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author	Brian Neal <bgneal@gmail.com>
date	Sat, 21 Jul 2018 17:47:55 -0500
parents	7ce6393e6d30
children

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bgneal@4	1 Fixed pages for Django
bgneal@4	2 ######################
bgneal@4	3
bgneal@4	4 :date: 2012-05-13 13:30
bgneal@4	5 :tags: Django
bgneal@4	6 :slug: fixed-pages-for-django
bgneal@4	7 :author: Brian Neal
bgneal@4	8
bgneal@4	9 I have been using Django's `flatpages app`_ for some simple, static pages that
bgneal@4	10 were supposed to be temporary. I slapped a Javascript editor on the admin page
bgneal@4	11 and it has worked very well. However some of the pages have long outlived their
bgneal@4	12 "temporary" status, and I find myself needing to update them. It is then that I
bgneal@4	13 get angry at the Javascript editor, and there is no way to keep any kind of
bgneal@4	14 history on the page without having to fish through old database backups. I
bgneal@4	15 started to think it would be nice to write the content in a nice markup
bgneal@4	16 language, for example reStructuredText_, which I could then commit to version
bgneal@4	17 control. I would just need a way to generate HTML from the source text to
bgneal@4	18 produce the flatpage content.
bgneal@4	19
bgneal@4	20 Of course I could use the template filters in `django.contrib.markup`_. But
bgneal@4	21 turning markup into HTML at page request time can be more expensive than I like.
bgneal@4	22 Yes, I could cache the page, but I'd like the process to be more explicit.
bgneal@4	23
bgneal@4	24 In my first attempt at doing this, I wrote a `custom management command`_ that
bgneal@4	25 used a dictionary in my ``settings.py`` file to map reStructuredText files to
bgneal@4	26 flatpage URLs. My management command would open the input file, convert it to
bgneal@4	27 HTML, then find the ``FlatPage`` object associated with the URL. It would then
bgneal@4	28 update the object with the new HTML content and save it.
bgneal@4	29
bgneal@4	30 This worked okay, but in the end I decided that the pages I wanted to update
bgneal@4	31 were not temporary, quick & dirty pages, which is kind of how I view flatpages.
bgneal@4	32 So I decided to stop leaning on the flatpages app for these pages.
bgneal@4	33
bgneal@4	34 I then modified the management command to read a given input file, convert it
bgneal@4	35 to an HTML fragment, then save it in my templates directory. Thus, a file stored
bgneal@4	36 in my project directory as ``fixed/about.rst`` would get transformed to
bgneal@4	37 ``templates/fixed/about.html``. Here is the source to the command which I saved
bgneal@4	38 as ``make_fixed_page.py``:
bgneal@4	39
bgneal@4	40 .. sourcecode:: python
bgneal@4	41
bgneal@4	42 import os.path
bgneal@4	43 import glob
bgneal@4	44
bgneal@4	45 import docutils.core
bgneal@4	46 from django.core.management.base import LabelCommand, CommandError
bgneal@4	47 from django.conf import settings
bgneal@4	48
bgneal@4	49
bgneal@4	50 class Command(LabelCommand):
bgneal@4	51 help = "Generate HTML from restructured text files"
bgneal@4	52 args = "<inputfile1> <inputfile2> ... \| all"
bgneal@4	53
bgneal@4	54 def handle_label(self, filename, **kwargs):
bgneal@4	55 """Process input file(s)"""
bgneal@4	56
bgneal@4	57 if not hasattr(settings, 'PROJECT_PATH'):
bgneal@4	58 raise CommandError("Please add a PROJECT_PATH setting")
bgneal@4	59
bgneal@4	60 self.src_dir = os.path.join(settings.PROJECT_PATH, 'fixed')
bgneal@4	61 self.dst_dir = os.path.join(settings.PROJECT_PATH, 'templates', 'fixed')
bgneal@4	62
bgneal@4	63 if filename == 'all':
bgneal@4	64 files = glob.glob("%s%s*.rst" % (self.src_dir, os.path.sep))
bgneal@4	65 files = [os.path.basename(f) for f in files]
bgneal@4	66 else:
bgneal@4	67 files = [filename]
bgneal@4	68
bgneal@4	69 for f in files:
bgneal@4	70 self.process_page(f)
bgneal@4	71
bgneal@4	72 def process_page(self, filename):
bgneal@4	73 """Processes one fixed page"""
bgneal@4	74
bgneal@4	75 # retrieve source text
bgneal@4	76 src_path = os.path.join(self.src_dir, filename)
bgneal@4	77 try:
bgneal@4	78 with open(src_path, 'r') as f:
bgneal@4	79 src_text = f.read()
bgneal@4	80 except IOError, ex:
bgneal@4	81 raise CommandError(str(ex))
bgneal@4	82
bgneal@4	83 # transform text
bgneal@4	84 content = self.transform_input(src_text)
bgneal@4	85
bgneal@4	86 # write output
bgneal@4	87 basename = os.path.splitext(os.path.basename(filename))[0]
bgneal@4	88 dst_path = os.path.join(self.dst_dir, '%s.html' % basename)
bgneal@4	89
bgneal@4	90 try:
bgneal@4	91 with open(dst_path, 'w') as f:
bgneal@4	92 f.write(content.encode('utf-8'))
bgneal@4	93 except IOError, ex:
bgneal@4	94 raise CommandError(str(ex))
bgneal@4	95
bgneal@4	96 prefix = os.path.commonprefix([src_path, dst_path])
bgneal@4	97 self.stdout.write("%s -> %s\n" % (filename, dst_path[len(prefix):]))
bgneal@4	98
bgneal@4	99 def transform_input(self, src_text):
bgneal@4	100 """Transforms input restructured text to HTML"""
bgneal@4	101
bgneal@4	102 return docutils.core.publish_parts(src_text, writer_name='html',
bgneal@4	103 settings_overrides={
bgneal@4	104 'doctitle_xform': False,
bgneal@4	105 'initial_header_level': 2,
bgneal@4	106 })['html_body']
bgneal@4	107
bgneal@4	108 Next I would need a template that could render these fragments. I remembered
bgneal@4	109 that the Django `include tag`_ could take a variable as an argument. Thus I
bgneal@4	110 could create a single template that could render all of these "fixed" pages.
bgneal@4	111 Here is the template ``templates/fixed/base.html``::
bgneal@4	112
bgneal@4	113 {% extends 'base.html' %}
bgneal@4	114 {% block title %}{{ title }}{% endblock %}
bgneal@4	115 {% block content %}
bgneal@4	116 {% include content_template %}
bgneal@4	117 {% endblock %}
bgneal@4	118
bgneal@4	119 I just need to pass in ``title`` and ``content_template`` context variables. The
bgneal@4	120 latter will control which HTML fragment I include.
bgneal@4	121
bgneal@4	122 I then turned to the view function which would render this template. I wanted to
bgneal@4	123 make this as generic and easy to do as possible. Since I was abandoning
bgneal@4	124 flatpages, I would need to wire these up in my ``urls.py``. At first I didn't
bgneal@4	125 think I could use Django's new `class-based generic views`_ for this, but after
bgneal@4	126 some fiddling around, I came up with a very nice solution:
bgneal@4	127
bgneal@4	128 .. sourcecode:: python
bgneal@4	129
bgneal@4	130 from django.views.generic import TemplateView
bgneal@4	131
bgneal@4	132 class FixedView(TemplateView):
bgneal@4	133 """
bgneal@4	134 For displaying our "fixed" views generated with the custom command
bgneal@4	135 make_fixed_page.
bgneal@4	136
bgneal@4	137 """
bgneal@4	138 template_name = 'fixed/base.html'
bgneal@4	139 title = ''
bgneal@4	140 content_template = ''
bgneal@4	141
bgneal@4	142 def get_context_data(self, **kwargs):
bgneal@4	143 context = super(FixedView, self).get_context_data(**kwargs)
bgneal@4	144 context['title'] = self.title
bgneal@4	145 context['content_template'] = self.content_template
bgneal@4	146 return context
bgneal@4	147
bgneal@4	148 This allowed me to do the following in my ``urls.py`` file:
bgneal@4	149
bgneal@4	150 .. sourcecode:: python
bgneal@4	151
bgneal@4	152 urlpatterns = patterns('',
bgneal@4	153 # ...
bgneal@4	154
bgneal@4	155 url(r'^about/$',
bgneal@4	156 FixedView.as_view(title='About', content_template='fixed/about.html'),
bgneal@4	157 name='about'),
bgneal@4	158 url(r'^colophon/$',
bgneal@4	159 FixedView.as_view(title='Colophon', content_template='fixed/colophon.html'),
bgneal@4	160 name='colophon'),
bgneal@4	161
bgneal@4	162 # ...
bgneal@4	163
bgneal@4	164 Now I have a way to efficiently serve reStructuredText files as "fixed pages"
bgneal@4	165 that I can put under source code control.
bgneal@4	166
bgneal@4	167 .. _flatpages app: https://docs.djangoproject.com/en/1.4/ref/contrib/flatpages/
bgneal@4	168 .. _reStructuredText: http://docutils.sourceforge.net/rst.html
bgneal@4	169 .. _custom management command: https://docs.djangoproject.com/en/1.4/howto/custom-management-commands/
bgneal@4	170 .. _include tag: https://docs.djangoproject.com/en/1.4/ref/templates/builtins/#include
bgneal@4	171 .. _class-based generic views: https://docs.djangoproject.com/en/1.4/topics/class-based-views/
bgneal@4	172 .. _django.contrib.markup: https://docs.djangoproject.com/en/1.4/ref/contrib/markup/

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