TROTransportChannel

Overview

TROTransportChannel is the common base class for all client channel implementations in Remoting SDK.

You will not use instances of this class directly, but work with the descendant channel implementations.

Location

Implements

 

constructor Create  override

Creates a new instance.

constructor Create(aOwner: TComponent)

Parameters:

  • aOwner: Owner.

Assign  override

Copies the contents of another, similar object.

procedure Assign(aSource: TPersistent)

Parameters:

  • aSource: Instance whose properties will be copied

AssignEvents  protected virtual

Copies the events of another, similar object.

procedure AssignEvents(aSource: TROTransportChannel)

Parameters:

  • aSource:

AssignSpecificProperties  protected virtual

Copies the specific properties of another, similar object.

procedure AssignSpecificProperties(aSource: TROTransportChannel)

Parameters:

  • aSource:

AsyncException  protected virtual

Notifies about an exception in an asynchronous mode.

procedure AsyncException(aAsyncInterface: IROAsyncInterface; AsyncException: Exception)

Parameters:

  • aAsyncInterface: Exception source
  • AsyncException: Exception data

BeforeDispatch  protected virtual

Allows an implimentation to do necessary preparatory actions (checking the readiness of the channel, restore session data, etc.).

procedure BeforeDispatch(aMessage: IROMessage)

Parameters:


Busy

Informs whether the channel is currently busy executing a remote request (true) or not (false). Most channels (except most notably the TROSuperTCPChannel) are only capable of performing one request at a time; if a second request is attempted while the channel is Busy, an EROChannelBusy exception will be raised.

property Busy: boolean read write

ChangeServerLocator  protected virtual

procedure ChangeServerLocator(var faultstartlocatoridx: integer; var aRetry: Boolean; const aException: Exception)

Parameters:

  • faultstartlocatoridx:
  • aRetry:
  • aException:

ChannelMatchingTargetUri

Creates a client channel instance with type, target host and target port matching the provided target Uri. F.e. for provided uri supertcp://192.168.1.100:7020/bin this method will return an instance of the Super Tcp channel with target host set to 192.168.1.100 and port set to 7020.

class function ChannelMatchingTargetUri(const aUri: TROUri): TROTransportChannel

Parameters:

  • aUri: Server Uri

ChannelMatchingTargetUrl

class function ChannelMatchingTargetUrl(const aUrl: string): TROTransportChannel

Parameters:

  • aUrl:

CheckProperties  virtual

Validates channel properties

procedure CheckProperties

CurrentLocator

Returns which of the fail-over/load balancing servers configured in the ServerLocators is currently active. Depending on the DispatchOptions defined, this value might change with each request, or only if the current server fails.

property CurrentLocator: TROServerLocator read write

DecryptStream (TStream)  protected overload    (declared in TROBaseConnection)

procedure DecryptStream(const iStream: TStream)

Parameters:

  • iStream:

DecryptStream (TStream, TStream)  protected overload    (declared in TROBaseConnection)

procedure DecryptStream(const aSource: TStream; const aDest: TStream)

Parameters:

  • aSource:
  • aDest:

Dispatch (IROMessage)  protected reintroduce overload

Sends a request message through the Self channel for processing and gets back an aMessage. CodeGen uses this method when generating a [proxy](/Understanding_the_Client_Side_(.NET_and_Delphi)#How does it work?) from RODL Files.

procedure Dispatch(aMessage: IROMessage)

Parameters:

  • aMessage: (In/out) message data

DispatchOptions

Configures the available fail-over and load balancing options provided by the Remoting SDK. By default, channels are set up to talk to one specific server only. Two independent options are available to provide fail-over and load balancing: * Enables fail-over support. If the connection to any given server fails, the channel will automatically keep trying the next server specified in ServerLocators, until a working server is found or all servers have been tried. * Enables load-balancing support. Each request dispatched through the channel will go to a different server configured in ServerLocators, resulting in calls being more or less equally distributed over the available servers. Enabling any of these options obviously requires the server to be implemented in a stateless way, so that it does not depend on all requests from a client going to the same server. This implies using a class factory different from Per-Client and, if sessions are used, a session manager that allows sharing of session state between servers.

property DispatchOptions: TRODispatchOptions read write

DoAfterProbingServerEvent  protected virtual

Fires OnAfterProbingServer event

procedure DoAfterProbingServerEvent(const aServerLocator: TROServerLocator; const Failed: Boolean)

Parameters:

  • aServerLocator: Server locator
  • Failed:

DoAfterProbingServersEvent  protected virtual

Fires OnAfterProbingServers event

procedure DoAfterProbingServersEvent(const ProbedCount: integer; const EnabledCount: integer; const DisabledCount: integer)

Parameters:

  • ProbedCount:
  • EnabledCount:
  • DisabledCount:

DoBeforeDecryptEvent  protected virtual    (declared in TROBaseConnection) obsolete

procedure DoBeforeDecryptEvent(aEncryptedStream: TStream)

Parameters:

  • aEncryptedStream:

DoBeforeProbingServerEvent  protected virtual

Fires OnBeforeProbingServer event

procedure DoBeforeProbingServerEvent(const aServerLocator: TROServerLocator)

Parameters:

  • aServerLocator: Server locator

DoBeforeProbingServersEvent  protected virtual

Fires OnBeforeProbingServers event

procedure DoBeforeProbingServersEvent

DoDecryption  virtual    (declared in TROBaseConnection) obsolete

procedure DoDecryption(iCipherText: TStream; iPlainText: TStream)

Parameters:

  • iCipherText:
  • iPlainText:

DoEncryption  virtual    (declared in TROBaseConnection) obsolete

procedure DoEncryption(iPlainText: TStream; iCipherText: TStream)

Parameters:

  • iPlainText:
  • iCipherText:

DoException  protected virtual

Fires OnException event

procedure DoException(anException: Exception; var aRetry: Boolean)

Parameters:

  • anException:
  • aRetry:

DoReceiveStreamEvent  protected virtual

Fires OnReceiveStream event

procedure DoReceiveStreamEvent(const aStream: TStream)

Parameters:

  • aStream: Stream

DoSendStreamEvent  protected virtual

Fires OnSendStream event

procedure DoSendStreamEvent(const aStream: TStream)

Parameters:

  • aStream: Stream

DoServerLocatorAssignmentEvent  protected virtual

Fires OnServerLocatorAssignment event

procedure DoServerLocatorAssignmentEvent(const aLocator: TROServerLocator; const aException: Exception)

Parameters:

  • aLocator:
  • aException:

Encryption    (declared in TROBaseConnection) obsolete

This is DES based enscryption, it is obsolete because works only for Delphi. Use message envelope AES Encryption Envelope instead.

property Encryption: TROEncryption read write

EncryptStream (TStream)  protected overload    (declared in TROBaseConnection)

Encrypts given stream

procedure EncryptStream(const iStream: TStream)

Parameters:

  • iStream: Source and Destination

EncryptStream (TStream, TStream)  protected overload    (declared in TROBaseConnection)

Encrypts given stream

procedure EncryptStream(const aSource: TStream; const aDest: TStream)

Parameters:

  • aSource: Source
  • aDest: Destination

FaultToleranceLocatorIdx

property FaultToleranceLocatorIdx: integer read write

GetTransportObject  protected virtual abstract

Returns itself.

function GetTransportObject: TObject

InitServerLocator  protected virtual

Sets CurrentLocator

function InitServerLocator: Integer

IsEncryptionUsed  protected    (declared in TROBaseConnection)

function IsEncryptionUsed: Boolean

isProbeMode  protected

Returns True if channel is used for probing purposes

property isProbeMode: Boolean read write

isStreamEncrypted  protected    (declared in TROBaseConnection)

Checks state of stream

function isStreamEncrypted(aStream: TStream): Boolean

Parameters:

  • aStream: Stream

LaunchAsyncTask  protected

procedure LaunchAsyncTask(aRequest: IROAsyncRequest)

Parameters:

  • aRequest:

LoadBalancerLocatorIdx

property LoadBalancerLocatorIdx: Integer read write

OnAfterEncrypt    (declared in TROBaseConnection)

property OnAfterEncrypt: TROBaseConnectionOperation read write
delegate: procedure OnAfterEncrypt(Sender: TROBaseConnection; aEncryptedStream: TStream)

OnAfterProbingServer

Fires after the channel is done probing a specific server for availability. You can use this event to check the result of the probing, possibly to update internal data structures or to display server status in the user interface.

property OnAfterProbingServer: TROEndProbeServerEvent read write
delegate: procedure OnAfterProbingServer(Sender: TROTransportChannel; aServerLocator: TROServerLocator; Failed: boolean)

OnAfterProbingServers

Fires after the channel is done probing all servers for availability. You can use this event to check the result of the probing, possibly to update internal data structures or to display server status in the user interface.

property OnAfterProbingServers: TROEndProbeServersEvent read write
delegate: procedure OnAfterProbingServers(Sender: TROTransportChannel; ProbedCount: integer; EnabledCount: integer; DisabledCount: integer)

OnAsyncException

Fires when exception is raised in asynchronous mode

property OnAsyncException: TROAsyncExceptionEvent read write
delegate: procedure OnAsyncException(Sender: TROTransportChannel; Async: IROAsyncInterface; anException: Exception)

OnBeforeDecrypt    (declared in TROBaseConnection)

property OnBeforeDecrypt: TROBaseConnectionOperation read write
delegate: procedure OnBeforeDecrypt(Sender: TROBaseConnection; aEncryptedStream: TStream)

OnBeforeProbingServer

Fires before the channel starts probing a specific server for availability. You can use this event to: * check or adjust the server configuration * to include/exclude the server from being probed by changing the TROServerLocator property.

property OnBeforeProbingServer: TROBeginProbeServerEvent read write
delegate: procedure OnBeforeProbingServer(Sender: TROTransportChannel; aServerLocator: TROServerLocator)

OnBeforeProbingServers

Fires before the channel starts probing all servers for availability. You can use this event: * to check or adjust the server configurations * to include/exclude individual server from being probed by changing their TROServerLocator properties.

property OnBeforeProbingServers: TROBeginProbeServersEvent read write
delegate: procedure OnBeforeProbingServers(Sender: TROTransportChannel)

OnException

Fires if an exception is raised during the execution of a remote request. This could be an exception returned from the server, a communication problem or an error within the client. Depending on the type of error, your event handler can try to rectify the problem, and set aRetry to true to have the channel try and perform the request again. For example, an application could show a dialog asking the user to confirm if his internet connection is available, with Cancel and Retry buttons.
If aRetry is set to true and the call succeeds at the second attempt, the call will return to the original code that initiated the request, as if the exception never happened.

property OnException: TROExceptionEvent read write
delegate: procedure OnException(Sender: TROTransportChannel; anException: Exception; var aRetry: Boolean)

OnLoginNeeded

Fires if an EROSessionNotFound (or the descendant SessionNotFoundException) exception is raised during the execution of a remote request. This usually indicates that the server cannot authenticate the client or that the session has expired. The most common use for this event is to perform a call to a special Login service provided by the server (possibly after prompting the user to enter username and password), and to set the aRetry parameter to true if login was successful.

property OnLoginNeeded: TROExceptionEvent read write
delegate: procedure OnLoginNeeded(Sender: TROTransportChannel; anException: Exception; var aRetry: Boolean)

OnProgress

This event fires as the channel is transferring data for a request or response to or from the server, informing of the current progress. It can be used to keep the user interface updated during lengthy transfers,e.g. by showing a progress bar or the remaining transfer volume. Note: the accuracy and frequency of calls to OnProgress depends on the channel type; since channels transport data packets in different sized chunks (or even all-at-once), OnProgress might show a very fine progress for some channels, while jumping from 0 to 100% in one step with others.

property OnProgress: TProgressEvent read write
delegate: procedure OnProgress(iSender: TObject; iType: TProgressType; iDirection: TProgressDirection; iTransferred: integer; iTotal: integer)

OnReceiveStream

Fires after a stream with a response message has been received from the server. Use this event handler to inspect and possibly modify the stream, before it continues to be processed by the higher levels of the Remoting SDK framework.

property OnReceiveStream: TStreamDispatch read write
delegate: procedure OnReceiveStream(aStream: TStream)

OnSendStream

Fires just as a stream with a request message will be sent to the server. The event handler can inspect and possibly modify the stream, before it continues to be sent off to the server.

property OnSendStream: TStreamDispatch read write
delegate: procedure OnSendStream(aStream: TStream)

OnServerLocatorAssignment

Fires before changing of a server locator.

property OnServerLocatorAssignment: TServerLocatorAssignment read write
delegate: procedure OnServerLocatorAssignment(Sender: TROTransportChannel; aLocator: TROServerLocator; aException: Exception)

Probe  protected

Checks the accessibility of servers from the ServerLocators. This method is intended to provide fail-over and load balancing support in the Remoting SDK Architecture.

function Probe(aServerLocator: TROServerLocator): boolean

Parameters:

  • aServerLocator: Server locator

ProbeAll  protected

Checks the availability of all known servers.

procedure ProbeAll

ProbeFrequency

Sets at what intervals, in milliseconds, the channel will probe the servers configured in ServerLocators for availability. The default value is 60,000 (60 seconds). See the ProbeServers property for a more detailed description. Although somewhat misnamed, this property defines the Interval between probes, not the actual probing Frequency. The property name is persisted for backward compatibility.

property ProbeFrequency: cardinal read write

ProbeServers

Toggles whether the channel will continuously probe the servers configured in ServerLocators for availability. If enabled (true), the channel will ping all servers at a regular interval to determine if they are reachable. If a server fails to respond, it will be disabled for future calls until a later probe can reach it again. The interval between probes can be configured using the ProbeFrequency property. By default, server probing is turned off.

property ProbeServers: boolean read write

ResetProbingClone  protected virtual

Resets channel that is used for probing

procedure ResetProbingClone(aProbe: TROTransportChannel)

Parameters:

  • aProbe: Probing clone

RetrieveMetadata  protected virtual

Retrieves metadata from server

procedure RetrieveMetadata(out Metadata: TStream)

Parameters:

  • Metadata: Destination stream

RetrieveRODL  protected

This method is used for to obtaining the RODL library from the server without havin to rely on a channel-specific mechanism (such as a HTTP request to http://servername:port/rodl).

procedure RetrieveRODL(out RODLLibrary: TRODLLibrary)

Parameters:

  • RODLLibrary: Result

ROFreeNotification    (declared in TROComponent)

Forwards notification messages to all owned RO components.

procedure ROFreeNotification(AComponent: TComponent)

Parameters:

  • AComponent: component

RORemoveFreeNotification    (declared in TROComponent)

Disables destruction notification for specified RO component.

procedure RORemoveFreeNotification(AComponent: TComponent)

Parameters:

  • AComponent: component

ServerLocators

Optionally, this collection property can be filled to contain a list of possible servers to be used for fail-over or load balancing purposes. Depending on the settings configured in DispatchOptions, the channel will automatically spread calls over the available servers, or fall back to another server if one fails.

property ServerLocators: TROServerLocatorCollection read write

SetAsyncBusy  protected virtual

procedure SetAsyncBusy(const Value: Boolean)

Parameters:

  • Value:

SetServerLocator  protected

Retrieves the location details of a server from aServerLocator.

procedure SetServerLocator(aServerLocator: TROServerLocator; anException: Exception)

Parameters:

  • aServerLocator: Configuration data of the server
  • anException: Exception

SynchronizedProbing

Determines whether server probing happens in the context of the main VCL thread (true, default) or in a background worker thread. See the ProbeServers property for a more detailed description.

property SynchronizedProbing: Boolean read write

TargetUri

Target URI

property TargetUri: TROUri read write

TargetUrl  protected

The address of the server.

property TargetUrl: string read write

ThreadSafe  protected

property ThreadSafe: Boolean read write

TriggerProgress  protected virtual

Fires OnProgress event

procedure TriggerProgress(iType: TProgressType; iDirection: TProgressDirection; iTransfered: integer; iTotal: integer)

Parameters:

  • iType: progress type
  • iDirection: direction
  • iTransfered: transfered bytes
  • iTotal: total bytes

 

Busy

Informs whether the channel is currently busy executing a remote request (true) or not (false). Most channels (except most notably the TROSuperTCPChannel) are only capable of performing one request at a time; if a second request is attempted while the channel is Busy, an EROChannelBusy exception will be raised.

property Busy: boolean read write

CurrentLocator

Returns which of the fail-over/load balancing servers configured in the ServerLocators is currently active. Depending on the DispatchOptions defined, this value might change with each request, or only if the current server fails.

property CurrentLocator: TROServerLocator read write

DispatchOptions

Configures the available fail-over and load balancing options provided by the Remoting SDK. By default, channels are set up to talk to one specific server only. Two independent options are available to provide fail-over and load balancing: * Enables fail-over support. If the connection to any given server fails, the channel will automatically keep trying the next server specified in ServerLocators, until a working server is found or all servers have been tried. * Enables load-balancing support. Each request dispatched through the channel will go to a different server configured in ServerLocators, resulting in calls being more or less equally distributed over the available servers. Enabling any of these options obviously requires the server to be implemented in a stateless way, so that it does not depend on all requests from a client going to the same server. This implies using a class factory different from Per-Client and, if sessions are used, a session manager that allows sharing of session state between servers.

property DispatchOptions: TRODispatchOptions read write

Encryption    (declared in TROBaseConnection) obsolete

This is DES based enscryption, it is obsolete because works only for Delphi. Use message envelope AES Encryption Envelope instead.

property Encryption: TROEncryption read write

FaultToleranceLocatorIdx

property FaultToleranceLocatorIdx: integer read write

isProbeMode  protected

Returns True if channel is used for probing purposes

property isProbeMode: Boolean read write

LoadBalancerLocatorIdx

property LoadBalancerLocatorIdx: Integer read write

ProbeFrequency

Sets at what intervals, in milliseconds, the channel will probe the servers configured in ServerLocators for availability. The default value is 60,000 (60 seconds). See the ProbeServers property for a more detailed description. Although somewhat misnamed, this property defines the Interval between probes, not the actual probing Frequency. The property name is persisted for backward compatibility.

property ProbeFrequency: cardinal read write

ProbeServers

Toggles whether the channel will continuously probe the servers configured in ServerLocators for availability. If enabled (true), the channel will ping all servers at a regular interval to determine if they are reachable. If a server fails to respond, it will be disabled for future calls until a later probe can reach it again. The interval between probes can be configured using the ProbeFrequency property. By default, server probing is turned off.

property ProbeServers: boolean read write

ServerLocators

Optionally, this collection property can be filled to contain a list of possible servers to be used for fail-over or load balancing purposes. Depending on the settings configured in DispatchOptions, the channel will automatically spread calls over the available servers, or fall back to another server if one fails.

property ServerLocators: TROServerLocatorCollection read write

SynchronizedProbing

Determines whether server probing happens in the context of the main VCL thread (true, default) or in a background worker thread. See the ProbeServers property for a more detailed description.

property SynchronizedProbing: Boolean read write

TargetUri

Target URI

property TargetUri: TROUri read write

TargetUrl  protected

The address of the server.

property TargetUrl: string read write

ThreadSafe  protected

property ThreadSafe: Boolean read write

 

ChannelMatchingTargetUri

Creates a client channel instance with type, target host and target port matching the provided target Uri. F.e. for provided uri supertcp://192.168.1.100:7020/bin this method will return an instance of the Super Tcp channel with target host set to 192.168.1.100 and port set to 7020.

class function ChannelMatchingTargetUri(const aUri: TROUri): TROTransportChannel

Parameters:

  • aUri: Server Uri

ChannelMatchingTargetUrl

class function ChannelMatchingTargetUrl(const aUrl: string): TROTransportChannel

Parameters:

  • aUrl:

 

constructor Create  override

Creates a new instance.

constructor Create(aOwner: TComponent)

Parameters:

  • aOwner: Owner.

Assign  override

Copies the contents of another, similar object.

procedure Assign(aSource: TPersistent)

Parameters:

  • aSource: Instance whose properties will be copied

AssignEvents  protected virtual

Copies the events of another, similar object.

procedure AssignEvents(aSource: TROTransportChannel)

Parameters:

  • aSource:

AssignSpecificProperties  protected virtual

Copies the specific properties of another, similar object.

procedure AssignSpecificProperties(aSource: TROTransportChannel)

Parameters:

  • aSource:

AsyncException  protected virtual

Notifies about an exception in an asynchronous mode.

procedure AsyncException(aAsyncInterface: IROAsyncInterface; AsyncException: Exception)

Parameters:

  • aAsyncInterface: Exception source
  • AsyncException: Exception data

BeforeDispatch  protected virtual

Allows an implimentation to do necessary preparatory actions (checking the readiness of the channel, restore session data, etc.).

procedure BeforeDispatch(aMessage: IROMessage)

Parameters:


ChangeServerLocator  protected virtual

procedure ChangeServerLocator(var faultstartlocatoridx: integer; var aRetry: Boolean; const aException: Exception)

Parameters:

  • faultstartlocatoridx:
  • aRetry:
  • aException:

CheckProperties  virtual

Validates channel properties

procedure CheckProperties

DecryptStream (TStream)  protected overload    (declared in TROBaseConnection)

procedure DecryptStream(const iStream: TStream)

Parameters:

  • iStream:

DecryptStream (TStream, TStream)  protected overload    (declared in TROBaseConnection)

procedure DecryptStream(const aSource: TStream; const aDest: TStream)

Parameters:

  • aSource:
  • aDest:

Dispatch (IROMessage)  protected reintroduce overload

Sends a request message through the Self channel for processing and gets back an aMessage. CodeGen uses this method when generating a [proxy](/Understanding_the_Client_Side_(.NET_and_Delphi)#How does it work?) from RODL Files.

procedure Dispatch(aMessage: IROMessage)

Parameters:

  • aMessage: (In/out) message data

DoAfterProbingServerEvent  protected virtual

Fires OnAfterProbingServer event

procedure DoAfterProbingServerEvent(const aServerLocator: TROServerLocator; const Failed: Boolean)

Parameters:

  • aServerLocator: Server locator
  • Failed:

DoAfterProbingServersEvent  protected virtual

Fires OnAfterProbingServers event

procedure DoAfterProbingServersEvent(const ProbedCount: integer; const EnabledCount: integer; const DisabledCount: integer)

Parameters:

  • ProbedCount:
  • EnabledCount:
  • DisabledCount:

DoBeforeDecryptEvent  protected virtual    (declared in TROBaseConnection) obsolete

procedure DoBeforeDecryptEvent(aEncryptedStream: TStream)

Parameters:

  • aEncryptedStream:

DoBeforeProbingServerEvent  protected virtual

Fires OnBeforeProbingServer event

procedure DoBeforeProbingServerEvent(const aServerLocator: TROServerLocator)

Parameters:

  • aServerLocator: Server locator

DoBeforeProbingServersEvent  protected virtual

Fires OnBeforeProbingServers event

procedure DoBeforeProbingServersEvent

DoDecryption  virtual    (declared in TROBaseConnection) obsolete

procedure DoDecryption(iCipherText: TStream; iPlainText: TStream)

Parameters:

  • iCipherText:
  • iPlainText:

DoEncryption  virtual    (declared in TROBaseConnection) obsolete

procedure DoEncryption(iPlainText: TStream; iCipherText: TStream)

Parameters:

  • iPlainText:
  • iCipherText:

DoException  protected virtual

Fires OnException event

procedure DoException(anException: Exception; var aRetry: Boolean)

Parameters:

  • anException:
  • aRetry:

DoReceiveStreamEvent  protected virtual

Fires OnReceiveStream event

procedure DoReceiveStreamEvent(const aStream: TStream)

Parameters:

  • aStream: Stream

DoSendStreamEvent  protected virtual

Fires OnSendStream event

procedure DoSendStreamEvent(const aStream: TStream)

Parameters:

  • aStream: Stream

DoServerLocatorAssignmentEvent  protected virtual

Fires OnServerLocatorAssignment event

procedure DoServerLocatorAssignmentEvent(const aLocator: TROServerLocator; const aException: Exception)

Parameters:

  • aLocator:
  • aException:

EncryptStream (TStream)  protected overload    (declared in TROBaseConnection)

Encrypts given stream

procedure EncryptStream(const iStream: TStream)

Parameters:

  • iStream: Source and Destination

EncryptStream (TStream, TStream)  protected overload    (declared in TROBaseConnection)

Encrypts given stream

procedure EncryptStream(const aSource: TStream; const aDest: TStream)

Parameters:

  • aSource: Source
  • aDest: Destination

GetTransportObject  protected virtual abstract

Returns itself.

function GetTransportObject: TObject

InitServerLocator  protected virtual

Sets CurrentLocator

function InitServerLocator: Integer

IsEncryptionUsed  protected    (declared in TROBaseConnection)

function IsEncryptionUsed: Boolean

isStreamEncrypted  protected    (declared in TROBaseConnection)

Checks state of stream

function isStreamEncrypted(aStream: TStream): Boolean

Parameters:

  • aStream: Stream

LaunchAsyncTask  protected

procedure LaunchAsyncTask(aRequest: IROAsyncRequest)

Parameters:

  • aRequest:

Probe  protected

Checks the accessibility of servers from the ServerLocators. This method is intended to provide fail-over and load balancing support in the Remoting SDK Architecture.

function Probe(aServerLocator: TROServerLocator): boolean

Parameters:

  • aServerLocator: Server locator

ProbeAll  protected

Checks the availability of all known servers.

procedure ProbeAll

ResetProbingClone  protected virtual

Resets channel that is used for probing

procedure ResetProbingClone(aProbe: TROTransportChannel)

Parameters:

  • aProbe: Probing clone

RetrieveMetadata  protected virtual

Retrieves metadata from server

procedure RetrieveMetadata(out Metadata: TStream)

Parameters:

  • Metadata: Destination stream

RetrieveRODL  protected

This method is used for to obtaining the RODL library from the server without havin to rely on a channel-specific mechanism (such as a HTTP request to http://servername:port/rodl).

procedure RetrieveRODL(out RODLLibrary: TRODLLibrary)

Parameters:

  • RODLLibrary: Result

ROFreeNotification    (declared in TROComponent)

Forwards notification messages to all owned RO components.

procedure ROFreeNotification(AComponent: TComponent)

Parameters:

  • AComponent: component

RORemoveFreeNotification    (declared in TROComponent)

Disables destruction notification for specified RO component.

procedure RORemoveFreeNotification(AComponent: TComponent)

Parameters:

  • AComponent: component

SetAsyncBusy  protected virtual

procedure SetAsyncBusy(const Value: Boolean)

Parameters:

  • Value:

SetServerLocator  protected

Retrieves the location details of a server from aServerLocator.

procedure SetServerLocator(aServerLocator: TROServerLocator; anException: Exception)

Parameters:

  • aServerLocator: Configuration data of the server
  • anException: Exception

TriggerProgress  protected virtual

Fires OnProgress event

procedure TriggerProgress(iType: TProgressType; iDirection: TProgressDirection; iTransfered: integer; iTotal: integer)

Parameters:

  • iType: progress type
  • iDirection: direction
  • iTransfered: transfered bytes
  • iTotal: total bytes

 

OnAfterEncrypt    (declared in TROBaseConnection)

property OnAfterEncrypt: TROBaseConnectionOperation read write
delegate: procedure OnAfterEncrypt(Sender: TROBaseConnection; aEncryptedStream: TStream)

OnAfterProbingServer

Fires after the channel is done probing a specific server for availability. You can use this event to check the result of the probing, possibly to update internal data structures or to display server status in the user interface.

property OnAfterProbingServer: TROEndProbeServerEvent read write
delegate: procedure OnAfterProbingServer(Sender: TROTransportChannel; aServerLocator: TROServerLocator; Failed: boolean)

OnAfterProbingServers

Fires after the channel is done probing all servers for availability. You can use this event to check the result of the probing, possibly to update internal data structures or to display server status in the user interface.

property OnAfterProbingServers: TROEndProbeServersEvent read write
delegate: procedure OnAfterProbingServers(Sender: TROTransportChannel; ProbedCount: integer; EnabledCount: integer; DisabledCount: integer)

OnAsyncException

Fires when exception is raised in asynchronous mode

property OnAsyncException: TROAsyncExceptionEvent read write
delegate: procedure OnAsyncException(Sender: TROTransportChannel; Async: IROAsyncInterface; anException: Exception)

OnBeforeDecrypt    (declared in TROBaseConnection)

property OnBeforeDecrypt: TROBaseConnectionOperation read write
delegate: procedure OnBeforeDecrypt(Sender: TROBaseConnection; aEncryptedStream: TStream)

OnBeforeProbingServer

Fires before the channel starts probing a specific server for availability. You can use this event to: * check or adjust the server configuration * to include/exclude the server from being probed by changing the TROServerLocator property.

property OnBeforeProbingServer: TROBeginProbeServerEvent read write
delegate: procedure OnBeforeProbingServer(Sender: TROTransportChannel; aServerLocator: TROServerLocator)

OnBeforeProbingServers

Fires before the channel starts probing all servers for availability. You can use this event: * to check or adjust the server configurations * to include/exclude individual server from being probed by changing their TROServerLocator properties.

property OnBeforeProbingServers: TROBeginProbeServersEvent read write
delegate: procedure OnBeforeProbingServers(Sender: TROTransportChannel)

OnException

Fires if an exception is raised during the execution of a remote request. This could be an exception returned from the server, a communication problem or an error within the client. Depending on the type of error, your event handler can try to rectify the problem, and set aRetry to true to have the channel try and perform the request again. For example, an application could show a dialog asking the user to confirm if his internet connection is available, with Cancel and Retry buttons.
If aRetry is set to true and the call succeeds at the second attempt, the call will return to the original code that initiated the request, as if the exception never happened.

property OnException: TROExceptionEvent read write
delegate: procedure OnException(Sender: TROTransportChannel; anException: Exception; var aRetry: Boolean)

OnLoginNeeded

Fires if an EROSessionNotFound (or the descendant SessionNotFoundException) exception is raised during the execution of a remote request. This usually indicates that the server cannot authenticate the client or that the session has expired. The most common use for this event is to perform a call to a special Login service provided by the server (possibly after prompting the user to enter username and password), and to set the aRetry parameter to true if login was successful.

property OnLoginNeeded: TROExceptionEvent read write
delegate: procedure OnLoginNeeded(Sender: TROTransportChannel; anException: Exception; var aRetry: Boolean)

OnProgress

This event fires as the channel is transferring data for a request or response to or from the server, informing of the current progress. It can be used to keep the user interface updated during lengthy transfers,e.g. by showing a progress bar or the remaining transfer volume. Note: the accuracy and frequency of calls to OnProgress depends on the channel type; since channels transport data packets in different sized chunks (or even all-at-once), OnProgress might show a very fine progress for some channels, while jumping from 0 to 100% in one step with others.

property OnProgress: TProgressEvent read write
delegate: procedure OnProgress(iSender: TObject; iType: TProgressType; iDirection: TProgressDirection; iTransferred: integer; iTotal: integer)

OnReceiveStream

Fires after a stream with a response message has been received from the server. Use this event handler to inspect and possibly modify the stream, before it continues to be processed by the higher levels of the Remoting SDK framework.

property OnReceiveStream: TStreamDispatch read write
delegate: procedure OnReceiveStream(aStream: TStream)

OnSendStream

Fires just as a stream with a request message will be sent to the server. The event handler can inspect and possibly modify the stream, before it continues to be sent off to the server.

property OnSendStream: TStreamDispatch read write
delegate: procedure OnSendStream(aStream: TStream)

OnServerLocatorAssignment

Fires before changing of a server locator.

property OnServerLocatorAssignment: TServerLocatorAssignment read write
delegate: procedure OnServerLocatorAssignment(Sender: TROTransportChannel; aLocator: TROServerLocator; aException: Exception)

Descendants

See Also