bbd1e6b0a4
* harbour/source/rtl/hbinet.c
! modified hb_inetRecv[All]() to always return number
of bytes read if at least one byte was successfully read
just like in documentation so it's not longer necessary to
use hb_inetCount() to check real number of read bytes.
On error they return -1 and 0 when foreign host closed connection.
! modified hb_inetSend[All]() to always return number of written
bytes if at least one byte was successfully written so it's not
longer necessary to use hb_inetCount() to check real number of
written bytes. On error they return -1.
! modified hb_inetRecvLine() to return "" on errors and always
set numeric value with error code or number of bytes read
in 2-nd parameter passed by reference
! modified hb_inetDataReady() to return -1 instead of .F. to
indicate errors when socket is not open socket
! modified hb_inetRecvLine() and hb_inetRecvEndBlock() to work
like in documentation and set in 2-nd parameter passed by
reference the size of read line with line terminator, -1
or error and 0 when foreign host closed connection.
! modified hb_inetRecvEndBlock() to always use default EOL when
there is no not empty string in passed string parameter or
passed array with line terminators
! fixed some small differences between hb_inetRecvLine() and
hb_inetRecvEndBlock()
! fixed returned values in hb_InetDGramSend() and hb_InetDGramRecv()
to be synced with documentation
* minor: modified hb_inetRecvEndBlock() to use as default EOL
s_inetCRLF instead of hardcoded "\r\n"
* eliminated some redundant code
+ added automatic socket initialization in windows builds
% added support for read ahead buffer in hb_inetRecvLine() and
hb_inetRecvEndBlock() and updated other functions which may
interact with it. It greatly improved the speed of code
which extensively uses above functions.
Warning!!! Above modifications may force updating other code which used
some undocumented hb_inet*() functions behavior i.e. some side
effects in previous implementation. Please update your code
if necessary.
* harbour/doc/inet.txt
! modified hb_inetAccept() documentation wrongly describing value
returned on error when it's NIL
* harbour/config/os2/watcom.cf
! fixes for real OS2 command processor - please test
365 lines
19 KiB
Plaintext
365 lines
19 KiB
Plaintext
/*
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* $Id$
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*/
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HARBOUR INET API
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------------------
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Giancarlo Niccolai <gian@niccolai.ws>
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/* $DOC$
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* $FUNCNAME$
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* harbour Inet functions
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* $CATEGORY$
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* harbour Enhacements
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* $ONELINER$
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* HARBOUR INET API
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* $DESCRIPTION$
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*
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* STATUS OF THIS DOCUMENT
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*
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*
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* This is just a draft, a survival guide with minimal API instructions
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* extracted from the inet.c program comments and from some posting to
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* the xharbour newsgroup.
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*
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* More adequate version will be available soon.
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*
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*
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* HARBOUR INET API
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* ================
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*
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*
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* Startup / cleanup functions
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* ---------------------------
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*
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* hb_InetInit() -->NIL
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* Activates inet support; mainly used for winsock start up at the moment, but
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* could be used in the future for many other purpose. Put it at the beginning
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* of every program using INET functions.
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*
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*
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* hb_InetCleanup() -->NIL
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* Closes Inet support; mainly used for Windows. Put it at the end of any program
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* using Inet functions, just before the program exits.
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*
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* hb_InetCreate() --> SOCKET
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* Creates the raw data of the socket, that can be passed to an asynchronous
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* connection function (hb_InetConnect or hb_InetConnectIP). This will prevent the
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* connection function from allocating some data that could be never used in
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* certain cases, i.e. an asynchronously detected timeout.
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*
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* hb_InetClose( SOCKET ) --> NUMERIC
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* Closes the socket, notifiying both ends of the communication pipe that the
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* connection is over. If you have threads waiting for data to be read from
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* this socket, this method will make them stop waiting and return an error
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* (socket closed) to their callers.
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* The method does not destroy the socket, which can be used by subordinate
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* threads to check that the socket is closed, and so they should stop as soon
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* as they can. Don't destroy the socket unless you are sure that no other
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* thread is using it.
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* RETURNS 0 on success or -1 on error; on error, the error code is set;
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* (actually, on success the socket error code is set to 1 -- socket closed )
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*
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*
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* hb_InetDestroy( SOCKET ) --> Numeric
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* Closes AND destroys a socket. After this call, the socket can't be used
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* anymore. Returns 0 on success -1 on failure.
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*
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*
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* hb_InetSetTimeout( SOCKET, nMillisecs ) --> NIL
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* Sets the default timeout of the given socket. Default timeout is used in all
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* blocking operations: if the operation can't be done in nMillisec milliseconds,
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* the function returns immediately and the hb_InetErrorCode( SOCKET ) returns -1.
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* The default timeout is not the maximum time that a function using the socket
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* is allowed to execute: it is the maximum time that each single blocking
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* operation inside that function is allowed to hold the control of the socket.
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* So, an function like hb_InetReadAll(), that may repeat a raw recv() several
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* times, is not guaranteed to terminate in nMillisecs, but you are guaranteed
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* that if any of that raw socket read operation is going to take more than
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* nMillisecs, the function will be terminated.
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* When created, a socket is created with an infinite default timeout (-1).
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*
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* hb_InetGetTimeout( SOCKET ) --> NUMERIC
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* Returns the timeout set for the given socket.
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*
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* hb_InetClearTimeout( SOCKET, nMillisecs ) --> NIL
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* Clears the default timeout of the given socket. Default timeout is used in all
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* blocking operations.
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*
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*
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* Informative functions
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* ---------------------
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*
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* hb_InetErrorCode( SOCKET ) --> Numeric
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* Returns the last error code that has been provoked by a network operation,
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* or 0 if none. Error codes are the ones used for winsock or UnixSockets (they
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* are the same); 1 is reserved for "connection closed" message.
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*
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*
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* hb_InetErrorDesc( SOCKET ) --> String
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* Returns a string describing the last error that occurred in the socket;
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* the string is system dependent, and should be used only for debugging
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* purposes.
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*
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*
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* hb_InetCount( SOCKET ) --> Numeric
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* Returns the amount of characters read or written in the latest socket
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* operation.
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*
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*
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* hb_InetAddress( SOCKET ) --> STRING
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* Returns a string representing the remote server address in quad dot notation,
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* e.g. "192.168.1.1", or the local server address if the socket is server
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* side.
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* TODO: have a version that returns a vector of 4 numbers.
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*
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*
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* hb_InetPort( SOCKET ) --> STRING
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* Returns the port to which this socket is bound, or the remote port if this
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* socket is connected with a remote host or client
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*
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* Server Side socket functions
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* ----------------------------
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*
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* hb_InetServer( port [, cBindAddr [, nListenLimit]] ) --> SOCKET
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* Creates a server that can accept connections from client on a certain port.
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* If the computer on which hb_InetServe is called has more than one logical
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* interface (e.g. one network card, one loopback and one PPP address),
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* cBindAddr can be specified to select only one of these interfaces to accept
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* connections for this process. This is useful when a server is present on
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* two networks, and the service is to be available only in one of them. Also,
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* the same port on other addresses is left free to be used, so you can have
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* different server programs running for different networks but managing
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* the same service. In example, an FTP server available to the internal
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* network could be radically different from an FTP server available for
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* the internet.
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* nListenLimit is an internal parameter and rarely needs to be specified.
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* This is the number of incoming connections accepted by kernel before the
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* kernel has the chance to report them to the application program. If
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* the sockets receive nListenLimit connections before accepting them
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* all, the nListenLimit + 1 connection will be notified to be "busy" by
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* the kernel. Usually, a value of 10 (the default) is enough for even
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* a heavy duty server.
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* On error, sets error description in the newly returned socket.
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*
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* hb_InetAccept( SOCKET ) --> SOCKET
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* Waits until a connection is available on a socket created with hb_InetServer;
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* Returns a socket that can be used to communicate with the incoming client.
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* On error, NIL is returned and error code sets in the passed SOCKET.
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* This error can be accessed using hb_InetErrorCode() function.
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*
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* Client side socket functions
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* ----------------------------
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*
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* hb_InetConnect( cAddress, nPort ) --> SOCKET
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* hb_InetConnect( cAddress, nPort, SOCKET ) --> NIL
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* Connects to a remote server described by cAddress, that can be in
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* quad dot notation (e.g. "192.168.1.1") or in DNS name (e.g.
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* "www.xharbour.org"), using the desired port.
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* hb_InetConnect uses "gethostbyname" C system call to
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* find the network address of the specified server; this means that
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* this call is an hybrid function doing both a DNS scan and a TCP/IP
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* connection. hb_InetConnect is not thread safe, and the xHarbour
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* program must take care that two hb_InetConnect functions are never
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* called at the same moment from two different threads (or that
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* hb_InetGetHosts is not called in the same moment as an hb_InetConnect).
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* The second version of this function accepts a pre-built socket
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* as a parameter. This allows to kill asyncronously a thread waiting
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* for hb_InetConnect to connect, and then cleaning up the leftover
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* socket data. Also, it is possible to give timeout to the given SOCKET,
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* but this timeout will be used only in the connection phase, after that
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* the network address resolution is completed. Use GetHosts() and
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* hb_InetConnectIP for a finer timeout control.
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* On error, the error of the returned socket is set. The error could
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* be due to unavailable name resolving service, host name not valid,
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* host address not reachable and host reachable but port not open.
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*
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*
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* hb_InetConnectIP( cAddress, PORT ) --> SOCKET
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* hb_InetConnectIP( cAddress, PORT, SOCKET ) --> NIL
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* Connects to a remote server described by cAddress, that can be specified
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* only in quad dot IPV4 notation (e.g. "127.0.0.1"), using the desired port.
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* This version of hb_InetConnect does not use gethostbyname, and thus is thread
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* safe and can be used in combination with hb_InetGetHosts to have a finer
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* timeout control while connecting to a server, and a finer error control.
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* The second version of this function accepts a pre-built socket
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* as a parameter. This allows to kill asyncronously a thread waiting
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* for hb_InetConnectIP to connect, and then cleaning up the leftover
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* socket data. Also, it is possible to give timeout at the given SOCKET.
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*
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* On error, the error of the returned socket is set.
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*
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*
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*
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* Sending and receiving data
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* ----------------------------
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*
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* hb_InetRecv( SOCKET, @cString [, nAmount] ) --> NUMERIC
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* Reads at maximum nAmount bytes (or a number of bytes equal to cString
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* length if nAmount is not given) from the socket into cString.
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* The parameter cString must be preallocated so that it has enough
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* space to receive the data. The routine will block the thread until some
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* bytes are read from the socket, the socket is closed (either from the
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* receiver or the sender side) or a network error occurs, whichever comes
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* first. In the latter cases, an error is set, and only the characters
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* received until premature end of communications are returned.
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* Notice that there is no guarantee that all the available bytes will be
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* read before the function returns, in fact, hb_InetRecv returns as soon it
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* is able to fill cString with one or more bytes. To block the current
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* process until the whole cString is filled (or nAmount bytes are read),
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* use the hb_InetRecvALL().
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* RETURNS the number of the characters read from the SOCKET.
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*
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*
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* hb_InetRecvAll( SOCKET, @cString [, @nAmount] ) --> NUMERIC
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* This function works exactly as hb_InetRecv, except for the fact that it
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* blocks until nAmount bytes are read, if nAmount is given, or
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* cString is filled for its whole length.
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* RETURNS the number of the characters read from the SOCKET. Might be
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* less than nAmount on premature socket closing or on network error.
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*
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*
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* hb_InetRecvLine( SOCKET [, @nResult, [, nMaxLength [, nBufSize]]] ) --> STRING
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* Blocks the calling thread until a sequence CRLF is read from the socket.
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* Incremental allocation and end-of-line checking are done in an efficient
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* way. If an error occurs, or if the stream is closed before a CRLF is read,
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* the function returns nothing and sets the socket error.
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* The returned string does not contain the trailing CRLF sequence, so an
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* empty line is effectively returned as an empty string.
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* If the nResult parameter is given, it will contain the number of bytes
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* read from the socket, including the CRLF sequence, so that in normal
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* conditions, nResult will report a count equal to the length of the
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* returned string plus 2. nResult will be 0 if stream is closed before
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* a CRLF sequence is read, and will be -1 on error.
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* An optional MaxLength parameter can be given to allow a maximum character
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* count before the data is returned anyway. If this number is hit before
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* a CRLF sequence is encountered, nResult will contain the value one.
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* Finally, a nBufSize parameter can be given. If not, memory allocation
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* will be increased by discrete amounts of 80 bytes. The programmer
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* can provide here a different allocation strategy (e.g. setting nBufSize
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* equal to nMaxLength, memory for reading the line will be allocated only
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* once, at the beginning of the function).
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*
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*
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* hb_InetRecvEndBlock( SOCKET [, cBlock [, @nResult, [, nMaxLength [,
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* nBufSize]]]] ) --> STRING
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* This function operates exactly the same way as hb_InetRecvLine, but
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* the "record termination" is customizable thorugh the cBlock parameter.
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* If not given, this parameter defaults to the CRLF sequence.
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* Provided by: Marcelo Lombardo
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*
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*
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* hb_InetDataReady( SOCKET [, nMillisecs] ) --> NUMERIC
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* Verifies if some data is available to be read in the socket without blocking
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* execution of the caller. If nMillisecs is not given, the function returns
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* immediately 1 if there is some data to be read, 0 if there isn't any data and
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* -1 in case of error. If nMillisecs is given, the functon will wait up to that
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* amount of milliseconds for data to be available; if some data arrives in the
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* meanwhile, the wait is immediately interrupted.
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* The next hb_InetRecv() function will read all the available data (up to the
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* required length) without blocking.
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* On error, hb_InetErrorCode and hb_InetErrorDesc can be use to determine what kind
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* of error happened.
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*
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*
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* hb_InetSend( SOCKET, STRING [, nLength ] ) --> NUMERIC
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* Send data being stored in a string over the socket. Returns the amount of
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* data written, 0 if the socket has been closed in the meanwhile or -1 on
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* error. The nLength parameter can be given to allow writing only a part of
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* the string.
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* Please, notice that there is no guarantee that all your string will be
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* sent, as this is a decision that is up to the OS; this function does not
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* take care to ensure that the data is really sent; so you should check for
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* the returned number, and send the part that has not been sent.
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* To ensure that all the data is sent before the function returns, use the
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* hb_InetSendAll() function.
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* On error, the error in the socket is set.
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*
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*
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* hb_InetSendAll( SOCKET, STRING [, nLength ] ) --> NUMERIC
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* This function works exactly as hb_InetSend() but it ensures that all the
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* data to be sent is written before returning.
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*
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* Utility Functions
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* ------------------
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*
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* hb_InetGetHosts( cName ) --> aHosts
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* Returns an array containing all the IP addresses associated with a given
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* host name. The IP addressess returned by this funtion are strings in
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* quad dot notations, eg "192.168.1.1", and can be directly used into
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* hb_InetConnectIP(). cName can be any string: valid DNS names (eg.
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* "www.myserver.com"), locally available names (e.g. "localhost" or
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* windows Network Neighborhood names), or even IP addresses in quad
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* dot notation.
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* NOTE: This function is not thread safe (by design), and programmers
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* must be sure not to use it at the same time in two different threads,
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* or not to use it together with a hb_InetConnect(). If this kind of situation
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* should ever arise, you are advised to use a thread MUTEX.
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* On error, and if the server can't be found, the function returns NIL.
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*
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*
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* hb_InetGetAlias( cName ) --> aHosts
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* Returns an array containing the aliases ( CNAME DNS records ) by
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* which the server is currently known. Whether this function is able
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* to have the complete list of aliases or not depends on the verbosity
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* of the DNS server.
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*
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*
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* hb_InetCRLF() --> String
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* Returns a CRLF sequence used in many internet protocols.
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*
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* UDP (User Datagram Protocol) Compliant Routines
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* -----------------------------------------------
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*
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* hb_InetDGram( [bBroadcast] ) --> SOCKET
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* Creates a datagram oriented socket that will be able to send data and
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* eventually receive data. Since the socket is not bound, the program can't
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* retrieve the address at which this socket appaers to be, but a second
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* socket receiving a message sent from this one would be able to reply
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* correctly with a datagram that can be read from a non-bound socket.
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* If bBroadcast is set to .T., the routine creates a broadcast capable socket:
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* it will be able to receive and send broadcast messages. On most systems this
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* requires special user privileges.
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* Returns the socket, and if an error occurs, the socket error message
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* and code are set.
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*
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*
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* hb_InetDGramBind( nPort, [cAddress [, bBroadcast] ] ) --> SOCKET
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* Creates a datagram oriented socket and binds it to a particular port, and
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* eventually to a certain interface if cAddress is given and not NIL.
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* If bBroadcast is set to .T., the routine creates a broadcast capable socket:
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* it will be able to receive and send broadcast messages. On most systems this
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* requires special user privileges.
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* Returns the socket, and if an error occurs, the socket error message
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* and code are set.
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*
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*
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* hb_InetDGramSend( SOCKET, cAddress, nPort, cBuffer [, nSize ] ) --> NUMERIC
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* Sends a datagram (a fixed length data) to a determined ip address (cAddress,
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* to be specified in quad-dot notation) and port. If nSize is not specified,
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* all the data in cBuffer will be sent; if nSize is specified, only
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* the first nSize bytes of cBuffer will be sent.
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* There isn't any guarantee that all the data required to be written is
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* really sent to the socket: the calling program should check for the
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* numeric return and send iteratively the unsent data to complete
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* the message.
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* Anyway, the raw datagram is sent and received as once, and any data
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* less than the system datagram size will be sent and received
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* as a single item.
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* If the socket is created in broadcast mode, the cAddress element
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* can be a broadcast address.
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* Returns -1 on error, or the number of bytes actually sent on success.
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*
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* hb_InetDGramRecv( SOCKET, cBuffer [, nSize ] ) --> NUMERIC
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* Reads at maximum nSize bytes incoming from a UDP socket, if nSize is
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* given, or reads at maximum cBuffer length if nSize is not given.
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* There isn't any guarantee that all the data required to be read is
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* really sent from the kernel to the application: the kernel should
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* just return the last complete datagram that has been received, up
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* to nSize bytes.
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* Returns -1 on error, or the number of bytes actually read on success.
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* $END$
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*/
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