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Good day all. I have a little issue on uploading image using flask. I can upload image on flask in localhost (the web app is hosted on my desktop). But when I loaded the flask app on Online Server, I always encounter the "FileNotFoundError". I also change the permission to 777 but still not working.

Here is the html upload code.

<form name="edit_vehicle_info" action="/vehicle_info_form/" method="POST" enctype="multipart/form-data" class="formfield">
    <div class="form-group">
    <label for="changeVehicleImg">Vehicle Image</label>
    <input type="file" id="changeVehicleImg" name="changeVehicleImg" accept="image/*">
</div>

Here is the python upload code.

#vehicle_info_form
@app.route('/vehicle_info_form/', methods=['GET', 'POST'])
def vehicle_info_form():
    try:
        if request.method == "GET":
            return render_template(
                'vehicleInfo.html'
            )

        elif request.method == "POST":
            inputVehicleImg = request.files['changeVehicleImg']
            if inputVehicleImg.filename == "":
                inputVehicleImg_filename = ""
            else:
                print(inputVehicleImg.filename)
                print(app.config['UPLOAD_FOLDER_IMG_VEHICLE'])
                inputVehicleImg_filename = secure_filename(inputVehicleImg.filename)
                inputVehicleImg.save(os.path.join(app.config['UPLOAD_FOLDER_IMG_VEHICLE'], inputVehicleImg_filename))
            print ('success')
    except Exception as e:
        print(e)
        return redirect(url_for('vehicle_info_form'))

The python upload code can print the inputVehicleImg.filename and app.config['UPLOAD_FOLDER_IMG_VEHICLE'] then after that, the error occurs.

Here is the error.

Traceback (most recent call last):
  File "/home/ubuntu/Projects/FMS/lib/python3.6/site-packages/flask/app.py", line 1985, in wsgi_app
    response = self.handle_exception(e)
  File "/home/ubuntu/Projects/FMS/lib/python3.6/site-packages/flask/app.py", line 1540, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "/home/ubuntu/Projects/FMS/lib/python3.6/site-packages/flask/_compat.py", line 33, in reraise
    raise value
  File "/home/ubuntu/Projects/FMS/lib/python3.6/site-packages/flask/app.py", line 1982, in wsgi_app
    response = self.full_dispatch_request()
  File "/home/ubuntu/Projects/FMS/lib/python3.6/site-packages/flask/app.py", line 1615, in full_dispatch_request
    return self.finalize_request(rv)
  File "/home/ubuntu/Projects/FMS/lib/python3.6/site-packages/flask/app.py", line 1632, in finalize_request
    response = self.process_response(response)
  File "/home/ubuntu/Projects/FMS/lib/python3.6/site-packages/flask/app.py", line 1858, in process_response
    self.save_session(ctx.session, response)
  File "/home/ubuntu/Projects/FMS/lib/python3.6/site-packages/flask/app.py", line 924, in save_session
    return self.session_interface.save_session(self, session, response)
  File "/home/ubuntu/Projects/FMS/lib/python3.6/site-packages/flask/sessions.py", line 363, in save_session
    val = self.get_signing_serializer(app).dumps(dict(session))
  File "/home/ubuntu/Projects/FMS/lib/python3.6/site-packages/itsdangerous/serializer.py", line 166, in dumps
    payload = want_bytes(self.dump_payload(obj))
  File "/home/ubuntu/Projects/FMS/lib/python3.6/site-packages/itsdangerous/url_safe.py", line 42, in dump_payload
    json = super(URLSafeSerializerMixin, self).dump_payload(obj)
  File "/home/ubuntu/Projects/FMS/lib/python3.6/site-packages/itsdangerous/serializer.py", line 133, in dump_payload
    return want_bytes(self.serializer.dumps(obj, **self.serializer_kwargs))
  File "/home/ubuntu/Projects/FMS/lib/python3.6/site-packages/flask/sessions.py", line 85, in dumps
    return json.dumps(_tag(value), separators=(',', ':'))
  File "/home/ubuntu/Projects/FMS/lib/python3.6/site-packages/flask/json.py", line 167, in dumps
    rv = _json.dumps(obj, **kwargs)
  File "/usr/lib/python3.6/json/__init__.py", line 238, in dumps
    **kw).encode(obj)
  File "/usr/lib/python3.6/json/encoder.py", line 199, in encode
    chunks = self.iterencode(o, _one_shot=True)
  File "/usr/lib/python3.6/json/encoder.py", line 257, in iterencode
    return _iterencode(o, 0)
  File "/home/ubuntu/Projects/FMS/lib/python3.6/site-packages/flask/json.py", line 81, in default
    return _json.JSONEncoder.default(self, o)
  File "/usr/lib/python3.6/json/encoder.py", line 180, in default
    o.__class__.__name__)
TypeError: Object of type 'FileNotFoundError' is not JSON serializable

Please help. Thank you.

Answers

I solved the issue by updating the app.config['UPLOAD_FOLDER_IMG_VEHICLE']. I use os.getcwd() to get the full current path and add the path where the image should be save.

First I check what is the root of the error by adding try and except FileNotFoundError:.

#vehicle_info_form
@app.route('/vehicle_info_form/', methods=['GET', 'POST'])
def vehicle_info_form():
    try:
        if request.method == "GET":
            return render_template(
                'vehicleInfo.html'
            )

        elif request.method == "POST":
            inputVehicleImg = request.files['changeVehicleImg']
            if inputVehicleImg.filename == "":
                inputVehicleImg_filename = ""
            else:
                print(inputVehicleImg.filename)
                print(app.config['UPLOAD_FOLDER_IMG_VEHICLE'])
                inputVehicleImg_filename = secure_filename(inputVehicleImg.filename)
                try:
                    inputVehicleImg.save(os.path.join(app.config['UPLOAD_FOLDER_IMG_VEHICLE'], inputVehicleImg_filename))
                except FileNotFoundError:
                    print("File does not exist")
            print ('success')
    except Exception as e:
        print(e)
        return redirect(url_for('vehicle_info_form'))

I try to upload an image and return in the console File does not exist.

Then I check the path of app.config['UPLOAD_FOLDER_IMG_VEHICLE'] where the image should be uploaded.

print(app.config['UPLOAD_FOLDER_IMG_VEHICLE'])

And there I found out that the path is not the same in my online server so I update it.

import os
path = os.getcwd()
print(path) 

UPLOAD_FOLDER_IMG_VEHICLE = path + "/apps/FMS/static/images/vehicleInfo"

app.config['UPLOAD_FOLDER_IMG_VEHICLE'] = UPLOAD_FOLDER_IMG_VEHICLE