#7 Basic flask app. Setup routes, DB, and made a user model. Made initial migrations

backend/.env.example

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+FLASK_APP=main.py

backend/app/__init__.py

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+from flask import Flask
+from flask_sqlalchemy import SQLAlchemy
+from flask_migrate import Migrate
+from flask_login import LoginManager
+from config import Config
+
+
+db = SQLAlchemy()
+migrate = Migrate()
+login = LoginManager()
+login.login_view = "login"
+login.login_message = "Please log in to access this page."
+
+
+def create_app(config_class=Config):
+    app = Flask(__name__)
+    app.config.from_object(config_class)
+
+    db.init_app(app)
+    migrate.init_app(app, db)
+    login.init_app(app)
+
+    app.app_context().push()
+
+    from app.bp import bp as main_bp
+
+    app.register_blueprint(main_bp)
+
+    app.app_context()
+    return app
+
+
+from app import models

backend/app/bp.py

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+from flask import Blueprint
+
+bp = Blueprint('index', __name__)
+
+from app import routes

backend/app/errors.py

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+from flask import jsonify
+from werkzeug.http import HTTP_STATUS_CODES
+
+
+def error_response(status_code, message=None):
+    payload = {"error": HTTP_STATUS_CODES.get(status_code, "Unknown error")}
+    if message:
+        payload["message"] = message
+    response = jsonify(payload)
+    response.status_code = status_code
+    return response
+
+
+def bad_request(message):
+    return error_response(400, message)

backend/app/models.py

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+from app import db
+from flask_login import UserMixin
+from datetime import datetime
+
+
+class User(UserMixin, db.Model):
+    id = db.Column(db.Integer, primary_key=True)
+    username = db.Column(db.String(64), index=True, unique=True)
+    email = db.Column(db.String(120), index=True, unique=True)
+    password_hash = db.Column(db.String(128))
+    about_me = db.Column(db.String(140))
+    last_seen = db.Column(db.DateTime, default=datetime.utcnow)
+    token = db.Column(db.String(32), index=True, unique=True)
+
+    def to_dict(self):
+        return {
+            "id": self.id,
+            "username": self.username,
+            "email": self.email,
+            "about_me": self.about_me,
+        }

backend/app/routes.py

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+from app.bp import bp
+from flask import Response, jsonify, request
+from app.errors import error_response
+
+from app import db
+from app.models import User
+
+
+@bp.route("/login", methods=["POST"])
+def login():
+    data = request.get_json()
+    print(data)
+    if not data.get("user_id"):
+        return error_response(400, "Must supply user_id")
+
+    user = User.query.get(data.get("user_id"))
+    if not user:
+        return error_response(400, "User not found")
+
+    resp = jsonify(user.to_dict())
+    resp.status_code = 200
+    return resp

backend/config.py

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+import os
+from dotenv import load_dotenv
+
+basedir = os.path.abspath(os.path.dirname(__file__))
+load_dotenv(os.path.join(basedir, ".env"))
+
+
+class Config(object):
+    SECRET_KEY = os.environ.get("SECRET_KEY") or "you-will-never-guess"
+    SQLALCHEMY_DATABASE_URI = os.environ.get("DATABASE_URL", "").replace(
+        "postgres://", "postgresql://"
+    ) or "sqlite:///" + os.path.join(basedir, "app.db")
+    SQLALCHEMY_TRACK_MODIFICATIONS = True
+    ADMINS = ["your-email@example.com"]

backend/main.py

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+import dotenv
+dotenv.load_dotenv()
+
+from app import create_app, db
+
+app = create_app()
+
+@app.shell_context_processor
+def make_shell_context():
+    return {}
+

backend/migrations/README

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+Single-database configuration for Flask.

backend/migrations/alembic.ini

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+# A generic, single database configuration.
+
+[alembic]
+# template used to generate migration files
+# file_template = %%(rev)s_%%(slug)s
+
+# set to 'true' to run the environment during
+# the 'revision' command, regardless of autogenerate
+# revision_environment = false
+
+
+# Logging configuration
+[loggers]
+keys = root,sqlalchemy,alembic,flask_migrate
+
+[handlers]
+keys = console
+
+[formatters]
+keys = generic
+
+[logger_root]
+level = WARN
+handlers = console
+qualname =
+
+[logger_sqlalchemy]
+level = WARN
+handlers =
+qualname = sqlalchemy.engine
+
+[logger_alembic]
+level = INFO
+handlers =
+qualname = alembic
+
+[logger_flask_migrate]
+level = INFO
+handlers =
+qualname = flask_migrate
+
+[handler_console]
+class = StreamHandler
+args = (sys.stderr,)
+level = NOTSET
+formatter = generic
+
+[formatter_generic]
+format = %(levelname)-5.5s [%(name)s] %(message)s
+datefmt = %H:%M:%S

backend/migrations/env.py

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+import logging
+from logging.config import fileConfig
+
+from flask import current_app
+
+from alembic import context
+
+# this is the Alembic Config object, which provides
+# access to the values within the .ini file in use.
+config = context.config
+
+# Interpret the config file for Python logging.
+# This line sets up loggers basically.
+fileConfig(config.config_file_name)
+logger = logging.getLogger('alembic.env')
+
+
+def get_engine():
+    try:
+        # this works with Flask-SQLAlchemy<3 and Alchemical
+        return current_app.extensions['migrate'].db.get_engine()
+    except TypeError:
+        # this works with Flask-SQLAlchemy>=3
+        return current_app.extensions['migrate'].db.engine
+
+
+def get_engine_url():
+    try:
+        return get_engine().url.render_as_string(hide_password=False).replace(
+            '%', '%%')
+    except AttributeError:
+        return str(get_engine().url).replace('%', '%%')
+
+
+# add your model's MetaData object here
+# for 'autogenerate' support
+# from myapp import mymodel
+# target_metadata = mymodel.Base.metadata
+config.set_main_option('sqlalchemy.url', get_engine_url())
+target_db = current_app.extensions['migrate'].db
+
+# other values from the config, defined by the needs of env.py,
+# can be acquired:
+# my_important_option = config.get_main_option("my_important_option")
+# ... etc.
+
+
+def get_metadata():
+    if hasattr(target_db, 'metadatas'):
+        return target_db.metadatas[None]
+    return target_db.metadata
+
+
+def run_migrations_offline():
+    """Run migrations in 'offline' mode.
+
+    This configures the context with just a URL
+    and not an Engine, though an Engine is acceptable
+    here as well.  By skipping the Engine creation
+    we don't even need a DBAPI to be available.
+
+    Calls to context.execute() here emit the given string to the
+    script output.
+
+    """
+    url = config.get_main_option("sqlalchemy.url")
+    context.configure(
+        url=url, target_metadata=get_metadata(), literal_binds=True
+    )
+
+    with context.begin_transaction():
+        context.run_migrations()
+
+
+def run_migrations_online():
+    """Run migrations in 'online' mode.
+
+    In this scenario we need to create an Engine
+    and associate a connection with the context.
+
+    """
+
+    # this callback is used to prevent an auto-migration from being generated
+    # when there are no changes to the schema
+    # reference: http://alembic.zzzcomputing.com/en/latest/cookbook.html
+    def process_revision_directives(context, revision, directives):
+        if getattr(config.cmd_opts, 'autogenerate', False):
+            script = directives[0]
+            if script.upgrade_ops.is_empty():
+                directives[:] = []
+                logger.info('No changes in schema detected.')
+
+    connectable = get_engine()
+
+    with connectable.connect() as connection:
+        context.configure(
+            connection=connection,
+            target_metadata=get_metadata(),
+            process_revision_directives=process_revision_directives,
+            **current_app.extensions['migrate'].configure_args
+        )
+
+        with context.begin_transaction():
+            context.run_migrations()
+
+
+if context.is_offline_mode():
+    run_migrations_offline()
+else:
+    run_migrations_online()

backend/migrations/script.py.mako

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+"""${message}
+
+Revision ID: ${up_revision}
+Revises: ${down_revision | comma,n}
+Create Date: ${create_date}
+
+"""
+from alembic import op
+import sqlalchemy as sa
+${imports if imports else ""}
+
+# revision identifiers, used by Alembic.
+revision = ${repr(up_revision)}
+down_revision = ${repr(down_revision)}
+branch_labels = ${repr(branch_labels)}
+depends_on = ${repr(depends_on)}
+
+
+def upgrade():
+    ${upgrades if upgrades else "pass"}
+
+
+def downgrade():
+    ${downgrades if downgrades else "pass"}

backend/migrations/versions/7736bc740f9b_.py

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+"""empty message
+
+Revision ID: 7736bc740f9b
+Revises: 
+Create Date: 2023-03-16 19:20:29.115598
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = '7736bc740f9b'
+down_revision = None
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.create_table('user',
+    sa.Column('id', sa.Integer(), nullable=False),
+    sa.Column('username', sa.String(length=64), nullable=True),
+    sa.Column('email', sa.String(length=120), nullable=True),
+    sa.Column('password_hash', sa.String(length=128), nullable=True),
+    sa.Column('about_me', sa.String(length=140), nullable=True),
+    sa.Column('last_seen', sa.DateTime(), nullable=True),
+    sa.Column('token', sa.String(length=32), nullable=True),
+    sa.PrimaryKeyConstraint('id')
+    )
+    with op.batch_alter_table('user', schema=None) as batch_op:
+        batch_op.create_index(batch_op.f('ix_user_email'), ['email'], unique=True)
+        batch_op.create_index(batch_op.f('ix_user_token'), ['token'], unique=True)
+        batch_op.create_index(batch_op.f('ix_user_username'), ['username'], unique=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_index(batch_op.f('ix_user_username'))
+        batch_op.drop_index(batch_op.f('ix_user_token'))
+        batch_op.drop_index(batch_op.f('ix_user_email'))
+
+    op.drop_table('user')
+    # ### end Alembic commands ###

backend/pyrightconfig.json

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+{
+  "venvPath": ".",
+  "venv": "venv",
+  "useLibraryCodeForTypes": true
+}