重新实践《轻量级DJANGO》这本书

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从手到尾,手写的DJANGO,不借助命令,效果一样的呢。

import os
import sys
import hashlib
from django.conf import settings

DEBUG = os.environ.get(DEBUG, on) == on
SECRET_KEY = os.environ.get(SECRET_KEY, %jv_4#hoaqwig2gu!eg#^ozptd*[email protected](aasv7z!7xt^5(*i&k)
ALLOWED_HOSTS = os.environ.get(ALLOWED_HOSTS, localhost).split(,)
BASE_DIR = os.path.dirname(__file__)

settings.configure(
    DEBUG=DEBUG,
    TEMPLATE_DEBUG = True,
    SECRET_KEY=SECRET_KEY,
    ALLOWED_HOSTS=ALLOWED_HOSTS,
    ROOT_URLCONF=__name__,
    MIDDLEWARE_CLASSES=(
        django.middleware.common.CommonMiddleware,
        django.middleware.csrf.CsrfViewMiddleware,
        django.middleware.clickjacking.XFrameOptionsMiddleware,
    ),
    INSTALLED_APPS=(
        django.contrib.staticfiles,
    ),
    TEMPLATES = [
        {
            BACKEND: django.template.backends.django.DjangoTemplates,
            DIRS: [
                os.path.join(BASE_DIR,templates).replace(\\, /),
            ],
            APP_DIRS: True,
        }
    ],
    STATICFILES_DIRS=(
        os.path.join(BASE_DIR, static),
    ),
    STATIC_URL=/static/,
)

from django import forms
from django.conf.urls import url
from django.core.urlresolvers import reverse
from django.core.cache import cache
from django.core.wsgi import get_wsgi_application
from django.http import HttpResponse, HttpResponseBadRequest
from django.shortcuts import render
from django.views.decorators.http import etag
from io import BytesIO
from PIL import Image, ImageDraw

class ImageForm(forms.Form):
    height = forms.IntegerField(min_value=1, max_value=2000)
    width = forms.IntegerField(min_value=1, max_value=2000)

    def generate(self, image_format=PNG):
        """Generate an image of the given type and return as raw bytes."""

        height = self.cleaned_data[height]
        width = self.cleaned_data[width]
        key = {}.{}.{}.format(width, height, image_format)
        content = cache.get(key)
        if content is None:
            image = Image.new(RGB, (width, height))
            draw = ImageDraw.Draw(image)
            text = {} X {} demo.format(width, height)
            textwidth, textheight = draw.textsize(text)
            if textwidth < width and textheight < height:
                texttop = (height - textheight) // 2
                textleft = (width - textwidth) // 2
                draw.text((textleft, texttop), text, fill=(255, 155, 5))
            content = BytesIO()
            image.save(content, image_format)
            content.seek(0)
            cache.set(key, content, 60 * 60)
        return content

def generate_etag(request, width, height):
    content = Placeholder: {0} x {1}.format(width, height)
    return hashlib.sha1(content.encode(utf-8)).hexdigest()

@etag(generate_etag)
def placeholder(request, width, height):
    form = ImageForm({height: height, width: width})
    if form.is_valid():
        image = form.generate()
        return HttpResponse(image, content_type=image/png)
    else:
        return HttpResponseBadRequest("Invalid Image Request")

def index(request):
    example = reverse(placeholder, kwargs={width: 500, height: 500})
    print example, #####################
    context = {
        example: request.build_absolute_uri(example)
    }
    print context, @@@@@@@@@@@@@@@@@@@@@@@
    return render(request, home.html, context)

urlpatterns = (
    url(r^image/(?P<width>[0-9]+)x(?P<height>[0-9]+)/$, placeholder, name=placeholder),
    url(r^$, index, name=homepage),
)

application = get_wsgi_application()

if __name__ == "__main__":
    from django.core.management import execute_from_command_line
    execute_from_command_line(sys.argv)

 

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