Upload app.py

app.py

@@ -11,55 +11,45 @@ import socket
 app = Flask(__name__, static_folder='.', static_url_path='')
 
 # --- Configuration ---
-DATA_DIR = "/data"  # Writable directory on Hugging Face Spaces
-if not os.path.exists(DATA_DIR) and not os.environ.get('SPACE_ID'): # For local dev if /data isn't preset
-    print(f"Warning: {DATA_DIR} not found. Using current directory for data.json (local dev mode).")
-    DATA_DIR = "." # Fallback to current dir for local testing if /data does not exist
-    
-DATA_FILE = os.path.join(DATA_DIR, "data.json")
-PING_INTERVAL_SECONDS = 60
-HISTORY_DURATION_SECONDS = 60 * 60
-
-monitored_urls_store = {}
-lock = threading.Lock()
+DATA_FILE = "/tmp/data.json" # MODIFIED LINE: Use the /tmp directory for writing
+PING_INTERVAL_SECONDS = 60  # Backend pings every 60 seconds
+HISTORY_DURATION_SECONDS = 60 * 60  # Store history for 1 hour
+
+# --- Data Store ---
+# Structure: { "id": "uuid", "url": "string", "status": "pending/ok/error/checking",
+#              "ip": "string", "responseTime": float_ms, "lastChecked": "iso_string_utc",
+#              "history": [{"timestamp": float_unix_ts_seconds, "status": "ok/error"}],
+#              "_thread": threading.Thread_object, "_stop_event": threading.Event_object }
+monitored_urls_store = {}  # In-memory store: id -> url_data
+lock = threading.Lock() # To protect access to monitored_urls_store
 
 # --- Helper Functions ---
-def ensure_data_dir_exists():
-    """Ensures the data directory exists."""
-    if DATA_DIR == ".": # No need to create current directory
-        return
-    if not os.path.exists(DATA_DIR):
-        try:
-            os.makedirs(DATA_DIR)
-            print(f"Created data directory: {DATA_DIR}")
-        except OSError as e:
-            print(f"Error creating data directory {DATA_DIR}: {e}. Data persistence may fail.")
-
 def save_data_to_json():
-    with lock:
-        ensure_data_dir_exists() # Ensure directory exists before attempting to write
-        serializable_data = {}
-        for url_id, data in monitored_urls_store.items():
-            s_data = data.copy()
-            s_data.pop("_thread", None)
-            s_data.pop("_stop_event", None)
-            serializable_data[url_id] = s_data
-        try:
-            with open(DATA_FILE, 'w') as f:
-                json.dump(serializable_data, f, indent=2)
-        except IOError as e:
-            print(f"Error saving data to {DATA_FILE}: {e}") # This is where your error was logged
+    # This function must be called with 'lock' acquired
+    serializable_data = {}
+    for url_id, data in monitored_urls_store.items():
+        s_data = data.copy()
+        s_data.pop("_thread", None)
+        s_data.pop("_stop_event", None)
+        serializable_data[url_id] = s_data
+    try:
+        with open(DATA_FILE, 'w') as f:
+            json.dump(serializable_data, f, indent=2)
+        print(f"Data saved to {DATA_FILE}")
+    except IOError as e:
+        print(f"Error saving data to {DATA_FILE}: {e}") # This error will now show the /tmp path
 
 def load_data_from_json():
     global monitored_urls_store
-    ensure_data_dir_exists() # Ensure directory exists before attempting to read
     if os.path.exists(DATA_FILE):
         try:
             with open(DATA_FILE, 'r') as f:
                 loaded_json_data = json.load(f)
+            print(f"Data loaded from {DATA_FILE}")
             
             temp_store = {}
             for url_id_key, data_item in loaded_json_data.items():
+                # Ensure essential fields and use 'id' from data if present, else key
                 data_item.setdefault('id', url_id_key)
                 current_id = data_item['id']
                 data_item.setdefault('status', 'pending')
@@ -69,7 +59,7 @@ def load_data_from_json():
                 data_item.setdefault('history', data_item.get('history', []))
                 temp_store[current_id] = data_item
             
-            with lock:
+            with lock: # Lock before modifying global monitored_urls_store
                 monitored_urls_store = temp_store
 
         except json.JSONDecodeError:
@@ -91,9 +81,11 @@ def load_data_from_json():
 
 def get_host_ip_address(hostname_str):
     try:
-        socket.inet_aton(hostname_str)
+        # Check if hostname_str is already a valid IP address
+        socket.inet_aton(hostname_str) # Throws an OSError if not a valid IPv4 string
         return hostname_str 
     except OSError:
+        # It's not an IP, so try to resolve it as a hostname
         try:
             ip_address = socket.gethostbyname(hostname_str)
             return ip_address
@@ -105,6 +97,7 @@ def get_host_ip_address(hostname_str):
         return 'N/A'
 
 def prune_url_history(url_data_entry):
+    # Assumes 'lock' is acquired or called from the thread managing this entry
     cutoff_time = time.time() - HISTORY_DURATION_SECONDS
     url_data_entry['history'] = [
         entry for entry in url_data_entry.get('history', []) if entry['timestamp'] >= cutoff_time
@@ -120,19 +113,21 @@ def execute_url_check(url_id_to_check):
         
         print(f"Checking {current_url_data['url']} (ID: {url_id_to_check})...")
         current_url_data['status'] = 'checking'
-        url_config_snapshot = current_url_data.copy()
+        url_config_snapshot = current_url_data.copy() # Snapshot for use outside lock
 
     if not url_config_snapshot: return
 
     check_start_time = time.perf_counter()
     final_check_status = 'error'
     http_response_time_ms = None
+    # Identify your bot to website owners
     http_headers = {'User-Agent': 'URLPinger/1.0 (HuggingFace Space Bot)'} 
     
     try:
+        # Attempt HEAD request first
         try:
             head_response = requests.head(url_config_snapshot['url'], timeout=10, allow_redirects=True, headers=http_headers)
-            if 200 <= head_response.status_code < 400:
+            if 200 <= head_response.status_code < 400: # OK or Redirect
                  final_check_status = 'ok'
             else:
                 print(f"HEAD for {url_config_snapshot['url']} returned {head_response.status_code}. Trying GET.")
@@ -141,10 +136,11 @@ def execute_url_check(url_id_to_check):
         except requests.RequestException as e_head:
             print(f"HEAD failed for {url_config_snapshot['url']}: {e_head}. Trying GET...")
 
+        # If HEAD was not conclusive, try GET
         if final_check_status != 'ok':
             try:
                 get_response = requests.get(url_config_snapshot['url'], timeout=15, allow_redirects=True, headers=http_headers)
-                if get_response.ok:
+                if get_response.ok: # Only 2xx status codes
                     final_check_status = 'ok'
                 else:
                     print(f"GET for {url_config_snapshot['url']} status: {get_response.status_code}")
@@ -164,24 +160,25 @@ def execute_url_check(url_id_to_check):
         final_check_status = 'error'
 
     with lock:
-        if url_id_to_check not in monitored_urls_store: return
+        if url_id_to_check not in monitored_urls_store: return # URL might have been removed during check
         
         live_url_data = monitored_urls_store[url_id_to_check] 
         live_url_data['status'] = final_check_status
         live_url_data['responseTime'] = round(http_response_time_ms) if http_response_time_ms is not None else None
-        live_url_data['lastChecked'] = time.strftime("%Y-%m-%dT%H:%M:%SZ", time.gmtime())
+        live_url_data['lastChecked'] = time.strftime("%Y-%m-%dT%H:%M:%SZ", time.gmtime()) # ISO 8601 UTC
         
         current_history_list = live_url_data.get('history', [])
-        current_history_list.append({'timestamp': time.time(), 'status': final_check_status})
+        current_history_list.append({'timestamp': time.time(), 'status': final_check_status}) # timestamp in seconds
         live_url_data['history'] = current_history_list
         prune_url_history(live_url_data)
         
-        save_data_to_json() # This will now try to save to /data/data.json
+        save_data_to_json()
         print(f"Finished check for {live_url_data['url']}: {final_check_status}, {http_response_time_ms} ms")
 
 def pinger_thread_function(url_id_param, stop_event_param):
     while not stop_event_param.is_set():
         execute_url_check(url_id_param)
+        # Sleep for PING_INTERVAL_SECONDS, but check stop_event periodically
         for _ in range(PING_INTERVAL_SECONDS): 
             if stop_event_param.is_set(): break
             time.sleep(1)
@@ -195,13 +192,15 @@ def start_url_monitoring_thread(target_url_id):
 
         url_data_entry = monitored_urls_store[target_url_id]
 
+        # Stop existing thread if it's alive
         if "_thread" in url_data_entry and url_data_entry["_thread"].is_alive():
             print(f"Monitor for URL ID {target_url_id} already running. Attempting to restart.")
-            if "_stop_event" in url_data_entry and url_data_entry["_stop_event"]:
+            if "_stop_event" in url_data_entry and url_data_entry["_stop_event"]: # Check if _stop_event exists
                 url_data_entry["_stop_event"].set()
-            url_data_entry["_thread"].join(timeout=3)
+            url_data_entry["_thread"].join(timeout=3) # Wait for thread to stop
 
         new_stop_event = threading.Event()
+        # daemon=True allows main program to exit even if threads are running
         new_thread = threading.Thread(target=pinger_thread_function, args=(target_url_id, new_stop_event), daemon=True)
         
         url_data_entry["_thread"] = new_thread
@@ -211,15 +210,16 @@ def start_url_monitoring_thread(target_url_id):
         print(f"Started/Restarted monitoring for URL ID {target_url_id}: {url_data_entry['url']}")
 
 def stop_url_monitoring_thread(target_url_id):
-    with lock:
-        if target_url_id in monitored_urls_store:
-            url_data_entry = monitored_urls_store[target_url_id]
-            if "_thread" in url_data_entry and url_data_entry["_thread"].is_alive():
-                print(f"Signaling stop for monitor thread of URL ID {target_url_id}")
-                if "_stop_event" in url_data_entry and url_data_entry["_stop_event"]:
-                    url_data_entry["_stop_event"].set()
-            url_data_entry.pop("_thread", None)
-            url_data_entry.pop("_stop_event", None)
+    # This function must be called with 'lock' acquired
+    if target_url_id in monitored_urls_store:
+        url_data_entry = monitored_urls_store[target_url_id]
+        if "_thread" in url_data_entry and url_data_entry["_thread"].is_alive():
+            print(f"Signaling stop for monitor thread of URL ID {target_url_id}")
+            if "_stop_event" in url_data_entry and url_data_entry["_stop_event"]: # Check if _stop_event exists
+                url_data_entry["_stop_event"].set()
+            # Not joining here to keep API responsive, daemon thread will exit.
+        url_data_entry.pop("_thread", None)
+        url_data_entry.pop("_stop_event", None)
 
 # --- API Endpoints ---
 @app.route('/')
@@ -229,6 +229,7 @@ def serve_index():
 @app.route('/api/urls', methods=['GET'])
 def get_all_urls():
     with lock:
+        # Prepare data for sending: list of url data, no thread objects
         response_list = []
         for data_item in monitored_urls_store.values():
             display_item = data_item.copy()
@@ -246,7 +247,7 @@ def add_new_url():
     input_url = request_data['url'].strip()
 
     if not input_url.startswith('http://') and not input_url.startswith('https://'):
-        input_url = 'https://' + input_url
+        input_url = 'https://' + input_url # Default to https
     
     try:
         parsed_input_url = urlparse(input_url)
@@ -257,11 +258,12 @@ def add_new_url():
         return jsonify({"error": "Invalid URL format"}), 400
 
     with lock:
+        # Check for duplicates (case-insensitive, ignoring trailing slashes)
         normalized_new_url = input_url.rstrip('/').lower()
-        for existing_url_id in list(monitored_urls_store.keys()):
+        for existing_url_id in list(monitored_urls_store.keys()): # Iterate over keys to avoid issues if store is modified
             existing_url_data = monitored_urls_store.get(existing_url_id)
             if existing_url_data and existing_url_data['url'].rstrip('/').lower() == normalized_new_url:
-                return jsonify({"error": "URL already monitored"}), 409
+                return jsonify({"error": "URL already monitored"}), 409 # Conflict
 
         new_url_id = str(uuid.uuid4())
         resolved_ip = get_host_ip_address(url_hostname) if url_hostname else 'N/A'
@@ -271,13 +273,19 @@ def add_new_url():
             "ip": resolved_ip, "responseTime": None, "lastChecked": None, "history": []
         }
         
+        # Make a copy of the entry for the response *before* it's potentially modified
+        # by start_url_monitoring_thread with non-serializable objects.
         response_payload = url_entry_to_add.copy()
-        monitored_urls_store[new_url_id] = url_entry_to_add
+
+        monitored_urls_store[new_url_id] = url_entry_to_add # url_entry_to_add will be modified by start_url_monitoring_thread
         save_data_to_json() 
     
-    start_url_monitoring_thread(new_url_id)
+    start_url_monitoring_thread(new_url_id) # This will add _thread and _stop_event to monitored_urls_store[new_url_id]
+
+    # Return the clean response_payload, which does not have _thread or _stop_event
     return jsonify(response_payload), 201
 
+
 @app.route('/api/urls/<string:target_url_id>', methods=['DELETE'])
 def delete_existing_url(target_url_id):
     with lock:
@@ -286,7 +294,8 @@ def delete_existing_url(target_url_id):
             removed_url_entry = monitored_urls_store.pop(target_url_id)
             save_data_to_json()
             
-            response_data = removed_url_entry.copy()
+            # Prepare data for response (without thread objects)
+            response_data = removed_url_entry.copy() # Copy before potential modification if stop_url_monitoring_thread didn't pop everything
             response_data.pop("_thread", None)
             response_data.pop("_stop_event", None)
             print(f"Deleted URL ID {target_url_id}")
@@ -295,13 +304,20 @@ def delete_existing_url(target_url_id):
             return jsonify({"error": "URL not found"}), 404
 
 # --- Main Execution / Gunicorn Entry Point ---
-if os.environ.get('WERKZEUG_RUN_MAIN') != 'true':
-    ensure_data_dir_exists() # Ensure data dir exists before loading
+# Load data once when the application module is initialized
+# This handles both `flask run` and gunicorn scenarios.
+if os.environ.get('WERKZEUG_RUN_MAIN') != 'true': # Avoids double load in Flask debug mode
     load_data_from_json() 
 
 if __name__ == '__main__':
-    if os.environ.get('WERKZEUG_RUN_MAIN') == 'true':
-        ensure_data_dir_exists() # Ensure data dir exists before loading in reloader
+    # This block is for local development (e.g., `python app.py`)
+    # `load_data_from_json()` is called above unless Werkzeug reloader is active.
+    # If using Flask's reloader, load_data_from_json will be called twice:
+    # once by the main process, once by the reloader's child process.
+    # The check for WERKZEUG_RUN_MAIN ensures it only loads in the main one or the child.
+    if os.environ.get('WERKZEUG_RUN_MAIN') == 'true': # Ensure data is loaded in the reloaded process too
         load_data_from_json()
-    # The DATA_DIR fallback for local dev will be used here if /data doesn't exist
-    app.run(debug=True, host='0.0.0.0', port=7860)
+    app.run(debug=True, host='0.0.0.0', port=7860)
+
+# When run with Gunicorn, Gunicorn imports `app` from this `app.py` file.
+# `load_data_from_json()` will have been called during that import (due to the WERKZEUG_RUN_MAIN check).