Flask read uploaded json file

Question

I'm uploading a json file via flask, but I'm having trouble actually reading what is in the file.

# named fJson b/c of other json imports
from flask import json as fJson
@app.route('/upload', methods=['GET', 'POST'])
def upload():
if request.method == 'POST':
    file = request.files['file']
    # data = fJson.load(file)
    # myfile = file.read()

I'm trying to deal with this by using the 'file' variable. I looked at http://flask.pocoo.org/docs/0.10/api/#flask.json.load, but I get the error "No JSON object could be decoded". I also looked at Read file data without saving it in Flask which recommended using file.read(), but that didn't work, returns either "None" or "".

score 3 · Answer 1 · answered Apr 06 '16 at 05:38

3

Request.files

A MultiDict with files uploaded as part of a POST or PUT request. Each file is stored as FileStorage object. It basically behaves like a standard file object you know from Python, with the difference that it also has a save() function that can store the file on the filesystem. http://flask.pocoo.org/docs/0.10/api/#flask.Request.files

You don't need use json, just use read(), like this:

if request.method == 'POST':
    file = request.files['file']        
    myfile = file.read()

answered Apr 06 '16 at 05:38

Jair Perrut

1,360
13
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When I try to print that, it only prints an empty string (and I checked, my file does have stuff in it) – Joe Johnson Apr 06 '16 at 05:53
Nice, share with us your solution. – Jair Perrut Apr 06 '16 at 17:23
1

I did below this one, but it won't let me accept it as an answer for another day. – Joe Johnson Apr 06 '16 at 21:17

score 1 · Accepted Answer · answered Apr 06 '16 at 06:55

1

For some reason the position in the file was at the end. Doing

file.seek(0)

before doing a read or load fixes the problem.

answered Apr 06 '16 at 06:55

Joe Johnson

105
1
2
9

Flask read uploaded json file

2 Answers2

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