PipeServer Component

Properties   Methods   Events   Config Settings   Errors  

The PipeServer component is a lightweight server component based on an asynchronous, event-driven architecture. It is designed to balance the load between connections for a fast, powerful server.

Syntax

TiipPipeServer

Remarks

PipeServer is the server complement of PipeClient (which is used to create client applications). They share a common design philosophy and interface. PipeServer is as easy to use as PipeClient.

The client connections are identified by a ConnectionId, an id generated by the component to identify each connection. This id is unique to each connection. PipeServer's events also have ConnectionId as a parameter to identify the connection to which they are related.

Our main goal in designing PipeServer was to make it easy to use without sacrificing performance. The component has a minimum of properties, and events: Connected, DataIn, Disconnected, ReadyToSend, and Error.

PipeServer can start to listen on a pipe by setting PipeName and then setting Listening to True. When a client connects the Connected event fires, a ConnectionId is assigned, and communication can start. From this point on, the operation is very similar to PipeClient. Data is sent by assigning the data string to the DataToSend property.

Property List

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The following is the full list of the properties of the component with short descriptions. Click on the links for further details.

Method List

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The following is the full list of the methods of the component with short descriptions. Click on the links for further details.

Event List

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The following is the full list of the events fired by the component with short descriptions. Click on the links for further details.

Config Settings

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The following is a list of config settings for the component with short descriptions. Click on the links for further details.

ConnectionCount Property (PipeServer Component)

The number of records in the arrays.

Syntax

__property int ConnectionCount = { read=FConnectionCount };

Default Value

0

Remarks

This property controls the size of the following arrays:

• AcceptData
• BytesSent
• Connected
• ConnectionId
• DataToSend
• EOL
• MaxLineLength
• SingleLineMode
• Timeout

The array indices start at 0 and end at ConnectionCount - 1.

This property is read-only and not available at design time.

Data Type

Integer

AcceptData Property (PipeServer Component)

Setting this property to false temporarily disables data reception (and the DataIn event) for the connection.

Syntax

__property bool AcceptData[int ConnectionId] = { read=FAcceptData, write=FSetAcceptData };

Default Value

True

Remarks

Setting this property to false temporarily disables data reception (and the DataIn event) for the connection. Setting this to true re-enables data reception.

Note: It is recommended to use the PauseData or ProcessData method instead of setting this property.

The ConnectionId parameter specifies the index of the item in the array. The size of the array is controlled by the ConnectionCount property.

This property is not available at design time.

Data Type

Boolean

BytesSent Property (PipeServer Component)

This property shows how many bytes were sent after the last assignment to DataToSend .

Syntax

__property int BytesSent[int ConnectionId] = { read=FBytesSent };

Default Value

0

Remarks

This property shows how many bytes were sent after the last assignment to DataToSend. Please check DataToSend for more information.

Note: This property will always return 0 when the component is operating in the synchronous mode (i.e., the Timeout property is set to a positive value).

The ConnectionId parameter specifies the index of the item in the array. The size of the array is controlled by the ConnectionCount property.

This property is read-only and not available at design time.

Data Type

Integer

Connected Property (PipeServer Component)

This property is used to disconnect individual connections and/or show their status.

Syntax

__property bool Connected[int ConnectionId] = { read=FConnected, write=FSetConnected };

Default Value

False

Remarks

This property is used to disconnect individual connections and/or show their status.

The Connected property may be set to false to close the connection.

Connected also shows the status of a particular connection (connected/disconnected).

Note: It is recommended to use the Connect or Disconnect method instead of setting this property.

The ConnectionId parameter specifies the index of the item in the array. The size of the array is controlled by the ConnectionCount property.

This property is not available at design time.

Data Type

Boolean

ConnectionId Property (PipeServer Component)

This property contains an identifier generated by the component to identify each connection.

Syntax

__property String ConnectionId[int ConnectionId] = { read=FConnectionId };

Default Value

""

Remarks

This property contains an identifier generated by the component to identify each connection. This identifier is unique to this connection.

The ConnectionId parameter specifies the index of the item in the array. The size of the array is controlled by the ConnectionCount property.

This property is read-only and not available at design time.

Data Type

String

DataToSend Property (PipeServer Component)

This property contains a string of data to be sent to the remote host.

Syntax

__property String DataToSend[int ConnectionId] = { write=FSetDataToSend };
__property DynamicArray<Byte> DataToSendB[int ConnectionId] = { write=FSetDataToSendB };

Default Value

""

Remarks

This property contains a string of data to be sent to the remote host. It is a write-only property.

Assigning a string to the DataToSend makes the component send the string to the remote host. The Send method provides similar functionality.

When Timeout is set to 0, the component will behave asynchronously. If you are sending data to the remote host faster than it can process it, or faster than the network's bandwidth allows, the outgoing queue might fill up. When this happens, the operation raises the exception with errorcode 10035 and message "[10035] Operation would block" (WSAEWOULDBLOCK). You can handle this exception, and then try to send the data again. . The BytesSent property shows how many bytes were sent (if any). If 0 bytes were sent, then you can wait for the ReadyToSend event before attempting to send data again.

Note: The ReadyToSend event is not fired when part of the data is sent successfully.

Note: It is recommended to use the Send or SendBytes method instead of setting this property.

The ConnectionId parameter specifies the index of the item in the array. The size of the array is controlled by the ConnectionCount property.

This property is write-only and not available at design time.

Data Type

Byte Array

EOL Property (PipeServer Component)

The EOL property is used to define boundaries in the input stream using the value of the property.

Syntax

__property String EOL[int ConnectionId] = { read=FEOL, write=FSetEOL };
__property DynamicArray<Byte> EOLB[int ConnectionId] = { read=FEOLB, write=FSetEOLB };

Default Value

""

Remarks

The EOL property is used to define boundaries in the input stream using the value of the property.

The EOL property is especially useful with ASCII files. By setting it to CRLF ("\r\n") , the incoming ASCII text stream can be split into lines. In this case, one event is fired for each line received (as well as in packet boundaries). The CRLF ("\r\n") . bytes are discarded.

The EOL property is a binary string. This means that it can be more than one byte long, and it can contain NULL bytes.

The ConnectionId parameter specifies the index of the item in the array. The size of the array is controlled by the ConnectionCount property.

This property is not available at design time.

Data Type

Byte Array

MaxLineLength Property (PipeServer Component)

This property is the size of an internal buffer that holds received data while waiting for an EOL string.

Syntax

__property int MaxLineLength[int ConnectionId] = { read=FMaxLineLength, write=FSetMaxLineLength };

Default Value

2048

Remarks

This property is the size of an internal buffer that holds received data while waiting for an EOL string.

If an EOL string is found in the input stream before MaxLineLength bytes are received, the DataIn event is fired with the EOL parameter set to True, and the buffer is reset.

If no EOL is found, and MaxLineLength bytes are accumulated in the buffer, the DataIn event is fired with the EOL parameter set to False, and the buffer is reset.

The minimum value for MaxLineLength is 256 bytes. The default value is 2048 bytes.

The ConnectionId parameter specifies the index of the item in the array. The size of the array is controlled by the ConnectionCount property.

This property is not available at design time.

Data Type

Integer

SingleLineMode Property (PipeServer Component)

This property shows the special mode for line-oriented protocols.

Syntax

__property bool SingleLineMode[int ConnectionId] = { read=FSingleLineMode, write=FSetSingleLineMode };

Default Value

False

Remarks

This property shows the special mode for line-oriented protocols. When SingleLineMode is True, the component treats the incoming data stream as lines separated by carriage return (CR), line feed (LF), or CRLF. The EOL property is ignored.

The ConnectionId parameter specifies the index of the item in the array. The size of the array is controlled by the ConnectionCount property.

This property is not available at design time.

Data Type

Boolean

Timeout Property (PipeServer Component)

This property specifies a timeout for the component.

Syntax

__property int Timeout[int ConnectionId] = { read=FTimeout, write=FSetTimeout };

Default Value

0

Remarks

This property specifies a timeout for the component.

If the Timeout property is set to 0, all operations return immediately, potentially failing with a WOULDBLOCK error if data cannot be sent immediately.

If Timeout is set to a positive value, data is sent in a blocking manner and the component will wait for the operation to complete before returning control. The component will handle any potential WOULDBLOCK errors internally and automatically retry the operation for a maximum of Timeout seconds.

The component will use DoEvents to enter an efficient wait loop during any potential waiting period, making sure that all system events are processed immediately as they arrive. This ensures that the host application does not "freeze" and remains responsive.

If Timeout expires, and the operation is not yet complete, the component raises an exception.

Please note that by default, all timeouts are inactivity timeouts, i.e. the timeout period is extended by Timeout seconds when any amount of data is successfully sent or received.

The default value for the Timeout property is 0 (asynchronous operation).

The ConnectionId parameter specifies the index of the item in the array. The size of the array is controlled by the ConnectionCount property.

This property is not available at design time.

Data Type

Integer

DefaultEOL Property (PipeServer Component)

This property includes a default end-of-line (EOL) value to be used by incoming connections.

Syntax

__property String DefaultEOL = { read=FDefaultEOL, write=FSetDefaultEOL };
__property DynamicArray<Byte> DefaultEOLB = { read=FDefaultEOLB, write=FSetDefaultEOLB };

Default Value

""

Remarks

This property contains a default end-of-line (EOL) value to be used by incoming connections. Once the component accepts and establishes an inbound connection, it will set that connection's EOL to the value in this property. By default, this value is empty (""), meaning that data will be fired as it is received.

Data Type

Byte Array

DefaultMaxLineLength Property (PipeServer Component)

The property includes the default maximum line length value for inbound connections.

Syntax

__property int DefaultMaxLineLength = { read=FDefaultMaxLineLength, write=FSetDefaultMaxLineLength };

Default Value

2048

Remarks

This property controls the default size of an internal buffer that holds received data while waiting for an end-of-line (EOL) string.

The minimum value for this property is 256 bytes. The default value is 2048 bytes.

Data Type

Integer

DefaultSingleLineMode Property (PipeServer Component)

This property tells the component whether or not to treat new connections as line oriented.

Syntax

__property bool DefaultSingleLineMode = { read=FDefaultSingleLineMode, write=FSetDefaultSingleLineMode };

Default Value

False

Remarks

This property instructs the component whether or not to treat newly established connections as line-oriented protocols. If this value is True, newly accepted connections will read the incoming data stream as lines separated by a carriage return line feed (CRLF), carriage return (CR), or line feed (LF) and will ignore the end of lines (EOLs).

Data Type

Boolean

DefaultTimeout Property (PipeServer Component)

This property includes an initial timeout value to be used by incoming connections.

Syntax

__property int DefaultTimeout = { read=FDefaultTimeout, write=FSetDefaultTimeout };

Default Value

0

Remarks

This property is used by the component to set the operational timeout value of all inbound connections once they are established.

By default, the timeout is 0, meaning that all inbound connections will behave asynchronously.

Data Type

Integer

Listening Property (PipeServer Component)

If True, the component accepts incoming connections.

Syntax

__property bool Listening = { read=FListening, write=FSetListening };

Default Value

False

Remarks

Use this property to make the component 'listen' (accept connections) on the pipe specified by PipeName. Setting this property to False will make the component stop listening. Please note that this does not close any existing connections.

Note: Use the StartListening and StopListening methods to control whether the component is listening.

This property is not available at design time.

Data Type

Boolean

PipeName Property (PipeServer Component)

The name of the pipe.

Syntax

__property String PipeName = { read=FPipeName, write=FSetPipeName };

Default Value

""

Remarks

This property specifies the name of the pipe on which to accept connections. Clients must use this name when establishing a connection to PipeServer.

Data Type

String

Config Method (PipeServer Component)

Sets or retrieves a configuration setting.

Syntax

String __fastcall Config(String ConfigurationString);

Remarks

Config is a generic method available in every component. It is used to set and retrieve configuration settings for the component.

These settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the component, access to these internal properties is provided through the Config method.

To set a configuration setting named PROPERTY, you must call Config("PROPERTY=VALUE"), where VALUE is the value of the setting expressed as a string. For boolean values, use the strings "True", "False", "0", "1", "Yes", or "No" (case does not matter).

To read (query) the value of a configuration setting, you must call Config("PROPERTY"). The value will be returned as a string.

Disconnect Method (PipeServer Component)

This method disconnects the specified client.

Syntax

void __fastcall Disconnect(int ConnectionId);

Remarks

Calling this method will disconnect the client specified by the ConnectionId parameter.

DoEvents Method (PipeServer Component)

Processes events from the internal message queue.

Syntax

void __fastcall DoEvents();

Remarks

When DoEvents is called, the component processes any available events. If no events are available, it waits for a preset period of time, and then returns.

Interrupt Method (PipeServer Component)

This method interrupts a synchronous send to the remote host.

Syntax

void __fastcall Interrupt(int ConnectionId);

Remarks

This property is called using the Connection Id if you wish to interrupt a connection and stop a file from uploading without disconnecting the client connected to the component. If you use SendFile to upload a file, the component will run synchronously on that Connection Id until it is completed.

Send Method (PipeServer Component)

This method sends binary data to the specified client.

Syntax

void __fastcall Send(int ConnectionId, DynamicArray<Byte> Text);

Remarks

This method sends binary data to the client identified by ConnectionId. To send text, use the SendText method instead.

When Timeout is set to 0, the component will behave asynchronously. If you are sending data to the remote host faster than it can process it, or faster than the network's bandwidth allows, the outgoing queue might fill up. When this happens, the operation raises the exception with errorcode 10035 and message "[10035] Operation would block" (WSAEWOULDBLOCK). You can handle this exception, and then try to send the data again. . The BytesSent property shows how many bytes were sent (if any). If 0 bytes were sent, then you can wait for the ReadyToSend event before attempting to send data again.

Note: The ReadyToSend event is not fired when part of the data is sent successfully.

SendFile Method (PipeServer Component)

This method sends the file to the remote host.

Syntax

void __fastcall SendFile(int ConnectionId, String FileName);

Remarks

This method sends the file to the client specified by the ConnectionId.

SendLine Method (PipeServer Component)

This method sends a string followed by a new line.

Syntax

void __fastcall SendLine(int ConnectionId, String Text);

Remarks

This method is used to send data with line-oriented protocols. The line is followed by CRLF ("\r\n") .

Please refer to the GetLine method and SingleLineMode property for more information.

Shutdown Method (PipeServer Component)

This method shuts down the server.

Syntax

void __fastcall Shutdown();

Remarks

This method shuts down the server. Calling this method is equivalent to calling StopListening and then breaking every client connection by calling Disconnect.

StartListening Method (PipeServer Component)

This method starts listening for incoming connections.

Syntax

void __fastcall StartListening();

Remarks

This method begins listening for incoming connections on the pipe specified by PipeName.

To stop listening for new connections, call StopListening. To stop listening for new connections and to disconnect all existing clients, call Shutdown.

StopListening Method (PipeServer Component)

This method stops listening for new connections.

Syntax

void __fastcall StopListening();

Remarks

This method stops listening for new connections. After being called, any new connection attempts will be rejected. Calling this method does not disconnect existing connections.

To stop listening and to disconnect all existing clients, call Shutdown instead.

Connected Event (PipeServer Component)

Fired immediately after a connection completes.

Syntax

typedef struct {
  int ConnectionId;
} TiipPipeServerConnectedEventParams;
typedef void __fastcall (__closure *TiipPipeServerConnectedEvent)(System::TObject* Sender, TiipPipeServerConnectedEventParams *e);
__property TiipPipeServerConnectedEvent OnConnected = { read=FOnConnected, write=FOnConnected };

Remarks

This event fires immediately after a client connects. The ConnectionId parameter identifies the client connection.

DataIn Event (PipeServer Component)

This event is fired when data come in.

Syntax

typedef struct {
  int ConnectionId;
  String Text;
  DynamicArray<Byte> TextB;
  bool EOL;
} TiipPipeServerDataInEventParams;
typedef void __fastcall (__closure *TiipPipeServerDataInEvent)(System::TObject* Sender, TiipPipeServerDataInEventParams *e);
__property TiipPipeServerDataInEvent OnDataIn = { read=FOnDataIn, write=FOnDataIn };

Remarks

Trapping the DataIn event is your only chance to get the data coming from the other end of the connection specified by ConnectionId. The incoming data are provided through the Text parameter.

EOL indicates whether or not the EOL string was found at the end of Text. If the EOL string was found, then EOL is True.

If Text is part of the data portion of length larger than either DefaultMaxLineLength or with no EOL strings in it, then EOL is False. Please note that this means that one or more DataIn events with EOL set to False can be received during a connection.

If the EOL property is "" (empty string), then EOL can be disregarded (it is always True).

Note: Events are not re-entrant. Performing time-consuming operations within this event will prevent it from firing again in a timely manner and may affect overall performance.

Disconnected Event (PipeServer Component)

Fires when a client disconnects.

Syntax

typedef struct {
  int ConnectionId;
} TiipPipeServerDisconnectedEventParams;
typedef void __fastcall (__closure *TiipPipeServerDisconnectedEvent)(System::TObject* Sender, TiipPipeServerDisconnectedEventParams *e);
__property TiipPipeServerDisconnectedEvent OnDisconnected = { read=FOnDisconnected, write=FOnDisconnected };

Remarks

This event fires when a client disconnects. The ConnectionId parameters identifies the client that is disconnected.

Error Event (PipeServer Component)

This event fires information about errors during data delivery.

Syntax

typedef struct {
  int ConnectionId;
  int ErrorCode;
  String Description;
} TiipPipeServerErrorEventParams;
typedef void __fastcall (__closure *TiipPipeServerErrorEvent)(System::TObject* Sender, TiipPipeServerErrorEventParams *e);
__property TiipPipeServerErrorEvent OnError = { read=FOnError, write=FOnError };

Remarks

The Error event is fired in case of exceptional conditions during message processing. Normally, the component raises an exception.

ErrorCode contains an error code and Description contains a textual description of the error. For a list of valid error codes and their descriptions, please refer to the Error Codes section.

ConnectionId indicates the connection for which the error is applicable.

ReadyToSend Event (PipeServer Component)

Fired when the component is ready to send data.

Syntax

typedef struct {
  int ConnectionId;
} TiipPipeServerReadyToSendEventParams;
typedef void __fastcall (__closure *TiipPipeServerReadyToSendEvent)(System::TObject* Sender, TiipPipeServerReadyToSendEventParams *e);
__property TiipPipeServerReadyToSendEvent OnReadyToSend = { read=FOnReadyToSend, write=FOnReadyToSend };

Remarks

The ReadyToSend event indicates that the underlying pipe is ready to accept data after a failed DataToSend. The event is also fired immediately after a connection to the remote host is established.

Config Settings (PipeServer Component)

The component accepts one or more of the following configuration settings. Configuration settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the component, access to these internal properties is provided through the Config method.

PipeServer Config Settings

Base Config Settings

Trappable Errors (PipeServer Component)

PipeServer Errors

	401   Failed to create event.
	402   Failed to create security descriptor.
	403   Error creating named pipe.
	404   Error connecting to named pipe.
	405   Error disconnecting named pipe.
	408   Error sending data.
	410   Invalid MaxLineLength value.
	411   Error reading data.
	412   Error invoking RegisterWaitForSingleObject.
	413   Operation would block.
	414   Named pipe does not exist.
	415   Named pipe is already connected.
	416   Error connecting to named pipe.
	417   Named pipe not connected.
	419   Unsupported operation, see error message for details.
	424   Invalid ConnectionID.