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nsIURILoader

IID:2f7e8051-f1c9-4bcc-8584-9cfd5849e343
Inherits From:nsISupports

The uri dispatcher is responsible for taking uri's, determining the content and routing the opened url to the correct content handler.

When you encounter a url you want to open, you typically call openURI, passing it the content listener for the window the uri is originating from. The uri dispatcher opens the url to discover the content type. It then gives the content listener first crack at handling the content. If it doesn't want it, the dispatcher tries to hand it off one of the registered content listeners. This allows running applications the chance to jump in and handle the content.

If that also fails, then the uri dispatcher goes to the registry looking for the preferred content handler for the content type of the uri. The content handler may create an app instance or it may hand the contents off to a platform specific plugin or helper app. Or it may hand the url off to an OS registered application.

This interface is implemented by the following components:


Constants

Should the content be displayed in a container that prefers the content-type, or will any container do.
PRUint32 IS_CONTENT_PREFERRED = 1
If this flag is set, only the listener of the specified window context will be considered for content handling; if it refuses the load, an error will be indicated.
PRUint32 DONT_RETARGET = 2

Methods

nsIStreamListener openChannel ( nsIChannel channel , PRUint32 flags , nsIInterfaceRequestor windowContext ) void openURI ( nsIChannel channel , PRBool isContentPreferred , nsIInterfaceRequestor windowContext ) void registerContentListener ( nsIURIContentListener contentListener ) void stop ( nsISupports loadCookie ) void unRegisterContentListener ( nsIURIContentListener contentListener )

nsIStreamListener openChannel ( nsIChannel channel , PRUint32 flags , nsIInterfaceRequestor windowContext )

Loads data from a channel. This differs from openURI in that the channel may already be opened, and that it returns a stream listener into which the caller should pump data. The caller is responsible for opening the channel and pumping the channel's data into the returned stream listener.

Note: If the channel already has a loadgroup, it will be replaced with the window context's load group, or null if the context doesn't have one.

If the window context's nsIURIContentListener refuses the load immediately (e.g. in nsIURIContentListener::onStartURIOpen), this method will return NS_ERROR_WONT_HANDLE_CONTENT. At that point, the caller should probably cancel the channel if it's already open (this method will not cancel the channel).

If flags include DONT_RETARGET, and the content listener refuses the load during onStartRequest (e.g. in canHandleContent/isPreferred), then the returned stream listener's onStartRequest method will return NS_ERROR_WONT_HANDLE_CONTENT.

Arguments:
channel: The channel that should be loaded. The channel may already be opened. It must not be closed (i.e. this must be called before the channel calls onStopRequest on its stream listener).
flags: Combination (bitwise OR) of the flags specified above. 0 indicates default handling.
windowContext: If you are running the url from a doc shell or a web shell, this is your window context. If you have a content listener you want to give first crack to, the uri loader needs to be able to get it from the window context. We will also be using the window context to get at the progress event sink interface. Must not be null!

void openURI ( nsIChannel channel , PRBool isContentPreferred , nsIInterfaceRequestor windowContext )

OpenURI requires the following parameters.....

Arguments:
channel: The channel that should be opened. This must not be asyncOpen'd yet! If a loadgroup is set on the channel, it will get replaced with a different one.
isContentPreferred: Should the content be displayed in a container that prefers the content-type, or will any container do.
windowContext: If you are running the url from a doc shell or a web shell, this is your window context. If you have a content listener you want to give first crack to, the uri loader needs to be able to get it from the window context. We will also be using the window context to get at the progress event sink interface. Must not be null!

void registerContentListener ( nsIURIContentListener contentListener )

As applications such as messenger and the browser are instantiated, they register content listener's with the uri dispatcher corresponding to content windows within that application.

Note to self: we may want to optimize things a bit more by requiring the content types the registered content listener cares about.

Arguments:
contentListener: The listener to register. This listener must implement nsISupportsWeakReference.

void stop ( nsISupports loadCookie )

Stops an in progress load

Arguments:
loadCookie

void unRegisterContentListener ( nsIURIContentListener contentListener )

Arguments:
contentListener

Reference documentation is generated from Mozilla's source.

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