TROIndyTCPChannel

Overview

TROIndyTCPChannel implements a TCP based channel that uses the socket implementation provided by the open source Indy components that ship with Delphi.

Due to a bug in Indy, the Indy HTTP and TCP Channels cannot be used inside the IDE at design time.

If you need to use your channels at design time, for example in combination with Data Abstract to receive schema information or live data preview, we recommend using one of the other channels such as the TROWinInetHTTPChannel.

Location

Implements

 

constructor Create  override    (declared in TROCustomIndyTCPChannel)

Creates a new instance.

constructor Create(aOwner: TComponent)

Parameters:

  • aOwner: Owner.

Assign  override    (declared in TROTransportChannel)

Copies the contents of another, similar object.

procedure Assign(aSource: TPersistent)

Parameters:

  • aSource: Instance whose properties will be copied

AssignEvents  protected virtual    (declared in TROTransportChannel)

Copies the events of another, similar object.

procedure AssignEvents(aSource: TROTransportChannel)

Parameters:

  • aSource:

AssignSpecificProperties  protected override    (declared in TROCustomIndyTCPChannel)

Copies the specific properties of another, similar object.

procedure AssignSpecificProperties(aSource: TROTransportChannel)

Parameters:

  • aSource:

AsyncException  protected virtual    (declared in TROTransportChannel)

Notifies about an exception in an asynchronous mode.

procedure AsyncException(aAsyncInterface: IROAsyncInterface; AsyncException: Exception)

Parameters:

  • aAsyncInterface: Exception source
  • AsyncException: Exception data

BeforeDispatch  protected virtual    (declared in TROTransportChannel)

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

procedure BeforeDispatch(aMessage: IROMessage)

Parameters:


Busy    (declared in TROTransportChannel)

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    (declared in TROTransportChannel)

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

Parameters:

  • faultstartlocatoridx:
  • aRetry:
  • aException:

ChannelMatchingTargetUri    (declared in TROTransportChannel)

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    (declared in TROTransportChannel)

class function ChannelMatchingTargetUrl(const aUrl: string): TROTransportChannel

Parameters:

  • aUrl:

CheckProperties  virtual    (declared in TROTransportChannel)

Validates channel properties

procedure CheckProperties

CreateIndyClient  protected virtual    (declared in TROCustomIndyTCPChannel)

This internal method is responsible for creating underlying Indy object to use by the channel. Returns the object created.

function CreateIndyClient: TIdTCPClientBaseClass

CurrentLocator    (declared in TROTransportChannel)

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:

DisableNagle

property DisableNagle:

Dispatch (IROMessage)  protected reintroduce overload    (declared in TROTransportChannel)

Sends a request message through the Self channel for processing and gets back an aMessage. CodeGen uses this method when generating a [proxy](http://docs.rosdk.com/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    (declared in TROCustomIndyTCPChannel)

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:

DoAfterProbingServerEvent  protected virtual    (declared in TROTransportChannel)

Fires OnAfterProbingServer event

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

Parameters:

  • aServerLocator: Server locator
  • Failed:

DoAfterProbingServersEvent  protected virtual    (declared in TROTransportChannel)

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    (declared in TROTransportChannel)

Fires OnBeforeProbingServer event

procedure DoBeforeProbingServerEvent(const aServerLocator: TROServerLocator)

Parameters:

  • aServerLocator: Server locator

DoBeforeProbingServersEvent  protected virtual    (declared in TROTransportChannel)

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    (declared in TROTransportChannel)

Fires OnException event

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

Parameters:

  • anException:
  • aRetry:

DoReceiveStreamEvent  protected virtual    (declared in TROTransportChannel)

Fires OnReceiveStream event

procedure DoReceiveStreamEvent(const aStream: TStream)

Parameters:

  • aStream: Stream

DoSendStreamEvent  protected virtual    (declared in TROTransportChannel)

Fires OnSendStream event

procedure DoSendStreamEvent(const aStream: TStream)

Parameters:

  • aStream: Stream

DoServerLocatorAssignmentEvent  protected virtual    (declared in TROTransportChannel)

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    (declared in TROTransportChannel)

property FaultToleranceLocatorIdx: integer read write

GetTransportObject  protected override    (declared in TROCustomIndyTCPChannel)

Returns itself.

function GetTransportObject: TObject

Host

Specifies the address of the server to talk to. This can be a host name or an IP address.

property Host:

IndyClient

Provides direct access to the underlying Indy implementation. You can use this property to control advanced settings on the Indy object. The exact available properties and settings depend on the version of Indy you are using.

property IndyClient:

InitServerLocator  protected virtual    (declared in TROTransportChannel)

Sets CurrentLocator

function InitServerLocator: Integer

IsEncryptionUsed  protected    (declared in TROBaseConnection)

function IsEncryptionUsed: Boolean

isProbeMode  protected    (declared in TROTransportChannel)

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

KeepAlive

Controls whether the TCP connection is retained for further use or disconnected immediately after remote request is completed. The default value is false, the connection is disconnected.

property KeepAlive:

LaunchAsyncTask  protected    (declared in TROTransportChannel)

procedure LaunchAsyncTask(aRequest: IROAsyncRequest)

Parameters:

  • aRequest:

LoadBalancerLocatorIdx    (declared in TROTransportChannel)

property LoadBalancerLocatorIdx: Integer read write

OnAfterEncrypt    (declared in TROBaseConnection)

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

OnAfterProbingServer    (declared in TROTransportChannel)

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)

OnAfterProbingServer    (declared in TROCustomIndyTCPChannel)

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:

OnAfterProbingServers    (declared in TROTransportChannel)

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)

OnAfterProbingServers    (declared in TROCustomIndyTCPChannel)

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:

OnAsyncException    (declared in TROTransportChannel)

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    (declared in TROTransportChannel)

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)

OnBeforeProbingServer    (declared in TROCustomIndyTCPChannel)

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:

OnBeforeProbingServers    (declared in TROTransportChannel)

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)

OnBeforeProbingServers    (declared in TROCustomIndyTCPChannel)

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:

OnException    (declared in TROTransportChannel)

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    (declared in TROTransportChannel)

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)

OnLoginNeeded    (declared in TROCustomIndyTCPChannel)

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:

OnProgress    (declared in TROTransportChannel)

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)

OnProgress    (declared in TROCustomIndyTCPChannel)

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:

OnReceiveStream    (declared in TROTransportChannel)

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)

OnReceiveStream    (declared in TROCustomIndyTCPChannel)

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:

OnSendStream    (declared in TROTransportChannel)

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)

OnSendStream    (declared in TROCustomIndyTCPChannel)

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:

OnServerLocatorAssignment    (declared in TROTransportChannel)

Fires before changing of a server locator.

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

OnServerLocatorAssignment    (declared in TROCustomIndyTCPChannel)

Fires before changing of a server locator.

property OnServerLocatorAssignment:

Port

Specifies the port number used by the server (default for Remoting SDK TCP servers is 8090).

property Port:

Probe  protected    (declared in TROTransportChannel)

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    (declared in TROTransportChannel)

Checks the availability of all known servers.

procedure ProbeAll

ProbeFrequency    (declared in TROCustomIndyTCPChannel)

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:

ProbeServers    (declared in TROCustomIndyTCPChannel)

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:

ResetProbingClone  protected virtual    (declared in TROTransportChannel)

Resets channel that is used for probing

procedure ResetProbingClone(aProbe: TROTransportChannel)

Parameters:

  • aProbe: Probing clone

RetrieveMetadata  protected virtual    (declared in TROTransportChannel)

Retrieves metadata from server

procedure RetrieveMetadata(out Metadata: TStream)

Parameters:

  • Metadata: Destination stream

RetrieveRODL  protected    (declared in TROTransportChannel)

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    (declared in TROCustomIndyTCPChannel)

See TROTransportChannel properties for description.

property ServerLocators:

SetAsyncBusy  protected virtual    (declared in TROTransportChannel)

procedure SetAsyncBusy(const Value: Boolean)

Parameters:

  • Value:

SetServerLocator  protected    (declared in TROTransportChannel)

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    (declared in TROCustomIndyTCPChannel)

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:

TargetUri    (declared in TROTransportChannel)

Target URI

property TargetUri: TROUri read write

TargetUrl    (declared in TROCustomIndyTCPChannel)

The IP address or host name of the server.

property TargetUrl:

ThreadSafe  protected    (declared in TROTransportChannel)

property ThreadSafe: Boolean read write

Timeout    (declared in TROCustomIndyTCPChannel)

The TCP socket timeout, controls underlying Indy object timeout property.

property Timeout: Integer read write

TriggerProgress  protected virtual    (declared in TROTransportChannel)

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    (declared in TROTransportChannel)

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    (declared in TROTransportChannel)

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

DisableNagle

property DisableNagle:

DispatchOptions    (declared in TROCustomIndyTCPChannel)

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:

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    (declared in TROTransportChannel)

property FaultToleranceLocatorIdx: integer read write

Host

Specifies the address of the server to talk to. This can be a host name or an IP address.

property Host:

IndyClient

Provides direct access to the underlying Indy implementation. You can use this property to control advanced settings on the Indy object. The exact available properties and settings depend on the version of Indy you are using.

property IndyClient:

isProbeMode  protected    (declared in TROTransportChannel)

Returns True if channel is used for probing purposes

property isProbeMode: Boolean read write

KeepAlive

Controls whether the TCP connection is retained for further use or disconnected immediately after remote request is completed. The default value is false, the connection is disconnected.

property KeepAlive:

LoadBalancerLocatorIdx    (declared in TROTransportChannel)

property LoadBalancerLocatorIdx: Integer read write

OnAfterProbingServer    (declared in TROCustomIndyTCPChannel)

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:

OnAfterProbingServers    (declared in TROCustomIndyTCPChannel)

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:

OnBeforeProbingServer    (declared in TROCustomIndyTCPChannel)

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:

OnBeforeProbingServers    (declared in TROCustomIndyTCPChannel)

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:

OnLoginNeeded    (declared in TROCustomIndyTCPChannel)

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:

OnProgress    (declared in TROCustomIndyTCPChannel)

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:

OnReceiveStream    (declared in TROCustomIndyTCPChannel)

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:

OnSendStream    (declared in TROCustomIndyTCPChannel)

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:

OnServerLocatorAssignment    (declared in TROCustomIndyTCPChannel)

Fires before changing of a server locator.

property OnServerLocatorAssignment:

Port

Specifies the port number used by the server (default for Remoting SDK TCP servers is 8090).

property Port:

ProbeFrequency    (declared in TROCustomIndyTCPChannel)

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:

ProbeServers    (declared in TROCustomIndyTCPChannel)

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:

ServerLocators    (declared in TROCustomIndyTCPChannel)

See TROTransportChannel properties for description.

property ServerLocators:

SynchronizedProbing    (declared in TROCustomIndyTCPChannel)

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:

TargetUri    (declared in TROTransportChannel)

Target URI

property TargetUri: TROUri read write

TargetUrl    (declared in TROCustomIndyTCPChannel)

The IP address or host name of the server.

property TargetUrl:

ThreadSafe  protected    (declared in TROTransportChannel)

property ThreadSafe: Boolean read write

Timeout    (declared in TROCustomIndyTCPChannel)

The TCP socket timeout, controls underlying Indy object timeout property.

property Timeout: Integer read write

 

ChannelMatchingTargetUri    (declared in TROTransportChannel)

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    (declared in TROTransportChannel)

class function ChannelMatchingTargetUrl(const aUrl: string): TROTransportChannel

Parameters:

  • aUrl:

 

constructor Create  override    (declared in TROCustomIndyTCPChannel)

Creates a new instance.

constructor Create(aOwner: TComponent)

Parameters:

  • aOwner: Owner.

Assign  override    (declared in TROTransportChannel)

Copies the contents of another, similar object.

procedure Assign(aSource: TPersistent)

Parameters:

  • aSource: Instance whose properties will be copied

AssignEvents  protected virtual    (declared in TROTransportChannel)

Copies the events of another, similar object.

procedure AssignEvents(aSource: TROTransportChannel)

Parameters:

  • aSource:

AssignSpecificProperties  protected override    (declared in TROCustomIndyTCPChannel)

Copies the specific properties of another, similar object.

procedure AssignSpecificProperties(aSource: TROTransportChannel)

Parameters:

  • aSource:

AsyncException  protected virtual    (declared in TROTransportChannel)

Notifies about an exception in an asynchronous mode.

procedure AsyncException(aAsyncInterface: IROAsyncInterface; AsyncException: Exception)

Parameters:

  • aAsyncInterface: Exception source
  • AsyncException: Exception data

BeforeDispatch  protected virtual    (declared in TROTransportChannel)

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    (declared in TROTransportChannel)

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

Parameters:

  • faultstartlocatoridx:
  • aRetry:
  • aException:

CheckProperties  virtual    (declared in TROTransportChannel)

Validates channel properties

procedure CheckProperties

CreateIndyClient  protected virtual    (declared in TROCustomIndyTCPChannel)

This internal method is responsible for creating underlying Indy object to use by the channel. Returns the object created.

function CreateIndyClient: TIdTCPClientBaseClass

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    (declared in TROTransportChannel)

Sends a request message through the Self channel for processing and gets back an aMessage. CodeGen uses this method when generating a [proxy](http://docs.rosdk.com/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    (declared in TROTransportChannel)

Fires OnAfterProbingServer event

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

Parameters:

  • aServerLocator: Server locator
  • Failed:

DoAfterProbingServersEvent  protected virtual    (declared in TROTransportChannel)

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    (declared in TROTransportChannel)

Fires OnBeforeProbingServer event

procedure DoBeforeProbingServerEvent(const aServerLocator: TROServerLocator)

Parameters:

  • aServerLocator: Server locator

DoBeforeProbingServersEvent  protected virtual    (declared in TROTransportChannel)

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    (declared in TROTransportChannel)

Fires OnException event

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

Parameters:

  • anException:
  • aRetry:

DoReceiveStreamEvent  protected virtual    (declared in TROTransportChannel)

Fires OnReceiveStream event

procedure DoReceiveStreamEvent(const aStream: TStream)

Parameters:

  • aStream: Stream

DoSendStreamEvent  protected virtual    (declared in TROTransportChannel)

Fires OnSendStream event

procedure DoSendStreamEvent(const aStream: TStream)

Parameters:

  • aStream: Stream

DoServerLocatorAssignmentEvent  protected virtual    (declared in TROTransportChannel)

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 override    (declared in TROCustomIndyTCPChannel)

Returns itself.

function GetTransportObject: TObject

InitServerLocator  protected virtual    (declared in TROTransportChannel)

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    (declared in TROTransportChannel)

procedure LaunchAsyncTask(aRequest: IROAsyncRequest)

Parameters:

  • aRequest:

Probe  protected    (declared in TROTransportChannel)

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    (declared in TROTransportChannel)

Checks the availability of all known servers.

procedure ProbeAll

ResetProbingClone  protected virtual    (declared in TROTransportChannel)

Resets channel that is used for probing

procedure ResetProbingClone(aProbe: TROTransportChannel)

Parameters:

  • aProbe: Probing clone

RetrieveMetadata  protected virtual    (declared in TROTransportChannel)

Retrieves metadata from server

procedure RetrieveMetadata(out Metadata: TStream)

Parameters:

  • Metadata: Destination stream

RetrieveRODL  protected    (declared in TROTransportChannel)

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    (declared in TROTransportChannel)

procedure SetAsyncBusy(const Value: Boolean)

Parameters:

  • Value:

SetServerLocator  protected    (declared in TROTransportChannel)

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    (declared in TROTransportChannel)

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    (declared in TROTransportChannel)

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    (declared in TROTransportChannel)

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    (declared in TROTransportChannel)

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    (declared in TROTransportChannel)

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    (declared in TROTransportChannel)

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    (declared in TROTransportChannel)

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    (declared in TROTransportChannel)

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    (declared in TROTransportChannel)

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    (declared in TROTransportChannel)

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    (declared in TROTransportChannel)

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    (declared in TROTransportChannel)

Fires before changing of a server locator.

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

See Also