Uploading multiple files with Flask

Question

Is there a way to receive multiple uploaded files with Flask? I've tried the following:

<form method="POST" enctype="multipart/form-data" action="/upload">
  <input type="file" name="file[]" multiple="">
  <input type="submit" value="add">
</form>

And then printed the contents of request.files['file']:

@app.route('/upload', methods=['POST'])
def upload():
  if not _upload_dir:
    raise ValueError('Uploads are disabled.')

  uploaded_file = flask.request.files['file']
  print uploaded_file
  media.add_for_upload(uploaded_file, _upload_dir)
  return flask.redirect(flask.url_for('_main'))

If I upload multiple files, it only prints the first file in the set:

<FileStorage: u'test_file.mp3' ('audio/mp3')>

Is there a way to receive multiple files using Flask's built-in upload handling? Thanks for any help!

One can skip brackets in "file[]", name="file" is ok to use. — Denis Trofimov, Feb 19 '19 at 14:08

score 130 · Accepted Answer · edited Jul 29 '16 at 18:53

130

You can use method getlist of flask.request.files, for example:

@app.route("/upload", methods=["POST"])
def upload():
    uploaded_files = flask.request.files.getlist("file[]")
    print uploaded_files
    return ""

edited Jul 29 '16 at 18:53

Iron Fist

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answered Aug 05 '12 at 14:41

Fedor Gogolev

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I tried this but it says 'flask' is not defined. where am I going wrong? what are the modules I need to import? – Chandan Gupta Jul 23 '13 at 04:40
5

from flask import request – Temere Nov 30 '13 at 00:19
request.files.getlist("file[]") – Temere Nov 30 '13 at 00:20
19

the square brackets are not a must. – simanacci Jul 28 '16 at 12:22
2

Doesn't work without square brackets for me on Flask 0.12.2 – boycy Oct 31 '17 at 15:11
no [] worked for me. Otherwise I was just getting an empty list – nEO Aug 13 '18 at 22:39
3

With Flask 1.0.2 I was getting an empty list with square brackets included, and correct file list when not included. – Liam Aug 22 '18 at 05:50
In addition to the answer, one would test this using curl -X POST -F "file[]=@/path/to/file1" -F "file[]=@/path/to/file2" ... srvaddr/upload – alleen1 Aug 03 '21 at 07:28
This worked for me `request.files.getlist("images")`. and also I needed to get form then I used `request.form.getlist("data")`. Working both! – Athif Saheer Apr 25 '23 at 19:22

score 29 · Answer 2 · answered Jul 26 '19 at 13:00

@app.route('/upload', methods=['GET','POST'])
def upload():
    if flask.request.method == "POST":
        files = flask.request.files.getlist("file")
        for file in files:
            file.save(os.path.join(app.config['UPLOAD_FOLDER'], file.filename))

It works for me.

for UPLOAD_FOLDER if you need add this just after app = flask.Flask(name)

UPLOAD_FOLDER = 'static/upload'
app.config['UPLOAD_FOLDER'] = UPLOAD_FOLDER

Jack · Answer 3 · 2021-03-29T08:44:18.853

15

Using Flask 1.0.2+:

files = request.files.getlist("images")

Where images is the key of the key/value pair. With the Value being the multiple images.

edited Mar 29 '21 at 08:44

answered Sep 28 '18 at 15:25

Jack

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Thanks! And as it may help others prevent some searching, note that `file.filename` gives the name of the file for each `file` in `files`. – Hans Bouwmeester Feb 24 '19 at 08:57

score 8 · Answer 4 · edited May 15 '19 at 12:38

8

this is a working solution for flask version '1.0.2':

images = request.files.to_dict() #convert multidict to dict
for image in images:     #image will be the key 
    print(images[image])        #this line will print value for the image key
    file_name = images[image].filename
    images[image].save(some_destination)

basically, images[image] has an image file with save function added to it Now do whatever you like to do with the data.

edited May 15 '19 at 12:38

Jean-François Fabre

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answered Aug 28 '18 at 19:41

SATYAJEET RANJAN

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to_dict doesn't get list of image. – TomSawyer Feb 22 '21 at 16:36
1

@TomSawyer Which flask version are you using? can you put print(type(request.files)) in your code and see what is the type of request.files. If it is multidict then to_dict method should give you a dictionary object in return. – SATYAJEET RANJAN Feb 23 '21 at 18:07
1

@Jean-François Fabre This is a workig solution for flask 2.0.1 too, but `to_dict` doesn't seem to the the whole list of files when I use `FormData` in JS. It only fetches the first file, Anything I am doing wrong? – collinsmarra Nov 17 '21 at 04:50
@collinsmarra before the for loop print the images and see what you are getting I am using this code in many projects and it returns me one file or more that one file based on what i send from client side. If possible check the code on your client side JS. You might find a clue there. – SATYAJEET RANJAN Dec 16 '21 at 04:54

Uploading multiple files with Flask

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