Django2.0手册:System check framework

The system check framework is a set of static checks for validating Django
projects. It detects common problems and provides hints for how to fix them.
The framework is extensible so you can easily add your own checks.

For details on how to add your own checks and integrate them with Django’s
system checks, see the System check topic guide.

API reference¶

CheckMessage¶

class CheckMessage(level, msg, hint=None, obj=None, id=None)[source]

The warnings and errors raised by system checks must be instances of
CheckMessage. An instance encapsulates a single reportable error or
warning. It also provides context and hints applicable to the message, and a
unique identifier that is used for filtering purposes.

Constructor arguments are:

level
The severity of the message. Use one of the predefined values: DEBUG,
INFO, WARNING, ERROR, CRITICAL. If the level is greater or
equal to ERROR, then Django will prevent management commands from
executing. Messages with level lower than ERROR (i.e. warnings) are
reported to the console, but can be silenced.
msg
A short (less than 80 characters) string describing the problem. The string
should not contain newlines.
hint
A single-line string providing a hint for fixing the problem. If no hint
can be provided, or the hint is self-evident from the error message, the
hint can be omitted, or a value of None can be used.
obj
Optional. An object providing context for the message (for example, the
model where the problem was discovered). The object should be a model,
field, or manager or any other object that defines a __str__() method.
The method is used while reporting all messages and its result precedes the
message.
id
Optional string. A unique identifier for the issue. Identifiers should
follow the pattern applabel.X001, where X is one of the letters
CEWID, indicating the message severity (C for criticals, E for
errors and so). The number can be allocated by the application, but should
be unique within that application.

There are subclasses to make creating messages with common levels easier. When
using them you can omit the level argument because it is implied by the
class name.

class Debug(msg, hint=None, obj=None, id=None)[source]
class Info(msg, hint=None, obj=None, id=None)[source]
class Warning(msg, hint=None obj=None, id=None)[source]
class Error(msg, hint=None, obj=None, id=None)[source]
class Critical(msg, hint=None, obj=None, id=None)[source]

Builtin tags¶

Django’s system checks are organized using the following tags:

  • admin: Checks of any admin site declarations.
  • caches: Checks cache related configuration.
  • compatibility: Flags potential problems with version upgrades.
  • database: Checks database-related configuration issues. Database checks
    are not run by default because they do more than static code analysis as
    regular checks do. They are only run by the migrate command or if
    you specify the database tag when calling the check command.
  • models: Checks of model, field, and manager definitions.
  • security: Checks security related configuration.
  • signals: Checks on signal declarations and handler registrations.
  • staticfiles: Checks django.contrib.staticfiles configuration.
  • templates: Checks template related configuration.
  • urls: Checks URL configuration.

Some checks may be registered with multiple tags.

Core system checks¶

Backwards compatibility¶

Compatibility checks warn of potential problems that might occur after
upgrading Django.

  • 2_0.W001: Your URL pattern <pattern> has a route that contains
    (?P<, begins with a ^, or ends with a $. This was likely an
    oversight when migrating from url() to path().

Caches¶

The following checks verify that your CACHES setting is correctly
configured:

  • caches.E001: You must define a 'default' cache in your
    CACHES setting.

Database¶

MySQL

If you’re using MySQL, the following checks will be performed:

  • mysql.E001: MySQL does not allow unique CharFields to have a
    max_length > 255.
  • mysql.W002: MySQL Strict Mode is not set for database connection
    ‘<alias>’. See also Setting sql_mode.

Model fields¶

  • fields.E001: Field names must not end with an underscore.
  • fields.E002: Field names must not contain "__".
  • fields.E003: pk is a reserved word that cannot be used as a field
    name.
  • fields.E004: choices must be an iterable (e.g., a list or tuple).
  • fields.E005: choices must be an iterable returning (actual value,
    human readable name)
    tuples.
  • fields.E006: db_index must be None, True or False.
  • fields.E007: Primary keys must not have null=True.
  • fields.E008: All validators must be callable.
  • fields.E100: AutoFields must set primary_key=True.
  • fields.E110: BooleanFields do not accept null values.
  • fields.E120: CharFields must define a max_length attribute.
  • fields.E121: max_length must be a positive integer.
  • fields.W122: max_length is ignored when used with IntegerField.
  • fields.E130: DecimalFields must define a decimal_places attribute.
  • fields.E131: decimal_places must be a non-negative integer.
  • fields.E132: DecimalFields must define a max_digits attribute.
  • fields.E133: max_digits must be a non-negative integer.
  • fields.E134: max_digits must be greater or equal to decimal_places.
  • fields.E140: FilePathFields must have either allow_files or
    allow_folders set to True.
  • fields.E150: GenericIPAddressFields cannot accept blank values if
    null values are not allowed, as blank values are stored as nulls.
  • fields.E160: The options auto_now, auto_now_add, and default
    are mutually exclusive. Only one of these options may be present.
  • fields.W161: Fixed default value provided.
  • fields.W162: <database> does not support a database index on
    <field data type> columns.
  • fields.E900: IPAddressField has been removed except for support in
    historical migrations.
  • fields.W900: IPAddressField has been deprecated. Support for it
    (except in historical migrations) will be removed in Django 1.9. This check
    appeared in Django 1.7 and 1.8
    .
  • fields.W901: CommaSeparatedIntegerField has been deprecated. Support
    for it (except in historical migrations) will be removed in Django 2.0. This
    check appeared in Django 1.10 and 1.11
    .
  • fields.E901: CommaSeparatedIntegerField is removed except for support
    in historical migrations.

File fields

  • fields.E200: unique is not a valid argument for a FileField.
    This check is removed in Django 1.11.
  • fields.E201: primary_key is not a valid argument for a FileField.
  • fields.E202: FileField’s upload_to argument must be a relative
    path, not an absolute path.
  • fields.E210: Cannot use ImageField because Pillow is not installed.

Models¶

  • models.E001: <swappable> is not of the form app_label.app_name.
  • models.E002: <SETTING> references <model>, which has not been
    installed, or is abstract.
  • models.E003: The model has two many-to-many relations through the
    intermediate model <app_label>.<model>.
  • models.E004: id can only be used as a field name if the field also
    sets primary_key=True.
  • models.E005: The field <field name> from parent model <model>
    clashes with the field <field name> from parent model <model>.
  • models.E006: The field clashes with the field <field name> from model
    <model>.
  • models.E007: Field <field name> has column name <column name>
    that is used by another field.
  • models.E008: index_together must be a list or tuple.
  • models.E009: All index_together elements must be lists or tuples.
  • models.E010: unique_together must be a list or tuple.
  • models.E011: All unique_together elements must be lists or tuples.
  • models.E012: index_together/unique_together refers to the
    nonexistent field <field name>.
  • models.E013: index_together/unique_together refers to a
    ManyToManyField <field name>, but ManyToManyFields are not
    supported for that option.
  • models.E014: ordering must be a tuple or list (even if you want to
    order by only one field).
  • models.E015: ordering refers to the nonexistent field
    <field name>.
  • models.E016: index_together/unique_together refers to field
    <field_name> which is not local to model <model>.
  • models.E017: Proxy model <model> contains model fields.
  • models.E018: Autogenerated column name too long for field <field>.
    Maximum length is <maximum length> for database <alias>.
  • models.E019: Autogenerated column name too long for M2M field
    <M2M field>. Maximum length is <maximum length> for database
    <alias>.
  • models.E020: The <model>.check() class method is currently overridden.
  • models.E021: ordering and order_with_respect_to cannot be used
    together.
  • models.E022: <function> contains a lazy reference to
    <app label>.<model>, but app <app label> isn’t installed or
    doesn’t provide model <model>.
  • models.E023: The model name <model> cannot start or end with an
    underscore as it collides with the query lookup syntax.
  • models.E024: The model name <model> cannot contain double underscores
    as it collides with the query lookup syntax.

Security¶

The security checks do not make your site secure. They do not audit code, do
intrusion detection, or do anything particularly complex. Rather, they help
perform an automated, low-hanging-fruit checklist. They help you remember the
simple things that improve your site’s security.

Some of these checks may not be appropriate for your particular deployment
configuration. For instance, if you do your HTTP to HTTPS redirection in a load
balancer, it’d be irritating to be constantly warned about not having enabled
SECURE_SSL_REDIRECT. Use SILENCED_SYSTEM_CHECKS to
silence unneeded checks.

The following checks are run if you use the check --deploy option:

  • security.W001: You do not have
    django.middleware.security.SecurityMiddleware in your
    MIDDLEWARE so the SECURE_HSTS_SECONDS,
    SECURE_CONTENT_TYPE_NOSNIFF, SECURE_BROWSER_XSS_FILTER,
    and SECURE_SSL_REDIRECT settings will have no effect.
  • security.W002: You do not have
    django.middleware.clickjacking.XFrameOptionsMiddleware in your
    MIDDLEWARE, so your pages will not be served with an
    'x-frame-options' header. Unless there is a good reason for your
    site to be served in a frame, you should consider enabling this
    header to help prevent clickjacking attacks.
  • security.W003: You don’t appear to be using Django’s built-in cross-site
    request forgery protection via the middleware
    (django.middleware.csrf.CsrfViewMiddleware is not in your
    MIDDLEWARE). Enabling the middleware is the safest
    approach to ensure you don’t leave any holes.
  • security.W004: You have not set a value for the
    SECURE_HSTS_SECONDS setting. If your entire site is served only
    over SSL, you may want to consider setting a value and enabling HTTP
    Strict Transport Security
    . Be sure to read
    the documentation first; enabling HSTS carelessly can cause serious,
    irreversible problems.
  • security.W005: You have not set the
    SECURE_HSTS_INCLUDE_SUBDOMAINS setting to True. Without this,
    your site is potentially vulnerable to attack via an insecure connection to a
    subdomain. Only set this to True if you are certain that all subdomains of
    your domain should be served exclusively via SSL.
  • security.W006: Your SECURE_CONTENT_TYPE_NOSNIFF setting is not
    set to True, so your pages will not be served with an
    'x-content-type-options: nosniff' header. You should consider enabling
    this header to prevent the browser from identifying content types incorrectly.
  • security.W007: Your SECURE_BROWSER_XSS_FILTER setting is not
    set to True, so your pages will not be served with an
    'x-xss-protection: 1; mode=block' header. You should consider enabling
    this header to activate the browser’s XSS filtering and help prevent XSS
    attacks.
  • security.W008: Your SECURE_SSL_REDIRECT setting is not set to
    True. Unless your site should be available over both SSL and non-SSL
    connections, you may want to either set this setting to True or configure
    a load balancer or reverse-proxy server to redirect all connections to HTTPS.
  • security.W009: Your SECRET_KEY has less than 50 characters or
    less than 5 unique characters. Please generate a long and random
    SECRET_KEY, otherwise many of Django’s security-critical features will be
    vulnerable to attack.
  • security.W010: You have django.contrib.sessions in your
    INSTALLED_APPS but you have not set
    SESSION_COOKIE_SECURE to True. Using a secure-only session
    cookie makes it more difficult for network traffic sniffers to hijack user
    sessions.
  • security.W011: You have
    django.contrib.sessions.middleware.SessionMiddleware in your
    MIDDLEWARE, but you have not set SESSION_COOKIE_SECURE
    to True. Using a secure-only session cookie makes it more difficult for
    network traffic sniffers to hijack user sessions.
  • security.W012: SESSION_COOKIE_SECURE is not set to True.
    Using a secure-only session cookie makes it more difficult for network traffic
    sniffers to hijack user sessions.
  • security.W013: You have django.contrib.sessions in your
    INSTALLED_APPS, but you have not set
    SESSION_COOKIE_HTTPONLY to True. Using an HttpOnly session
    cookie makes it more difficult for cross-site scripting attacks to hijack user
    sessions.
  • security.W014: You have
    django.contrib.sessions.middleware.SessionMiddleware in your
    MIDDLEWARE, but you have not set SESSION_COOKIE_HTTPONLY
    to True. Using an HttpOnly session cookie makes it more difficult for
    cross-site scripting attacks to hijack user sessions.
  • security.W015: SESSION_COOKIE_HTTPONLY is not set to True.
    Using an HttpOnly session cookie makes it more difficult for cross-site
    scripting attacks to hijack user sessions.
  • security.W016: CSRF_COOKIE_SECURE is not set to True.
    Using a secure-only CSRF cookie makes it more difficult for network traffic
    sniffers to steal the CSRF token.
  • security.W017: CSRF_COOKIE_HTTPONLY is not set to True.
    Using an HttpOnly CSRF cookie makes it more difficult for cross-site
    scripting attacks to steal the CSRF token. This check is removed in Django
    1.11 as the
    CSRF_COOKIE_HTTPONLY setting offers no pratical
    benefit.
  • security.W018: You should not have DEBUG set to True in
    deployment.
  • security.W019: You have
    django.middleware.clickjacking.XFrameOptionsMiddleware in your
    MIDDLEWARE, but X_FRAME_OPTIONS is not set to
    'DENY'. The default is 'SAMEORIGIN', but unless there is a good reason
    for your site to serve other parts of itself in a frame, you should change
    it to 'DENY'.
  • security.W020: ALLOWED_HOSTS must not be empty in deployment.
  • security.W021: You have not set the
    SECURE_HSTS_PRELOAD setting to True. Without this, your site
    cannot be submitted to the browser preload list.

Signals¶

  • signals.E001: <handler> was connected to the <signal> signal with
    a lazy reference to the sender <app label>.<model>, but app <app label>
    isn’t installed or doesn’t provide model <model>.

Templates¶

The following checks verify that your TEMPLATES setting is correctly
configured:

  • templates.E001: You have 'APP_DIRS': True in your
    TEMPLATES but also specify 'loaders' in OPTIONS. Either
    remove APP_DIRS or remove the 'loaders' option.
  • templates.E002: string_if_invalid in TEMPLATES
    OPTIONS must be a string but got: {value}
    ({type}).

URLs¶

The following checks are performed on your URL configuration:

  • urls.W001: Your URL pattern <pattern> uses
    include() with a route ending with a $. Remove the
    dollar from the route to avoid problems including URLs.
  • urls.W002: Your URL pattern <pattern> has a route beginning with
    a /. Remove this slash as it is unnecessary. If this pattern is targeted
    in an include(), ensure the include()
    pattern has a trailing /.
  • urls.W003: Your URL pattern <pattern> has a name
    including a :. Remove the colon, to avoid ambiguous namespace
    references.
  • urls.E004: Your URL pattern <pattern> is invalid. Ensure that
    urlpatterns is a list of path() and/or
    re_path() instances.
  • urls.W005: URL namespace <namespace> isn’t unique. You may not be
    able to reverse all URLs in this namespace.
  • urls.E006: The MEDIA_URL/ STATIC_URL setting must
    end with a slash.

contrib app checks¶

admin¶

Admin checks are all performed as part of the admin tag.

The following checks are performed on any
ModelAdmin (or subclass) that is registered
with the admin site:

  • admin.E001: The value of raw_id_fields must be a list or tuple.
  • admin.E002: The value of raw_id_fields[n] refers to <field name>,
    which is not an attribute of <model>.
  • admin.E003: The value of raw_id_fields[n] must be a foreign key or
    a many-to-many field.
  • admin.E004: The value of fields must be a list or tuple.
  • admin.E005: Both fieldsets and fields are specified.
  • admin.E006: The value of fields contains duplicate field(s).
  • admin.E007: The value of fieldsets must be a list or tuple.
  • admin.E008: The value of fieldsets[n] must be a list or tuple.
  • admin.E009: The value of fieldsets[n] must be of length 2.
  • admin.E010: The value of fieldsets[n][1] must be a dictionary.
  • admin.E011: The value of fieldsets[n][1] must contain the key
    fields.
  • admin.E012: There are duplicate field(s) in fieldsets[n][1].
  • admin.E013: fields[n]/fieldsets[n][m] cannot include the
    ManyToManyField <field name>, because that field manually specifies a
    relationship model.
  • admin.E014: The value of exclude must be a list or tuple.
  • admin.E015: The value of exclude contains duplicate field(s).
  • admin.E016: The value of form must inherit from BaseModelForm.
  • admin.E017: The value of filter_vertical must be a list or tuple.
  • admin.E018: The value of filter_horizontal must be a list or tuple.
  • admin.E019: The value of filter_vertical[n]/filter_vertical[n] refers
    to <field name>, which is not an attribute of <model>.
  • admin.E020: The value of filter_vertical[n]/filter_vertical[n] must
    be a many-to-many field.
  • admin.E021: The value of radio_fields must be a dictionary.
  • admin.E022: The value of radio_fields refers to <field name>,
    which is not an attribute of <model>.
  • admin.E023: The value of radio_fields refers to <field name>,
    which is not a ForeignKey, and does not have a choices definition.
  • admin.E024: The value of radio_fields[<field name>] must be either
    admin.HORIZONTAL or admin.VERTICAL.
  • admin.E025: The value of view_on_site must be either a callable or a
    boolean value.
  • admin.E026: The value of prepopulated_fields must be a dictionary.
  • admin.E027: The value of prepopulated_fields refers to
    <field name>, which is not an attribute of <model>.
  • admin.E028: The value of prepopulated_fields refers to
    <field name>, which must not be a DateTimeField, a ForeignKey,
    a OneToOneField, or a ManyToManyField field.
  • admin.E029: The value of prepopulated_fields[<field name>] must be a
    list or tuple.
  • admin.E030: The value of prepopulated_fields refers to
    <field name>, which is not an attribute of <model>.
  • admin.E031: The value of ordering must be a list or tuple.
  • admin.E032: The value of ordering has the random ordering marker
    ?, but contains other fields as well.
  • admin.E033: The value of ordering refers to <field name>, which
    is not an attribute of <model>.
  • admin.E034: The value of readonly_fields must be a list or tuple.
  • admin.E035: The value of readonly_fields[n] is not a callable, an
    attribute of <ModelAdmin class>, or an attribute of <model>.
  • admin.E036: The value of autocomplete_fields must be a list or tuple.
  • admin.E037: The value of autocomplete_fields[n] refers to
    <field name>, which is not an attribute of <model>.
  • admin.E038: The value of autocomplete_fields[n] must be a foreign
    key or a many-to-many field.
  • admin.E039: An admin for model <model> has to be registered to be
    referenced by <modeladmin>.autocomplete_fields.
  • admin.E040: <modeladmin> must define search_fields, because
    it’s referenced by <other_modeladmin>.autocomplete_fields.

ModelAdmin

The following checks are performed on any
ModelAdmin that is registered
with the admin site:

  • admin.E101: The value of save_as must be a boolean.
  • admin.E102: The value of save_on_top must be a boolean.
  • admin.E103: The value of inlines must be a list or tuple.
  • admin.E104: <InlineModelAdmin class> must inherit from
    InlineModelAdmin.
  • admin.E105: <InlineModelAdmin class> must have a model attribute.
  • admin.E106: The value of <InlineModelAdmin class>.model must be a
    Model.
  • admin.E107: The value of list_display must be a list or tuple.
  • admin.E108: The value of list_display[n] refers to <label>,
    which is not a callable, an attribute of <ModelAdmin class>, or an
    attribute or method on <model>.
  • admin.E109: The value of list_display[n] must not be a
    ManyToManyField field.
  • admin.E110: The value of list_display_links must be a list, a tuple,
    or None.
  • admin.E111: The value of list_display_links[n] refers to <label>,
    which is not defined in list_display.
  • admin.E112: The value of list_filter must be a list or tuple.
  • admin.E113: The value of list_filter[n] must inherit from
    ListFilter.
  • admin.E114: The value of list_filter[n] must not inherit from
    FieldListFilter.
  • admin.E115: The value of list_filter[n][1] must inherit from
    FieldListFilter.
  • admin.E116: The value of list_filter[n] refers to <label>,
    which does not refer to a Field.
  • admin.E117: The value of list_select_related must be a boolean,
    tuple or list.
  • admin.E118: The value of list_per_page must be an integer.
  • admin.E119: The value of list_max_show_all must be an integer.
  • admin.E120: The value of list_editable must be a list or tuple.
  • admin.E121: The value of list_editable[n] refers to <label>,
    which is not an attribute of <model>.
  • admin.E122: The value of list_editable[n] refers to <label>,
    which is not contained in list_display.
  • admin.E123: The value of list_editable[n] cannot be in both
    list_editable and list_display_links.
  • admin.E124: The value of list_editable[n] refers to the first field
    in list_display (<label>), which cannot be used unless
    list_display_links is set.
  • admin.E125: The value of list_editable[n] refers to <field name>,
    which is not editable through the admin.
  • admin.E126: The value of search_fields must be a list or tuple.
  • admin.E127: The value of date_hierarchy refers to <field name>,
    which does not refer to a Field.
  • admin.E128: The value of date_hierarchy must be a DateField or
    DateTimeField.

InlineModelAdmin

The following checks are performed on any
InlineModelAdmin that is registered as an
inline on a ModelAdmin.

  • admin.E201: Cannot exclude the field <field name>, because it is the
    foreign key to the parent model <app_label>.<model>.
  • admin.E202: <model> has no ForeignKey to <parent model>./
    <model> has more than one ForeignKey to <parent model>.
  • admin.E203: The value of extra must be an integer.
  • admin.E204: The value of max_num must be an integer.
  • admin.E205: The value of min_num must be an integer.
  • admin.E206: The value of formset must inherit from
    BaseModelFormSet.

GenericInlineModelAdmin

The following checks are performed on any
GenericInlineModelAdmin that is
registered as an inline on a ModelAdmin.

  • admin.E301: 'ct_field' references <label>, which is not a field
    on <model>.
  • admin.E302: 'ct_fk_field' references <label>, which is not a
    field on <model>.
  • admin.E303: <model> has no GenericForeignKey.
  • admin.E304: <model> has no GenericForeignKey using content type
    field <field name> and object ID field <field name>.

AdminSite

The following checks are performed on the default
AdminSite:

auth¶

  • auth.E001: REQUIRED_FIELDS must be a list or tuple.
  • auth.E002: The field named as the USERNAME_FIELD for a custom user
    model must not be included in REQUIRED_FIELDS.
  • auth.E003: <field> must be unique because it is named as the
    USERNAME_FIELD.
  • auth.W004: <field> is named as the USERNAME_FIELD, but it is not
    unique.
  • auth.E005: The permission codenamed <codename> clashes with a builtin
    permission for model <model>.
  • auth.E006: The permission codenamed <codename> is duplicated for model
    <model>.
  • auth.E007: The verbose_name of model <model> must be at most
    244 characters for its builtin permission names
    to be at most 255 characters.
  • auth.E008: The permission named <name> of model <model> is longer
    than 255 characters.
  • auth.C009: <User model>.is_anonymous must be an attribute or property
    rather than a method. Ignoring this is a security issue as anonymous users
    will be treated as authenticated!
  • auth.C010: <User model>.is_authenticated must be an attribute or
    property rather than a method. Ignoring this is a security issue as anonymous
    users will be treated as authenticated!

contenttypes¶

The following checks are performed when a model contains a
GenericForeignKey or
GenericRelation:

  • contenttypes.E001: The GenericForeignKey object ID references the
    nonexistent field <field>.
  • contenttypes.E002: The GenericForeignKey content type references the
    nonexistent field <field>.
  • contenttypes.E003: <field> is not a ForeignKey.
  • contenttypes.E004: <field> is not a ForeignKey to
    contenttypes.ContentType.
  • contenttypes.E005: Model names must be at most 100 characters.

sites¶

The following checks are performed on any model using a
CurrentSiteManager:

  • sites.E001: CurrentSiteManager could not find a field named
    <field name>.
  • sites.E002: CurrentSiteManager cannot use <field> as it is not a
    foreign key or a many-to-many field.

staticfiles¶

The following checks verify that django.contrib.staticfiles is correctly
configured: