UnderCover/app/pdf_builder.py

# Copyright Sage Vaillancourt 2021

import os
import subprocess
from dataclasses import dataclass

from flask import send_from_directory, Response


proj_dir = os.path.dirname(os.getcwd())
output_dir = proj_dir + '/outputs/'

base_tex_text = open(proj_dir + '/letter_templates/base.tex', 'r').read()


@dataclass
class CLData:
    # Metadata:
    selectedLetter: int

    # Form Data:
    username: str
    company: str
    jobAndPronoun: str
    skillTypes: str
    mySkills: str

    body: str
    closingText: str

    def get_pairs(self) -> list[(str, str)]:
        return [
            ('username', self.username),
            ('company', self.company),
            ('jobAndPronoun', self.jobAndPronoun),
            ('skillTypes', self.skillTypes),
            ('mySkills', self.mySkills),

            ('closingText', self.closingText),
            ('body', self.body),
        ]

    def generate_pdf(self) -> Response:
        """
        :return: Response with the pdf attached as a download when successful
        :raise ValueError: e.args[0] is a list of error strings, if generation fails
        """
        import threading
        unique_id = get_unique()
        unique_file = output_dir + unique_id + '.tex'
        f = open(unique_file, 'w')
        for pair in self.get_pairs():
            f.write('\\def \\' + pair[0] + '{' + pair[1] + '}\n')
        f.write(base_tex_text)
        f.close()

        com = f'pdflatex -halt-on-error -jobname=outputs/{unique_id} {unique_file}'
        result = subprocess.run(
            ['bash', '-c', com],
            stdout=subprocess.PIPE,
            text=True
        )

        build_text = f'[{get_datetime()}] Building for {unique_id} '
        if result.returncode != 0:
            print(build_text + '[FAIL]')
            # Collect output but delete boilerplate text
            errors = list(map(str.strip, result.stdout.split('\n')))
            del errors[:13]
            del errors[-2:]
            raise ValueError(errors)

        print(build_text + '[SUCCESS]')

        result = subprocess.run(
            [
                'gs',
                '-sDEVICE=pdfwrite',
                '-dCompatibilityLevel=1.5',
                '-dNOPAUSE',
                '-dQUIET',
                '-dBATCH',
                '-dPrinted=false',
                '-sOutputFile=outputs/' + unique_id + '.compressed.pdf',
                'outputs/' + unique_id + '.pdf'
            ],
            stdout=subprocess.PIPE,
            text=True
        )

        threading.Timer(60 * 5, cleanup, [output_dir + unique_id]).start()

        extension = 'compressed.pdf' if result.returncode == 0 else 'pdf'
        output_file = f'{unique_id}.{extension}'

        return send_from_directory(
            output_dir,
            output_file,
            download_name=self.username.replace(' ', '') + '_CoverLetter.pdf',
            as_attachment=True
        )


def cleanup(unique) -> None:
    subprocess.run(['bash', '-c', 'rm ' + unique + '.*'])


def get_unique() -> str:
    import uuid
    unique = str(uuid.uuid1().hex)
    return unique


def get_datetime() -> str:
    from datetime import datetime
    now = datetime.now()
    return now.strftime('%Y-%m-%d %H:%M:%S')