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*
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#include "nsIRequest.idl"
interface nsIURI;
interface nsIInterfaceRequestor;
interface nsIInputStream;
interface nsIStreamListener;
/**
* The nsIChannel interface allows clients to construct "GET" requests for
* specific protocols, and manage them in a uniform way. Once a channel is
* created (via nsIIOService::newChannel), parameters for that request may
* be set by using the channel attributes, or by QI'ing to a subclass of
* nsIChannel for protocol-specific parameters. Then, the URI can be fetched
* by calling nsIChannel::open or nsIChannel::asyncOpen.
*
* After a request has been completed, the channel is still valid for accessing
* protocol-specific results. For example, QI'ing to nsIHttpChannel allows
* response headers to be retrieved for the corresponding http transaction.
*
* @status FROZEN
*/
[scriptable, uuid(c63a055a-a676-4e71-bf3c-6cfa11082018)]
interface nsIChannel : nsIRequest
{
/**
* The original URI used to construct the channel. This is used in the case
* of a redirect or URI "resolution" (e.g. resolving a resource: URI to a
* file: URI) so that the original pre-redirect URI can still be obtained.
*
* NOTE: this is distinctly different from the http Referer (referring URI),
* which is typically the page that contained the original URI (accessible
* from nsIHttpChannel).
*/
attribute nsIURI originalURI;
/**
* The URI corresponding to the channel. Its value is immutable.
*/
readonly attribute nsIURI URI;
/**
* The owner, corresponding to the entity that is responsible for this
* channel. Used by the security manager to grant or deny privileges to
* mobile code loaded from this channel.
*
* NOTE: this is a strong reference to the owner, so if the owner is also
* holding a strong reference to the channel, care must be taken to
* explicitly drop its reference to the channel.
*/
attribute nsISupports owner;
/**
* The notification callbacks for the channel. This is set by clients, who
* wish to provide a means to receive progress, status and protocol-specific
* notifications. If this value is NULL, the channel implementation may use
* the notification callbacks from its load group. The channel may also
* query the notification callbacks from its load group if its notification
* callbacks do not supply the requested interface.
*
* Interfaces commonly requested include: nsIProgressEventSink, nsIPrompt,
* and nsIAuthPrompt.
*
* When the channel is done, it must not continue holding references to
* this object.
*
* NOTE: A channel implementation should take care when "caching" an
* interface pointer queried from its notification callbacks. If the
* notification callbacks are changed, then a cached interface pointer may
* become invalid and may therefore need to be re-queried.
*/
attribute nsIInterfaceRequestor notificationCallbacks;
/**
* Transport-level security information (if any) corresponding to the channel.
*/
readonly attribute nsISupports securityInfo;
/**
* The MIME type of the channel's content if available.
*
* NOTE: the content type can often be wrongly specified (e.g., wrong file
* extension, wrong MIME type, wrong document type stored on a server, etc.),
* and the caller most likely wants to verify with the actual data.
*
* Setting contentType before the channel has been opened provides a hint
* to the channel as to what the MIME type is. The channel may ignore this
* hint in deciding on the actual MIME type that it will report.
*
* Setting contentType after onStartRequest has been fired or after open()
* is called will override the type determined by the channel.
*
* Setting contentType between the time that asyncOpen() is called and the
* time when onStartRequest is fired has undefined behavior at this time.
*
* The value of the contentType attribute is a lowercase string. A value
* assigned to this attribute will be parsed and normalized as follows:
* 1- any parameters (delimited with a ';') will be stripped.
* 2- if a charset parameter is given, then its value will replace the
* the contentCharset attribute of the channel.
* 3- the stripped contentType will be lowercased.
* Any implementation of nsIChannel must follow these rules.
*/
attribute ACString contentType;
/**
* The character set of the channel's content if available and if applicable.
* This attribute only applies to textual data.
*
* The value of the contentCharset attribute is a mixedcase string.
*/
attribute ACString contentCharset;
/**
* The length of the data associated with the channel if available. A value
* of -1 indicates that the content length is unknown.
*
* Callers should prefer getting the "content-length" property
* as 64-bit value by QIing the channel to nsIPropertyBag2,
* if that interface is exposed by the channel.
*/
attribute long contentLength;
/**
* Synchronously open the channel.
*
* @return blocking input stream to the channel's data.
*
* NOTE: nsIChannel implementations are not required to implement this
* method. Moreover, since this method may block the calling thread, it
* should not be called on a thread that processes UI events.
*/
nsIInputStream open();
/**
* Asynchronously open this channel. Data is fed to the specified stream
* listener as it becomes available. The stream listener's methods are
* called on the thread that calls asyncOpen and are not called until
* after asyncOpen returns.
*
* @param aListener the nsIStreamListener implementation
* @param aContext an opaque parameter forwarded to aListener's methods
*/
void asyncOpen(in nsIStreamListener aListener, in nsISupports aContext);
/**************************************************************************
* Channel specific load flags:
*
* Bits 21-31 are reserved for future use by this interface or one of its
* derivatives (e.g., see nsICachingChannel).
*/
/**
* Set (e.g., by the docshell) to indicate whether or not the channel
* corresponds to a document URI.
*/
const unsigned long LOAD_DOCUMENT_URI = 1 << 16;
/**
* If the end consumer for this load has been retargeted after discovering
* it's content, this flag will be set:
*/
const unsigned long LOAD_RETARGETED_DOCUMENT_URI = 1 << 17;
/**
* This flag is set to indicate that onStopRequest may be followed by
* another onStartRequest/onStopRequest pair. This flag is, for example,
* used by the multipart/replace stream converter.
*/
const unsigned long LOAD_REPLACE = 1 << 18;
/**
* Set (e.g., by the docshell) to indicate whether or not the channel
* corresponds to an initial document URI load (e.g., link click).
*/
const unsigned long LOAD_INITIAL_DOCUMENT_URI = 1 << 19;
/**
* Set (e.g., by the URILoader) to indicate whether or not the end consumer
* for this load has been determined.
*/
const unsigned long LOAD_TARGETED = 1 << 20;
};