Calculate md5 from werkzeug.datastructures.FileStorage without saving the object as file

Question

I'm using Flask for uploading files. In order to prevent storing same file twice, I'm intending to calculate md5 from the file content, and store the file as . unless the file is already there.

@app.route('/upload', methods=['GET', 'POST'])
def upload_file():
    if request.method == 'POST':
        file = request.files['file']
        #next line causes exception
        img_key = hashlib.md5(file).hexdigest()

Unfortunatelly, hashlib.md5 throws the exception:

TypeError: must be string or buffer, not FileStorage

I've already tried file.stream - same effect.

Is there any way to get md5 from the file without saving it temporarily?

Answer 1

request.files['file'] is of type FileStorage which has a read() method. Try doing:

file = request.files['file']

#file.read() is the same as file.stream.read()
img_key = hashlib.md5(file.read()).hexdigest() 

More info on FileStorage: http://werkzeug.pocoo.org/docs/datastructures/#werkzeug.datastructures.FileStorage

Answer 2

From the Flask docs

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.

If it's the same as a file object you should be able to do this

img_key = hashlib.md5(file.read()).hexdigest()