modular parser framework

openmensa_parsers/views.py

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+# -*- encoding: utf-8 -*-
+
+import os
+import urllib.parse
+
+import cachetools as ct
+
+from flask import Flask, jsonify, make_response, url_for
+from flask.logging import create_logger
+
+from openmensa_parsers.config import read_canteen_config
+from openmensa_parsers.parsers import create_parser
+from openmensa_parsers.xml_types.builder import Builder
+
+CACHE_TIMEOUT = 45 * 60
+PARSER_ID = os.environ.get("OM_PARSER_ID", "potsdam")
+
+# pragma pylint: disable=invalid-name
+
+app = Flask(__name__)
+app.url_map.strict_slashes = False
+cache = ct.TTLCache(maxsize=30, ttl=CACHE_TIMEOUT)
+config = read_canteen_config()
+log = create_logger(app)
+
+if "BASE_URL" in os.environ:  # pragma: no cover
+    base_url = urllib.parse.urlparse(os.environ.get("BASE_URL"))
+    if base_url.scheme:
+        app.config["PREFERRED_URL_SCHEME"] = base_url.scheme
+    if base_url.netloc:
+        app.config["SERVER_NAME"] = base_url.netloc
+    if base_url.path:
+        app.config["APPLICATION_ROOT"] = base_url.path
+
+
+def canteen_not_found(canteen_name):
+    log.warning("Canteen %s not found", canteen_name)
+    configured = ", ".join(f"'{c}'" for c in config.keys())
+    message = f"Canteen '{canteen_name}' not found, available: {configured}"
+    return make_response(message, 404)
+
+
+@ct.cached(cache=cache)
+def update_builder():
+    log.debug("Downloading menu using parser %s", PARSER_ID)
+    return Builder(config, parser=create_parser(PARSER_ID))
+
+
+@app.route("/canteens/<canteen_name>")
+@app.route("/canteens/<canteen_name>/xml")
+def canteen_xml_feed(canteen_name):
+    if canteen_name not in config:
+        return canteen_not_found(canteen_name)
+
+    builder = update_builder()
+    xml = builder.get_xml(canteen_name)
+    response = make_response(xml)
+    response.mimetype = "text/xml"
+    return response
+
+
+@app.route("/")
+@app.route("/canteens")
+def canteen_index():
+    return jsonify(
+        {
+            key: url_for("canteen_xml_feed", canteen_name=key, _external=True)
+            for key in config
+        }
+    )
+
+
+@app.route("/health_check")
+def health_check():
+    return make_response("OK", 200)
+
+
+if __name__ == '__main__':
+    app.run()