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https://github.com/justanr/Flask-Transfer

Tired of validating and manipulating uploaded files manually? Try this instead.
https://github.com/justanr/Flask-Transfer

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Tired of validating and manipulating uploaded files manually? Try this instead.

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README 

        

Flask-Transfer

==============



Validate, process and persist file uploads easily through a single

object instead of cramming all that stuff into your routes.



Tired of this?

--------------



.. code:: python



    @app.route('/upload', methods=['GET', 'POST'])

    def handle_upload():

        form = FileUploadForm()

        

        if form.validate_on_submit():

            filehandle = form.uploaded.data

            allowed_exts = ('md', 'txt', 'rst')

            if not os.path.splitext(filehandle.filename)[1] in allowed_exts:

                raise SomeError('Unallowed extension!')

            if filehandle.read() != b'Hello World!':

                raise SomeError('File contents not allowed!')

            filehandle.seek(0)

            

            username = g.current_user.name

            upload_dir = current_app.config['UPLOAD_DIR']

            full_path = os.path.join(upload_dir, username, secure_filename(filehandle.filename))

            filehandle.save(full_path)

            flash("Uploaded {}!".format(filehandle.filename), 'success')

            return redirect(url_for('handle_upload'))

        else:

            return render_template('upload.html', form=form)



That's a mess. Your test runner is literally running away from you.

There's like four or five different things going on in this single

route! Argh.



There's a better way

--------------------



.. code:: python



    from flask_transfer import Transfer, UploadError

    from flask_transfer.validators import AllowedExts

    

    TextFileTransfer = Transfer(validators=[AllowedExts('md', 'rst', 'txt')])

    

    @TextFileTransfer.destination

    def save_to_user_dir(filehandle, metadata):

        username = g.current_user.name

        upload_path = current_app.config['UPLOAD_DIR']

        full_path = os.path.join(upload_dir, username, secure_filename(filehandle.filename))

        filehandle.save(full_path)

    

    

    @TextFileTransfer.validator

    def check_file_contents(filehandle, metadata):

        if filehandle.read() != metadata['allowed_contents']:

            raise UploadError('File contents not allowed!')

        filehandle.seek(0)

        return True

    

    

    @app.route('/upload', methods=['GET', 'POST'])

    def handle_upload():

        form = FileUploadForm()

        

        if form.validate_on_submit():

            filehandle = form.uploaded.data

            TextFileTransfer.save(filehandle, metadata={'allowed_contents': b'Hello World!'})

            flash('Uploaded {}!'.format(filehandle.filename), 'success')

            return redirect(url_for('handle_upload'))

        else:

            return render_template('upload.html', form=form)



Aaaah. Sure, it's a little bit more code. But it's separated out into

bits and pieces. It's easy to test each bit and the intent in the route

is very clear.



More Power

----------



Flask-Transfer supplies hooks for validation, preprocessing and

postprocessing file uploads via decorators. If you need to always create

thumbnails of uploaded images, you can supply a callable to

``MyTransfer.preprocessor`` or ``MyTransfer.postprocessor`` that'll do

that for you.



And validation beyond just simple extension checking is at your

fingertips as well. Perhaps, you've limited your user to a certain

amount of disk space and they should be told to delete data before

uploading more. Write a simple function to check current disk usage and

if the upload would exceed the cap. Then hook it to your Transfer object

with ``MyTransfer.validator``.



Finally, persisting files is easy! Maybe you're running on Heroku and

can't rely on the local filesystem. Just write a callable that'll pass

the file to your S3 bucket! Hook it in with ``MyTransfer.destination``.

Flask-Transfer handles using string paths and writable objects as

destinations as well.



Check out the `quickstart `__ for some more information,

as well!



Todo

----



There's still quite a bit to do. For example, better error handle.

Perhaps a tighter integration with Flask, or running the opposite way

and cleaving the already few dependencies on werkzeug to become

framework independent.



Contributions

-------------



Given the infancy of this project, pull requests and issue are more than

welcome. Just add yourself to the authors file, write some tests for the

added or change functionality and submit it!