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
- Unit: uROIndyTCPChannel.pas
- Ancestry: TComponent | TROComponent | TROBaseConnection | TROTransportChannel | TROSimpleTransportChannel | TROCustomIndyTCPChannel | TROIndyTCPChannel
constructor Create override (declared in TROCustomIndyTCPChannel)
Standard component constructor
constructor Create(aOwner: TComponent)
Parameters:
- aOwner: Owner
Assign override (declared in TROTransportChannel)
Copies the contents of another, similar object.
procedure Assign(Source: TPersistent)
Parameters:
- Source: 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: Instance whose properties will be copied
AssignSpecificProperties protected override (declared in TROCustomIndyTCPChannel)
Copies the specific properties of another, similar object.
procedure AssignSpecificProperties(aSource: TROTransportChannel)
Parameters:
- aSource: Instance whose properties will be copied
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:
- aMessage: Message
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
ChangeServerLocator protected virtual (declared in TROTransportChannel)
procedure ChangeServerLocator(var aFaultStartLocatorIdx: Integer; var aRetry: Boolean; const aException: Exception)
Parameters:
- aFaultStartLocatorIdx:
- 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
ClearConnectionPool (declared in TROSimpleTransportChannel)
Clears connection pool
procedure ClearConnectionPool
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, TStream) protected overload (declared in TROBaseConnection)
Decrypt stream
procedure DecryptStream(const Source: TStream; const Dest: TStream)
Parameters:
- Source: Source
- Dest: Destination
DecryptStream (TStream) protected overload (declared in TROBaseConnection)
Decrypt stream
procedure DecryptStream(const Stream: TStream)
Parameters:
- Stream: Stream
DisableNagle
Controls whether data packets are sent individually or if small packets are held back to send as part of fewer larger data packets. Normally, you will want this disabled as it can have a significant effect on performance. The only time when its worth keeping the property enabled is when there are many small packets to be sent and you need to keep network bandwidth to a minimum.
See more at Nagle's algorithm
property DisableNagle: Boolean read write
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 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: TRODispatchOptions read write
DoAfterProbingServerEvent protected virtual (declared in TROTransportChannel)
Fires OnAfterProbingServer event
procedure DoAfterProbingServerEvent(const aServerLocator: TROServerLocator; const aFailed: Boolean)
Parameters:
- aServerLocator: Server locator
- aFailed:
DoAfterProbingServersEvent protected virtual (declared in TROTransportChannel)
Fires OnAfterProbingServer event
procedure DoAfterProbingServersEvent(const aProbedCount: Integer; const aEnabledCount: Integer; const aDisabledCount: Integer)
Parameters:
- aProbedCount:
- aEnabledCount:
- aDisabledCount:
DoBeforeDecryptEvent protected virtual (declared in TROBaseConnection) obsolete
procedure DoBeforeDecryptEvent(aEncryptedStream: TStream)
Parameters:
- aEncryptedStream: Stream
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
DoNeedSSL protected override (declared in TROCustomIndyTCPChannel)
Detects SSL state
function DoNeedSSL: Boolean
DoReceiveStreamEvent protected virtual (declared in TROTransportChannel)
Fires OnSendStream event
procedure DoReceiveStreamEvent(const Dest: TStream)
Parameters:
- Dest: Stream
DoSendStreamEvent protected virtual (declared in TROTransportChannel)
Fires OnSendStream event
procedure DoSendStreamEvent(const Source: TStream)
Parameters:
- Source: 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, TStream) protected overload (declared in TROBaseConnection)
Encrypt stream
procedure EncryptStream(const Source: TStream; const Dest: TStream)
Parameters:
- Source: Source
- Dest: Destination
EncryptStream (TStream) protected overload (declared in TROBaseConnection)
Encrypt stream
procedure EncryptStream(const Stream: TStream)
Parameters:
- Stream: Stream
FaultToleranceLocatorIdx (declared in TROTransportChannel)
property FaultToleranceLocatorIdx: Integer read write
GetBusy protected override (declared in TROSimpleTransportChannel)
Returns current channel state
function GetBusy: Boolean
GetChannelFromPool protected override (declared in TROSimpleTransportChannel)
function GetChannelFromPool: TROTransportChannel
GetTransportObject protected virtual (declared in TROTransportChannel)
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: string read write
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: TIdTCPClientBaseClass read
InitServerLocator protected virtual (declared in TROTransportChannel)
Sets CurrentLocator
function InitServerLocator: Integer
IsEncryptionUsed protected (declared in TROBaseConnection)
Checks if encryption was used
function IsEncryptionUsed: Boolean
IsProbeMode protected (declared in TROTransportChannel)
property IsProbeMode: Boolean read
IsStreamEncrypted protected (declared in TROBaseConnection)
Checks state of stream
function IsStreamEncrypted(Source: TStream): Boolean
Parameters:
- Source: 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: Boolean read write
LaunchAsyncTask protected (declared in TROTransportChannel)
procedure LaunchAsyncTask(aRequest: IROAsyncRequest)
Parameters:
- aRequest:
LoadBalancerLocatorIdx (declared in TROTransportChannel)
property LoadBalancerLocatorIdx: Integer read write
LoadSSL protected override (declared in TROCustomIndyTCPChannel)
Loads SSL library if SSL protocol is used
procedure LoadSSL
Notification protected override (declared in TROTransportChannel)
Forwards notification messages to all owned components.
procedure Notification(AComponent: TComponent; Operation: TOperation)
Parameters:
- AComponent: component
- Operation: operation
OnAfterEncrypt (declared in TROBaseConnection)
Fired after stream was encrypted
property OnAfterEncrypt: TROBaseConnectionOperation read write
delegate: procedure OnAfterEncrypt(Sender: TROBaseConnection; aEncryptedStream: TStream)
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: TROEndProbeServerEvent read write
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: TROEndProbeServersEvent read write
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)
Fired before stream will be decrypted
property OnBeforeDecrypt: TROBaseConnectionOperation read write
delegate: procedure OnBeforeDecrypt(Sender: TROBaseConnection; aEncryptedStream: TStream)
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: TROBeginProbeServerEvent read write
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: TROBeginProbeServersEvent read write
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 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: TROExceptionEvent read write
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: TProgressEvent read write
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: TStreamDispatch read write
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: TStreamDispatch read write
OnServerLocatorAssignment (declared in TROCustomIndyTCPChannel)
Fires before changing of a server locator.
property OnServerLocatorAssignment: TServerLocatorAssignment read write
Port
Specifies the port number used by the server (default for Remoting SDK TCP servers is 8090).
property Port: Integer read write
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: Cardinal read write
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: Boolean read write
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)
Returns server-side RODL.
procedure RetrieveMetadata(out Dest: TStream)
Parameters:
- Dest: 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
ReturnChannelToPool protected override (declared in TROSimpleTransportChannel)
procedure ReturnChannelToPool(aChannel: TROTransportChannel)
Parameters:
- aChannel:
ROFreeNotification (declared in TROComponent)
Forwards notification messages to all owned components.
procedure ROFreeNotification(aComponent: TComponent)
Parameters:
- aComponent: component
RORemoveFreeNotification (declared in TROComponent)
Forwards notification messages to all owned components.
procedure RORemoveFreeNotification(aComponent: TComponent)
Parameters:
- aComponent: component
SendRemoveNotification protected (declared in TROComponent)
Forwards notification messages to all owned components.
procedure SendRemoveNotification(aComponent: TComponent)
Parameters:
- aComponent: component
ServerLocators (declared in TROCustomIndyTCPChannel)
See TROTransportChannel properties for description.
property ServerLocators: TROServerLocatorCollection read write
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: Boolean read write
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: string read write
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(aType: TProgressType; aDirection: TProgressDirection; aTransfered: Integer; aTotal: Integer)
Parameters:
- aType: progress type
- aDirection: direction
- aTransfered: transfered bytes
- aTotal: total bytes
UseConnectionPooling (declared in TROSimpleTransportChannel)
Specifies can be the pooling be used or not
property UseConnectionPooling: Boolean read write
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
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
Controls whether data packets are sent individually or if small packets are held back to send as part of fewer larger data packets. Normally, you will want this disabled as it can have a significant effect on performance. The only time when its worth keeping the property enabled is when there are many small packets to be sent and you need to keep network bandwidth to a minimum.
See more at Nagle's algorithm
property DisableNagle: Boolean read write
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: 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 (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: string read write
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: TIdTCPClientBaseClass read
IsProbeMode protected (declared in TROTransportChannel)
property IsProbeMode: Boolean read
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: Boolean read write
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: TROEndProbeServerEvent read write
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: TROEndProbeServersEvent read write
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: TROBeginProbeServerEvent read write
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: TROBeginProbeServersEvent read write
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: TROExceptionEvent read write
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: TProgressEvent read write
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: TStreamDispatch read write
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: TStreamDispatch read write
OnServerLocatorAssignment (declared in TROCustomIndyTCPChannel)
Fires before changing of a server locator.
property OnServerLocatorAssignment: TServerLocatorAssignment read write
Port
Specifies the port number used by the server (default for Remoting SDK TCP servers is 8090).
property Port: Integer read write
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: Cardinal read write
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: Boolean read write
ServerLocators (declared in TROCustomIndyTCPChannel)
See TROTransportChannel properties for description.
property ServerLocators: TROServerLocatorCollection read write
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: Boolean read write
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: string read write
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
UseConnectionPooling (declared in TROSimpleTransportChannel)
Specifies can be the pooling be used or not
property UseConnectionPooling: Boolean 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)
Standard component constructor
constructor Create(aOwner: TComponent)
Parameters:
- aOwner: Owner
Assign override (declared in TROTransportChannel)
Copies the contents of another, similar object.
procedure Assign(Source: TPersistent)
Parameters:
- Source: 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: Instance whose properties will be copied
AssignSpecificProperties protected override (declared in TROCustomIndyTCPChannel)
Copies the specific properties of another, similar object.
procedure AssignSpecificProperties(aSource: TROTransportChannel)
Parameters:
- aSource: Instance whose properties will be copied
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:
- aMessage: Message
ChangeServerLocator protected virtual (declared in TROTransportChannel)
procedure ChangeServerLocator(var aFaultStartLocatorIdx: Integer; var aRetry: Boolean; const aException: Exception)
Parameters:
- aFaultStartLocatorIdx:
- aRetry:
- aException:
CheckProperties virtual (declared in TROTransportChannel)
Validates channel properties
procedure CheckProperties
ClearConnectionPool (declared in TROSimpleTransportChannel)
Clears connection pool
procedure ClearConnectionPool
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, TStream) protected overload (declared in TROBaseConnection)
Decrypt stream
procedure DecryptStream(const Source: TStream; const Dest: TStream)
Parameters:
- Source: Source
- Dest: Destination
DecryptStream (TStream) protected overload (declared in TROBaseConnection)
Decrypt stream
procedure DecryptStream(const Stream: TStream)
Parameters:
- Stream: Stream
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 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 aFailed: Boolean)
Parameters:
- aServerLocator: Server locator
- aFailed:
DoAfterProbingServersEvent protected virtual (declared in TROTransportChannel)
Fires OnAfterProbingServer event
procedure DoAfterProbingServersEvent(const aProbedCount: Integer; const aEnabledCount: Integer; const aDisabledCount: Integer)
Parameters:
- aProbedCount:
- aEnabledCount:
- aDisabledCount:
DoBeforeDecryptEvent protected virtual (declared in TROBaseConnection) obsolete
procedure DoBeforeDecryptEvent(aEncryptedStream: TStream)
Parameters:
- aEncryptedStream: Stream
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
DoNeedSSL protected override (declared in TROCustomIndyTCPChannel)
Detects SSL state
function DoNeedSSL: Boolean
DoReceiveStreamEvent protected virtual (declared in TROTransportChannel)
Fires OnSendStream event
procedure DoReceiveStreamEvent(const Dest: TStream)
Parameters:
- Dest: Stream
DoSendStreamEvent protected virtual (declared in TROTransportChannel)
Fires OnSendStream event
procedure DoSendStreamEvent(const Source: TStream)
Parameters:
- Source: Stream
DoServerLocatorAssignmentEvent protected virtual (declared in TROTransportChannel)
Fires OnServerLocatorAssignment event
procedure DoServerLocatorAssignmentEvent(const aLocator: TROServerLocator; const aException: Exception)
Parameters:
- aLocator:
- aException:
EncryptStream (TStream, TStream) protected overload (declared in TROBaseConnection)
Encrypt stream
procedure EncryptStream(const Source: TStream; const Dest: TStream)
Parameters:
- Source: Source
- Dest: Destination
EncryptStream (TStream) protected overload (declared in TROBaseConnection)
Encrypt stream
procedure EncryptStream(const Stream: TStream)
Parameters:
- Stream: Stream
GetBusy protected override (declared in TROSimpleTransportChannel)
Returns current channel state
function GetBusy: Boolean
GetChannelFromPool protected override (declared in TROSimpleTransportChannel)
function GetChannelFromPool: TROTransportChannel
GetTransportObject protected virtual (declared in TROTransportChannel)
Returns itself.
function GetTransportObject: TObject
InitServerLocator protected virtual (declared in TROTransportChannel)
Sets CurrentLocator
function InitServerLocator: Integer
IsEncryptionUsed protected (declared in TROBaseConnection)
Checks if encryption was used
function IsEncryptionUsed: Boolean
IsStreamEncrypted protected (declared in TROBaseConnection)
Checks state of stream
function IsStreamEncrypted(Source: TStream): Boolean
Parameters:
- Source: Stream
LaunchAsyncTask protected (declared in TROTransportChannel)
procedure LaunchAsyncTask(aRequest: IROAsyncRequest)
Parameters:
- aRequest:
LoadSSL protected override (declared in TROCustomIndyTCPChannel)
Loads SSL library if SSL protocol is used
procedure LoadSSL
Notification protected override (declared in TROTransportChannel)
Forwards notification messages to all owned components.
procedure Notification(AComponent: TComponent; Operation: TOperation)
Parameters:
- AComponent: component
- Operation: operation
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)
Returns server-side RODL.
procedure RetrieveMetadata(out Dest: TStream)
Parameters:
- Dest: 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
ReturnChannelToPool protected override (declared in TROSimpleTransportChannel)
procedure ReturnChannelToPool(aChannel: TROTransportChannel)
Parameters:
- aChannel:
ROFreeNotification (declared in TROComponent)
Forwards notification messages to all owned components.
procedure ROFreeNotification(aComponent: TComponent)
Parameters:
- aComponent: component
RORemoveFreeNotification (declared in TROComponent)
Forwards notification messages to all owned components.
procedure RORemoveFreeNotification(aComponent: TComponent)
Parameters:
- aComponent: component
SendRemoveNotification protected (declared in TROComponent)
Forwards notification messages to all owned components.
procedure SendRemoveNotification(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(aType: TProgressType; aDirection: TProgressDirection; aTransfered: Integer; aTotal: Integer)
Parameters:
- aType: progress type
- aDirection: direction
- aTransfered: transfered bytes
- aTotal: total bytes
OnAfterEncrypt (declared in TROBaseConnection)
Fired after stream was encrypted
property OnAfterEncrypt: TROBaseConnectionOperation read write
delegate: procedure OnAfterEncrypt(Sender: TROBaseConnection; aEncryptedStream: TStream)
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)
Fired before stream will be decrypted
property OnBeforeDecrypt: TROBaseConnectionOperation read write
delegate: procedure OnBeforeDecrypt(Sender: TROBaseConnection; aEncryptedStream: TStream)
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)