- clean syntax
- fully-typed
- speed -- often faster than jinja
- zero dependencies
- escaped by default
- usually renders fewer bytes than templating
pip install simple-html
from simple_html import h1, render
node = h1("Hello World!")
render(node)
# <h1>Hello World!</h1> To add attributes to a tag, pass a dictionary as the first argument:
node = h1({"id": "heading"}, "Hello World!")
render(node)
# <h1 id="heading">Hello World!</h1> Here's a fuller-featured example:
from simple_html import render, DOCTYPE_HTML5, html, head, title, body, h1, div, p, br, ul, li
render(
DOCTYPE_HTML5,
html(
head(
title("A Great Webpage!")
),
body(
h1({"class": "great header"},
"Welcome!"),
div(
p("This webpage is great for three reasons:"),
ul(li(f"{s} reason") for s in ["first", "second", "third"]),
),
br,
"Hope you like it!"
)
)
)The above renders to a minified version of the following html:
<!doctype html>
<html>
<head><title>A Great Webpage!</title></head>
<body><h1 class="great header">Welcome!</h1>
<div><p>This webpage is great for three reasons:</p>
<ul>
<li>first reason</li>
<li>second reason</li>
<li>third reason</li>
</ul>
</div>
<br/>Hope you like it!
</body>
</html>As you might have noticed, there are several ways to use Tags:
from simple_html import br, div, h1, img, span, render
# raw node renders to empty tag
render(br)
# <br/>
# node with attributes but no children
render(
img({"src": "/some-image.jpg", "alt": "a great picture"})
)
# <img src="/some-image.jpg" alt="a great picture"/>
# nodes with children and (optional) attributes
render(
div(
h1({"class": "neat-class"},
span("cool"),
br)
)
)
# <div><h1 class="neat-class"><span>cool</span><br/></h1></div>Strings, ints, floats, and Decimals are generally rendered as one would expect expect. For safety, strs are
escaped by default; SafeStrings can be used to bypass escaping.
from simple_html import br, p, SafeString, render
node = p("Escaped & stuff",
br,
SafeString("Not escaped & stuff"))
render(node)
# <p>Escaped & stuff<br/>Not escaped & stuff</p> Tag attributes are defined as simple dictionaries -- typically you'll just use strings for both keys and values. Note
that Tag attributes with None as the value will only render the attribute name:
from simple_html import div, render
node = div({"empty-str-attribute": "",
"key-only-attr": None})
render(node)
# <div empty-str-attribute="" key-only-attr></div>String attributes are escaped by default -- both keys and values. You can use SafeString to bypass, if needed.
from simple_html import div, render, SafeString
render(
div({"<bad>":"</also bad>"})
)
# <div &lt;bad&gt;="&lt;/also bad&gt;"></div>
render(
div({SafeString("<bad>"): SafeString("</also bad>")})
)
# <div <bad>="</also bad>"></div>You can also use int, float, and Decimal instances for attribute values.
from decimal import Decimal
from simple_html import div, render, SafeString
render(
div({"x": 1, "y": 2.3, "z": Decimal('3.45')})
)
# <div x="1" y="2.3" z="3.45"></div>You can render inline CSS styles with render_styles:
from simple_html import div, render, render_styles
styles = render_styles({"min-width": "25px"})
node = div({"style": styles}, "cool")
render(node)
# <div style="min-width:25px;">cool</div>
# ints, floats, and Decimals are legal values
styles = render_styles({"padding": 0, "flex-grow": 0.6})
node = div({"style": styles}, "wow")
render(node)
# <div style="padding:0;flex-grow:0.6;">wow</div>You can pass many items as a Tag's children using *args, lists or generators:
from typing import Generator
from simple_html import div, render, Node, br, p
div(
*["neat", br], p("cool")
)
# renders to <div>neat<br/><p>cool</p></div>
# passing the raw list instead of *args
div(
["neat", br],
p("cool")
)
# renders to <div>neat<br/><p>cool</p></div>
def node_generator() -> Generator[Node, None, None]:
yield "neat"
yield br
div(node_generator(), p("cool"))
# renders to <div>neat<br/><p>cool</p></div>For convenience, most common tags are provided, but you can also create your own:
from simple_html import Tag, render
custom_elem = Tag("custom-elem")
# works the same as any other tag
node = custom_elem(
{"id": "some-custom-elem-id"},
"Wow"
)
render(node)
# <custom-elem id="some-custom-elem-id">Wow</custom-elem>prerender is a very simple function. It just renders a Node and puts the resulting string inside
a SafeString (so its contents won't be escaped again). It's most useful for prerendering at the module level,
which ensures the render operation happens only once. A simple use case might be a website's footer:
from simple_html import SafeString, prerender, footer, div, a, head, body, title, h1, html, render
prerendered_footer: SafeString = prerender(
footer(
div(a({"href": "/about"}, "About Us")),
div(a({"href": "/blog"}, "Blog")),
div(a({"href": "/contact"}, "Contact"))
)
)
def render_page(page_title: str) -> str:
return render(
html(
head(title(page_title)),
body(
h1(page_title),
prerendered_footer # this is extremely fast to render
)
)
)This greatly reduces the amount of work render needs to do on the prerendered content when outputting HTML.
You may want to cache rendered content. This is easy to do; the main thing to keep in
mind is you'll likely want to return a SafeString. For example, here's how you might cache with lru_cache:
from simple_html import prerender, SafeString, h1
from functools import lru_cache
@lru_cache
def greeting(name: str) -> SafeString:
return prerender(
h1(f"Hello, {name}")
)One thing to remember is that not all variants of Node are hashable, and thus cannot be passed directly to a function
where the arguments constitute the cache key -- e.g. lists and generators are not hashable, but they can be
valid Nodes. Another way to use prerender in combination with a caching function is to prerender arguments:
from simple_html import prerender, SafeString, h1, div, html, body, head, ul, li
from functools import lru_cache
@lru_cache
def cached_content(children: SafeString) -> SafeString:
return prerender(
div(
h1("This content is cached according to the content of the children"),
children,
# presumably this function would have a lot more elements for it to be worth
# the caching overhead
)
)
def page(words_to_render: list[str]):
return html(
head,
body(
cached_content(
prerender(ul([
li(word) for word in words_to_render
]))
)
)
)Keep in mind that using prerender on dynamic content -- not at the module level -- still incurs all the overhead
of render each time that content is rendered, so, for this approach to make sense, the prerendered content should
be a small portion of the full content of the cached_content function.