Python Flask, Uploading a file - raise BuildError(endpoint, values, method) -

i followed this tutorial uploading files webserver via flask, notable exception of return part.

my intention upload pictures.

here's code:

from flask import flask, request, jsonify, json, blueprint, redirect, url_for, send_from_directory werkzeug import secure_filename  app = flask(__name__)  allowed_extensions = set(['png', 'jpg', 'jpeg', 'gif', 'bmp']) folder_upload = '/users/myusername/documents/project_upload/'  @customersapi.route('/customers/addpicture', methods=['post']) def add_picture():     file = request.files['value']     print file.filename     if file , allowed_file(file.filename):         filename = secure_filename(file.filename)         file.save(os.path.join(app.config['upload_folder'], filename))         #return redirect(url_for('uploaded_file', filename=filename))         return str(url_for('uploaded_file', filename=filename))      return "unable upload."  def allowed_file(filename):     return '.' in filename , filename.rsplit('.', 1)[1] in allowed_extensions  if __name__ == '__main__':     app.config['upload folder'] = folder_upload     app.run(host = '0.0.0.0', debug=true) 

as not have html files yet (hence commented out return redirect), use cocoarestclient testing, , here parameters used:

everything okay far, until hit submit button. then, following error appears:

traceback (most recent call last):   file "/library/python/2.7/site-packages/flask/app.py", line 1836, in __call__     return self.wsgi_app(environ, start_response)   file "/library/python/2.7/site-packages/flask/app.py", line 1820, in wsgi_app     response = self.make_response(self.handle_exception(e))   file "/library/python/2.7/site-packages/flask/app.py", line 1403, in handle_exception     reraise(exc_type, exc_value, tb)   file "/library/python/2.7/site-packages/flask/app.py", line 1817, in wsgi_app     response = self.full_dispatch_request()   file "/library/python/2.7/site-packages/flask/app.py", line 1477, in full_dispatch_request     rv = self.handle_user_exception(e)   file "/library/python/2.7/site-packages/flask/app.py", line 1381, in handle_user_exception     reraise(exc_type, exc_value, tb)   file "/library/python/2.7/site-packages/flask/app.py", line 1475, in full_dispatch_request     rv = self.dispatch_request()   file "/library/python/2.7/site-packages/flask/app.py", line 1461, in dispatch_request     return self.view_functions[rule.endpoint](**req.view_args)   file "/users/myusername/documents/project_omnimoda/api/main.py", line 192, in add_picture     return redirect(url_for('uploaded_file', filename=filename))   file "/library/python/2.7/site-packages/flask/helpers.py", line 312, in url_for     return appctx.app.handle_url_build_error(error, endpoint, values)   file "/library/python/2.7/site-packages/flask/app.py", line 1641, in handle_url_build_error     reraise(exc_type, exc_value, tb)   file "/library/python/2.7/site-packages/flask/helpers.py", line 305, in url_for     force_external=external)   file "/library/python/2.7/site-packages/werkzeug/routing.py", line 1649, in build     raise builderror(endpoint, values, method) builderror: ('uploaded_file', multidict([('filename', '3611571-dc_holiday.jpg')]), none) 

funny thing is, image '3611571-dc_holiday.jpg' did copied downloads folder project_upload folder, worked, there's error i'm not sure how solve.

any ideas? thanks.

you haven't defined uploaded_file endpoint. need that.

@customersapi.route('/customers/somethingogesthere') def uploaded_file(filename):     # here file, return it.     return send_from_directory(         folder_upload, filename, as_attachment=true)