Extremely fast HTML tag generator
Project description
FastTag
FastTag is a fast HTML generation module written in C for Python. It allows for efficient and easy generation of HTML tags with support for attributes and nested content.
It's almost as fast as string join, and it's built as a mostly drop in replacement for FastHTML's tag library (but 20x faster).
Installation
You can install the module using pip:
pip install fasttag
Usage:
from fasttag import *
Div( # HTML Tags are exported in fasttag, but fasttag.tag("div", ...) can be used as well.
# Label("First Name") returns the HTML as a bytes (which is not escaped, just indented), but all passed strings in the element children and attribute values are escaped
Div(Label("First Name"), ": Joe"),
Div(Label("Last Name"), ": Blow"),
Div(Label("Email"), ": joe@blow.com")
# if a keyword starts with _, the first _ is ignored and the rest is used as an argument unchanged.
Button("Click To Edit", hx_get="/contact/1/edit", _class="btn primary"),
# If the keyword argument doesn't start with _, underscores are converted to hypens (-) in the attibute name
hx_target="this", hx_swap="outerHTML")
=>
<div hx-target="this" hx-swap="outerHTML">
<div>
<label>First Name</label>
: Joe
</div>
<div>
<label>Last Name</label>
: Blow
</div>
<div>
<label>Email</label>
: joe@blow.com
</div>
<button hx-get="/contact/1/edit" class="btn primary">Click To Edit</button>
</div>
Keyword argument values can be string, boolean or numeric. Boolean values will appear as attributes without values if True, and not appear if False. Numeric values are quoted.
Input(type="checkbox", id="scales", name="scales", checked=True, disabled=False)
# => HTML('<input type="checkbox" id="scales" name="scales" checked>')
The HTML is represented as UTF-8. The bytes can be extracted / converted to str with:
HTML('<div>Example HTML</div>').bytes() # => b'<div>Example HTML</div>'
str(HTML('<div>Example HTML</div>')) # => '<div>Example HTML</div>'
Text node can be created with Text (although it's automatically created for strings inside tags):
Text('This is an <example> text ') # => HTML('This is an <example> text')
The DOCTYPE constant can be used to prepend DOCTYPE html:
DOCTYPE + Html(Head(Title("Hello"), Body("Hello, world")))
=>
<!DOCTYPE html>
<html>
<head>
<title>Hello</title>
<body>Hello, world</body>
</head>
</html>
Changing indentation
Indentation can be set with fasttag.set_indent. Default value is 2, but it can set to any non-negative number, or -1 which achieves no indentation and no newline between children. It improves performance, memory usage and output size for large data. 1 space is still added between text children siblings even with -1 indentation.
from fasttag import *
set_indent(-1)
Div("hello", Span("world"))
# => HTML('<div>hello<span>world</span></div>')
Using with FastHTML:
FastTag was built to be mostly mirror FastHTML API. One important missing feature is automatically concatenating tuples.
To use it, import fasttag after fasthtml.common:
from fasthtml.common import *
from fasttag import *
Also when returning data inside a handler, use .bytes() to convert it into bytes object.
Right now to_xml() inside FastCore needs a modification: https://github.com/fastai/fastcore/pull/597
It's a one line change in to_xml() inside xml.py:
def to_xml(elm, lvl=0):
"Convert `ft` element tree into an XML string"
if elm is None: return ''
if isinstance(elm, tuple): return '\n'.join(to_xml(o) for o in elm)
if hasattr(elm, '__ft__'): elm = elm.__ft__()
if isinstance(elm, bytes): return elm.decode('utf-8') # This line needs to be inserted
sp = ' ' * lvl
if not isinstance(elm, list): return f'{_escape(elm)}\n'
Benchmark:
fasttag latency: 0.16us 1x
join+html.escape latency: 0.45us 3x
dominate latency: 2.92us 18x
fasthtml latency: 3.23us 20x
lxml latency: 1.66us 10x
join without escaping latency: 0.12us 0.75x
Download files
Download the file for your platform. If you're not sure which to choose, learn more about installing packages.
Source Distribution
Built Distribution
Hashes for fasttag-0.1.1-cp312-cp312-macosx_14_0_arm64.whl
| Algorithm | Hash digest | |
|---|---|---|
| SHA256 | e24a817d41194b9d9fdcfd7c7192fdbd82cf6b3444b2c4384726d0c5055e8206 |
|
| MD5 | 4777fcc129a49bb2d5456a091c2f9f76 |
|
| BLAKE2b-256 | 837417d17d3ffc07b57a2c090cc9e9a1c753730106a628e0b29a22a9f96430ae |
