XML

Concise generation of XML. 
from IPython.display import Markdown
from pprint import pprint

from fastcore.test import test_eq, test_ne

FT functions

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attrmap


def attrmap(
    o
):

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valmap


def valmap(
    o
):

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FT


def FT(
    tag:str, cs:tuple, attrs:dict=None, void_:bool=False, kwargs:VAR_KEYWORD
):

A ‘Fast Tag’ structure, containing tag,children,and attrs

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ft


def ft(
    tag:str, c:VAR_POSITIONAL, void_:bool=False, attrmap:callable=<function attrmap at 0x7fac34d0bc70>,
    valmap:callable=<function valmap at 0x7fac34d0bd00>, ft_cls:type=<class '__main__.FT'>, kw:VAR_KEYWORD
):

Create an FT structure for to_xml()

The main HTML tags are exported as ft partials.

Attributes are passed as keywords. Use ‘klass’ and ‘fr’ instead of ‘class’ and ‘for’, to avoid Python reserved word clashes.

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Html


def Html(
    c:VAR_POSITIONAL, doctype:bool=True, kwargs:VAR_KEYWORD
)->FT:

An HTML tag, optionally preceeded by !DOCTYPE HTML

samp = Html(
    Head(Title('Some page')),
    Body(Div('Some text\nanother line', (Input(name="jph's"), Img(src="filename", data=1)),
             cls=['myclass', 'another'],
             style={'padding':1, 'margin':2}))
)
pprint(samp)
(!doctype((),{'html': True}),
 html((head((title(('Some page',),{}),),{}), body((div(('Some text\nanother line', input((),{'name': "jph's"}), img((),{'src': 'filename', 'data': 1})),{'class': 'myclass another', 'style': 'padding:1; margin:2'}),),{})),{}))
elem = P('Some text', id="myid")
print(elem.tag)
print(elem.children)
print(elem.attrs)
p
('Some text',)
{'id': 'myid'}

You can get and set attrs directly:

elem.id = 'newid'
print(elem.id, elem.get('id'), elem.get('foo', 'missing'))
elem
newid newid missing
p(('Some text',),{'id': 'newid'})

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Safe


def Safe(
    args:VAR_POSITIONAL, kwargs:VAR_KEYWORD
):

str(object=’’) -> str str(bytes_or_buffer[, encoding[, errors]]) -> str

Create a new string object from the given object. If encoding or errors is specified, then the object must expose a data buffer that will be decoded using the given encoding and error handler. Otherwise, returns the result of object.__str__() (if defined) or repr(object). encoding defaults to sys.getdefaultencoding(). errors defaults to ‘strict’.

Conversion to XML/HTML

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to_xml


def to_xml(
    elm, lvl:int=0, indent:bool=True, do_escape:bool=True
):

Convert ft element tree into an XML string

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FT.__html__


def __html__(
    
):

to_xml(Div("<script>alert('XSS')</script>"), do_escape=True)
"<div>&lt;script&gt;alert('XSS')&lt;/script&gt;</div>\n"
h = to_xml(samp, do_escape=False)
print(h)
<!doctype html>
<html>
  <head>
    <title>Some page</title>
  </head>
  <body>
    <div class="myclass another" style="padding:1; margin:2">
Some text
another line      <input name="jph's">
<img src="filename" data="1">    </div>
  </body>
</html>

c = I('hello')
print(c)
<i>hello</i>
c
hello 
class PageTitle:
    def __ft__(self): return H1("Hello")

class HomePage:
    def __ft__(self): return Div(PageTitle(), Div('hello'))

h = to_xml(Div(HomePage()))
expected_output = """<div>
  <div>
    <h1>Hello</h1>
    <div>hello</div>
  </div>
</div>
"""
assert h == expected_output
print(h)
<div>
  <div>
    <h1>Hello</h1>
    <div>hello</div>
  </div>
</div>

h = to_xml(samp, indent=False)
print(h)
<!doctype html><html><head><title>Some page</title></head><body><div class="myclass another" style="padding:1; margin:2">Some text
another line<input name="jph's"><img src="filename" data="1"></div></body></html>

Interoperability both directions with Django and Jinja using the html() protocol:

def _esc(s): return s.__html__() if hasattr(s, '__html__') else Safe(escape(s))

r = Safe('<b>Hello from Django</b>')
print(to_xml(Div(r)))
print(_esc(Div(P('Hello from fastcore <3'))))
<div><b>Hello from Django</b></div>

<div><p>Hello from fastcore &lt;3</p></div>

FT attributes are rendered with to_xml:

print(to_xml(P('hi', value=Div('ho'))))
<p value="<div>ho</div>">hi</p>

FT components also stringify with to_xml:

print(Div('ho'))
<div>ho</div>

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FT.__hash__


def __hash__(
    
):

Return hash(self).

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FT.__eq__


def __eq__(
    other
):

Return self==value.

FT object equality and hashing is based on tag, attrs, and children.

test_eq(Div('hello', id='x'), Div('hello', id='x'))
test_ne(Div('hello'), Div('goodbye'))
test_ne(Div('hello', id='a'), Div('hello', id='b'))
test_ne(P('hello'), Div('hello'))

test_eq(hash(Div('hello', id='x')), hash(Div('hello', id='x')))
assert hash(Div('hello')), hash(Div('goodbye'))

Display

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highlight


def highlight(
    s, lang:str='html'
):

Markdown to syntax-highlight s in language lang

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showtags


def showtags(
    s
):

You can also reorder the children to come after the attrs, if you use this alternative syntax for FT where the children are in a second pair of () (behind the scenes this is because FT implements __call__ to add children).

hl_md(
Body(klass='myclass')(
    Div(style='padding:3px')(
        'Some text 1<2',
        I(spurious=True)('in italics'),
        Input(name='me'),
        Img(src="filename", data=1)
    )
))
<body class="myclass">
  <div style="padding:3px">
Some text 1&lt;2<i spurious>in italics</i>    <input name="me">
<img src="filename" data="1">  </div>
</body>

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getattr


def __getattr__(
    tag
):