generator.py

from os import system
from os import unlink
from os.path import dirname
from os.path import realpath
import re

def generate_certificate_for(event_id, certificate_name, name_of_certificate_holder):
    resources_path             = dirname(realpath(__file__)) + '/resources/'
    static_files_path          = dirname(dirname(realpath(__file__))) + '/staticfiles/certificates/'

    generic_template_path      = resources_path + 'template.tex'
    personalized_template_path = resources_path + str(event_id) + '.tex'
    resulting_certificate_path = static_files_path + certificate_name

    with open(generic_template_path) as template:
        personalized_certificate_content = template.read().replace(
            '<CERTIFICATE_HOLDER_NAME>', tex_escape(name_of_certificate_holder))

    with open(personalized_template_path, 'w') as personalized_template:
        personalized_template.write(personalized_certificate_content.encode('utf-8'))

    commands = [
        'cd ' + resources_path,
        'pdflatex -interaction=nonstopmode -output-directory ' + resources_path + ' ' + personalized_template_path,
        'mkdir -p ' + static_files_path,
        'mv -f ' + personalized_template_path.replace('.tex', '.pdf') + ' ' + resulting_certificate_path,
        'rm -rf ' + resources_path + str(event_id) + '.*',
    ]

    if system(' && '.join(commands)) != 0:
        return False

    return resulting_certificate_path

def tex_escape(text):
    """
        Escapes special chars in a text to be safely included in a LaTeX document.
        See: http://stackoverflow.com/a/25875504/75715
        :param text: a plain text message
        :return: the message escaped to appear correctly in LaTeX
    """
    conv = {
        '&': r'\&',
        '%': r'\%',
        '$': r'\$',
        '#': r'\#',
        '_': r'\_',
        '{': r'\{',
        '}': r'\}',
        '~': r'\textasciitilde{}',
        '^': r'\^{}',
        '\\': r'\textbackslash{}',
        '<': r'\textless',
        '>': r'\textgreater',
    }
    replacements = (re.escape(unicode(key)) for key in sorted(conv.keys(), key = lambda item: - len(item)))

    regex = re.compile('|'.join(replacements))
    return regex.sub(lambda match: conv[match.group()], text)