File from the URL doesn't have to be a zip anymore (#63)

ibkr_report/exchangerates.py

@@ -13,7 +13,7 @@
 from typing import Iterable
 from urllib.error import HTTPError
 from urllib.request import urlopen
-from zipfile import ZipFile
+from zipfile import BadZipFile, ZipFile
 
 from google.cloud import exceptions, storage  # type: ignore
 
@@ -98,10 +98,15 @@ def download_official_rates(self, url: str) -> None:
                 log.warning(error_msg, err.code, err.reason)
                 retries += 1
         log.debug("Successfully downloaded the latest exchange rates: %s", url)
-        with ZipFile(bytes_io) as rates_zip:
-            for filename in rates_zip.namelist():
-                with rates_zip.open(filename) as rates_file:
-                    self.add_to_exchange_rates(rates_file)
+        try:
+            with ZipFile(bytes_io) as rates_zip:
+                for filename in rates_zip.namelist():
+                    with rates_zip.open(filename) as rates_file:
+                        self.add_to_exchange_rates(rates_file)
+        except BadZipFile:
+            bytes_io.seek(0)
+            self.add_to_exchange_rates(bytes_io)
+
         log.debug("Parsed exchange rates from the retrieved data.")
 
     def get_rate(self, currency_from: str, currency_to: str, date_str: str) -> Decimal:

test.py

@@ -14,7 +14,9 @@
 from main import app
 
 TEST_BUCKET = "test"
-TEST_URL = "file://" + os.path.abspath(os.getcwd()) + "/test-data/eurofxref-hist.zip"
+THIS_PATH = os.path.abspath(os.getcwd())
+TEST_URL = f"file://{THIS_PATH}/test-data/eurofxref-hist.zip"
+TEST_BROKEN_URL = f"file://{THIS_PATH}/test-data/eurofxref-broken.csv"
 
 
 @patch("ibkr_report.exchangerates.BUCKET_ID", TEST_BUCKET)
@@ -282,6 +284,13 @@ def test_broken_input(self):
         eur_usd = self.rates.get_rate("EUR", "USD", "2021-10-25")
         self.assertEqual(eur_usd, Decimal("1.1603"))
 
+    def test_download_without_zip(self):
+        rates = ExchangeRates(TEST_BROKEN_URL)
+        eur_usd = rates.get_rate("EUR", "USD", "2021-10-26")
+        self.assertEqual(eur_usd, Decimal("1.1618"))
+        with self.assertRaises(ValueError):
+            eur_usd = rates.get_rate("EUR", "USD", "2021-10-25")
+
 
 if __name__ == "__main__":
     unittest.main()