flask 常用辅助类utils.py(flask 90)

import os
import uuid

try:
from urlparse import urlparse, urljoin
except ImportError:
from urllib.parse import urlparse, urljoin

import PIL
from PIL import Image
from flask import current_app, request, url_for, redirect, flash
from itsdangerous import BadSignature, SignatureExpired
from itsdangerous import TimedJSONWebSignatureSerializer as Serializer

from extensions import db
from model import User
from settings import Operations

def generate_token(user, operation, expire_in=None, **kwargs):
s = Serializer(current_app.config['SECRET_KEY'], expire_in)

data = {'id': user.id, 'operation': operation}
data.update(**kwargs)
return s.dumps(data)

def validate_token(user, token, operation, new_password=None):
s = Serializer(current_app.config['SECRET_KEY'])

try:
    data = s.loads(token)
except (SignatureExpired, BadSignature):
    return False

if operation != data.get('operation') or user.id != data.get('id'):
    return False

if operation == Operations.CONFIRM:
    user.confirmed = True
elif operation == Operations.RESET_PASSWORD:
    user.set_password(new_password)
elif operation == Operations.CHANGE_EMAIL:
    new_email = data.get('new_email')
    if new_email is None:
        return False
    if User.query.filter_by(email=new_email).first() is not None:
        return False
    user.email = new_email
else:
    return False

db.session.commit()
return True

def rename_image(old_filename):
ext = os.path.splitext(old_filename)[1]
new_filename = uuid.uuid4().hex + ext
return new_filename

def resize_image(image, filename, base_width):
filename, ext = os.path.splitext(filename)
img = Image.open(image)
if img.size[0] <= base_width:
return filename + ext
w_percent = (base_width / float(img.size[0]))
h_size = int((float(img.size[1]) * float(w_percent)))
img = img.resize((base_width, h_size), PIL.Image.ANTIALIAS)

filename += current_app.config['ALBUMY_PHOTO_SUFFIX'][base_width] + ext
img.save(os.path.join(current_app.config['ALBUMY_UPLOAD_PATH'], filename), optimize=True, quality=85)
return filename

def is_safe_url(target):
ref_url = urlparse(request.host_url)
test_url = urlparse(urljoin(request.host_url, target))
return test_url.scheme in ('http', 'https') and
ref_url.netloc == test_url.netloc

def redirect_back(default='main.index', **kwargs):
for target in request.args.get('next'), request.referrer:
if not target:
continue
if is_safe_url(target):
return redirect(target)
return redirect(url_for(default, **kwargs))

def flash_errors(form):
for field, errors in form.errors.items():
for error in errors:
flash(u"Error in the %s field - %s" % (
getattr(form, field).label.text,
error
))