From 3e89605d36793f16d35ae81b9ce5ffbc5c1bca2f Mon Sep 17 00:00:00 2001
From: Alex Schofield <git@ajschof.me>
Date: Tue, 5 May 2026 22:22:12 +0100
Subject: improve error handling when fetching data

---
 fnme/cli.py  | 14 ++++++++++++--
 fnme/data.py | 21 +++++++++++++++++----
 2 files changed, 29 insertions(+), 6 deletions(-)

(limited to 'fnme')

diff --git a/fnme/cli.py b/fnme/cli.py
index 22d1a86..5437ff0 100644
--- a/fnme/cli.py
+++ b/fnme/cli.py
@@ -6,7 +6,7 @@ from tabulate import tabulate
 
 from fnme.constants import SORT_KV
 from fnme.data import get_latest_data
-from fnme.exceptions import LocationError
+from fnme.exceptions import DataFetchError, LocationError
 from fnme.geo import get_location
 from fnme.station import process_stations, sort_stations
 
@@ -64,7 +64,17 @@ def main():
         print(f"An unexpected error occurred: {e}")
         sys.exit(1)
 
-    df, last_modified = get_latest_data()
+    try:
+        df, last_modified = get_latest_data()
+    except DataFetchError as e:
+        print(f"Error: {e.message}")
+        print(
+            "Check your internet connection or verify that this script can access the cache location."
+        )
+        sys.exit(1)
+    except Exception as e:
+        print(f"An unexpected error occurred: {e}")
+        sys.exit(1)
 
     print(f"Last updated: {last_modified}")
 
diff --git a/fnme/data.py b/fnme/data.py
index 6d85f43..9bb0f74 100644
--- a/fnme/data.py
+++ b/fnme/data.py
@@ -6,6 +6,7 @@ import requests
 from platformdirs import user_cache_path
 
 from fnme.constants import ENDPOINT, HEADERS
+from fnme.exceptions import DataFetchError
 
 
 def get_latest_data() -> tuple[pd.DataFrame, str | None]:
@@ -28,8 +29,12 @@ def get_latest_data() -> tuple[pd.DataFrame, str | None]:
         ),
     }
 
-    response = requests.get(ENDPOINT, headers=conditional_headers, timeout=10)
-    response.raise_for_status()
+    try:
+        response = requests.get(
+            ENDPOINT, headers=conditional_headers, timeout=10
+        )
+    except requests.RequestException as e:
+        raise DataFetchError(message=f"GET request failed: {e}")
 
     if response.status_code == 304:
         print(f"[*] Using cached data. Last modified: {cached_last_modified}")
@@ -38,6 +43,14 @@ def get_latest_data() -> tuple[pd.DataFrame, str | None]:
     print("[!] Cache is stale. Refreshing.")
 
     last_modified = response.headers.get("Last-Modified")
-    csv_path.write_text(response.text, encoding="utf-8")
-    timestamp_path.write_text(last_modified or "")
+
+    try:
+        csv_path.write_text(response.text, encoding="utf-8")
+    except Exception as e:
+        raise DataFetchError(message=f"Error writing CSV cache: {e}")
+    try:
+        timestamp_path.write_text(last_modified or "")
+    except Exception as e:
+        raise DataFetchError(message=f"Error writing timestamp file: {e}")
+
     return pd.read_csv(csv_path), last_modified
-- 
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