import re
import sys
import os
def print_usage():
print(f"usage: python {sys.argv[0]} INPUT")
sys.exit(1)
argc = len(sys.argv)
if argc < 2:
print_usage()
def error(message):
print(f"error: {message}:", file=sys.stderr)
sys.exit(1)
path = sys.argv[1]
if not os.path.isfile(path):
error(f"{path} does not exist.")
def read_metadata(path):
pattern = re.compile(r"^\+{3}\n((?:.*|\n)*)\n\+{3}")
metadata = {}
with open(path) as f:
match = re.search(pattern, f.read())
if not match:
error(f"no metadata found at start of {path}")
lines = match.group(1).split('\n')
for l in lines:
pair = [s.strip() for s in l.split('=')]
metadata[pair[0]] = pair[1]
return metadata
def strip_metadata(path):
pattern = re.compile(r"(\+{3}\n(?:.*|\n)*\n\+{3})")
with open(path) as f:
return re.sub(pattern, "", f.read()).strip()
def generate_header(metadata):
if metadata is None:
error("no metadata, can't generate header")
# TODO: is the description meta tag length-restricted?
description = metadata["description"]
keywords = metadata["keywords"]
# if "description" or "keywords" don't exist we can't do anything: crash out
if description is None or keywords is None:
error("empty metadata parameters, can't generate header")
header = """
"""
header = header.replace("{{DESCRIPTION}}", description)
header = header.replace("{{KEYWORDS}}", keywords)
return header
html = strip_metadata(path)
metadata = read_metadata(path)
header = generate_header(metadata)
# Inject the generated element between the opening and elements.
pattern = r"()(?:\n|.)*()"
replacement = f"\\1\\n{header}\\n\\2"
html = re.sub(pattern, replacement, html)
print(html)