move updateData to /r page, only call when needed

test.py

@@ -12,7 +12,9 @@ attributes= ["title",
 
 fields = {}
 
+@app.route("/r")
 def updateData():
+    global data
     out = []
 
     f = zipfile.ZipFile("library.tc")
@@ -63,16 +65,19 @@ def updateData():
             else:
                 bookout[datum] = ""
         out.append(bookout.copy())
-    return out.copy()
+    data = out.copy()
+    return "success"
 
 @app.route("/")
 def main():
-    data = updateData();
+    if data == []:
+        updateData()
     return render_template("main.html", books = data, attributes = attributes)
 
 @app.route("/book/<int:id>")
 def book(id):
-    data = updateData();
+    if data == []:
+        updateData()
     book = next((item for item in data if int(item["id"]) == id), {})
     return render_template("book.html", book = book, fields = fields)