nsIURILoader in Firefox 3.0

Implemented by

@mozilla.org/uriloader;1

 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.

[scriptable, uuid(2f7e8051-f1c9-4bcc-8584-9cfd5849e343)]

Constants

 @name Flags for opening URIs.


 Should the content be displayed in a container that prefers the
 content-type, or will any container do.

const unsigned long 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.

const unsigned long DONT_RETARGET = 2

Methods

 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.

 @param aChannel
        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).
 @param aFlags
        Combination (bitwise OR) of the flags specified above. 0 indicates
        default handling.
 @param aWindowContext
        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.
        <b>Must not be null!</b>

nsIStreamListener openChannel(in nsIChannel aChannel, in unsigned long aFlags, in nsIInterfaceRequestor aWindowContext)

 OpenURI requires the following parameters.....
 @param aChannel
        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.
 @param aIsContentPreferred
        Should the content be displayed in a container that prefers the
        content-type, or will any container do.
 @param aWindowContext
        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.
        <b>Must not be null!</b>

void openURI(in nsIChannel aChannel, in boolean aIsContentPreferred, in nsIInterfaceRequestor aWindowContext)

 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.

 @param aContentListener
        The listener to register. This listener must implement
        nsISupportsWeakReference.

 @see the nsIURILoader class description

void registerContentListener(in nsIURIContentListener aContentListener)

 Stops an in progress load

void stop(in nsISupports aLoadCookie)

void unRegisterContentListener(in nsIURIContentListener aContentListener)