Module bs_processors.xml_util

Utilities for working with BeautifulSoup trees

This module contains utilities useful for implementing custom processors and predicates.

"""
Utilities for working with BeautifulSoup trees

This module contains utilities useful for implementing custom processors and predicates.
"""
from typing import Any, Callable, List

from bs4 import BeautifulSoup


def set_new_children(elm, children):
    """
    Sets new children to an element

    * **elm**: the element to have its children set
    * **children**: a sequence of children
    * **return**: the element

    >>> xml = BeautifulSoup("<root>X<a/>X<b/>X</root>",'xml')
    >>> xml
    <?xml version="1.0" encoding="utf-8"?>
    <root>X<a/>X<b/>X</root>
    >>> new_children = [xml.new_tag("x"), xml.new_tag("y")]
    >>> set_new_children( xml.root, new_children)
    <root><x/><y/></root>

    """

    new_children = list(children)
    if list(elm.children) == new_children:
        return elm

    elm.clear()
    for child in new_children:
        elm.append(child)

    return elm


def process_children(processor: Callable[[Any], List[Any]], elm):
    """
    Processes the children of an element

    * **processor**: A processor that takes an element and returns a list of elements
    * **elm**: the element to process
    * **return**: A list with the joined results of processing each child with the provided processor

    >>> doc = BeautifulSoup("<div>a<span>b</span>c<p>d<span>e</span>f<a/>g</p>h</div>", "html.parser")
    >>> counter = [0]
    >>> def processor(elm):
    ...     counter[0] +=1
    ...     elm['id'] = str(counter[0])
    ...     return [elm]
    >>> process_children(processor, doc.div)
    ['a', <span id="1">b</span>, 'c', <p id="2">d<span>e</span>f<a></a>g</p>, 'h']
    """
    result = []
    for child in elm.children:
        if is_tag(child):
            result += processor(child)
        else:
            result.append(child)
    return result


def is_tag(elm):
    """
    True if the passed object is a HTML/XML tag

    * **elm**:
    * **return**:

    >>> from bs4 import BeautifulSoup as bs
    >>> doc = bs("<span></span><p>bubu</p>", "html.parser")
    >>> span = doc.span
    >>> is_tag(doc.span)
    True
    >>> is_tag(doc.p)
    True
    >>> is_tag(list(doc.p.children)[0])
    False
    """
    return elm is not None and elm.name is not None


_bs = BeautifulSoup("<a/>", "html.parser")


def copy_element_type(elm):
    """
    Creates a new element with the same tag name as the passed element

    >>> xml = BeautifulSoup("<root><abc/></root>", "xml")
    >>> copy_element_type(xml.root.abc)
    <abc></abc>
    """
    return _bs.new_tag(elm.name)

Functions

def copy_element_type(elm)

Creates a new element with the same tag name as the passed element

>>> xml = BeautifulSoup("<root><abc/></root>", "xml")
>>> copy_element_type(xml.root.abc)
<abc></abc>

Expand source code

def copy_element_type(elm):
    """
    Creates a new element with the same tag name as the passed element

    >>> xml = BeautifulSoup("<root><abc/></root>", "xml")
    >>> copy_element_type(xml.root.abc)
    <abc></abc>
    """
    return _bs.new_tag(elm.name)

def is_tag(elm)

True if the passed object is a HTML/XML tag

• elm:
• return:

>>> from bs4 import BeautifulSoup as bs
>>> doc = bs("<span></span><p>bubu</p>", "html.parser")
>>> span = doc.span
>>> is_tag(doc.span)
True
>>> is_tag(doc.p)
True
>>> is_tag(list(doc.p.children)[0])
False

Expand source code

def is_tag(elm):
    """
    True if the passed object is a HTML/XML tag

    * **elm**:
    * **return**:

    >>> from bs4 import BeautifulSoup as bs
    >>> doc = bs("<span></span><p>bubu</p>", "html.parser")
    >>> span = doc.span
    >>> is_tag(doc.span)
    True
    >>> is_tag(doc.p)
    True
    >>> is_tag(list(doc.p.children)[0])
    False
    """
    return elm is not None and elm.name is not None

def process_children(processor: Callable[[Any], List[Any]], elm)

Processes the children of an element

• processor: A processor that takes an element and returns a list of elements
• elm: the element to process
• return: A list with the joined results of processing each child with the provided processor

>>> doc = BeautifulSoup("<div>a<span>b</span>c<p>d<span>e</span>f<a/>g</p>h</div>", "html.parser")
>>> counter = [0]
>>> def processor(elm):
...     counter[0] +=1
...     elm['id'] = str(counter[0])
...     return [elm]
>>> process_children(processor, doc.div)
['a', <span id="1">b</span>, 'c', <p id="2">d<span>e</span>f<a></a>g</p>, 'h']

Expand source code

def process_children(processor: Callable[[Any], List[Any]], elm):
    """
    Processes the children of an element

    * **processor**: A processor that takes an element and returns a list of elements
    * **elm**: the element to process
    * **return**: A list with the joined results of processing each child with the provided processor

    >>> doc = BeautifulSoup("<div>a<span>b</span>c<p>d<span>e</span>f<a/>g</p>h</div>", "html.parser")
    >>> counter = [0]
    >>> def processor(elm):
    ...     counter[0] +=1
    ...     elm['id'] = str(counter[0])
    ...     return [elm]
    >>> process_children(processor, doc.div)
    ['a', <span id="1">b</span>, 'c', <p id="2">d<span>e</span>f<a></a>g</p>, 'h']
    """
    result = []
    for child in elm.children:
        if is_tag(child):
            result += processor(child)
        else:
            result.append(child)
    return result

def set_new_children(elm, children)

Sets new children to an element

• elm: the element to have its children set
• children: a sequence of children
• return: the element

>>> xml = BeautifulSoup("<root>X<a/>X<b/>X</root>",'xml')
>>> xml
<?xml version="1.0" encoding="utf-8"?>
<root>X<a/>X<b/>X</root>
>>> new_children = [xml.new_tag("x"), xml.new_tag("y")]
>>> set_new_children( xml.root, new_children)
<root><x/><y/></root>

Expand source code

def set_new_children(elm, children):
    """
    Sets new children to an element

    * **elm**: the element to have its children set
    * **children**: a sequence of children
    * **return**: the element

    >>> xml = BeautifulSoup("<root>X<a/>X<b/>X</root>",'xml')
    >>> xml
    <?xml version="1.0" encoding="utf-8"?>
    <root>X<a/>X<b/>X</root>
    >>> new_children = [xml.new_tag("x"), xml.new_tag("y")]
    >>> set_new_children( xml.root, new_children)
    <root><x/><y/></root>

    """

    new_children = list(children)
    if list(elm.children) == new_children:
        return elm

    elm.clear()
    for child in new_children:
        elm.append(child)

    return elm