Simplify PDF rendering backend

- Drop Puppeteer and Selenium backends
- "Inline" pdfoid, and move `pdf_problems.py` to `utils` + rename it
  `pdfoid.py`
- Drop a lot of pointless error checking; if we fail we'll want to raise
  a 500 regardless

Co-authored-by: Quantum <[email protected]>

dmoj/settings.py

@@ -11,7 +11,6 @@
 # Build paths inside the project like this: os.path.join(BASE_DIR, ...)
 import datetime
 import os
-import tempfile
 
 from django.utils.translation import gettext_lazy as _
 from django_jinja.builtins import DEFAULT_EXTENSIONS
@@ -165,8 +164,6 @@
 
 SITE_FULL_URL = None  # ie 'https://oj.vnoi.info', please remove the last / if needed
 
-NODEJS = '/usr/bin/node'
-EXIFTOOL = '/usr/bin/exiftool'
 ACE_URL = '//cdnjs.cloudflare.com/ajax/libs/ace/1.1.3'
 SELECT2_JS_URL = '//cdnjs.cloudflare.com/ajax/libs/select2/4.0.3/js/select2.min.js'
 SELECT2_CSS_URL = '//cdnjs.cloudflare.com/ajax/libs/select2/4.0.3/css/select2.min.css'
@@ -175,41 +172,54 @@
 DMOJ_CAMO_KEY = None
 DMOJ_CAMO_HTTPS = False
 DMOJ_CAMO_EXCLUDE = ()
+
 DMOJ_PROBLEM_DATA_ROOT = None
+
 DMOJ_PROBLEM_MIN_TIME_LIMIT = 0  # seconds
 DMOJ_PROBLEM_MAX_TIME_LIMIT = 60  # seconds
 DMOJ_PROBLEM_MIN_MEMORY_LIMIT = 0  # kilobytes
 DMOJ_PROBLEM_MAX_MEMORY_LIMIT = 1048576  # kilobytes
 DMOJ_PROBLEM_MIN_PROBLEM_POINTS = 0
 DMOJ_PROBLEM_HOT_PROBLEM_COUNT = 7
+
 DMOJ_PROBLEM_STATEMENT_DISALLOWED_CHARACTERS = {'“', '”', '‘', '’', '−', 'ff', 'fi', 'fl', 'ffi', 'ffl'}
 DMOJ_RATING_COLORS = True
 DMOJ_EMAIL_THROTTLING = (10, 60)
 VNOJ_DISCORD_WEBHOOK_THROTTLING = (10, 60)  # Max 10 messages in 60 seconds
-DMOJ_STATS_LANGUAGE_THRESHOLD = 10
-DMOJ_SUBMISSIONS_REJUDGE_LIMIT = 10
+
 # Maximum number of submissions a single user can queue without the `spam_submission` permission
 DMOJ_SUBMISSION_LIMIT = 2
+DMOJ_SUBMISSIONS_REJUDGE_LIMIT = 10
+
 # Whether to allow users to view source code: 'all' | 'all-solved' | 'only-own'
 DMOJ_SUBMISSION_SOURCE_VISIBILITY = 'all-solved'
 DMOJ_BLOG_NEW_PROBLEM_COUNT = 7
 DMOJ_TOTP_TOLERANCE_HALF_MINUTES = 1
 DMOJ_SCRATCH_CODES_COUNT = 5
 DMOJ_USER_MAX_ORGANIZATION_COUNT = 3
+
 # Whether to allow users to download their data
 DMOJ_USER_DATA_DOWNLOAD = False
 DMOJ_USER_DATA_CACHE = ''
 DMOJ_USER_DATA_INTERNAL = ''
 DMOJ_USER_DATA_DOWNLOAD_RATELIMIT = datetime.timedelta(days=1)
+
 # Whether to allow contest authors to download contest data
 DMOJ_CONTEST_DATA_DOWNLOAD = False
 DMOJ_CONTEST_DATA_CACHE = ''
 DMOJ_CONTEST_DATA_INTERNAL = ''
 DMOJ_CONTEST_DATA_DOWNLOAD_RATELIMIT = datetime.timedelta(days=1)
+
 DMOJ_COMMENT_VOTE_HIDE_THRESHOLD = -5
 DMOJ_COMMENT_REPLY_TIMEFRAME = datetime.timedelta(days=365)
-DMOJ_PDF_PROBLEM_CACHE = ''
-DMOJ_PDF_PROBLEM_TEMP_DIR = tempfile.gettempdir()
+
+DMOJ_PDF_PDFOID_URL = None
+# Optional but recommended to save resources, path on disk to cache PDFs
+DMOJ_PDF_PROBLEM_CACHE = None
+# Optional, URL serving DMOJ_PDF_PROBLEM_CACHE with X-Accel-Redirect
+DMOJ_PDF_PROBLEM_INTERNAL = None
+
+DMOJ_STATS_LANGUAGE_THRESHOLD = 10
 DMOJ_STATS_SUBMISSION_RESULT_COLORS = {
     'TLE': '#a3bcbd',
     'AC': '#00a92a',
@@ -260,16 +270,6 @@
 TERMS_OF_SERVICE_URL = None
 DEFAULT_USER_LANGUAGE = 'CPP17'
 
-PUPPETEER_MODULE = '/usr/lib/node_modules/puppeteer'
-PUPPETEER_PAPER_SIZE = 'Letter'
-
-USE_SELENIUM = False
-SELENIUM_CUSTOM_CHROME_PATH = None
-SELENIUM_CHROMEDRIVER_PATH = 'chromedriver'
-
-USE_PDFOID = False
-PDFOID_URL = ''
-
 INLINE_JQUERY = True
 INLINE_FONTAWESOME = True
 JQUERY_JS = '//ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js'
@@ -725,6 +725,11 @@
 except IOError:
     pass
 
-# Compute these values after local_settings.py is loaded
+if DMOJ_PDF_PDFOID_URL:
+    # If a cache is configured, it must already exist and be a directory
+    assert DMOJ_PDF_PROBLEM_CACHE is None or os.path.isdir(DMOJ_PDF_PROBLEM_CACHE)
+    # If using X-Accel-Redirect, the cache directory must be configured
+    assert DMOJ_PDF_PROBLEM_INTERNAL is None or DMOJ_PDF_PROBLEM_CACHE is not None
+
 ACE_DEFAULT_LIGHT_THEME = DMOJ_THEME_DEFAULT_ACE_THEME['light']
 ACE_DEFAULT_DARK_THEME = DMOJ_THEME_DEFAULT_ACE_THEME['dark']

judge/management/commands/render_pdf.py

@@ -1,28 +1,19 @@
-import os
-import shutil
-import sys
-
 from django.conf import settings
 from django.core.management.base import BaseCommand
 from django.template.loader import get_template
 from django.utils import translation
 
 from judge.models import Problem, ProblemTranslation
-from judge.pdf_problems import DefaultPdfMaker, PdfoidPDFRender, PuppeteerPDFRender, SeleniumPDFRender
+from judge.utils.pdfoid import render_pdf
 
 
 class Command(BaseCommand):
     help = 'renders a PDF file of a problem'
 
     def add_arguments(self, parser):
         parser.add_argument('code', help='code of problem to render')
-        parser.add_argument('directory', nargs='?', help='directory to store temporaries')
         parser.add_argument('-l', '--language', default=settings.LANGUAGE_CODE,
                             help='language to render PDF in')
-        parser.add_argument('-c', '--chrome', '--puppeteer', action='store_const',
-                            const=PuppeteerPDFRender, default=DefaultPdfMaker, dest='engine')
-        parser.add_argument('-S', '--selenium', action='store_const', const=SeleniumPDFRender, dest='engine')
-        parser.add_argument('-p', '--pdfoid', action='store_const', const=PdfoidPDFRender, dest='engine')
 
     def handle(self, *args, **options):
         try:
@@ -36,22 +27,14 @@ def handle(self, *args, **options):
         except ProblemTranslation.DoesNotExist:
             trans = None
 
-        directory = options['directory']
-        with options['engine'](directory, clean_up=directory is None) as maker, \
-                translation.override(options['language']):
+        with open(problem.code + '.pdf', 'wb') as f, translation.override(options['language']):
             problem_name = problem.name if trans is None else trans.name
-            maker.html = get_template('problem/raw.html').render({
-                'problem': problem,
-                'problem_name': problem_name,
-                'description': problem.description if trans is None else trans.description,
-                'url': '',
-                'math_engine': maker.math_engine,
-            }).replace('"//', '"https://').replace("'//", "'https://")
-            maker.title = problem_name
-            for file in ('style.css', 'mathjax_config.js'):
-                maker.load(file, os.path.join(settings.DMOJ_RESOURCES, file))
-            maker.make(debug=True)
-            if not maker.success:
-                print(maker.log, file=sys.stderr)
-            elif directory is None:
-                shutil.move(maker.pdffile, problem.code + '.pdf')
+            f.write(render_pdf(
+                html=get_template('problem/raw.html').render({
+                    'problem': problem,
+                    'problem_name': problem_name,
+                    'description': problem.description if trans is None else trans.description,
+                    'url': '',
+                }).replace('"//', '"https://').replace("'//", "'https://"),
+                title=problem_name,
+            ))