PInternetProtocol Class Reference

A TCP/IP socket for process/application layer high level protocols. More...

`#include <inetprot.h>`

Inheritance diagram for PInternetProtocol:

## Public Member Functions

virtual PBoolean | Read (void *buf, PINDEX len)
| Low level read from the channel. More...
virtual PBoolean | Write (const void *buf, PINDEX len)
| Low level write to the channel. More...
void | SetReadLineTimeout (const PTimeInterval &t)
| Set the maximum timeout between characters within a line. More...
virtual PBoolean | Connect (const PString &address, WORD port=0)
| Connect a socket to a remote host for the internet protocol. More...
virtual PBoolean | Connect (const PString &address, const PString &service)
virtual PBoolean | Accept (PSocket &listener)
| Accept a server socket to a remote host for the internet protocol. More...
const PString & | GetDefaultService () const
| Get the default service name or port number to use in socket connections. More...
PIPSocket * | GetSocket () const
| Get the eventual socket for the series of indirect channels that may be between the current protocol and the actual I/O channel. More...
virtual PBoolean | WriteLine (const PString &line)
| Write a string to the socket channel followed by a CR/LF pair. More...
virtual PBoolean | ReadLine (PString &line, PBoolean allowContinuation=false)
| Read a string from the socket channel up to a CR/LF pair. More...
virtual void | UnRead (int ch)
| Put back the characters into the data stream so that the next Read() function call will return them first. More...
virtual void | UnRead (const PString &str)
virtual void | UnRead (const void *buffer, PINDEX len)
virtual PBoolean | WriteCommand (PINDEX cmdNumber)
| Write a single line for a command. More...
virtual PBoolean | WriteCommand (PINDEX cmdNumber, const PString &param)
virtual PBoolean | ReadCommand (PINDEX &num, PString &args)
| Read a single line of a command which ends with a CR/LF pair. More...
virtual PBoolean | WriteResponse (unsigned numericCode, const PString &info)
| Write a response code followed by a text string describing the response to a command. More...
virtual PBoolean | WriteResponse (const PString &code, const PString &info)
virtual PBoolean | ReadResponse ()
| Read a response code followed by a text string describing the response to a command. More...
virtual PBoolean | ReadResponse (int &code, PString &info)
virtual int | ExecuteCommand (PINDEX cmdNumber)
| Write a command to the socket, using `WriteCommand()` and await a response using `ReadResponse()`. More...
virtual int | ExecuteCommand (PINDEX cmdNumber, const PString &param)
int | GetLastResponseCode () const
| Return the code associated with the last response received by the socket. More...
PString | GetLastResponseInfo () const
| Return the last response received by the socket. More...
Public Member Functions inherited from PIndirectChannel
| PIndirectChannel ()
| Create a new indirect channel without any channels to redirect to. More...
| ~PIndirectChannel ()
| Close the indirect channel, deleting read/write channels if desired. More...
Comparison | Compare (const PObject &obj) const
| Determine if the two objects refer to the same indirect channel. More...
virtual PString | GetName () const
| Get the name of the channel. More...
virtual PBoolean | Close ()
| Close the channel. More...
virtual PBoolean | IsOpen () const
| Determine if the channel is currently open and read and write operations can be executed on it. More...
virtual PBoolean | Shutdown (ShutdownValue option)
| Close one or both of the data streams associated with a channel. More...
virtual bool | SetLocalEcho (bool localEcho)
| Set local echo mode. More...
virtual PChannel * | GetBaseReadChannel () const
| This function returns the eventual base channel for reading of a series of indirect channels provided by descendents of `PIndirectChannel`. More...
virtual PChannel * | GetBaseWriteChannel () const
| This function returns the eventual base channel for writing of a series of indirect channels provided by descendents of `PIndirectChannel`. More...
virtual PString | GetErrorText (ErrorGroup group=NumErrorGroups) const
| Get error message description. More...
PBoolean | Open (PChannel &channel)
| Set the channel for both read and write operations. More...
PBoolean | Open (PChannel *channel, PBoolean autoDelete=true)
| Set the channel for both read and write operations. More...
PBoolean | Open (PChannel *readChannel, PChannel *writeChannel, PBoolean autoDeleteRead=true, PBoolean autoDeleteWrite=true)
| Set the channel for both read and write operations. More...
PChannel * | GetReadChannel () const
| Get the channel used for read operations. More...
bool | SetReadChannel (PChannel *channel, bool autoDelete=true, bool closeExisting=false)
| Set the channel for read operations. More...
PChannel * | GetWriteChannel () const
| Get the channel used for write operations. More...
PBoolean | SetWriteChannel (PChannel *channel, bool autoDelete=true, bool closeExisting=false)
| Set the channel for read operations. More...
Public Member Functions inherited from PChannel
PBoolean | SetErrorValues (Errors errorCode, int osError, ErrorGroup group=LastGeneralError)
| Set error values to those specified. More...
| PChannel ()
| Create the channel. More...
| ~PChannel ()
| Close down the channel. More...
virtual PINDEX | HashFunction () const
| Calculate a hash value for use in sets and dictionaries. More...
int | GetHandle () const
| Get the integer operating system handle for the channel. More...
void | SetReadTimeout (const PTimeInterval &time)
| Set the timeout for read operations. More...
PTimeInterval | GetReadTimeout () const
| Get the timeout for read operations. More...
virtual PINDEX | GetLastReadCount () const
| Get the number of bytes read by the last Read() call. More...
virtual int | ReadChar ()
| Read a single 8 bit byte from the channel. More...
PBoolean | ReadBlock (void *buf, PINDEX len)
| Read len bytes into the buffer from the channel. More...
PString | ReadString (PINDEX len)
| Read `len` character into a string from the channel. More...
virtual PBoolean | ReadAsync (void *buf, PINDEX len)
| Begin an asynchronous read from channel. More...
virtual void | OnReadComplete (void *buf, PINDEX len)
| User callback function for when a `ReadAsync()` call has completed or timed out. More...
void | SetWriteTimeout (const PTimeInterval &time)
| Set the timeout for write operations to complete. More...
PTimeInterval | GetWriteTimeout () const
| Get the timeout for write operations to complete. More...
virtual PBoolean | Write (const void *buf, PINDEX len, const void *mark)
| Low level write to the channel with marker. More...
virtual PINDEX | GetLastWriteCount () const
| Get the number of bytes written by the last Write() call. More...
PBoolean | WriteChar (int c)
| Write a single character to the channel. More...
PBoolean | WriteString (const PString &str)
| Write a string to the channel. More...
virtual PBoolean | WriteAsync (const void *buf, PINDEX len)
| Begin an asynchronous write from channel. More...
virtual void | OnWriteComplete (const void *buf, PINDEX len)
| User callback function for when a WriteAsync() call has completed or timed out. More...
virtual bool | FlowControl (const void *flowData)
| Flow Control information Pass data to the channel for flowControl determination. More...
PBoolean | SetBufferSize (PINDEX newSize)
| Set the iostream buffer size for reads and writes. More...
PBoolean | SendCommandString (const PString &command)
| Send a command meta-string. More...
void | AbortCommandString ()
| Abort a command string that is in progress. More...
Errors | GetErrorCode (ErrorGroup group=NumErrorGroups) const
| Get normalised error code. More...
int | GetErrorNumber (ErrorGroup group=NumErrorGroups) const
| Get OS errro code. More...
virtual PBoolean | Read (const VectorOfSlice &slices)
| Low level scattered read from the channel. More...
virtual PBoolean | Write (const VectorOfSlice &slices)
| Low level scattered write to the channel. More...
Public Member Functions inherited from PObject
virtual | ~PObject ()
virtual PObject * | Clone () const
| Create a copy of the class on the heap. More...
virtual Comparison | CompareObjectMemoryDirect (const PObject &obj) const
| Determine the byte wise comparison of two objects. More...
bool | operator== (const PObject &obj) const
| Compare the two objects. More...
bool | operator!= (const PObject &obj) const
| Compare the two objects. More...
bool | operator< (const PObject &obj) const
| Compare the two objects. More...
bool | operator> (const PObject &obj) const
| Compare the two objects. More...
bool | operator<= (const PObject &obj) const
| Compare the two objects. More...
bool | operator>= (const PObject &obj) const
| Compare the two objects. More...
virtual const char * | GetClass (unsigned ancestor=0) const
| Get the current dynamic type of the object instance. More...
PBoolean | IsClass (const char *cls) const
virtual PBoolean | InternalIsDescendant (const char *clsName) const
| Determine if the dynamic type of the current instance is a descendent of the specified class. More...
virtual void | PrintOn (ostream &strm) const
| Output the contents of the object to the stream. More...
virtual void | ReadFrom (istream &strm)
| Input the contents of the object from the stream. More...

## Protected Types

enum | StuffState { DontStuff, StuffIdle, StuffCR, StuffCRLF, StuffCRLFdot, StuffCRLFdotCR }

## Protected Member Functions

| PInternetProtocol (const char *defaultServiceName, PINDEX cmdCount, char const *const *cmdNames)
virtual PINDEX | ParseResponse (const PString &line)
| Parse a response line string into a response code and any extra info on the line. More...
Protected Member Functions inherited from PIndirectChannel
virtual PBoolean | OnOpen ()
| This callback is executed when the Open() function is called with open channels. More...
Protected Member Functions inherited from PChannel
| PChannel (const PChannel &)
PChannel & | operator= (const PChannel &)
virtual PBoolean | ConvertOSError (int libcReturnValue, ErrorGroup group=LastGeneralError)
| Convert an operating system error into platform independent error. More...
int | ReadCharWithTimeout (PTimeInterval &timeout)
| Read a character with specified timeout. More...
PBoolean | ReceiveCommandString (int nextChar, const PString &reply, PINDEX &pos, PINDEX start)
PBoolean | PXSetIOBlock (PXBlockType type, const PTimeInterval &timeout)
int | PXClose ()
Protected Member Functions inherited from PObject
| PObject ()
| Constructor for PObject, made protected so cannot ever create one on its own. More...

## Protected Attributes

PString | defaultServiceName
PStringArray | commandNames
PCharArray | unReadBuffer
PINDEX | unReadCount
PTimeInterval | readLineTimeout
enum PInternetProtocol::StuffState | stuffingState
PBoolean | newLineToCRLF
int | lastResponseCode
PString | lastResponseInfo
Protected Attributes inherited from PIndirectChannel
PChannel * | readChannel
| Channel for read operations. More...
PBoolean | readAutoDelete
| Automatically delete read channel on destruction. More...
PChannel * | writeChannel
| Channel for write operations. More...
PBoolean | writeAutoDelete
| Automatically delete write channel on destruction. More...
PReadWriteMutex | channelPointerMutex
| Race condition prevention on closing channel. More...
Protected Attributes inherited from PChannel
int | os_handle
| The operating system file handle return by standard open() function. More...
Errors | lastErrorCode [NumErrorGroups+1]
| The platform independant error code. More...
int | lastErrorNumber [NumErrorGroups+1]
| The operating system error number (eg as returned by errno). More...
PINDEX | lastReadCount
| Number of byte last read by the Read() function. More...
PINDEX | lastWriteCount
| Number of byte last written by the Write() function. More...
PTimeInterval | readTimeout
| Timeout for read operations. More...
PTimeInterval | writeTimeout
| Timeout for write operations. More...
PString | channelName
PMutex | px_threadMutex
PXBlockType | px_lastBlockType
PThread * | px_readThread
PThread * | px_writeThread
PMutex | px_writeMutex
PThread * | px_selectThread [3]
PMutex | px_selectMutex [3]

## Additional Inherited Members

Public Types inherited from PChannel
enum | PXBlockType { PXReadBlock, PXWriteBlock, PXAcceptBlock, PXConnectBlock }
enum | ShutdownValue { ShutdownRead = 0, ShutdownWrite = 1, ShutdownReadAndWrite = 2 }
enum | Errors { NoError, NotFound, FileExists, DiskFull, AccessDenied, DeviceInUse, BadParameter, NoMemory, NotOpen, Timeout, Interrupted, BufferTooSmall, Miscellaneous, ProtocolFailure, NumNormalisedErrors }
| Normalised error codes. More...
enum | ErrorGroup { LastReadError, LastWriteError, LastGeneralError, NumErrorGroups }
| Error groups. More...
typedef std::vector< Slice > | VectorOfSlice
Public Types inherited from PObject
enum | Comparison { LessThan = -1, EqualTo = 0, GreaterThan = 1 }
| Result of the comparison operation performed by the `Compare()` function. More...
Static Public Member Functions inherited from PChannel
static PBoolean | ConvertOSError (int libcReturnValue, Errors &lastError, int &osError)
| Convert an operating system error into platform independent error. More...
static PString | GetErrorText (Errors lastError, int osError=0)
| Get error message description. More...
Static Public Member Functions inherited from PObject
static Comparison | InternalCompareObjectMemoryDirect (const PObject *obj1, const PObject *obj2, PINDEX size)
| Internal function caled from CompareObjectMemoryDirect() More...
static const char * | Class ()
| Get the name of the class as a C string. More...

## Detailed Description

A TCP/IP socket for process/application layer high level protocols.

All of these protocols execute commands and responses in a standard manner.

A command consists of a line starting with a short, case insensitive command string terminated by a space or the end of the line. This may be followed by optional arguments.

A response to a command is usually a number and/or a short string eg "OK". The response may be followed by additional information about the response but this is not typically used by the protocol. It is only for user information and may be tracked in log files etc.

All command and reponse lines of the protocol are terminated by a CR/LF pair. A command or response line may be followed by additional data as determined by the protocol, but this data is "outside" the protocol specification as defined by this class.

The default read timeout is to 10 minutes by the constructor.

## Member Enumeration Documentation

enum PInternetProtocol::StuffState

protected

Enumerator
DontStuff |
StuffIdle |
StuffCR |
StuffCRLF |
StuffCRLFdot |
StuffCRLFdotCR |

## Constructor & Destructor Documentation

PInternetProtocol::PInternetProtocol | ( | const char * | defaultServiceName,
|  | PINDEX | cmdCount,
|  | char const *const * | cmdNames
| ) |  |

protected

Parameters

  defaultServiceName | Service name for the protocol.
  cmdCount | Number of command strings.
  cmdNames | Strings for each command.

## Member Function Documentation

virtual PBoolean PInternetProtocol::Accept | ( | PSocket & | listener | ) |

virtual

Accept a server socket to a remote host for the internet protocol.

Returns
  true if the channel was successfully connected to the remote host.

Parameters

  listener | Address of remote machine to connect to.

virtual PBoolean PInternetProtocol::Connect | ( | const PString & | address,
|  | WORD | port = `0`
| ) |  |

virtual

Connect a socket to a remote host for the internet protocol.

Returns
  true if the channel was successfully connected to the remote host.

Parameters

  address | Address of remote machine to connect to.
  port | Port number to use for the connection.

virtual PBoolean PInternetProtocol::Connect | ( | const PString & | address,
|  | const PString & | service
| ) |  |

virtual

Parameters

  address | Address of remote machine to connect to.
  service | Service name to use for the connection.

virtual int PInternetProtocol::ExecuteCommand | ( | PINDEX | cmdNumber | ) |

virtual

Write a command to the socket, using `WriteCommand()` and await a response using `ReadResponse()`.

The first character of the response is returned, as well as the entire response being saved into the protected member variables `lastResponseCode` and `lastResponseInfo`.

This function is typically used by client forms of the socket.

Returns
  First character of response string or '\0' if a socket error occurred.

Parameters

  cmdNumber | Number of command to write.

virtual int PInternetProtocol::ExecuteCommand | ( | PINDEX | cmdNumber,
|  | const PString & | param
| ) |  |

virtual

Parameters

  cmdNumber | Number of command to write.
  param | Extra parameters required by the command.

const PString& PInternetProtocol::GetDefaultService | ( |  | ) | const

Get the default service name or port number to use in socket connections.

Returns
  string for the default service name.

int PInternetProtocol::GetLastResponseCode | ( |  | ) | const

Return the code associated with the last response received by the socket.

Returns
  Response code

PString PInternetProtocol::GetLastResponseInfo | ( |  | ) | const

Return the last response received by the socket.

Returns
  Response as a string

PIPSocket* PInternetProtocol::GetSocket | ( |  | ) | const

Get the eventual socket for the series of indirect channels that may be between the current protocol and the actual I/O channel.

This will assert if the I/O channel is not an IP socket.

Returns
  true if the string and CR/LF were completely written.

virtual PINDEX PInternetProtocol::ParseResponse | ( | const PString & | line | ) |

protected virtual

Parse a response line string into a response code and any extra info on the line.

Results are placed into the member variables `lastResponseCode` and `lastResponseInfo`.

The default bahaviour looks for a space or a '-' and splits the code and info either side of that character, then returns false.

Returns
  Position of continuation character in response, 0 if no continuation lines are possible.

Parameters

  line | Input response line to be parsed

Reimplemented in PPOP3, and PHTTP.

virtual PBoolean PInternetProtocol::Read | ( | void * | buf,
|  | PINDEX | len
| ) |  |

virtual

Low level read from the channel.

This override also supports the mechanism in the UnRead() function allowing characters to be be "put back" into the data stream. This allows a look-ahead required by the logic of some protocols. This is completely independent of the standard iostream mechanisms which do not support the level of timeout control required by the protocols.

Returns
  true if at least len bytes were written to the channel.

Parameters

  buf | Pointer to a block of memory to receive the read bytes.
  len | Maximum number of bytes to read into the buffer.

Reimplemented from PIndirectChannel.

virtual PBoolean PInternetProtocol::ReadCommand | ( | PINDEX & | num,
|  | PString & | args
| ) |  |

virtual

Read a single line of a command which ends with a CR/LF pair.

The command number for the command name is parsed from the input, then the remaining text on the line is returned in the `args` parameter.

If the command does not match any of the command names then the entire line is placed in the `args` parameter and a value of P_MAX_INDEX is returned.

Note this function will block for the time specified by the PChannel::SetReadTimeout() function.

This function is typically used by server forms of the socket.

Returns
  true if something was read, otherwise an I/O error occurred.

Parameters

  num | Number of the command parsed from the command line, or P_MAX_INDEX if no match.
  args | String to receive the arguments to the command.

virtual PBoolean PInternetProtocol::ReadLine | ( | PString & | line,
|  | PBoolean | allowContinuation = `false`
| ) |  |

virtual

Read a string from the socket channel up to a CR/LF pair.

If the `unstuffLine` parameter is set then the function will remove the '.' character from the start of any line that begins with two consecutive '.' characters. A line that has is exclusively a '.' character will make the function return false.

Note this function will block for the time specified by the PChannel::SetReadTimeout() function for only the first character in the line. The rest of the characters must each arrive within the time set by the `readLineTimeout` member variable. The timeout is set back to the original setting when the function returns.

Returns
  true if a CR/LF pair was received, false if a timeout or error occurred.

Parameters

  line | String to receive a CR/LF terminated line.
  allowContinuation | Flag to handle continued lines.

virtual PBoolean PInternetProtocol::ReadResponse | ( |  | ) |

virtual

Read a response code followed by a text string describing the response to a command.

The form of the response is to have the code string, then the info string.

The response may have multiple lines in it. A '-' character separates the code from the text on all lines but the last where a ' ' character is used. The `info` parameter will have placed in it all of the response lines separated by a single '\n' character.

The first form places the response code and info into the protected member variables `lastResponseCode` and `lastResponseInfo`.

This function is typically used by client forms of the socket.

Returns
  true if the response was completely read without a socket error.

virtual PBoolean PInternetProtocol::ReadResponse | ( | int & | code,
|  | PString & | info
| ) |  |

virtual

Parameters

  code | Response code for command response.
  info | Extra information available after response code.

void PInternetProtocol::SetReadLineTimeout | ( | const PTimeInterval & | t | ) |

Set the maximum timeout between characters within a line.

Default value is 10 seconds.

virtual void PInternetProtocol::UnRead | ( | int | ch | ) |

virtual

Put back the characters into the data stream so that the next Read() function call will return them first.

Parameters

  ch | Individual character to be returned.

virtual void PInternetProtocol::UnRead | ( | const PString & | str | ) |

virtual

Parameters

  str | String to be put back into data stream.

virtual void PInternetProtocol::UnRead | ( | const void * | buffer,
|  | PINDEX | len
| ) |  |

virtual

Parameters

  buffer | Characters to be put back into data stream.
  len | Number of characters to be returned.

virtual PBoolean PInternetProtocol::Write | ( | const void * | buf,
|  | PINDEX | len
| ) |  |

virtual

Low level write to the channel.

This override assures that the sequence CR/LF/./CR/LF does not occur by byte stuffing an extra '.' character into the data stream, whenever a line begins with a '.' character.

Note that this only occurs if the member variable `stuffingState` has been set to some value other than `DontStuff`, usually `StuffIdle`. Also, if the `newLineToCRLF` member variable is true then all occurrences of a '\n' character will be translated to a CR/LF pair.

Returns
  true if at least len bytes were written to the channel.

Parameters

  buf | Pointer to a block of memory to write.
  len | Number of bytes to write.

Reimplemented from PIndirectChannel.

virtual PBoolean PInternetProtocol::WriteCommand | ( | PINDEX | cmdNumber | ) |

virtual

Write a single line for a command.

The command name for the command number is output, then a space, the the `param` string followed at the end with a CR/LF pair.

If the `cmdNumber` parameter is outside of the range of valid command names, then the function does not send anything and returns false.

This function is typically used by client forms of the socket.

Returns
  true if the command was completely written.

Parameters

  cmdNumber | Number of command to write.

virtual PBoolean PInternetProtocol::WriteCommand | ( | PINDEX | cmdNumber,
|  | const PString & | param
| ) |  |

virtual

Parameters

  cmdNumber | Number of command to write.
  param | Extra parameters required by the command.

virtual PBoolean PInternetProtocol::WriteLine | ( | const PString & | line | ) |

virtual

Write a string to the socket channel followed by a CR/LF pair.

If there are any lone CR or LF characters in the `line` parameter string, then these are translated into CR/LF pairs.

Returns
  true if the string and CR/LF were completely written.

Parameters

  line | String to write as a command line.

virtual PBoolean PInternetProtocol::WriteResponse | ( | unsigned | numericCode,
|  | const PString & | info
| ) |  |

virtual

Write a response code followed by a text string describing the response to a command.

The form of the response is to place the code string, then the info string.

If the `info` parameter has multiple lines then each line has the response code at the start. A '-' character separates the code from the text on all lines but the last where a ' ' character is used.

The first form assumes that the response code is a 3 digit numerical code. The second form allows for any arbitrary string to be the code.

This function is typically used by server forms of the socket.

Returns
  true if the response was completely written.

Parameters

  numericCode | Response code for command response.
  info | Extra information available after response code.

virtual PBoolean PInternetProtocol::WriteResponse | ( | const PString & | code,
|  | const PString & | info
| ) |  |

virtual

Parameters

  code | Response code for command response.
  info | Extra information available after response code.

## Member Data Documentation

PStringArray PInternetProtocol::commandNames

protected

PString PInternetProtocol::defaultServiceName

protected

int PInternetProtocol::lastResponseCode

protected

PString PInternetProtocol::lastResponseInfo

protected

PBoolean PInternetProtocol::newLineToCRLF

protected

PTimeInterval PInternetProtocol::readLineTimeout

protected

enum PInternetProtocol::StuffState PInternetProtocol::stuffingState

protected

PCharArray PInternetProtocol::unReadBuffer

protected

PINDEX PInternetProtocol::unReadCount

protected

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

- inetprot.h