Custom indent width for BeautifulSoup .prettify()

问题

Is there any way to define custom indent width for .prettify() function? From what I can get from it's source -

def prettify(self, encoding=None, formatter="minimal"):
    if encoding is None:
        return self.decode(True, formatter=formatter)
    else:
        return self.encode(encoding, True, formatter=formatter)

There is no way to specify indent width. I think it's because of this line in the decode_contents() function -

s.append(" " * (indent_level - 1))

Which has a fixed length of 1 space! (WHY!!) I tried specifying indent_level=4, that just results in this -

    <section>
     <article>
      <h1>
      </h1>
      <p>
      </p>
     </article>
    </section>

Which looks just plain stupid. :|

Now, I can hack this away, but I just want to be sure if there is anything I'm missing. Because this should be a basic feature. :-/

If you have some better way of prettifying HTML codes, let me know.

回答1:

I actually dealt with this myself, in the hackiest way possible: by post-processing the result.

r = re.compile(r'^(\s*)', re.MULTILINE)
def prettify_2space(s, encoding=None, formatter="minimal"):
    return r.sub(r'\1\1', s.prettify(encoding, formatter))

Actually, I monkeypatched prettify_2space in place of prettify in the class. That's not essential to the solution, but let's do it anyway, and make the indent width a parameter instead of hardcoding it to 2:

orig_prettify = bs4.BeautifulSoup.prettify
r = re.compile(r'^(\s*)', re.MULTILINE)
def prettify(self, encoding=None, formatter="minimal", indent_width=4):
    return r.sub(r'\1' * indent_width, orig_prettify(self, encoding, formatter))
bs4.BeautifulSoup.prettify = prettify

So:

x = '''<section><article><h1></h1><p></p></article></section>'''
soup = bs4.BeautifulSoup(x)
print(soup.prettify(indent_width=3))

… gives:

<html>
   <body>
      <section>
         <article>
            <h1>
            </h1>
            <p>
            </p>
         </article>
      </section>
   </body>
</html>

Obviously if you want to patch Tag.prettify as well as BeautifulSoup.prettify, you have to do the same thing there. (You might want to create a generic wrapper that you can apply to both, instead of repeating yourself.) And if there are any other prettify methods, same deal.

回答2:

As far as I can tell, this feature is not built in, as there are a handful of solutions out there for this problem.

Assuming you are using BeautifulSoup 4, here are the solutions I came up with

Hardcode it in. This requires minimal changes, this is fine if you don't need the indent to be different in different circumstances:

myTab = 4 # add this
if pretty_print:
   # space = (' ' * (indent_level - 1))
    space = (' ' * (indent_level - myTab))
    #indent_contents = indent_level + 1
    indent_contents = indent_level + myTab

Another problem with the previous solution is that the text content wont be indented entirely consistently, but attractively, still. If you need a more flexible/consistent solution, you can just modify the class.

Find the prettify function and modify it as such (it is located in the Tag class in element.py):

#Add the myTab keyword to the functions parameters (or whatever you want to call it), set it to your preferred default.
def prettify(self, encoding=None, formatter="minimal", myTab=2): 
    Tag.myTab= myTab # add a reference to it in the Tag class
    if encoding is None:
        return self.decode(True, formatter=formatter)
    else:
        return self.encode(encoding, True, formatter=formatter)

And then scroll up to the decode method in the Tag class and make the following changes:

if pretty_print:
    #space = (' ' * (indent_level - 1))
    space = (' ' * (indent_level - Tag.myTab))
    #indent_contents = indent_level + Tag.myTab 
    indent_contents = indent_level + Tag.myTab

Then go to the decode_contents method in the Tag class and make these changes:

#s.append(" " * (indent_level - 1))
s.append(" " * (indent_level - Tag.myTab))

Now BeautifulSoup('<root><child><desc>Text</desc></child></root>').prettify(myTab=4) will return:

<root>
    <child>
        <desc>
            Text
        </desc>
    </child>
</root>

**No need to patch BeautifulSoup class as it inherits the Tag class. Patching Tag class is sufficient enough to achieve the goal.

来源：https://stackoverflow.com/questions/15509397/custom-indent-width-for-beautifulsoup-prettify

标签

python

beautifulsoup

indentation

code-formatting