$sceDelegate is a service that is used by the $sce service to provide Strict
Contextual Escaping (SCE) services to AngularJS.
For an overview of this service and the functionnality it provides in AngularJS, see the main page for SCE. The current page is targeted for developers who need to alter how SCE works in their application, which shouldn't be needed in most cases.
Typically, you would configure or override the $sceDelegate instead of
the $sce service to customize the way Strict Contextual Escaping works in AngularJS. This is
because, while the $sce provides numerous shorthand methods, etc., you really only need to
override 3 core functions (trustAs, getTrusted and valueOf) to replace the way things
work because $sce delegates to $sceDelegate for these operations.
Refer $sceDelegateProvider to configure this service.
The default instance of $sceDelegate should work out of the box with little pain. While you
can override it completely to change the behavior of $sce, the common case would
involve configuring the $sceDelegateProvider instead by setting
your own whitelists and blacklists for trusting URLs used for loading AngularJS resources such as
templates. Refer $sceDelegateProvider.resourceUrlWhitelist and $sceDelegateProvider.resourceUrlBlacklist
$sceDelegate();
trustAs(type, value);
Returns a trusted representation of the parameter for the specified context. This trusted
object will later on be used as-is, without any security check, by bindings or directives
that require this security context.
For instance, marking a string as trusted for the $sce.HTML context will entirely bypass
the potential $sanitize call in corresponding $sce.HTML bindings or directives, such as
ng-bind-html. Note that in most cases you won't need to call this function: if you have the
sanitizer loaded, passing the value itself will render all the HTML that does not pose a
security risk.
See getTrusted for the function that will consume those trusted values, and $sce for general documentation about strict contextual escaping.
| Param | Type | Details |
|---|---|---|
| type | string |
The context in which this value is safe for use, e.g. |
| value | * |
The value that should be considered trusted. |
| * | A trusted representation of value, that can be used in the given context. |
valueOf(value);
If the passed parameter had been returned by a prior call to $sceDelegate.trustAs, returns the value that had been passed to $sceDelegate.trustAs.
If the passed parameter is not a value that had been returned by $sceDelegate.trustAs, it must be returned as-is.
| Param | Type | Details |
|---|---|---|
| value | * |
The result of a prior |
| * | The |
getTrusted(type, maybeTrusted);
Given an object and a security context in which to assign it, returns a value that's safe to
use in this context, which was represented by the parameter. To do so, this function either
unwraps the safe type it has been given (for instance, a $sceDelegate.trustAs result), or it might try to sanitize the value given, depending on
the context and sanitizer availablility.
The contexts that can be sanitized are $sce.MEDIA_URL, $sce.URL and $sce.HTML. The first two are available
by default, and the third one relies on the $sanitize service (which may be loaded through
the ngSanitize module). Furthermore, for $sce.RESOURCE_URL context, a plain string may be
accepted if the resource url policy defined by $sceDelegateProvider.resourceUrlWhitelist and $sceDelegateProvider.resourceUrlBlacklist accepts that resource.
This function will throw if the safe type isn't appropriate for this context, or if the value given cannot be accepted in the context (which might be caused by sanitization not being available, or the value not being recognized as safe).
| Param | Type | Details |
|---|---|---|
| type | string |
The context in which this value is to be used (such as |
| maybeTrusted | * |
The result of a prior |
| * | A version of the value that's safe to use in the given context, or throws an exception if this is impossible. |