Show the structure of an HTML file (or part thereof) in the shell

dump_html.py

#!/usr/bin/env python3

''' Show HTML file structure

    Written by PM 2Ring 2017.06.19
'''

import sys
from html.parser import HTMLParser

#HTML tags that do not have end tags.
unpaired = {'br', 'img', 'link', 'meta', 'hr', 'p', 'input'}

def bold(s):
    ''' Wrap `s` in ANSI escape sequences to make it bold '''
    return '\x1b[1m%s\x1b[0m' % s

labels = ('START', 'END', 'DATA', 'COMMENT')
startlbl, endlbl, datalbl, commentlbl = map(bold, labels)

class DumpHTML(HTMLParser):
    ''' Dump HTML tags & data, with depth indicated by indentation '''
    def __init__(self):
        super().__init__()
        self.depth = 0

    @property
    def line_head(self):
        ''' Line number and indentation '''
        return str(self.getpos()[0]).zfill(4) + '  ' * self.depth

    def handle_starttag(self, tag, attrs):
        ''' Print a start tag '''
        print(self.line_head, startlbl, tag, dict(attrs))
        if tag not in unpaired:
            self.depth += 1

    def handle_endtag(self, tag):
        ''' Print an end tag, unless it's an unpaired tag '''
        if tag not in unpaired:
            self.depth -= 1
        print(self.line_head, endlbl, tag)
        if self.depth < 0:
            raise StopIteration

    def handle_data(self, data):
        ''' Print data, unless it's all whitespace '''
        if data.strip():
            print(self.line_head, datalbl, repr(data))

    def handle_comment(self, comment):
        ''' Print comment '''
        print(self.line_head, commentlbl, repr(comment))

def main():
    if len(sys.argv) != 2:
        print('HTML file dumper\nUsage:\n%s filename' % sys.argv[0])
        sys.exit()

    with open(sys.argv[1]) as f:
        data = f.read()

    parser = DumpHTML()
    try:
        parser.feed(data)
        parser.close()
    except StopIteration:
        msg = 'Data found at a higher nesting level than the starting data; skipping.'
        print(bold('Warning:'), msg)

if __name__ == '__main__':
    main()