Какой нужен валидатор для проверки типа и размера в MultipleFileField?

Question

[Ganki]

Делаю форму для загрузки сразу нескольких картинок.

Не знаю, каким валидатором проверить, являются ли выбранные файлы картинками,
а также не больше ли они определенного размера.

from flask_wtf import FlaskForm
from wtforms import SubmitField, MultipleFileField
from wtforms.validators import Required


class UploadImagesForm(FlaskForm):
    images = MultipleFileField('Upload images', validators=[Required()])
    submit = SubmitField('Upload')

Answer 1

[alternativshik]

Собственным валидатором.

Answer 2

[Ganki]

Понял что такого валидатора нет, написал свой валидатор для проверки типа файла. Но не могу понять почему flask перехватывает эту ошибку раньше моего валидатора и выдает ошибку 413:

# config.py

import os

basedir = os.path.abspath(os.path.dirname(__file__))

class Config(object):
    SECRET_KEY = os.environ.get('SECRET_KEY') or 'you-will-never-guess'
    SQLALCHEMY_DATABASE_URI = os.environ.get('DATABASE_URL') or \
        'sqlite:///' + os.path.join(basedir, 'app.db')
    SQLALCHEMY_TRACK_MODIFICATIONS = False
    UPLOADED_IMAGES_DEST = basedir + '/app/static/shoes'
    UPLOADED_IMAGES_URL = 'http://localhost:5000/static/shoes/'
    MAX_CONTENT_LENGTH = 5 * 1024 * 1024

    @staticmethod
    def init_app(app):
        pass


# __init.py__

import os
from flask import Flask, request, current_app
from flask_sqlalchemy import SQLAlchemy
from flask_migrate import Migrate
from config import Config
from flask_uploads import UploadSet, IMAGES, configure_uploads, patch_request_class


db = SQLAlchemy()
migrate = Migrate()
images = UploadSet('shoes', IMAGES)


def create_app(config_class=Config):
    app = Flask(__name__)
    app.config.from_object(config_class)
    configure_uploads(app, images)
    patch_request_class(app, app.config['MAX_CONTENT_LENGTH'])

    db.init_app(app)
    migrate.init_app(app, db)
    login.init_app(app)

    from app.errors import bp as errors_bp
    app.register_blueprint(errors_bp)

    from app.albums import bp as albums_bp
    app.register_blueprint(albums_bp, url_prefix='/albums')

    return app


from app import models


# routes.py

from flask import render_template, flash, redirect, url_for, request, current_app
from flask_login import current_user, login_required
from app import db, images
from app.albums import bp
from app.albums.forms import NewAlbumForm, UploadImages
from app.models import Album, SImage, User

@bp.route('/<username>/<int:id>', methods=['GET', 'POST'])
@login_required
def view_album(username, id):
    user = User.query.filter_by(username=username).first_or_404()
    album = Album.query.filter_by(author=user, id=id).first_or_404()
    shoe_images = SImage.query.filter_by(album=album).all()
    form = UploadImages()
    if form.validate_on_submit():
        for file in form.images.data:
            filename = images.save(file, name=file.filename.lower())
            url = images.url(filename)
            up_shoe_img = SImage(image_filename=filename, image_url=url, 
                                    author_id=user.id, album_id=album.id)
            db.session.add(up_shoe_img)
            db.session.commit()
        flash('Image uploaded!')
        return redirect(url_for('albums.view_album', 
                                username=current_user.username, id=album.id))



# forms.py

from flask_wtf import FlaskForm
from wtforms import SubmitField, MultipleFileField
from wtforms.validators import Required, ValidationError
from app import images


class UploadImages(FlaskForm):
    images = MultipleFileField('Upload images', validators=[Required()])
    submit = SubmitField('Upload')

    def validate_images(self, images):
        for file in images.data:
            extension = file.filename.lower().split('.')[1]
            if extension not in images.extensions:
                raise ValidationError('Images only!')

Comments

[alternativshik]

Потому что MAX_CONTENT_LENGTH = 5 * 1024 * 1024 == 5 мегабайт, наверное, ваш файл гораздо большего размера...

[Ganki]

Благодарю за помощь, решил данную проблему:

# config.py

MAX_UPLOAD_SIZE = 5 * 1024 * 1024
MAX_CONTENT_LENGTH = 16 * 1024 * 1024

forms.py

class UploadImages(FlaskForm):
    images = MultipleFileField('Upload images', validators=[Required()])
    submit = SubmitField('Upload')

    def validate_images(self, images):
        for file in images.data:
            # File extension check
            extension = file.filename.lower().split('.')[-1]
            if extension not in images.extensions:
                raise ValidationError('Images only!')

            # File size check
            file.seek(0, 2)
            file_size = file.tell()
            file.seek(0)
            if file_size > current_app.config['MAX_UPLOAD_SIZE']:
                raise ValidationError('5 Mb maximum!')