pjs/netwerk/base/public/nsIChannel.idl

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* The contents of this file are subject to the Netscape Public
* License Version 1.1 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at http://www.mozilla.org/NPL/
*
* Software distributed under the License is distributed on an "AS
* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
* implied. See the License for the specific language governing
* rights and limitations under the License.
*
* The Original Code is mozilla.org code.
*
* The Initial Developer of the Original Code is Netscape
* Communications Corporation. Portions created by Netscape are
* Copyright (C) 1998 Netscape Communications Corporation. All
* Rights Reserved.
*
* Contributor(s):
*/
#include "nsIRequest.idl"
interface nsIURI;
interface nsIInputStream;
interface nsIOutputStream;
interface nsIStreamObserver;
interface nsIStreamListener;
interface nsILoadGroup;
interface nsIInterfaceRequestor;
interface nsIFile;
typedef unsigned long nsLoadFlags;
/**
* The nsIChannel interface allows the user to construct I/O 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 QueryInterfacing to a
* subclass of nsIChannel for protocol-specific parameters. Then the actual
* request can be issued in one of several ways:
*
* - AsyncRead and AsyncWrite allow for asynchronous requests, calling
* back the user's stream listener or observer,
* - OpenInputStream and OpenOutputStream allow for synchronous reads
* and writes on the underlying channel.
*
* After a request has been completed, the channel is still valid for
* accessing protocol-specific results. For example, QueryInterfacing to
* nsIHTTPChannel allows response headers to be retrieved that result from
* http transactions.
*
* Note that a channel is really only valid for one request. Reusing a channel
* after a request has completed for a subsequent request may have undefined
* results, depending on the channel implementation.
*
* Also of note are a special kind of channel called "transports." Transports
* also implement the nsIChannel interface, but operate at a lower level from
* protocol channels. The socket and file transports are notable implementations
* of transports and allow higher level channels to be implemented. The cache
* may also behave as a transport, and possibly things like sound playing services
* etc. Transports usually operate in a separate thread and often multiplex
* multiple requests for the same kind of service or resources.
*/
[scriptable, uuid(1788e79e-f947-11d3-8cda-0060b0fc14a3)]
interface nsIChannel : nsIRequest
{
////////////////////////////////////////////////////////////////////////////
// nsIChannel accessors
////////////////////////////////////////////////////////////////////////////
/**
* Returns the original URL 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 that this is distinctly different from the http referrer
* (referring URI) which is typically the page that contained the
* original URI (accessible from nsIHTTPChannel).
*/
attribute nsIURI originalURI;
/**
* Returns the URL to which the channel currently refers. If a redirect
* or URI resolution occurs, this accessor returns the current location
* to which the channel is referring.
*/
attribute nsIURI URI;
/**
* Accesses the start offset from the beginning of the data from/to which
* reads/writes will occur. Users may set the transferOffset before making
* any of the following requests: asyncOpen, asyncRead, asyncWrite,
* openInputStream, openOutputstream.
*/
attribute unsigned long transferOffset;
/**
* Accesses the count of bytes to be transfered. For openInputStream and
* asyncRead, this specifies the amount to read, for asyncWrite, this
* specifies the amount to write (note that for openOutputStream, the
* end of the data can be signified simply by closing the stream).
* If the transferCount is set after reading has been initiated, the
* amount specified will become the current remaining amount to read
* before the channel is closed (this can be useful if the content
* length is encoded at the start of the stream).
*
* A transferCount value of -1 means the amount is unspecified, i.e.
* read or write all the data that is available.
*/
attribute long transferCount;
/**
* Accesses the load attributes for the channel. E.g. setting the load
* attributes with the LOAD_QUIET bit set causes the loading process to
* not deliver status notifications to the program performing the load,
* and to not contribute to keeping any nsILoadGroup it may be contained
* in from firing its OnLoadComplete notification.
*/
attribute nsLoadFlags loadAttributes;
/**
* Returns the content MIME type of the channel if available. Note that the
* content type can often be wrongly specified (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.
*/
attribute string contentType;
/**
* Returns the length of the data associated with the channel if available.
* If the length is unknown then -1 is returned.
*/
attribute long contentLength;
/**
* Accesses the owner corresponding to the entity that is
* responsible for this channel. Used by security code 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 pointer to the channel, care must be taken to explicitly drop
* its reference to the channel -- otherwise a leak will result.
*/
attribute nsISupports owner;
/**
* Accesses the load group in which the channel is a currently a member.
*/
attribute nsILoadGroup loadGroup;
/**
* Accesses the capabilities callbacks of the channel. This is set by clients
* who wish to provide a means to receive progress, status and protocol-specific
* notifications.
*/
attribute nsIInterfaceRequestor notificationCallbacks;
/**
* Any security information about this channel. This can be null.
*/
readonly attribute nsISupports securityInfo;
/**
* Accesses the buffer segment size. The buffer segment size is used as
* the initial size for any transfer buffers, and the increment size for
* whenever the buffer space needs to be grown.
* (Note this parameter is passed along to any underlying nsIPipe objects.)
* If unspecified, the channel implementation picks a default.
*/
attribute unsigned long bufferSegmentSize;
/**
* Accesses the buffer maximum size. The buffer maximum size is the limit
* size that buffer will be grown to before suspending the channel.
* (Note this parameter is passed along to any underlying nsIPipe objects.)
* If unspecified, the channel implementation picks a default.
*/
attribute unsigned long bufferMaxSize;
/**
* Returns true if the data from this channel should be cached. Local files
* report false because they exist on the local disk and need not be cached.
* Input stream channels, data protocol, datetime protocol and finger
* protocol channels also should not be cached. Http and ftp on the other
* hand should. Note that the value of this attribute doesn't reflect any
* http headers that may specify that this channel should not be cached.
*/
readonly attribute boolean shouldCache;
/**
* Setting pipeliningAllowed causes the load of a URL (issued via asyncOpen,
* asyncRead or asyncWrite) to be deferred in order to allow the request to
* be pipelined for greater throughput efficiency. Pipelined requests will
* be forced to load when the first non-pipelined request is issued.
*/
attribute boolean pipeliningAllowed;
////////////////////////////////////////////////////////////////////////////
// Load attribute flags. These may be or'd together.
////////////////////////////////////////////////////////////////////////////
/**
* Note that more will follow for each protocol's implementation of a channel,
* although channel writers have to be careful to not let the flag bits
* overlap. Otherwise, users won't be able to create a single flag word
* of load attributes that applies to a number of different channel types.
*/
/**
* No special load attributes -- use defaults:
*/
const unsigned long LOAD_NORMAL = 0;
/**
* Don't deliver status notifications to the nsIProgressEventSink, or keep
* this load from completing the nsILoadGroup it may belong to:
*/
const unsigned long LOAD_BACKGROUND = 1 << 0;
const unsigned long LOAD_DOCUMENT_URI = 1 << 1;
/**
* 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 << 2;
////////////////////////////////////////////////////////////////////////////
/**
* The following flags control caching behavior. Not all protocols pay
* attention to all these flags, but they are applicable to more than one
* protocol, so they are defined here.
*/
/**
* Don't store data in the disk cache. This can be used to preserve
* privacy, e.g. so that no https transactions are recorded, or to avoid
* caching a stream to disk that is already stored in a local file,
* e.g. the mailbox: protocol.
*/
const unsigned long INHIBIT_PERSISTENT_CACHING = 1 << 8;
/**
* Force an end-to-end download of content data from the origin server (and
* any intervening proxies that sit between it and the client), e.g. this
* flag is used for a shift-reload.
*/
const unsigned long FORCE_RELOAD = 1 << 9;
/**
* Force revalidation with server (or proxy) to verify that cached content
* is up-to-date, e.g. by comparing last-modified date on server with that
* of the cached version. For example, this flag is used when the reload
* button is pressed.
*/
const unsigned long FORCE_VALIDATION = 1 << 10;
/**
* If the CACHE_AS_FILE flag is set, any stream content is stored in the
* cache as a single disk file. Content will not be cached in the memory
* cache nor will it be stored in any other type of cache, e.g. a flat-file
* cache database. This is used to implement the jar protocol handler and
* to provide the stream-as-file semantics required by the classic browser
* plugin API.
*/
const unsigned long CACHE_AS_FILE = 1 << 11;
/**
* When cache data is potentially out of date, it can be revalidated with
* the origin server to see if the content needs to be reloaded. The
* following four flags control how often this validation occurs.
* These flags are commonly used for "normal" loading. Note that
* the VALIDATE_HEURISTICALLY and VALIDATE_ONCE_PER_SESSION flags can be
* combined to validate heuristically but no more than once per session.
*/
const unsigned long VALIDATE_NEVER = 1 << 12;
const unsigned long VALIDATE_ALWAYS = 1 << 13;
const unsigned long VALIDATE_ONCE_PER_SESSION = 1 << 14;
const unsigned long VALIDATE_HEURISTICALLY = 1 << 15;
////////////////////////////////////////////////////////////////////////////
// nsIChannel operations
////////////////////////////////////////////////////////////////////////////
/**
* Opens a blocking input stream to the URL's specified source.
* @param startPosition - The offset from the start of the data
* from which to read.
* @param readCount - The number of bytes to read. If -1, everything
* up to the end of the data is read. If greater than the end of
* the data, the amount available is returned in the stream.
*/
nsIInputStream openInputStream();
/**
* Opens a blocking output stream to the URL's specified destination.
* @param startPosition - The offset from the start of the data
* from which to begin writing.
*/
nsIOutputStream openOutputStream();
/**
* Opens the channel asynchronously. The nsIStreamObserver's OnStartRequest
* method is called back when the channel actually becomes open, providing
* the content type. Its OnStopRequest method is called when the channel
* becomes closed.
*/
void asyncOpen(in nsIStreamObserver observer,
in nsISupports ctxt);
/**
* Reads asynchronously from the URL's specified source. Notifications
* are provided to the stream listener on the thread of the specified
* event queue.
* The startPosition argument designates the offset in the source where
* the data will be read.
* If the readCount == -1 then all the available data is delivered to
* the stream listener.
*/
void asyncRead(in nsIStreamListener listener,
in nsISupports ctxt);
/**
* Writes asynchronously to the URL's specified destination. Notifications
* are provided to the stream observer on the thread of the specified
* event queue.
* The startPosition argument designates the offset in the destination where
* the data will be written.
* If the writeCount == -1, then all the available data in the input
* stream is written.
*/
void asyncWrite(in nsIInputStream fromStream,
in nsIStreamObserver observer,
in nsISupports ctxt);
};
////////////////////////////////////////////////////////////////////////////////
/**
* nsIInputStreamChannel is an interface that allows for the initialization
* of a simple nsIChannel that is constructed from a single input stream and
* associated content type. Input stream channels only allow the input stream
* to be accessed, not the output stream.
*/
[scriptable, uuid(43070d6a-f947-11d3-8cda-0060b0fc14a3)]
interface nsIInputStreamChannel : nsIChannel
{
void init(in nsIURI uri,
in nsIInputStream inStr,
in string contentType,
in long contentLength);
};
%{C++
#define NS_INPUTSTREAMCHANNEL_CID \
{ /* 54d0d8e6-f947-11d3-8cda-0060b0fc14a3 */ \
0x54d0d8e6, \
0xf947, \
0x11d3, \
{0x8c, 0xda, 0x00, 0x60, 0xb0, 0xfc, 0x14, 0xa3} \
}
%}
////////////////////////////////////////////////////////////////////////////////
/**
* nsIFileChannel is an interface that allows for the initialization
* of a simple nsIChannel that is constructed from a single nsIFile and
* associated content type.
*/
[scriptable, uuid(68a26506-f947-11d3-8cda-0060b0fc14a3)]
interface nsIFileChannel : nsIChannel
{
void init(in nsIFile file,
in long ioFlags,
in long perm);
readonly attribute nsIFile file;
attribute long ioFlags;
attribute long permissions;
};
%{C++
#define NS_LOCALFILECHANNEL_CLASSNAME "Local File Channel"
#define NS_LOCALFILECHANNEL_PROGID "component://netscape/network/local-file-channel"
#define NS_LOCALFILECHANNEL_CID \
{ /* 6d5b2d44-f947-11d3-8cda-0060b0fc14a3 */ \
0x6d5b2d44, \
0xf947, \
0x11d3, \
{0x8c, 0xda, 0x00, 0x60, 0xb0, 0xfc, 0x14, 0xa3} \
}
%}
////////////////////////////////////////////////////////////////////////////////