当 Flask 服务器正在保存图像文件时，如何解决出现“权限被拒绝”的问题

Question

We are having problem having Flask save image files on our server. We've made sure that the directory we're trying to write to has write permission. We used chmod images 777. But we are getting “Permission Denied”.

I did "chmod 777 images" directory ls -l result is drwxrwxrwx 2 someuser someuser 4096 Jul 16 2021 images

Result of form with file submission: Same response: Permission Denied

Here are the relevant fragments of code we have:

<form action="/someurl" method="post" enctype="multipart/form-data" id="workform">
<input  type="file" name="photobefore” />
<input  type="file" name="photoafter" />
<input type=“submit” />
</form>

SERVER:

@main_blueprint.route(‘/someurl’, methods=['GET', 'POST'])
def workperformed():
        message = “submitted”
        before = ""
        after = ""
        try:
            if len(request.files) > 0:
                for name in request.files:
                    file = request.files[name]
                    if name == 'photobefore':
                        before = file.filename
                    if name == 'photoafter':
                        after = file.filename
                    if not file.filename == '':
                        if file and allowed_file(file.filename):
                            filename = secure_filename(file.filename)
                            file.save(os.path.join(app.config['UPLOAD_FOLDER'], filename))

        except Exception as e:
            message = "dir:" + os.getcwd() + " error:" + str(e)

        return message

Result: dir:/ error:[Errno 13] Permission denied: '/home/someuser/public_html/mydefensiblespace.org/html/templates/static/images/20190721_184017_HDR.jpg'

Answer 1

The web server (assuming Apache or Nginx on Ubuntu) needs to be the owner of the folder where you are saving images

chown -R www-data:www-data /path/to/folder

I believe Nginx also needs the folder to be executable

chmod +x /path/to/folder 

Also since your path to folder is outside of /var/www you will need a directive in your virtual host

<VirtualHost *:80>
 ServerName domain.com
 # ...
 <Directory /path/to/folder>
  Options Indexes FollowSymLinks
  AllowOverride All
  Require all granted
 </Directory> 
</VirtualHost>