(this post was moved from the Educators category)
I’m just getting started with XBlock development. I’m trying to render LateX within my XBlock. The following gives a KeyError on the LateX fraction. Any suggestions on what I’m doing wrong?
<head>
<script src="https://polyfill.io/v3/polyfill.min.js?features=es6"></script>
<script type="text/javascript" id="MathJax-script" async src="https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-chtml.js">
</script>
</head>
<div class="test01_block">
<p>Test01XBlock: count is now
<span class='count'>{self.count}</span> (click me to increment).
</p>
<p>A point charge of +1\(\mu\)C is placed at (x, y, z) = (0, 0, 0). Units of the Cartesian coordinate system are in meters.</p>
<p>The electric field that results from a point charge can be calculated with the following equation:</p>
<p>\[\frac{a}{b}\]</p>
</div>
error message in the browser:
KeyError at /scenario/test02.0/
'a'
Request Method: GET
Request URL: http://localhost:8000/scenario/test02.0/
Django Version: 3.2.18
Exception Type: KeyError
Exception Value:
'a'
Exception Location: /Users/d24lau/src/xblock3/test02/test02/test02.py, line 35, in student_view
Python Executable: /Users/d24lau/src/xblock3/venv/bin/python
Python Version: 3.9.0
Python Path:
['/Users/d24lau/src/xblock3/xblock-sdk',
'/Users/d24lau/.pyenv/versions/3.9.0/lib/python39.zip',
'/Users/d24lau/.pyenv/versions/3.9.0/lib/python3.9',
'/Users/d24lau/.pyenv/versions/3.9.0/lib/python3.9/lib-dynload',
'/Users/d24lau/src/xblock3/venv/lib/python3.9/site-packages',
'/Users/d24lau/src/xblock3/xblock-sdk',
'/Users/d24lau/src/xblock3/test02']
Server time: Tue, 23 May 2023 08:11:58 -0400
Traceback Switch to copy-and-paste view
/Users/d24lau/src/xblock3/venv/lib/python3.9/site-packages/django/core/handlers/exception.py, line 47, in inner
response = get_response(request) …
▶ Local vars
/Users/d24lau/src/xblock3/venv/lib/python3.9/site-packages/django/core/handlers/base.py, line 181, in _get_response
response = wrapped_callback(request, *callback_args, **callback_kwargs) …
▶ Local vars
/Users/d24lau/src/xblock3/venv/lib/python3.9/site-packages/django/utils/decorators.py, line 130, in _wrapped_view
response = view_func(request, *args, **kwargs) …
▶ Local vars
/Users/d24lau/src/xblock3/xblock-sdk/workbench/views.py, line 77, in show_scenario
frag = block.render(view_name, render_context) …
▶ Local vars
/Users/d24lau/src/xblock3/venv/lib/python3.9/site-packages/xblock/core.py, line 198, in render
return self.runtime.render(self, view, context) …
▶ Local vars
/Users/d24lau/src/xblock3/xblock-sdk/workbench/runtime.py, line 319, in render
return super().render(block, view_name, context) …
▶ Local vars
/Users/d24lau/src/xblock3/venv/lib/python3.9/site-packages/xblock/runtime.py, line 847, in render
frag = view_fn(context) …
▶ Local vars
/Users/d24lau/src/xblock3/test02/test02/test02.py, line 35, in student_view
frag = Fragment(html.format(self=self)) …
▶ Local vars
Request information
USER
AnonymousUser
GET
No GET data
POST
No POST data
FILES
No FILES data
COOKIES
Variable Value
csrftoken
'Q9AAcrNgFMakYF1rGZ5l2uIGsWS5ohps2eSDeaEAQXtC06ksFkPd9PtJPaLLCAGy'
META
Variable Value
CONTENT_LENGTH
''
CONTENT_TYPE
'text/plain'
CSRF_COOKIE
'Q9AAcrNgFMakYF1rGZ5l2uIGsWS5ohps2eSDeaEAQXtC06ksFkPd9PtJPaLLCAGy'
CSRF_COOKIE_USED
True
DJANGO_SETTINGS_MODULE
'workbench.settings'
GATEWAY_INTERFACE
'CGI/1.1'
HOME
'/Users/d24lau'
HTTP_ACCEPT
'text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7'
HTTP_ACCEPT_ENCODING
'gzip, deflate, br'
HTTP_ACCEPT_LANGUAGE
'en-US,en;q=0.9'
HTTP_CACHE_CONTROL
'max-age=0'
HTTP_CONNECTION
'keep-alive'
HTTP_COOKIE
'csrftoken=Q9AAcrNgFMakYF1rGZ5l2uIGsWS5ohps2eSDeaEAQXtC06ksFkPd9PtJPaLLCAGy'
HTTP_DNT
'1'
HTTP_HOST
'localhost:8000'
HTTP_REFERER
'http://localhost:8000/'
HTTP_SEC_CH_UA
'"Google Chrome";v="113", "Chromium";v="113", "Not-A.Brand";v="24"'
HTTP_SEC_CH_UA_MOBILE
'?0'
HTTP_SEC_CH_UA_PLATFORM
'"macOS"'
HTTP_SEC_FETCH_DEST
'document'
HTTP_SEC_FETCH_MODE
'navigate'
HTTP_SEC_FETCH_SITE
'same-origin'
HTTP_SEC_FETCH_USER
'?1'
HTTP_UPGRADE_INSECURE_REQUESTS
'1'
HTTP_USER_AGENT
('Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, '
'like Gecko) Chrome/113.0.0.0 Safari/537.36')
LANG
'en_CA.UTF-8'
LOGNAME
'd24lau'
LaunchInstanceID
'25A5A1D3-85EF-4B5A-A9DD-69E4C1D3EE85'
OLDPWD
'/Users/d24lau/src'
PATH
'/Users/d24lau/src/xblock3/venv/bin:/Users/d24lau/.pyenv/shims:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin'
PATH_INFO
'/scenario/test02.0/'
PS1
'(venv) \\h:\\W \\u\\$ '
PWD
'/Users/d24lau/src/xblock3'
PYENV_SHELL
'bash'
QUERY_STRING
''
REMOTE_ADDR
'127.0.0.1'
REMOTE_HOST
''
REQUEST_METHOD
'GET'
RUN_MAIN
'true'
SCRIPT_NAME
''
SECURITYSESSIONID
'186a3'
SERVER_NAME
'1.0.0.127.in-addr.arpa'
SERVER_PORT
'8000'
SERVER_PROTOCOL
'HTTP/1.1'
SERVER_SOFTWARE
'WSGIServer/0.2'
SHELL
'/bin/bash'
SHLVL
'1'
SSH_AUTH_SOCK
'/private/tmp/com.apple.launchd.YUg2X6Ccjl/Listeners'
TERM
'xterm-256color'
TERM_PROGRAM
'Apple_Terminal'
TERM_PROGRAM_VERSION
'445'
TERM_SESSION_ID
'6138864A-0F78-45B8-BF89-693E8BBFAA5B'
TMPDIR
'/var/folders/bt/hbj1wpcd5m321tqj6tyv8jsr0000gn/T/'
TZ
'America/New_York'
USER
'd24lau'
VIRTUAL_ENV
'/Users/d24lau/src/xblock3/venv'
XPC_FLAGS
'0x0'
XPC_SERVICE_NAME
'0'
_
'/Users/d24lau/src/xblock3/venv/bin/python'
__CFBundleIdentifier
'com.apple.Terminal'
__CF_USER_TEXT_ENCODING
'0x1F5:0x0:0x52'
wsgi.errors
<_io.TextIOWrapper name='<stderr>' mode='w' encoding='utf-8'>
wsgi.file_wrapper
<class 'wsgiref.util.FileWrapper'>
wsgi.input
<django.core.handlers.wsgi.LimitedStream object at 0x104ff9af0>
wsgi.multiprocess
False
wsgi.multithread
True
wsgi.run_once
False
wsgi.url_scheme
'http'
wsgi.version
(1, 0)
Settings
Using settings module workbench.settings
Setting Value
ABSOLUTE_URL_OVERRIDES
{}
ADMINS
()
ALLOWED_HOSTS
[]
APPEND_SLASH
True
AUTHENTICATION_BACKENDS
['django.contrib.auth.backends.ModelBackend']
AUTH_PASSWORD_VALIDATORS
'********************'
AUTH_USER_MODEL
'auth.User'
BASE_DIR
'/Users/d24lau/src/xblock3/xblock-sdk'
CACHES
{'default': {'BACKEND': 'django.core.cache.backends.locmem.LocMemCache',
'LOCATION': 'unique-snowflake'}}
CACHE_MIDDLEWARE_ALIAS
'default'
CACHE_MIDDLEWARE_KEY_PREFIX
'********************'
CACHE_MIDDLEWARE_SECONDS
600
CSRF_COOKIE_AGE
31449600
CSRF_COOKIE_DOMAIN
None
CSRF_COOKIE_HTTPONLY
False
CSRF_COOKIE_NAME
'csrftoken'
CSRF_COOKIE_PATH
'/'
CSRF_COOKIE_SAMESITE
'Lax'
CSRF_COOKIE_SECURE
False
CSRF_FAILURE_VIEW
'django.views.csrf.csrf_failure'
CSRF_HEADER_NAME
'HTTP_X_CSRFTOKEN'
CSRF_TRUSTED_ORIGINS
[]
CSRF_USE_SESSIONS
False
DATABASES
{'default': {'ATOMIC_REQUESTS': False,
'AUTOCOMMIT': True,
'CONN_MAX_AGE': 0,
'ENGINE': 'django.db.backends.sqlite3',
'HOST': '',
'NAME': 'var/workbench.db',
'OPTIONS': {},
'PASSWORD': '********************',
'PORT': '',
'TEST': {'CHARSET': None,
'COLLATION': None,
'MIGRATE': True,
'MIRROR': None,
'NAME': None},
'TIME_ZONE': None,
'USER': ''}}
DATABASE_ROUTERS
[]
DATA_UPLOAD_MAX_MEMORY_SIZE
2621440
DATA_UPLOAD_MAX_NUMBER_FIELDS
1000
DATA_UPLOAD_MAX_NUMBER_FILES
100
DATETIME_FORMAT
'N j, Y, P'
DATETIME_INPUT_FORMATS
['%Y-%m-%d %H:%M:%S',
'%Y-%m-%d %H:%M:%S.%f',
'%Y-%m-%d %H:%M',
'%m/%d/%Y %H:%M:%S',
'%m/%d/%Y %H:%M:%S.%f',
'%m/%d/%Y %H:%M',
'%m/%d/%y %H:%M:%S',
'%m/%d/%y %H:%M:%S.%f',
'%m/%d/%y %H:%M']
DATE_FORMAT
'N j, Y'
DATE_INPUT_FORMATS
['%Y-%m-%d',
'%m/%d/%Y',
'%m/%d/%y',
'%b %d %Y',
'%b %d, %Y',
'%d %b %Y',
'%d %b, %Y',
'%B %d %Y',
'%B %d, %Y',
'%d %B %Y',
'%d %B, %Y']
DEBUG
True
DEBUG_PROPAGATE_EXCEPTIONS
False
DECIMAL_SEPARATOR
'.'
DEFAULT_AUTO_FIELD
'django.db.models.AutoField'
DEFAULT_CHARSET
'utf-8'
DEFAULT_EXCEPTION_REPORTER
'django.views.debug.ExceptionReporter'
DEFAULT_EXCEPTION_REPORTER_FILTER
'django.views.debug.SafeExceptionReporterFilter'
DEFAULT_FILE_STORAGE
'django.core.files.storage.FileSystemStorage'
DEFAULT_FROM_EMAIL
'webmaster@localhost'
DEFAULT_HASHING_ALGORITHM
'sha256'
DEFAULT_INDEX_TABLESPACE
''
DEFAULT_TABLESPACE
''
DISALLOWED_USER_AGENTS
[]
DJFS
{'directory_root': 'workbench/static/djpyfs',
'type': 'osfs',
'url_root': '/static/djpyfs'}
EMAIL_BACKEND
'django.core.mail.backends.smtp.EmailBackend'
EMAIL_HOST
'localhost'
EMAIL_HOST_PASSWORD
'********************'
EMAIL_HOST_USER
''
EMAIL_PORT
25
EMAIL_SSL_CERTFILE
None
EMAIL_SSL_KEYFILE
'********************'
EMAIL_SUBJECT_PREFIX
'[Django] '
EMAIL_TIMEOUT
None
EMAIL_USE_LOCALTIME
False
EMAIL_USE_SSL
False
EMAIL_USE_TLS
False
EXCLUDED_XBLOCKS
set()
FILE_UPLOAD_DIRECTORY_PERMISSIONS
None
FILE_UPLOAD_HANDLERS
['django.core.files.uploadhandler.MemoryFileUploadHandler',
'django.core.files.uploadhandler.TemporaryFileUploadHandler']
FILE_UPLOAD_MAX_MEMORY_SIZE
2621440
FILE_UPLOAD_PERMISSIONS
420
FILE_UPLOAD_TEMP_DIR
None
FIRST_DAY_OF_WEEK
0
FIXTURE_DIRS
[]
FORCE_SCRIPT_NAME
None
FORMAT_MODULE_PATH
None
FORM_RENDERER
'django.forms.renderers.DjangoTemplates'
IGNORABLE_404_URLS
[]
INSTALLED_APPS
['django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.messages',
'django.contrib.staticfiles',
'djpyfs',
'workbench',
'django.contrib.admin']
INTERNAL_IPS
[]
LANGUAGES
[('af', 'Afrikaans'),
('ar', 'Arabic'),
('ar-dz', 'Algerian Arabic'),
('ast', 'Asturian'),
('az', 'Azerbaijani'),
('bg', 'Bulgarian'),
('be', 'Belarusian'),
('bn', 'Bengali'),
('br', 'Breton'),
('bs', 'Bosnian'),
('ca', 'Catalan'),
('cs', 'Czech'),
('cy', 'Welsh'),
('da', 'Danish'),
('de', 'German'),
('dsb', 'Lower Sorbian'),
('el', 'Greek'),
('en', 'English'),
('en-au', 'Australian English'),
('en-gb', 'British English'),
('eo', 'Esperanto'),
('es', 'Spanish'),
('es-ar', 'Argentinian Spanish'),
('es-co', 'Colombian Spanish'),
('es-mx', 'Mexican Spanish'),
('es-ni', 'Nicaraguan Spanish'),
('es-ve', 'Venezuelan Spanish'),
('et', 'Estonian'),
('eu', 'Basque'),
('fa', 'Persian'),
('fi', 'Finnish'),
('fr', 'French'),
('fy', 'Frisian'),
('ga', 'Irish'),
('gd', 'Scottish Gaelic'),
('gl', 'Galician'),
('he', 'Hebrew'),
('hi', 'Hindi'),
('hr', 'Croatian'),
('hsb', 'Upper Sorbian'),
('hu', 'Hungarian'),
('hy', 'Armenian'),
('ia', 'Interlingua'),
('id', 'Indonesian'),
('ig', 'Igbo'),
('io', 'Ido'),
('is', 'Icelandic'),
('it', 'Italian'),
('ja', 'Japanese'),
('ka', 'Georgian'),
('kab', 'Kabyle'),
('kk', 'Kazakh'),
('km', 'Khmer'),
('kn', 'Kannada'),
('ko', 'Korean'),
('ky', 'Kyrgyz'),
('lb', 'Luxembourgish'),
('lt', 'Lithuanian'),
('lv', 'Latvian'),
('mk', 'Macedonian'),
('ml', 'Malayalam'),
('mn', 'Mongolian'),
('mr', 'Marathi'),
('my', 'Burmese'),
('nb', 'Norwegian Bokmål'),
('ne', 'Nepali'),
('nl', 'Dutch'),
('nn', 'Norwegian Nynorsk'),
('os', 'Ossetic'),
('pa', 'Punjabi'),
('pl', 'Polish'),
('pt', 'Portuguese'),
('pt-br', 'Brazilian Portuguese'),
('ro', 'Romanian'),
('ru', 'Russian'),
('sk', 'Slovak'),
('sl', 'Slovenian'),
('sq', 'Albanian'),
('sr', 'Serbian'),
('sr-latn', 'Serbian Latin'),
('sv', 'Swedish'),
('sw', 'Swahili'),
('ta', 'Tamil'),
('te', 'Telugu'),
('tg', 'Tajik'),
('th', 'Thai'),
('tk', 'Turkmen'),
('tr', 'Turkish'),
('tt', 'Tatar'),
('udm', 'Udmurt'),
('uk', 'Ukrainian'),
('ur', 'Urdu'),
('uz', 'Uzbek'),
('vi', 'Vietnamese'),
('zh-hans', 'Simplified Chinese'),
('zh-hant', 'Traditional Chinese')]
LANGUAGES_BIDI
['he', 'ar', 'ar-dz', 'fa', 'ur']
LANGUAGE_CODE
'en-us'
LANGUAGE_COOKIE_AGE
None
LANGUAGE_COOKIE_DOMAIN
None
LANGUAGE_COOKIE_HTTPONLY
False
LANGUAGE_COOKIE_NAME
'django_language'
LANGUAGE_COOKIE_PATH
'/'
LANGUAGE_COOKIE_SAMESITE
None
LANGUAGE_COOKIE_SECURE
False
LOCALE_PATHS
[]
LOGGING
{'disable_existing_loggers': False,
'filters': {'require_debug_false': {'()': 'django.utils.log.RequireDebugFalse'}},
'handlers': {'logfile': {'backupCount': 2,
'class': 'logging.handlers.RotatingFileHandler',
'filename': 'var/workbench.log',
'level': 'DEBUG',
'maxBytes': 50000},
'null': {'class': 'logging.NullHandler', 'level': 'DEBUG'}},
'loggers': {'django': {'handlers': ['logfile'], 'level': 'DEBUG'},
'django.request': {'handlers': ['logfile'],
'level': 'DEBUG',
'propagate': True}},
'version': 1}
LOGGING_CONFIG
'logging.config.dictConfig'
LOGIN_REDIRECT_URL
'/accounts/profile/'
LOGIN_URL
'/accounts/login/'
LOGOUT_REDIRECT_URL
None
MANAGERS
()
MEDIA_ROOT
''
MEDIA_URL
'/'
MESSAGE_STORAGE
'django.contrib.messages.storage.fallback.FallbackStorage'
MIDDLEWARE
['django.middleware.common.CommonMiddleware',
'django.contrib.sessions.middleware.SessionMiddleware',
'django.middleware.csrf.CsrfViewMiddleware',
'django.contrib.auth.middleware.AuthenticationMiddleware',
'django.contrib.messages.middleware.MessageMiddleware']
MIGRATION_MODULES
{}
MONTH_DAY_FORMAT
'F j'
NUMBER_GROUPING
0
PASSWORD_HASHERS
'********************'
PASSWORD_RESET_TIMEOUT
'********************'
PASSWORD_RESET_TIMEOUT_DAYS
'********************'
PREPEND_WWW
False
ROOT_URLCONF
'workbench.urls'
SECRET_KEY
'********************'
SECURE_BROWSER_XSS_FILTER
False
SECURE_CONTENT_TYPE_NOSNIFF
True
SECURE_HSTS_INCLUDE_SUBDOMAINS
False
SECURE_HSTS_PRELOAD
False
SECURE_HSTS_SECONDS
0
SECURE_PROXY_SSL_HEADER
None
SECURE_REDIRECT_EXEMPT
[]
SECURE_REFERRER_POLICY
'same-origin'
SECURE_SSL_HOST
None
SECURE_SSL_REDIRECT
False
SERVER_EMAIL
'root@localhost'
SESSION_CACHE_ALIAS
'default'
SESSION_COOKIE_AGE
1209600
SESSION_COOKIE_DOMAIN
None
SESSION_COOKIE_HTTPONLY
True
SESSION_COOKIE_NAME
'sessionid'
SESSION_COOKIE_PATH
'/'
SESSION_COOKIE_SAMESITE
'Lax'
SESSION_COOKIE_SECURE
False
SESSION_ENGINE
'django.contrib.sessions.backends.db'
SESSION_EXPIRE_AT_BROWSER_CLOSE
False
SESSION_FILE_PATH
None
SESSION_SAVE_EVERY_REQUEST
False
SESSION_SERIALIZER
'django.contrib.sessions.serializers.JSONSerializer'
SETTINGS_MODULE
'workbench.settings'
SHORT_DATETIME_FORMAT
'm/d/Y P'
SHORT_DATE_FORMAT
'm/d/Y'
SIGNING_BACKEND
'django.core.signing.TimestampSigner'
SILENCED_SYSTEM_CHECKS
[]
SITE_ID
1
STATICFILES_DIRS
()
STATICFILES_FINDERS
['django.contrib.staticfiles.finders.FileSystemFinder',
'django.contrib.staticfiles.finders.AppDirectoriesFinder']
STATICFILES_STORAGE
'django.contrib.staticfiles.storage.StaticFilesStorage'
STATIC_ROOT
''
STATIC_URL
'/static/'
TEMPLATES
[{'APP_DIRS': True,
'BACKEND': 'django.template.backends.django.DjangoTemplates',
'DIRS': ['/Users/d24lau/src/xblock3/xblock-sdk/workbench/templates',
'/Users/d24lau/src/xblock3/xblock-sdk/sample_xblocks/basic/templates'],
'OPTIONS': {'context_processors': ['django.contrib.auth.context_processors.auth',
'django.template.context_processors.debug',
'django.template.context_processors.i18n',
'django.template.context_processors.media',
'django.template.context_processors.static',
'django.template.context_processors.tz',
'django.contrib.messages.context_processors.messages'],
'debug': True}}]
TEMPLATE_DIRS
[]
TEST_NON_SERIALIZED_APPS
[]
TEST_RUNNER
'django.test.runner.DiscoverRunner'
THOUSAND_SEPARATOR
','
TIME_FORMAT
'P'
TIME_INPUT_FORMATS
['%H:%M:%S', '%H:%M:%S.%f', '%H:%M']
TIME_ZONE
'America/New_York'
USE_I18N
True
USE_L10N
True
USE_THOUSAND_SEPARATOR
False
USE_TZ
True
USE_X_FORWARDED_HOST
False
USE_X_FORWARDED_PORT
False
WORKBENCH
{'reset_state_on_restart': False,
'services': {'fs': 'xblock.reference.plugins.FSService',
'settings': 'workbench.services.SettingsService'}}
WSGI_APPLICATION
'workbench.wsgi.application'
X_FRAME_OPTIONS
'DENY'
YEAR_MONTH_FORMAT
'F Y'
You’re seeing this error because you have DEBUG = True in your Django settings file. Change that to False, and Django will display a standard page generated by the handler for this status code.