在 python 中生成 HTML 文档

在 python 中,生成 HTML 文档的最佳方式是什么。我目前手动追加所有的标签到一个巨大的字符串,并写入一个文件。还有比这更优雅的方式吗?

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I would recommend using xml.dom to do this.

http://docs.python.org/library/xml.dom.html

Read this manual page, it has methods for building up XML (and therefore XHTML). It makes all XML tasks far easier, including adding child nodes, document types, adding attributes, creating texts nodes. This should be able to assist you in the vast majority of things you will do to create HTML.

It is also very useful for analysing and processing existing xml documents.

Here is a tutorial that should help you with applying the syntax:

http://www.postneo.com/projects/pyxml/

I would suggest using one of the many template languages available for python, for example the one built into Django (you don't have to use the rest of Django to use its templating engine) - a google query should give you plenty of other alternative template implementations.

I find that learning a template library helps in so many ways - whenever you need to generate an e-mail, HTML page, text file or similar, you just write a template, load it with your template library, then let the template code create the finished product.

Here's some simple code to get you started:

#!/usr/bin/env python


from django.template import Template, Context
from django.conf import settings
settings.configure() # We have to do this to use django templates standalone - see
# http://stackoverflow.com/questions/98135/how-do-i-use-django-templates-without-the-rest-of-django


# Our template. Could just as easily be stored in a separate file
template = """
<html>
<head>
<title>Template \{\{ title }}</title>
</head>
<body>
Body with \{\{ mystring }}.
</body>
</html>
"""


t = Template(template)
c = Context({"title": "title from code",
"mystring":"string from code"})
print t.render(c)

It's even simpler if you have templates on disk - check out the render_to_string function for django 1.7 that can load templates from disk from a predefined list of search paths, fill with data from a dictory and render to a string - all in one function call. (removed from django 1.8 on, see Engine.from_string for comparable action)

You can use yattag to do this in an elegant way. FYI I'm the author of the library.

from yattag import Doc


doc, tag, text = Doc().tagtext()


with tag('html'):
with tag('body'):
with tag('p', id = 'main'):
text('some text')
with tag('a', href='/my-url'):
text('some link')


result = doc.getvalue()

It reads like html, with the added benefit that you don't have to close tags.

I am using the code snippet known as throw_out_your_templates for some of my own projects:

https://github.com/tavisrudd/throw_out_your_templates

https://bitbucket.org/tavisrudd/throw-out-your-templates/src

Unfortunately, there is no pypi package for it and it's not part of any distribution as this is only meant as a proof-of-concept. I was also not able to find somebody who took the code and started maintaining it as an actual project. Nevertheless, I think it is worth a try even if it means that you have to ship your own copy of throw_out_your_templates.py with your code.

Similar to the suggestion to use yattag by John Smith Optional, this module does not require you to learn any templating language and also makes sure that you never forget to close tags or quote special characters. Everything stays written in Python. Here is an example of how to use it:

html(lang='en')[
head[title['An example'], meta(charset='UTF-8')],
body(onload='func_with_esc_args(1, "bar")')[
div['Escaped chars: ', '< ', u'>', '&'],
script(type='text/javascript')[
'var lt_not_escaped = (1 < 2);',
'\nvar escaped_cdata_close = "]]>";',
'\nvar unescaped_ampersand = "&";'
],
Comment('''
not escaped "< & >"
escaped: "-->"
'''),
div['some encoded bytes and the equivalent unicode:',
'你好', unicode('你好', 'utf-8')],
safe_unicode('<b>My surrounding b tags are not escaped</b>'),
]
]

If you're building HTML documents than I highly suggest using a template system (like jinja2) as others have suggested. If you're in need of some low level generation of html bits (perhaps as an input to one of your templates), then the xml.etree package is a standard python package and might fit the bill nicely.

import sys
from xml.etree import ElementTree as ET


html = ET.Element('html')
body = ET.Element('body')
html.append(body)
div = ET.Element('div', attrib={'class': 'foo'})
body.append(div)
span = ET.Element('span', attrib={'class': 'bar'})
div.append(span)
span.text = "Hello World"


if sys.version_info < (3, 0, 0):
# python 2
ET.ElementTree(html).write(sys.stdout, encoding='utf-8',
method='html')
else:
# python 3
ET.ElementTree(html).write(sys.stdout, encoding='unicode',
method='html')

Prints the following:

<html><body><div class="foo"><span class="bar">Hello World</span></div></body></html>

There is also a nice, modern alternative: airium: https://pypi.org/project/airium/

from airium import Airium


a = Airium()


a('<!DOCTYPE html>')
with a.html(lang="pl"):
with a.head():
a.meta(charset="utf-8")
a.title(_t="Airium example")


with a.body():
with a.h3(id="id23409231", klass='main_header'):
a("Hello World.")


html = str(a) # casting to string extracts the value


print(html)

Prints such a string:

<!DOCTYPE html>
<html lang="pl">
<head>
<meta charset="utf-8" />
<title>Airium example</title>
</head>
<body>
<h3 id="id23409231" class="main_header">
Hello World.
</h3>
</body>
</html>

The greatest advantage of airium is - it has also a reverse translator, that builds python code out of html string. If you wonder how to implement a given html snippet - the translator gives you the answer right away.

Its repository contains tests with example pages translated automatically with airium in: tests/documents. A good starting point (any existing tutorial) - is this one: tests/documents/w3_architects_example_original.html.py

I wrote a simple wrapper for the lxml module (should work fine with xml as well) that makes tags for HTML/XML -esq documents.

Really, I liked the format of the answer by John Smith but I didn't want to install yet another module to accomplishing something that seemed so simple.

Example first, then the wrapper.

Example

from Tag import Tag




with Tag('html') as html:
with Tag('body'):
with Tag('div'):
with Tag('span', attrib={'id': 'foo'}) as span:
span.text = 'Hello, world!'
with Tag('span', attrib={'id': 'bar'}) as span:
span.text = 'This was an example!'


html.write('test_html.html')


Output:

<html><body><div><span id="foo">Hello, world!</span><span id="bar">This was an example!</span></div></body></html>

Output after some manual formatting:

<html>
<body>
<div>
<span id="foo">Hello, world!</span>
<span id="bar">This was an example!</span>
</div>
</body>
</html>

Wrapper

from dataclasses import dataclass, field
from lxml import etree




PARENT_TAG = None




@dataclass
class Tag:
tag: str
attrib: dict = field(default_factory=dict)
parent: object = None
_text: str = None


@property
def text(self):
return self._text


@text.setter
def text(self, value):
self._text = value
self.element.text = value


def __post_init__(self):
self._make_element()
self._append_to_parent()


def write(self, filename):
etree.ElementTree(self.element).write(filename)


def _make_element(self):
self.element = etree.Element(self.tag, attrib=self.attrib)


def _append_to_parent(self):
if self.parent is not None:
self.parent.element.append(self.element)


def __enter__(self):
global PARENT_TAG
if PARENT_TAG is not None:
self.parent = PARENT_TAG
self._append_to_parent()
PARENT_TAG = self
return self


def __exit__(self, typ, value, traceback):
global PARENT_TAG
if PARENT_TAG is self:
PARENT_TAG = self.parent