diff options
| author | Leonard Richardson <leonardr@segfault.org> | 2019-07-15 15:22:32 -0400 |
|---|---|---|
| committer | Leonard Richardson <leonardr@segfault.org> | 2019-07-15 15:22:32 -0400 |
| commit | 07d84a4e9af51863459a1e3d988f2806835fc110 (patch) | |
| tree | aeb1f3dfd752d67b18b9e24f46590b23120e78cb /doc/source | |
| parent | 81e86c866490ba9a5ce7109023b657d09d39dae1 (diff) | |
Moved the formatter to its own class and updated its documentation.
Diffstat (limited to 'doc/source')
| -rw-r--r-- | doc/source/index.rst | 58 |
1 files changed, 28 insertions, 30 deletions
diff --git a/doc/source/index.rst b/doc/source/index.rst index 8376549..0c09964 100644 --- a/doc/source/index.rst +++ b/doc/source/index.rst @@ -2264,16 +2264,17 @@ to Beautiful Soup generating invalid HTML/XML, as in these examples:: print(link_soup.a.encode(formatter=None)) # <a href="http://example.com/?foo=val1&bar=val2">A link</a> -Finally, if you pass in a function for ``formatter``, Beautiful Soup -will call that function once for every string and attribute value in -the document. You can do whatever you want in this function. Here's a -formatter that converts strings to uppercase and does absolutely -nothing else:: +If you need more sophisticated control over your output, you can +use Beautiful Soup's ``Formatter`` class. Here's a formatter that +converts strings to uppercase, whether they occur in a text node or in an +attribute value:: + from bs4.formatter import HTMLFormatter def uppercase(str): return str.upper() + formatter = HTMLFormatter(uppercase) - print(soup.prettify(formatter=uppercase)) + print(soup.prettify(formatter=formatter)) # <html> # <body> # <p> @@ -2282,34 +2283,31 @@ nothing else:: # </body> # </html> - print(link_soup.a.prettify(formatter=uppercase)) + print(link_soup.a.prettify(formatter=formatter)) # <a href="HTTP://EXAMPLE.COM/?FOO=VAL1&BAR=VAL2"> # A LINK # </a> -If you're writing your own function, you should know about the -``EntitySubstitution`` class in the ``bs4.dammit`` module. This class -implements Beautiful Soup's standard formatters as class methods: the -"html" formatter is ``EntitySubstitution.substitute_html``, and the -"minimal" formatter is ``EntitySubstitution.substitute_xml``. You can -use these functions to simulate ``formatter=html`` or -``formatter==minimal``, but then do something extra. - -Here's an example that replaces Unicode characters with HTML entities -whenever possible, but `also` converts all strings to uppercase:: - - from bs4.dammit import EntitySubstitution - def uppercase_and_substitute_html_entities(str): - return EntitySubstitution.substitute_html(str.upper()) - - print(soup.prettify(formatter=uppercase_and_substitute_html_entities)) - # <html> - # <body> - # <p> - # IL A DIT <<SACRÉ BLEU!>> - # </p> - # </body> - # </html> +Subclassing ``HTMLFormatter`` or ``XMLFormatter`` will give you even +more control over the output. For example, Beautiful Soup sorts the +attributes in every tag by default:: + + attr_soup = BeautifulSoup('<p z="1" m="2" a="3"></p>') + print(attr_soup.p.encode()) + # <p a="3" m="2" z="1"></p> + +To turn this off, you can subclass the ``Formatter.attributes()`` +method, which controls which attributes are output and in what +order. This implementation also filters out out one of the attributes. + + class UnsortedAttributes(HTMLFormatter): + def attributes(self, tag): + for k, v in tag.attrs.items(): + if k == 'm': + continue + yield k, v + print(attr_soup.p.encode(formatter=UnsortedAttributes())) + # <p z="1" a="3"></p> One last caveat: if you create a ``CData`` object, the text inside that object is always presented `exactly as it appears, with no |