File is empty after saving flask uploads - html

Question

I've been trying to upload a file using Flask and HTML forms. Now I can save an uploaded file but it shows up empty (0 bytes). After that I store the form entries in a database.
So im stuck at saving the file.
This is the python code
#app.route('/handle_data', methods=['POST'])
def handle_data():
naam = request.form['naam']
leeftijd = request.form['leeftijd']
gewicht = request.form['gewicht']
geslacht = request.form['geslacht']
filename = "x"
if request.method == 'POST' and 'photo' in request.files:
filename = photos.save(request.files['photo'])
photos.save(request.files['photo'], opslag)
cur = mysql.connect()
cursor = cur.cursor()
cursor.execute("INSERT INTO gekko (naam, leeftijd, gewicht, geslacht, foto) VALUES (%s, %s, %s, %s, %s)", (naam, leeftijd, gewicht, geslacht, filename))
# cursor.execute("INSERT INTO gekko (naam, leeftijd, gewicht) VALUES (" + str(naam) + "," + leeftijd + "," + gewicht + ")")
cur.commit()
cursor.close()
cur.close()
return "added"
HTML form:
{% extends "base.html" %}
{% block body %}
<form action="{{ url_for('handle_data') }}" enctype=multipart/form-data
method="POST">
Naam van de gekko:<br>
<input type="text" name="naam">
<br>
Leeftijd van de gekko:<br>
<input type="text" name="leeftijd">
<br>
Gewicht van de gekko:<br>
<input type="text" name="gewicht">
<br>
Geslacht van de gekko:<br>
<input type="radio" name="geslacht" value="man"> Man
<input type="radio" name="geslacht" value="vrouw"> Vrouw<br>
<br>
<input type="file" id="photo" name="photo">
<br>
<input type="submit" value="Submit">
</form>
{% endblock %}

Answer 1

We don't really know what the class photos is, nor what it's method save does, but that's where the error is probably occurring.
Try this instead:
request.files['photo'].save('test.jpg')

Answer 2

I realized that flask has a habit of including one empty file upload with the exact same name and details as one of the file attachments(usually the first attachment) WHEN you use the 'multiple' attribute in your form.
My workaround was to
create a temporary random filename and save the file upload
use os.stat(temp_filename).st_size to check if the file is empty
if the file is empty, delete it with os.remove, otherwise, rename the file to your preferred [secure] filename
an example...
# ...
def upload_file(req):
if req.method != 'POST': return
# file with 'multiple' attribute is 'uploads'
files = req.files.getlist("uploads")
# get other single file attachments
if req.files:
for f in req.files: files.append(req.files[f])
for f in files:
if not f.filename: continue
tmp_fname = YOUR_TEMPORARY_FILENAME
while os.path.isfile(tmp_fname):
# you can never rule out the possibility of similar random
# names
tmp_fname = NEW_TEMPORARY_FILENAME
# TEMP_FPATH is he root temporary directory
f.save(os.path.join(TEMP_FPATH, tmp_fname))
# and here comes the trick
if os.stat(os.path.join(TEMP_FPATH, tmp_fname)).st_size:
os.system("mv \"{}\" \"{}\" > /dev/null 2> /dev/null".format(
os.path.join(TEMP_FPATH, tmp_fname),
os.path.join(ACTUAL_FILEPATH, f.filename))
))
else:
# cleanup
os.remove(os.path.join(TEMP_FPATH, tmp_fname))
pass
#app.route("/upload", methods=["POST"])
def upload():
upload_files(request)
return "files are uploaded!"
# ...