Import test code, add small Flask server

Signed-off-by: Emmy D'Anello <ynerant@emy.lu>

.gitignore

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+__pycache__
+.idea
+env
+venv
+instance/
+
+config.py
+tgvmax.csv
+migrations/versions

app.py

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+#!/usr/bin/env python3
+
+import csv
+from datetime import date, datetime, time
+import os
+import json
+from pytz import timezone
+import requests
+
+from flask import Flask
+from flask_migrate import Migrate
+from flask_sqlalchemy import SQLAlchemy
+from sqlalchemy import Boolean, Column, Date, Integer, String, Time
+from tqdm import tqdm
+
+import config
+
+
+app = Flask(__name__)
+
+app.config |= config.FLASK_CONFIG
+
+db = SQLAlchemy(app)
+Migrate(app, db)
+
+
+class Train(db.Model):
+    __tablename__ = 'train'
+    id = Column(String, primary_key=True)
+    day = Column(Date, index=True)
+    number = Column(Integer, index=True)
+    entity = Column(String(255))
+    axe = Column(String(255), index=True)
+    orig_iata = Column(String(5), index=True)
+    dest_iata = Column(String(5), index=True)
+    orig = Column(String(255))
+    dest = Column(String(255))
+    dep = Column(String(255))
+    arr = Column(Time)
+    tgvmax = Column(Boolean, index=True)
+    remaining_seats = Column(Integer)
+
+
+def update_dataset():
+    try:
+        resp = requests.get('https://ressources.data.sncf.com/explore/dataset/tgvmax/information/')
+        content = resp.content.decode().split('<script type="application/ld+json">')[1].split('</script>')[0].strip()
+        content = content.replace('\r', '')
+        content = content.replace('" \n', '" \\n')
+        content = content.replace('.\n', '.\\n')
+        content = content.replace('\n\n \nLa', '\\n\\n \\nLa')
+        content = content.replace('\n"', '\\n"')
+
+        info = json.loads(content)
+        modified_date = datetime.fromisoformat(info['dateModified'])
+
+        utc = timezone('UTC')
+        last_modified = datetime.utcfromtimestamp(os.path.getmtime('tgvmax.csv')).replace(tzinfo=utc) if os.path.isfile('tgvmax.csv') else datetime(1, 1, 1, tzinfo=utc)
+
+        if last_modified < modified_date:
+            print("Updating tgvmax.csv…")
+            with requests.get(info['distribution'][0]['contentUrl'], stream=True) as resp:
+                resp.raise_for_status()
+                with open('tgvmax.csv', 'wb') as f:
+                    with tqdm(unit='io', unit_scale=True) as t:
+                        for chunk in resp.iter_content(chunk_size=512 * 1024):
+                            if chunk:
+                                f.write(chunk)
+                                t.update(len(chunk))
+            os.utime('tgvmax.csv', (modified_date.timestamp(), modified_date.timestamp()))
+            print("Done")
+
+        print("Last modification:", modified_date)
+    except Exception as e:
+        print("An error occured while updating tgvmax.csv")
+        print(e)
+
+
+def parse_trains(*, filter_day: date | None = None,
+                 filter_number: int | None = None,
+                 filter_tgvmax: bool | None = None):
+    trains = []
+
+    with open('tgvmax.csv') as f:
+        first_line = True
+        for line in csv.reader(f, delimiter=';'):
+            if first_line:
+                first_line = False
+                continue
+
+            train = Train(*line)
+            train.day = date.fromisoformat(train.day)
+            train.number = int(train.number)
+            train.dep = time.fromisoformat(train.dep)
+            train.arr = time.fromisoformat(train.arr)
+            train.tgvmax = train.tgvmax == 'OUI'
+
+            if filter_day is not None and train.day != filter_day:
+                continue
+
+            if filter_number is not None and train.number != filter_number:
+                continue
+
+            if filter_tgvmax is not None and train.tgvmax != filter_tgvmax:
+                continue
+
+            trains.append(train)
+
+    return trains
+
+
+def find_routes(day, orig, dest):
+    trains = parse_trains(filter_day=date(2023, 2, 17),
+                          filter_tgvmax=True)
+
+    trains.sort(key=lambda train: train.dep)
+
+    origin = "STRASBOURG"
+    dest = "LYON (intramuros)"
+
+    explore = []
+    per_arr_explore = {}
+    valid_routes = []
+
+    for train in tqdm(trains):
+        if train.orig == origin:
+            it = [train]
+            if train.dest == dest:
+                # We hope that we have a direct train
+                valid_routes.append(it)
+            else:
+                explore.append(it)
+                per_arr_explore.setdefault(train.dest, [])
+                per_arr_explore[train.dest].append(it)
+            continue
+
+        for it in list(per_arr_explore.get(train.orig, [])):
+            if any(train.dest == tr.dest or train.dest == origin for tr in it):
+                # Avoid loops
+                continue
+
+            last_train = it[-1]
+
+            if last_train.arr <= train.dep:
+                new_it = it + [train]
+                if train.dest == dest:
+                    # Goal is achieved
+                    valid_routes.append(new_it)
+                else:
+                    explore.append(new_it)
+                    per_arr_explore.setdefault(train.dest, [])
+                    per_arr_explore[train.dest].append(new_it)
+
+    return valid_routes
+
+
+def print_route(route: list[Train]):
+    s = f"{route[0].orig} "
+    for tr in route:
+        s += f"({tr.dep}) --> ({tr.arr}) {tr.dest}, "
+    print(s[:-2])
+
+
+@app.get('/')
+def index():
+    return "Hello world!"
+
+
+if __name__ == '__main__':
+    app.run(debug=True)

config.example.py

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+FLASK_CONFIG = {
+    "SQLALCHEMY_DATABASE_URI": "postgresql://user:password@host:5432/dbname",
+    'SQLALCHEMY_TRACK_MODIFICATIONS': True,
+    'SECRET_KEY': "random string",
+}

migrations/README

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+Single-database configuration for Flask.

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

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()

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"}