Error message template

db.py

@@ -6,6 +6,7 @@ adb = db.accounts
 
 live_quotes_count = lambda: qdb.find({ "hidden": False, "approved": True })
 quote_live = lambda quote_id: bool(qdb.find_one({ "hidden": False, "approved": True }))
+tag_live = lambda tag: bool(qdb.find_one({ "hidden": False, "approved": True, "tags": tag }))
 
 def get_random_quote():
 

main.py

@@ -64,12 +64,24 @@ def tags():
 
 @app.route('/tags/<t>')
 def tag(t):
-    return render_template(
-        "list.html",
-        title=t,
-        header="Quotes matching: " + t, 
-        quotes=db.get_live_quotes_by_tag(t)
-    )
+    if db.tag_live(t):
+        return render_template(
+            "list.html",
+            title=t,
+            header="Quotes matching: " + t,
+            quotes=db.get_live_quotes_by_tag(t)
+        )
+    else:
+        return render_template(
+            "message.html",
+            title="Error!",
+            message={
+                "type": "danger",
+                "heading": "No matching quotes",
+                "message": f"There are no quotes with the tag \"{t}\" in the database"
+            }
+        )
+
 
 @app.route('/quote/<quote_id>')
 def quote(quote_id):

templates/message.html

@@ -0,0 +1,14 @@
+{% extends "layout.html" %}
+{% block customhead %}
+    <title>{{ title }}</title>
+{% endblock %}
+{% block content %}
+
+<div class="container">
+    <div class="alert alert-{{ message.type }}" role="alert">
+        <h4 class="alert-heading">{{ message.heading }}</h4>
+        <p>{{ message.message }}</p>
+    </div>
+</div>
+
+{% endblock %}