_app
 from flask_login import UserMixin
@@ -79,6 +80,16 @@ class User(UserMixin, db.Model):
         primaryjoin=(followers.c.followed_id == id),
         secondaryjoin=(followers.c.follower_id == id),
         lazy='dynamic', back_populates='following')
+    messages_sent = db.relationship('Message',
+                                    foreign_keys='Message.sender_id',
+                                    lazy='dynamic', back_populates='author')
+    messages_received = db.relationship('Message',
+                                        foreign_keys='Message.recipient_id',
+                                        lazy='dynamic',
+                                        back_populates='recipient')
+    last_message_read_time = db.Column(db.DateTime)
+    notifications = db.relationship('Notification', lazy='dynamic',
+                                    back_populates='user')
 
     def __repr__(self):
         return '<User {}>'.format(self.username)
@@ -125,6 +136,17 @@ class User(UserMixin, db.Model):
             return
         return User.query.get(id)
 
+    def new_messages(self):
+        last_read_time = self.last_message_read_time or datetime(1900, 1, 1)
+        return Message.query.filter_by(recipient=self).filter(
+            Message.timestamp > last_read_time).count()
+
+    def add_notification(self, name, data):
+        self.notifications.filter_by(name=name).delete()
+        n = Notification(name=name, payload_json=json.dumps(data), user=self)
+        db.session.add(n)
+        return n
+
 
 @login.user_loader
 def load_user(id):
@@ -142,3 +164,30 @@ class Post(SearchableMixin, db.Model):
 
     def __repr__(self):
         return '<Post {}>'.format(self.body)
+
+
+class Message(db.Model):
+    id = db.Column(db.Integer, primary_key=True)
+    sender_id = db.Column(db.Integer, db.ForeignKey('user.id'), index=True)
+    recipient_id = db.Column(db.Integer, db.ForeignKey('user.id'), index=True)
+    body = db.Column(db.String(140))
+    timestamp = db.Column(db.DateTime, index=True, default=datetime.utcnow)
+    author = db.relationship('User', foreign_keys='Message.sender_id',
+                             back_populates='messages_sent')
+    recipient = db.relationship('User', foreign_keys='Message.recipient_id',
+                                back_populates='messages_received')
+
+    def __repr__(self):
+        return '<Message {}>'.format(self.body)
+
+
+class Notification(db.Model):
+    id = db.Column(db.Integer, primary_key=True)
+    name = db.Column(db.String(128), index=True)
+    user_id = db.Column(db.Integer, db.ForeignKey('user.id'), index=True)
+    timestamp = db.Column(db.Float, index=True, default=time)
+    payload_json = db.Column(db.Text)
+    user = db.relationship('User', back_populates='notifications')
+
+    def get_data(self):
+        return json.loads(str(self.payload_json))

app/templates/base.html

@@ -39,6 +39,16 @@
               <a class="nav-link" aria-current="page" href="{{ url_for('auth.login') }}">{{ _('Login') }}</a>
             </li>
             {% else %}
+            <li class="nav-item">
+              <a class="nav-link" aria-current="page" href="{{ url_for('main.messages') }}">{{ _('Messages') }}
+                {% set new_messages = current_user.new_messages() %}
+                <span id="message_count" class="badge text-bg-danger"
+                      style="visibility: {% if new_messages %}visible
+                                         {% else %}hidden{% endif %};">
+                    {{ new_messages }}
+                </span>
+              </a>
+            </li>
             <li class="nav-item">
               <a class="nav-link" aria-current="page" href="{{ url_for('main.user', username=current_user.username) }}">{{ _('Profile') }}</a>
             </li>
@@ -109,6 +119,28 @@
         }
       }
       document.addEventListener('DOMContentLoaded', initialize_popovers);
+
+      function set_message_count(n) {
+        const count = document.getElementById('message_count');
+        count.innerText = n;
+        count.style.visibility = n ? 'visible' : 'hidden';
+      }
+
+      {% if current_user.is_authenticated %}
+      function initialize_notifications() {
+        let since = 0;
+        setInterval(async function() {
+          const response = await fetch('{{ url_for('main.notifications') }}?since=' + since);
+          const notifications = await response.json();
+          for (let i = 0; i < notifications.length; i++) {
+            if (notifications[i].name == 'unread_message_count')
+              set_message_count(notifications[i].data);
+            since = notifications[i].timestamp;
+          }
+        }, 10000);
+      }
+      document.addEventListener('DOMContentLoaded', initialize_notifications);
+      {% endif %}
     </script>
   </body>
 </html>

app/templates/messages.html

@@ -0,0 +1,22 @@
+{% extends "base.html" %}
+
+{% block content %}
+    <h1>{{ _('Messages') }}</h1>
+    {% for post in messages %}
+        {% include '_post.html' %}
+    {% endfor %}
+    <nav aria-label="Post navigation">
+        <ul class="pagination">
+            <li class="page-item{% if not prev_url %} disabled{% endif %}">
+                <a class="page-link" href="#">
+                    <span aria-hidden="true">&larr;</span> {{ _('Newer messages') }}
+                </a>
+            </li>
+            <li class="page-item{% if not next_url %} disabled{% endif %}">
+                <a class="page-link" href="#">
+                    {{ _('Older messages') }} <span aria-hidden="true">&rarr;</span>
+                </a>
+            </li>
+        </ul>
+    </nav>
+{% endblock %}

app/templates/send_message.html

@@ -0,0 +1,7 @@
+{% extends "base.html" %}
+{% import "bootstrap_wtf.html" as wtf %}
+
+{% block content %}
+    <h1>{{ _('Send Message to %(recipient)s', recipient=recipient) }}</h1>
+    {{ wtf.quick_form(form) }}
+{% endblock %}

app/templates/user.html

@@ -28,6 +28,9 @@
                     </form>
                 </p>
                 {% endif %}
+                {% if user != current_user %}
+                <p><a href="{{ url_for('main.send_message', recipient=user.username) }}">{{ _('Send private message') }}</a></p>
+                {% endif %}
             </td>
         </tr>
     </table>

app/translations/es/LC_MESSAGES/messages.po

@@ -7,7 +7,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: PROJECT VERSION\n"
 "Report-Msgid-Bugs-To: EMAIL@ADDRESS\n"
-"POT-Creation-Date: 2017-11-25 18:23-0800\n"
+"POT-Creation-Date: 2017-11-25 18:26-0800\n"
 "PO-Revision-Date: 2017-09-29 23:25-0700\n"
 "Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
 "Language: es\n"
@@ -94,7 +94,7 @@ msgstr "Tu contraseña ha sido cambiada."
 msgid "About me"
 msgstr "Acerca de mí"
 
-#: app/main/forms.py:13 app/main/forms.py:28
+#: app/main/forms.py:13 app/main/forms.py:28 app/main/forms.py:44
 msgid "Submit"
 msgstr "Enviar"
 
@@ -106,47 +106,59 @@ msgstr "Dí algo"
 msgid "Search"
 msgstr "Buscar"
 
+#: app/main/forms.py:43
+msgid "Message"
+msgstr "Mensaje"
+
 #: app/main/routes.py:36
 msgid "Your post is now live!"
 msgstr "¡Tu artículo ha sido publicado!"
 
-#: app/main/routes.py:87
+#: app/main/routes.py:94
 msgid "Your changes have been saved."
 msgstr "Tus cambios han sido salvados."
 
-#: app/main/routes.py:92 app/templates/edit_profile.html:5
+#: app/main/routes.py:99 app/templates/edit_profile.html:5
 msgid "Edit Profile"
 msgstr "Editar Perfil"
 
-#: app/main/routes.py:101 app/main/routes.py:117
+#: app/main/routes.py:108 app/main/routes.py:124
 #, python-format
 msgid "User %(username)s not found."
 msgstr "El usuario %(username)s no ha sido encontrado."
 
-#: app/main/routes.py:104
+#: app/main/routes.py:111
 msgid "You cannot follow yourself!"
 msgstr "¡No te puedes seguir a tí mismo!"
 
-#: app/main/routes.py:108
+#: app/main/routes.py:115
 #, python-format
 msgid "You are following %(username)s!"
 msgstr "¡Ahora estás siguiendo a %(username)s!"
 
-#: app/main/routes.py:120
+#: app/main/routes.py:127
 msgid "You cannot unfollow yourself!"
 msgstr "¡No te puedes dejar de seguir a tí mismo!"
 
-#: app/main/routes.py:124
+#: app/main/routes.py:131
 #, python-format
 msgid "You are not following %(username)s."
 msgstr "No estás siguiendo a %(username)s."
 
-#: app/templates/_post.html:14
+#: app/main/routes.py:170
+msgid "Your message has been sent."
+msgstr "Tu mensaje ha sido enviado."
+
+#: app/main/routes.py:172
+msgid "Send Message"
+msgstr "Enviar Mensaje"
+
+#: app/templates/_post.html:16
 #, python-format
 msgid "%(username)s said %(when)s"
 msgstr "%(username)s dijo %(when)s"
 
-#: app/templates/_post.html:25
+#: app/templates/_post.html:27
 msgid "Translate"
 msgstr "Traducir"
 
@@ -166,15 +178,19 @@ msgstr "Explorar"
 msgid "Login"
 msgstr "Ingresar"
 
-#: app/templates/base.html:35
+#: app/templates/base.html:36 app/templates/messages.html:4
+msgid "Messages"
+msgstr "Mensajes"
+
+#: app/templates/base.html:45
 msgid "Profile"
 msgstr "Perfil"
 
-#: app/templates/base.html:36
+#: app/templates/base.html:46
 msgid "Logout"
 msgstr "Salir"
 
-#: app/templates/base.html:73
+#: app/templates/base.html:83
 msgid "Error: Could not contact server."
 msgstr "Error: el servidor no pudo ser contactado."
 
@@ -183,40 +199,53 @@ msgstr "Error: el servidor no pudo ser contactado."
 msgid "Hi, %(username)s!"
 msgstr "¡Hola, %(username)s!"
 
-#: app/templates/index.html:17 app/templates/user.html:31
+#: app/templates/index.html:17 app/templates/user.html:34
 msgid "Newer posts"
 msgstr "Artículos siguientes"
 
-#: app/templates/index.html:22 app/templates/user.html:36
+#: app/templates/index.html:22 app/templates/user.html:39
 msgid "Older posts"
 msgstr "Artículos previos"
 
+#: app/templates/messages.html:12
+msgid "Newer messages"
+msgstr "Mensajes siguientes"
+
+#: app/templates/messages.html:17
+msgid "Older messages"
+msgstr "Mensajes previos"
+
 #: app/templates/search.html:4
 msgid "Search Results"
-msgstr "Resultados de Búsqueda"
+msgstr ""
 
 #: app/templates/search.html:12
 msgid "Previous results"
-msgstr "Resultados previos"
+msgstr ""
 
 #: app/templates/search.html:17
 msgid "Next results"
-msgstr "Resultados próximos"
+msgstr ""
+
+#: app/templates/send_message.html:5
+#, python-format
+msgid "Send Message to %(recipient)s"
+msgstr "Enviar Mensaje a %(recipient)s"
 
 #: app/templates/user.html:8
 msgid "User"
 msgstr "Usuario"
 
-#: app/templates/user.html:11
+#: app/templates/user.html:11 app/templates/user_popup.html:9
 msgid "Last seen on"
 msgstr "Última visita"
 
-#: app/templates/user.html:13
+#: app/templates/user.html:13 app/templates/user_popup.html:11
 #, python-format
 msgid "%(count)d followers"
 msgstr "%(count)d seguidores"
 
-#: app/templates/user.html:13
+#: app/templates/user.html:13 app/templates/user_popup.html:11
 #, python-format
 msgid "%(count)d following"
 msgstr "siguiendo a %(count)d"
@@ -225,14 +254,18 @@ msgstr "siguiendo a %(count)d"
 msgid "Edit your profile"
 msgstr "Editar tu perfil"
 
-#: app/templates/user.html:17
+#: app/templates/user.html:17 app/templates/user_popup.html:14
 msgid "Follow"
 msgstr "Seguir"
 
-#: app/templates/user.html:19
+#: app/templates/user.html:19 app/templates/user_popup.html:16
 msgid "Unfollow"
 msgstr "Dejar de seguir"
 
+#: app/templates/user.html:22
+msgid "Send private message"
+msgstr "Enviar mensaje privado"
+
 #: app/templates/auth/login.html:12
 msgid "New User?"
 msgstr "¿Usuario Nuevo?"

microblog.py

@@ -1,9 +1,10 @@
 from app import create_app, db
-from app.models import User, Post
+from app.models import User, Post, Message, Notification
 
 app = create_app()
 
 
 @app.shell_context_processor
 def make_shell_context():
-    return {'db': db, 'User': User, 'Post': Post}
+    return {'db': db, 'User': User, 'Post': Post, 'Message': Message,
+            'Notification': Notification}

migrations/versions/d049de007ccf_private_messages.py

@@ -0,0 +1,53 @@
+"""private messages
+
+Revision ID: d049de007ccf
+Revises: 834b1a697901
+Create Date: 2017-11-12 23:30:28.571784
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = 'd049de007ccf'
+down_revision = '2b017edaa91f'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.create_table('message',
+    sa.Column('id', sa.Integer(), nullable=False),
+    sa.Column('sender_id', sa.Integer(), nullable=True),
+    sa.Column('recipient_id', sa.Integer(), nullable=True),
+    sa.Column('body', sa.String(length=140), nullable=True),
+    sa.Column('timestamp', sa.DateTime(), nullable=True),
+    sa.ForeignKeyConstraint(['recipient_id'], ['user.id'], ),
+    sa.ForeignKeyConstraint(['sender_id'], ['user.id'], ),
+    sa.PrimaryKeyConstraint('id')
+    )
+
+    with op.batch_alter_table('message', schema=None) as batch_op:
+        batch_op.create_index(batch_op.f('ix_message_recipient_id'), ['recipient_id'], unique=False)
+        batch_op.create_index(batch_op.f('ix_message_sender_id'), ['sender_id'], unique=False)
+        batch_op.create_index(batch_op.f('ix_message_timestamp'), ['timestamp'], unique=False)
+
+    with op.batch_alter_table('user', schema=None) as batch_op:
+        batch_op.add_column(sa.Column('last_message_read_time', sa.DateTime(), nullable=True))
+    # ### end Alembic commands ###
+
+
+def downgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    with op.batch_alter_table('user', schema=None) as batch_op:
+        batch_op.drop_column('last_message_read_time')
+
+    with op.batch_alter_table('notification', schema=None) as batch_op:
+        batch_op.drop_index(batch_op.f('ix_notification_timestamp'))
+        batch_op.drop_index(batch_op.f('ix_message_sender_id'))
+        batch_op.drop_index(batch_op.f('ix_message_recipient_id'))
+
+    op.drop_table('message')
+    # ### end Alembic commands ###

migrations/versions/f7ac3d27bb1d_notifications.py

@@ -0,0 +1,46 @@
+"""notifications
+
+Revision ID: f7ac3d27bb1d
+Revises: d049de007ccf
+Create Date: 2017-11-22 19:48:39.945858
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = 'f7ac3d27bb1d'
+down_revision = 'd049de007ccf'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.create_table('notification',
+    sa.Column('id', sa.Integer(), nullable=False),
+    sa.Column('name', sa.String(length=128), nullable=True),
+    sa.Column('user_id', sa.Integer(), nullable=True),
+    sa.Column('timestamp', sa.Float(), nullable=True),
+    sa.Column('payload_json', sa.Text(), nullable=True),
+    sa.ForeignKeyConstraint(['user_id'], ['user.id'], ),
+    sa.PrimaryKeyConstraint('id')
+    )
+
+    with op.batch_alter_table('notification', schema=None) as batch_op:
+        batch_op.create_index(batch_op.f('ix_notification_name'), ['name'], unique=False)
+        batch_op.create_index(batch_op.f('ix_notification_timestamp'), ['timestamp'], unique=False)
+        batch_op.create_index(batch_op.f('ix_notification_user_id'), ['user_id'], unique=False)
+    # ### end Alembic commands ###
+
+
+def downgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    with op.batch_alter_table('notification', schema=None) as batch_op:
+        batch_op.drop_index(batch_op.f('ix_notification_user_id'))
+        batch_op.drop_index(batch_op.f('ix_notification_timestamp'))
+        batch_op.drop_index(batch_op.f('ix_notification_name'))
+
+    op.drop_table('notification')
+    # ### end Alembic commands ###