add some comments

app/routes.py

@@ -6,20 +6,23 @@ from app import app, db
 from flask import redirect, url_for, render_template, send_from_directory, current_app, abort
 from app.models import Share, Attachment
 from app.forms import UploadForm
+from shutil import rmtree
 
 
 def check_expired(share):
-    if share.download_limit <= 0 or datetime.now() > share.expires:
+    if share.download_limit < 0 or datetime.now() > share.expires:
+        # delete files
         try:
-            os.removedirs(os.path.join(current_app.config['MEDIA_LOCATION'], share.id))
+            rmtree(os.path.join(current_app.config['MEDIA_LOCATION'], share.id))
         except OSError as e:
             print("Error: %s - %s." % (e.filename, e.strerror))
-
+        # delete from database
         for att in share.files:
             db.session.delete(att)
         db.session.delete(share)
         db.session.commit()
-        return redirect('expired')
+        return True
+    return False
 
 
 @app.route('/')
@@ -32,24 +35,26 @@ def upload():
     form = UploadForm()
 
     if form.validate_on_submit():
+        # generate unique uuid
         share_id = str(uuid.uuid4())
         while Share.query.get(share_id) is not None:
             share_id = str(uuid.uuid4())
-
+        # create share object
         up = Share(id=share_id, name=form.name.data, expires=datetime.now() + timedelta(minutes=int(form.timer.data)),
                    download_limit=form.download_limit.data)
         db.session.add(up)
+        # create share folder
         try:
             os.makedirs(os.path.join(current_app.config['MEDIA_LOCATION'], share_id))
         except OSError as e:
             print("Error: %s - %s." % (e.filename, e.strerror))
-
+        # create attachments
         for file in form.files.data:
             fn = secure_filename(filename=file.filename)
             file.save(os.path.join(current_app.config['MEDIA_LOCATION'], share_id, fn))
             att = Attachment(filename=fn, share_id=share_id)
             db.session.add(att)
-
+        # wrap it up
         db.session.commit()
         return redirect(url_for('download', share_id=share_id))
 
@@ -61,23 +66,23 @@ def download(share_id):
     share = Share.query.get_or_404(share_id)
     share.download_limit -= 1
     db.session.commit()
-    check_expired(share)
-    return render_template('Download.html', up=share)
+    if check_expired(share):
+        return redirect(url_for('expired'))
+    else:
+        return render_template('Download.html', up=share)
 
 
 @app.route('/media/<string:share_id>/<string:filename>', methods=['GET'])
 def media(share_id, filename):
     share = Share.query.get_or_404(share_id)
-    check_expired(share)
+    if check_expired(share):
+        return redirect(url_for('expired'))
+    else:
+        return send_from_directory(os.path.join(current_app.config['MEDIA_LOCATION'], share_id), filename=filename,
+                                   as_attachment=True)
 
-    # if filename not in [a.filename for a in share.files]:
-    #    return abort(404)
 
-    return send_from_directory(os.path.join(current_app.config['MEDIA_LOCATION'], share_id), filename=filename,
-                               as_attachment=True)
-
-
-@app.errorhandler(404)
 @app.route('/expired')
-def expired():
+@app.errorhandler(404)
+def expired(e=None):
     return render_template('Expired.html')