michael@0: /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #include "nsIRequest.idl"
michael@0: 
michael@0: interface nsIURI;
michael@0: interface nsIChannel;
michael@0: interface nsIRequestObserver;
michael@0: 
michael@0: /**
michael@0:  * nsIURIChecker
michael@0:  *
michael@0:  * The URI checker is a component that can be used to verify the existence
michael@0:  * of a resource at the location specified by a given URI.  It will use
michael@0:  * protocol specific methods to verify the URI (e.g., use of HEAD request
michael@0:  * for HTTP URIs).
michael@0:  */
michael@0: [scriptable, uuid(4660c1a1-be2d-4c78-9baf-c22984176c28)]
michael@0: interface nsIURIChecker : nsIRequest
michael@0: {
michael@0:     /**
michael@0:      * Initializes the URI checker.  After this method is called, it is valid
michael@0:      * to further configure the URI checker by calling its nsIRequest methods.
michael@0:      * This method creates the channel that will be used to verify the URI.
michael@0:      * In the case of the HTTP protocol, only a HEAD request will be issued.
michael@0:      *
michael@0:      * @param aURI
michael@0:      *        The URI to be checked.
michael@0:      */
michael@0:     void init(in nsIURI aURI);
michael@0: 
michael@0:     /**
michael@0:      * Returns the base channel that will be used to verify the URI.
michael@0:      */
michael@0:     readonly attribute nsIChannel baseChannel;
michael@0: 
michael@0:     /**
michael@0:      * Begin asynchronous checking URI for validity.  Notification will be
michael@0:      * asynchronous through the nsIRequestObserver callback interface.  When
michael@0:      * OnStartRequest is fired, the baseChannel attribute will have been
michael@0:      * updated to reflect the final channel used (corresponding to any redirects
michael@0:      * that may have been followed).
michael@0:      *
michael@0:      * Our interpretations of the nsIRequestObserver status codes:
michael@0:      *   NS_BINDING_SUCCEEDED:   link is valid
michael@0:      *   NS_BINDING_FAILED:      link is invalid (gave an error)
michael@0:      *   NS_BINDING_ABORTED:     timed out, or cancelled
michael@0:      *
michael@0:      * @param aObserver
michael@0:      *        The object to notify when the link is verified.  We will
michael@0:      *        call aObserver.OnStartRequest followed immediately by
michael@0:      *        aObserver.OnStopRequest.  It is recommended that the caller use
michael@0:      *        OnStopRequest to act on the link's status.  The underlying request
michael@0:      *        will not be cancelled until after OnStopRequest has been called.
michael@0:      * @param aContext
michael@0:      *        A closure that will be passed back to the nsIRequestObserver
michael@0:      *        methods.
michael@0:      */
michael@0:     void asyncCheck(in nsIRequestObserver aObserver, in nsISupports aContext);
michael@0: };