Added os.path.join() to a few filesystem related string operations.

[cmless] / bin / misc.py

# (c) 2017 Aaron Taylor <ataylor at subgeniuskitty dot com>
# See LICENSE file for copyright and license details.

# Python imports
import os, sys, subprocess, configparser

# CMless imports
import debug, config, template

def load_file(path):
    """Open the text file at 'path' and return the contents as a string."""
    try:
        with open(path) as f:
            contents = f.read()
    except:
        if debug.print_to_browser: print("Unable to open " + path + " for reading.")
        sys.exit("Unable to open " + path + " for reading.")
    return contents

def process_markup(text):
    """Execute external markup processor and return processed 'text'.

    Markup processor is specified by config.markup_processor variable
    and should accept markup on stdin while returning HTML on stdout.
    """
    try:
        p = subprocess.Popen(config.markup_processor,
                stdout=subprocess.PIPE,stdin=subprocess.PIPE)
    except:
        if debug.print_to_browser: print("Unable to open markup processor: " +
                config.markup_processor)
        sys.exit("Unable to open markup processor: " + config.markup_processor)
    text = p.communicate(text.encode('UTF-8'))[0]
    return(text.decode('UTF-8'))

def strip_page_metadata(content):
    """Strip metadata from the beginning of 'content' and return whatever remains."""
    keyword = template.add_delimiter("END_PAGE_METADATA")
    index = content.find(keyword)
    if index != -1:
        return content[index+len(keyword):]
    else:
        return content

def lookup_current_metadata(key):
    """Wrapper for lookup_file_metadata() supplying the current REQUEST_URI as 'file'."""
    file = os.path.join(config.site_data_prefix + os.environ['REQUEST_URI'] +
            config.markup_file_extension)
    return lookup_file_metadata(key,file)

def lookup_file_metadata(key,file):
    """Read 'key' metadata in 'file' and return corresponding value.

    Assumes key is contained in the [DEFAULT] category.
    Returns empty string if key is not present.
    """
    page_file = load_file(file)

    # Extract just the metadata block so we can pass it to ConfigParser.
    keyword_begin = template.add_delimiter("BEGIN_PAGE_METADATA")
    keyword_end = template.add_delimiter("END_PAGE_METADATA")
    index = page_file.find(keyword_end)
    if index != -1:
        page_file = page_file[len(keyword_begin):index]
    else:
        # ConfigParser will accept an empty string so use that as fallback.
        page_file = ""

    page_metadata = configparser.ConfigParser()
    page_metadata.read_string(page_file)

    if 'DEFAULT' in page_metadata and key in page_metadata['DEFAULT']:
        return page_metadata['DEFAULT'][key]
    else:
        # An empty string is technically a valid value for a key but we will
        # overload it as also indicating 'key' wasn't present since a key
        # without a value is functionally equivalent to no key at all for our
        # purposes.
        return ""