phoenix-firestorm/indra/llcorehttp/httprequest.h

366 lines
11 KiB
C++

/**
* @file httprequest.h
* @brief Public-facing declarations for HttpRequest class
*
* $LicenseInfo:firstyear=2012&license=viewerlgpl$
* Second Life Viewer Source Code
* Copyright (C) 2012, Linden Research, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License only.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
* Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA
* $/LicenseInfo$
*/
#ifndef _LLCORE_HTTP_REQUEST_H_
#define _LLCORE_HTTP_REQUEST_H_
#include "httpcommon.h"
#include "httphandler.h"
namespace LLCore
{
class HttpRequestQueue;
class HttpReplyQueue;
class HttpService;
class HttpOptions;
class HttpHeaders;
class HttpOperation;
class BufferArray;
/// HttpRequest supplies the entry into the HTTP transport
/// services in the LLCore libraries. Services provided include:
///
/// - Some, but not all, global initialization of libcurl.
/// - Starting asynchronous, threaded HTTP requests.
/// - Definition of policy classes affect request handling.
/// - Utilities to control request options and headers
///
/// Requests
///
/// The class supports the current HTTP request operations:
///
/// - requestGetByteRange: GET with Range header for a single range of bytes
///
/// Policy Classes
///
/// <TBD>
///
/// Usage
///
/// <TBD>
///
/// Threading: An instance may only be used by one application/
/// consumer thread. But a thread may have as many instances of
/// this as it likes.
///
/// Allocation: Not refcounted, may be stack allocated though that
/// hasn't been tested. Queued requests can still run and any
/// queued replies will keep refcounts to the reply queue leading
/// to memory leaks.
///
/// @pre Before using this class (static or instances), some global
/// initialization is required. See @see httpcommon.h for more information.
///
/// @nosubgrouping
///
class HttpRequest
{
public:
HttpRequest();
virtual ~HttpRequest();
private:
HttpRequest(const HttpRequest &); // Disallowed
void operator=(const HttpRequest &); // Disallowed
public:
typedef unsigned int policy_t;
typedef unsigned int priority_t;
public:
/// @name PolicyMethods
/// @{
/// Represents a default, catch-all policy class that guarantees
/// eventual service for any HTTP request.
static const int DEFAULT_POLICY_ID = 0;
/// Maximum number of policies that may be defined. No policy
/// ID will equal or exceed this value.
static const int POLICY_CLASS_LIMIT = 1;
enum EGlobalPolicy
{
/// Maximum number of connections the library will use to
/// perform operations. This is somewhat soft as the underlying
/// transport will cache some connections (up to 5).
GLOBAL_CONNECTION_LIMIT
};
/// Set a parameter on a global policy option. Calls
/// made after the start of the servicing thread are
/// not honored and return an error status.
///
/// @param opt Enum of option to be set.
/// @param value Desired value of option.
/// @return Standard status code.
HttpStatus setPolicyGlobalOption(EGlobalPolicy opt, long value);
/// Create a new policy class into which requests can be made.
///
/// @return If positive, the policy_id used to reference
/// the class in other methods. If -1, an error
/// occurred and @see getStatus() may provide more
/// detail on the reason.
policy_t createPolicyClass();
enum EClassPolicy
{
/// Limits the number of connections used for the class.
CLASS_CONNECTION_LIMIT,
/// Limits the number of connections used for a single
/// literal address/port pair within the class.
PER_HOST_CONNECTION_LIMIT,
/// Suitable requests are allowed to pipeline on their
/// connections when they ask for it.
ENABLE_PIPELINING
};
/// Set a parameter on a class-based policy option. Calls
/// made after the start of the servicing thread are
/// not honored and return an error status.
///
/// @param policy_id ID of class as returned by @see createPolicyClass().
/// @param opt Enum of option to be set.
/// @param value Desired value of option.
/// @return Standard status code.
HttpStatus setPolicyClassOption(policy_t policy_id,
EClassPolicy opt,
long value);
/// @}
/// @name RequestMethods
///
/// @{
/// Some calls expect to succeed as the normal part of operation and so
/// return a useful value rather than a status. When they do fail, the
/// status is saved and can be fetched with this method.
///
/// @return Status of the failing method invocation. If the
/// preceding call succeeded or other HttpStatus
/// returning calls immediately preceded this method,
/// the returned value may not be reliable.
///
HttpStatus getStatus() const;
/// Queue a full HTTP GET request to be issued with a 'Range' header.
/// The request is queued and serviced by the working thread and
/// notification of completion delivered to the optional HttpHandler
/// argument during @see update() calls.
///
/// With a valid handle returned, it can be used to reference the
/// request in other requests (like cancellation) and will be an
/// argument when any HttpHandler object is invoked.
///
/// @param policy_id Default or user-defined policy class under
/// which this request is to be serviced.
/// @param priority Standard priority scheme inherited from
/// Indra code base (U32-type scheme).
/// @param url
/// @param offset
/// @param len
/// @param options (optional)
/// @param headers (optional)
/// @param handler (optional)
/// @return The handle of the request if successfully
/// queued or LLCORE_HTTP_HANDLE_INVALID if the
/// request could not be queued. In the latter
/// case, @see getStatus() will return more info.
///
HttpHandle requestGetByteRange(policy_t policy_id,
priority_t priority,
const std::string & url,
size_t offset,
size_t len,
HttpOptions * options,
HttpHeaders * headers,
HttpHandler * handler);
///
/// @param policy_id Default or user-defined policy class under
/// which this request is to be serviced.
/// @param priority Standard priority scheme inherited from
/// Indra code base.
/// @param url
/// @param body Byte stream to be sent as the body. No
/// further encoding or escaping will be done
/// to the content.
/// @param options (optional)
/// @param headers (optional)
/// @param handler (optional)
/// @return The handle of the request if successfully
/// queued or LLCORE_HTTP_HANDLE_INVALID if the
/// request could not be queued. In the latter
/// case, @see getStatus() will return more info.
///
HttpHandle requestPost(policy_t policy_id,
priority_t priority,
const std::string & url,
BufferArray * body,
HttpOptions * options,
HttpHeaders * headers,
HttpHandler * handler);
/// Queue a NoOp request.
/// The request is queued and serviced by the working thread which
/// immediately processes it and returns the request to the reply
/// queue.
///
/// @param handler (optional)
/// @return The handle of the request if successfully
/// queued or LLCORE_HTTP_HANDLE_INVALID if the
/// request could not be queued. In the latter
/// case, @see getStatus() will return more info.
///
HttpHandle requestNoOp(HttpHandler * handler);
/// While all the heavy work is done by the worker thread, notifications
/// must be performed in the context of the application thread. These
/// are done synchronously during calls to this method which gives the
/// library control so notification can be performed. Application handlers
/// are expected to return 'quickly' and do any significant processing
/// outside of the notification callback to onCompleted().
///
/// @param millis Maximum number of wallclock milliseconds to
/// spend in the call. As hinted at above, this
/// is partly a function of application code so it's
/// a soft limit. (And not currently implemented.)
///
/// @return Standard status code.
HttpStatus update(long millis);
/// @}
/// @name RequestMgmtMethods
///
/// @{
HttpHandle requestCancel(HttpHandle request, HttpHandler *);
/// Request that a previously-issued request be reprioritized.
/// The status of whether the change itself succeeded arrives
/// via notification.
///
/// @param request Handle of previously-issued request to
/// be changed.
/// @param priority New priority value.
/// @param handler (optional)
/// @return The handle of the request if successfully
/// queued or LLCORE_HTTP_HANDLE_INVALID if the
/// request could not be queued.
///
HttpHandle requestSetPriority(HttpHandle request, priority_t priority, HttpHandler * handler);
/// @}
/// @name UtilityMethods
///
/// @{
/// Initialization method that needs to be called before queueing any
/// requests. Doesn't start the worker thread and may be called befoer
/// or after policy setup.
static HttpStatus createService();
/// Mostly clean shutdown of services prior to exit. Caller is expected
/// to have stopped a running worker thread before calling this.
static HttpStatus destroyService();
/// Called once after @see createService() to start the worker thread.
/// Stopping the thread is achieved by requesting it via @see requestStopThread().
/// May be called before or after requests are issued.
static HttpStatus startThread();
/// Queues a request to the worker thread to have it stop processing
/// and exit (without exiting the program). When the operation is
/// picked up by the worker thread, it immediately processes it and
/// begins detaching from refcounted resources like request and
/// reply queues and then returns to the host OS. It *does* queue a
/// reply to give the calling application thread a notification that
/// the operation has been performed.
///
/// @param handler (optional)
/// @return The handle of the request if successfully
/// queued or LLCORE_HTTP_HANDLE_INVALID if the
/// request could not be queued. In the latter
/// case, @see getStatus() will return more info.
/// As the request cannot be cancelled, the handle
/// is generally not useful.
///
HttpHandle requestStopThread(HttpHandler * handler);
/// @}
protected:
void generateNotification(HttpOperation * op);
class InternalHandler;
friend class InternalHandler;
private:
/// @name InstanceData
///
/// @{
HttpStatus mLastReqStatus;
HttpReplyQueue * mReplyQueue;
HttpRequestQueue * mRequestQueue;
InternalHandler * mSelfHandler;
/// @}
// ====================================
/// @name GlobalState
///
/// @{
///
/// Must be established before any threading is allowed to
/// start.
///
static policy_t sNextPolicyID;
/// @}
// End Global State
// ====================================
}; // end class HttpRequest
} // end namespace LLCore
#endif // _LLCORE_HTTP_REQUEST_H_