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How to reset the file.stream in flask / werkzeug?

It seems to me, that you cannot access file.stream.read() after the file has been written with file.save('path',filename') and vice versa.

Example code (derived from the file uploading pattern):

import os
from flask import Flask, request, redirect, url_for, send_from_directory
from werkzeug import secure_filename

UPLOAD_FOLDER = 'uploads/'
ALLOWED_EXTENSIONS = set(['txt', 'pdf', 'png', 'jpg', 'jpeg', 'gif'])

app = Flask(__name__)
app.config['UPLOAD_FOLDER'] = UPLOAD_FOLDER
def allowed_file(filename):
    return '.' in filename and \
           filename.rsplit('.', 1)[1] in ALLOWED_EXTENSIONS

@app.route('/', methods=['GET', 'POST'])
def upload_file():
    if request.method == 'POST':
        file = request.files['file']
        if file and allowed_file(file.filename):
            filename = secure_filename(file.filename)
            print '##########################'
            print os.path.join(app.config['UPLOAD_FOLDER'],filename)
            file.save(os.path.join(app.config['UPLOAD_FOLDER'], filename))
            print file.stream.read() # <- gives no output
            print '##########################'
            return redirect(url_for('uploaded_file',
                                    filename=filename))
    return '''
    <!doctype html>
    <title>Upload new File</title>
    <h1>Upload new File</h1>
    <form action="" method=post enctype=multipart/form-data>
      <p><input type=file name=file>
         <input type=submit value=Upload>
    </form>
    '''

@app.route('/uploads/<filename>')
def uploaded_file(filename):
    return send_from_directory(app.config['UPLOAD_FOLDER'],
                               filename)

if __name__ == '__main__':
    app.run(debug=True)                    
like image 978
Framester Avatar asked Sep 09 '11 22:09

Framester


1 Answers

You should be able to seek back to the start of the stream. (See Werkzeug's docs on werkzeug.datastructures.FileStorage). When you try to read the file a second time you start reading from the end of the file.

file.save(os.path.join(app.config['UPLOAD_FOLDER'], filename))
file.stream.seek(0) # Go back to the start of the file
print file.stream.read() # <- should work now.
like image 197
Sean Vieira Avatar answered Oct 07 '22 04:10

Sean Vieira