Flask form does not let me upload TSV files - html

Question

I have the following flask app where I want to be able to upload a TXT or TSV file to a form. The problem is, when I try to upload a TXT file, it works, but when I try to upload a TSV file, I get the following error:
File "/Users/cdastmalchi/Desktop/author_script/main.py", line 89, in process_file
if not places_exist(os.path.join(app.config['UPLOAD_FOLDER'], filename)):
File "/Users/cdastmalchi/Desktop/author_script/main.py", line 27, in places_exist
infile = open(filename, 'rU')
IOError: [Errno 2] No such file or directory: './Authors_Template.tsv'
Authors_Template.tsv is a template file that gets downloaded from the form and goes into the Downloads, and then I want users to be able to edit this template and then re-upload it. When I make the template Authors_Template.txt instead and then Download and re-upload it, it works. How can I solve this problem? I've even tried narrowing down the ALLOWED_EXTENSIONS list to just TSV and I still get the same issue.
app.py
from werkzeug.utils import secure_filename
import flask, string, random
import json
import subprocess
import os
import re
import time
UPLOAD_FOLDER = '.'
ALLOWED_EXTENSIONS = set(['txt','tsv'])
app = flask.Flask(__name__)
app.config['UPLOAD_FOLDER'] = UPLOAD_FOLDER
app.secret_key = ''.join(random.choice(string.ascii_letters) for _ in range(20)) #needed to use flask.session
def allowed_file(filename):
return '.' in filename and \
filename.rsplit('.', 1)[1] in ALLOWED_EXTENSIONS
def places_exist(filename):
infile = open(filename, 'rU')
placeDict = {}
addresses_temp = []
addresses = []
places_temp =[]
places = []
places_exist = True
for i in infile:
item = i.rstrip("\n").split("\t")
places_temp.append(item[0])
addresses_temp.append(item[1])
p_index = (places_temp.index('Place')) + 1
a_index = (addresses_temp.index('Address')) + 1
places = places_temp[p_index:]
addresses = addresses_temp[a_index:]
infile.close()
infile = open(filename, 'rU')
return places_exist
#app.route('/', methods=['GET'])
def home():
return flask.render_template('index.html')
#app.route('/process_file', methods=['POST'])
def process_file():
#here, you can run all the checks as before, but instead of flash, you can return jsonified results to read in the front-end
if 'file' not in flask.request.files or not flask.request.files['file'].filename:
return flask.jsonify({'result':'False', 'message':'no files selected'})
return flask.redirect(url_for('home'))
file = flask.request.files['file']
filename = secure_filename(file.filename)
if not allowed_file(file.filename):
return flask.jsonify({'result':'False', 'message':'Must be TXT file!'})
return flask.redirect(url_for('home'))
if not places_exist(os.path.join(app.config['UPLOAD_FOLDER'], filename)):
return flask.jsonify({'result':'False', 'message':'There is an affiliation missing from your Place list. Please re-try.'})
return flask.redirect(url_for('home'))
file.save(os.path.join(app.config['UPLOAD_FOLDER'], filename))
flask.session['filename'] = filename
return flask.jsonify({'result':'True'})
UPDATE:
def process_file():
#here, you can run all the checks as before, but instead of flash, you can return jsonified results to read in the front-end
if 'file' not in flask.request.files or not flask.request.files['file'].filename:
return flask.jsonify({'result':'False', 'message':'no files selected'})
return flask.redirect(url_for('home'))
file = flask.request.files['file']
filename = secure_filename(file.filename)
if not allowed_file(file.filename):
return flask.jsonify({'result':'False', 'message':'Must be TXT file!'})
return flask.redirect(url_for('home'))
# Save the file in the temp folder
file.save(os.path.join(app.config['TEMP_FOLDER'], filename))
# Process the file
if not places_exist(os.path.join(app.config['TEMP_FOLDER'], filename)):
return flask.jsonify({'result':'False', 'message':'There is an affiliation missing from your Place list. Please re-try.'})
return flask.redirect(url_for('home'))
file.save(os.path.join(app.config['UPLOAD_FOLDER'], filename))
flask.session['filename'] = filename
return flask.jsonify({'result':'True'})

Answer 1

You are trying to read a file before its writing in your directory. First you need to save the file in your application upload directory then read it.
def process_file():
# here, you can run all the checks as before, but instead of flash, you can return jsonified results to read in the front-end
if 'file' not in flask.request.files or not flask.request.files['file'].filename:
return flask.jsonify({'result':'False', 'message':'no files selected'})
return flask.redirect(url_for('home'))
file = flask.request.files['file']
filename = secure_filename(file.filename)
if not allowed_file(file.filename):
return flask.jsonify({'result':'False', 'message':'Must be TXT file!'})
return flask.redirect(url_for('home'))
# Save the file in the correct Location
file.save(os.path.join(app.config['UPLOAD_FOLDER'], filename))
# Process your file already saved
if not places_exist(os.path.join(app.config['UPLOAD_FOLDER'], filename)):
return flask.jsonify({'result':'False', 'message':'There is an affiliation missing from your Place list. Please re-try.'})
return flask.redirect(url_for('home'))
flask.session['filename'] = filename
return flask.jsonify({'result':'True'})
EDIT: You have to be careful if you need to check the file before saving, if you save right away you will override your old file, a good approach will be to save the file in a temp location, check that file and then save in the final directory, and obviously delete the file in the tmp folder.
PS: Also you have 2 return, if you need to respond as a HTML or JSON you have to check the headers of the request.