BazisLib::Network::Filters::BasicHTTPFilter Class Reference

Provides functionality for filtering HTTP connections. More...

#include <filter.h>

Inherits BazisLib::Win32::NetworkFilterBase.

Collaboration diagram for BazisLib::Network::Filters::BasicHTTPFilter:

[legend]

List of all members.

Classes
class	ConnectionContext
	Used internally to maintain connection context. More...
Public Member Functions
	BasicHTTPFilter ()
Protected Types
enum	Operation { DoNotFilterFile, GetHeaderAndFilter, SkipRequestAndFilter }
enum	{ TrackHeadRequests = 0x02 }
enum	{ MaximumFirstLineLength = 1024, MaximumHeaderSize = 131072 }
Protected Member Functions
std::string	ExtractURLFromRequest (const std::string &HTTPRequestHeader)
	Extracts URL from a HTTP request body.
virtual Operation	OnFileRequested (std::string &HTTPRequest, void *pSystemContext)
	Called when a HTTP request is issued.
virtual ManagedPointer< AIFile >	GetReplacementForFile (const std::string &HTTPRequest, const char *pHTTPReply, void *pSystemContext)
	Called to get a managed file to replace the original HTTP reply.
Protected Attributes
unsigned	m_ModeFlags
Private Member Functions
virtual BazisLib::ActionStatus	OnStartConnect (BazisLib::Network::_PlatformSpecificInternetAddress *pAddr, void **ppUserContext) override
virtual void	OnDisconnect (void *pSystemContext, void *pUserContext) override
virtual size_t	OnSend (void *pSystemContext, void *pSystemContext2, void *pBuf, size_t MaxSize, void *pUserContext, bool ForceBlockingMode) override
virtual size_t	OnReceive (void *pSystemContext, void *pSystemContext2, void *pBuf, size_t MaxSize, void *pUserContext, bool ForceBlockingMode) override
virtual void	FreeUserContext (void *pContext) override

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Detailed Description

Provides functionality for filtering HTTP connections.

This class performs analyzis of intercepted network connections, extracts HTTP sessions and parses them in order to extract request headers and reply headers. Basically, it allows doing the following:

• Monitoring all HTTP requests issued by an application in a convenient way
• Monitoring all HTTP replies returned by servers
• Replacing content returned by a HTTP client with filter-generated one

One of the applications for such a filter is a download catcher for a download manager. Such a catcher monitors all HTTP connections of a web browser and when it notices a big file being returned by the server, it sends the URL (and the header) to the download manager, and replaces server reply with a message that the file was successfully queued for downloading.

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Member Enumeration Documentation

anonymous enum [protected]

Enumerator:

TrackHeadRequests

anonymous enum [protected]

Enumerator:

MaximumFirstLineLength
MaximumHeaderSize

enum BazisLib::Network::Filters::BasicHTTPFilter::Operation [protected]

Enumerator:

DoNotFilterFile
GetHeaderAndFilter
SkipRequestAndFilter

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Constructor & Destructor Documentation

BazisLib::Network::Filters::BasicHTTPFilter::BasicHTTPFilter

(

)

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Member Function Documentation

std::string BazisLib::Network::Filters::BasicHTTPFilter::ExtractURLFromRequest

(

const std::string &

HTTPRequestHeader

)

[inline, protected]

Extracts URL from a HTTP request body.

Here is the call graph for this function:

virtual void BazisLib::Network::Filters::BasicHTTPFilter::FreeUserContext

(

void *

pContext

)

[override, private, virtual]

Reimplemented from BazisLib::Win32::NetworkFilterBase.

virtual ManagedPointer<AIFile> BazisLib::Network::Filters::BasicHTTPFilter::GetReplacementForFile	(	const std::string &	HTTPRequest,
		const char *	pHTTPReply,
		void *	pSystemContext
	)			[inline, protected, virtual]

Called to get a managed file to replace the original HTTP reply.

This method is called after OnFileRequested() call either immediately, or when a HTTP reply is fetched. If the call was immediate (OnFileRequested() returned SkipRequestAndFilter), the pHTTPReply parameter will be NULL, as no reply header is available in that case.

Parameters:

	HTTPRequest	Contains a HTTP request header (and body, if exists).
	pHTTPReply	Contains HTTP reply header (and no body). This parameter can be NULL, if SkipRequestAndFilter was returned by OnFileRequested(). Otherwise, it points to a NULL-terminated ASCII string containing the header.

virtual void BazisLib::Network::Filters::BasicHTTPFilter::OnDisconnect	(	void *	pSystemContext,
		void *	pUserContext
	)			[override, private, virtual]

Reimplemented from BazisLib::Win32::NetworkFilterBase.

virtual Operation BazisLib::Network::Filters::BasicHTTPFilter::OnFileRequested	(	std::string &	HTTPRequest,
		void *	pSystemContext
	)			[inline, protected, virtual]

Called when a HTTP request is issued.

This method is called by the filter when a HTTP request was detected. Child class can override it.

Parameters:

	HTTPRequest	Contains HTTP request (header + body, if one exists). Note that in current version modifying HTTPRequest from this method gives no effect, as the header was already sent to the server. In future versions this behaviour may change.
	pSystemContext	Contains system context that can be used to call OnSend()/OnReceive()/etc Note that in this version calling one of this functions from this handler can make the filter to become unstable if the hooked application uses asynchronous/non-blocking API.

Returns:

If the child class decides not to replace the file by its own content, it returns the DoNotFilterFile value. If it requires reply header to make the final decision, it should return GetHeaderAndFilter. If if is ready to replace the file now, it returns SkipRequestAndFilter. In the last case, the GetReplacementForFile() method will be called immediately after.

virtual size_t BazisLib::Network::Filters::BasicHTTPFilter::OnReceive	(	void *	pSystemContext,
		void *	pSystemContext2,
		void *	pBuf,
		size_t	MaxSize,
		void *	pUserContext,
		bool	ForceBlockingMode
	)			[override, private, virtual]

Reimplemented from BazisLib::Win32::NetworkFilterBase.

virtual size_t BazisLib::Network::Filters::BasicHTTPFilter::OnSend	(	void *	pSystemContext,
		void *	pSystemContext2,
		void *	pBuf,
		size_t	MaxSize,
		void *	pUserContext,
		bool	ForceBlockingMode
	)			[override, private, virtual]

Reimplemented from BazisLib::Win32::NetworkFilterBase.

virtual BazisLib::ActionStatus BazisLib::Network::Filters::BasicHTTPFilter::OnStartConnect	(	BazisLib::Network::_PlatformSpecificInternetAddress *	pAddr,
		void **	ppUserContext
	)			[override, private, virtual]

Reimplemented from BazisLib::Win32::NetworkFilterBase.

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Member Data Documentation

unsigned BazisLib::Network::Filters::BasicHTTPFilter::m_ModeFlags [protected]

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The documentation for this class was generated from the following file:

• bzsnet/filter.h