Why am I getting the 404 error when running my Flask app and How can I fix it?

Question

I am trying to run this app on Flask but I keep getting this error:

Not Found

The requested URL was not found on the server. If you entered
the URL manually please check your spelling and try again.

I have tried using other ports and everything else possible but it still comes with that error.

Any help will be greatly appreciated.

upload.py

from flask import Flask, render_template, request
from flask_uploads import UploadSet, configure_uploads, IMAGES

app = Flask(__name__)

photos = UploadSet('photos', IMAGES)

app.config['UPLOADED_PHOTOS_DEST'] = 'static/img'
configure_uploads(app, photos)

@app.route('/upload', methods=['GET', 'POST'])
def upload():
if request.method == 'POST' and 'photo' in request.files:
    filename = photos.save(request.files['photo'])
    return filename
return render_template('upload.html')


if __name__ == '__main__':
app.run(debug=True)

upload.html

<html>
<head>
<title>Upload</title>
 </head>
 <body>
 <form method=POST enctype=multipart/form-data action="{{ url_for('upload')        }}">
<input type=file name=photo>
<input type="submit">
</form>
</body>
</html>

Is this flask app running behind nginx or other reverse-proxy? How are you trying to access it, from localhost or externally? — gkivanov, Jan 21 '19 at 13:56

score 2 · Answer 1 · edited Jan 21 '19 at 15:32

2

You can use

app.run(host='0.0.0.0')

to make the development server visible on your network. Note that you should never make the debugger available in this case, and should never use the development server in production.

edited Jan 21 '19 at 15:32

davidism

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answered Jan 21 '19 at 13:47

CrmXao

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I always got some warning about "never using the development server in production". I was only using this for PoCs and initial demos. Could you explain the reason for this warning? – CrmXao Jan 26 '19 at 05:39

Why am I getting the 404 error when running my Flask app and How can I fix it?

1 Answers1