You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
275 lines
12 KiB
275 lines
12 KiB
<HTML>
|
|
<HEAD>
|
|
<TITLE> DwProtocolClient Man Page </TITLE>
|
|
</HEAD>
|
|
<BODY BGCOLOR="#FFFFFF">
|
|
<H2>
|
|
<FONT COLOR="navy"> NAME </FONT>
|
|
</H2>
|
|
<P>
|
|
DwProtocolClient -- Base class for all protocol clients
|
|
<H2>
|
|
<FONT COLOR="navy"> SYNOPSIS </FONT>
|
|
</H2>
|
|
<PRE>class DW_EXPORT DwProtocolClient {
|
|
|
|
public:
|
|
|
|
enum Failure {
|
|
kFailNoFailure = 0, // No failure
|
|
kFailNoWinsock = 1, // A usable Winsock DLL could not be found
|
|
kFailNetDown = 2, // The network is down
|
|
kFailHostNotFound = 3, // The server was not found
|
|
kFailConnReset = 4, // The connection was reset
|
|
kFailNetUnreachable = 5, // The network is unreachable
|
|
kFailTimedOut = 6, // Timed out while waiting for an operation
|
|
// to complete
|
|
kFailConnDropped = 7,
|
|
kFailConnRefused = 8,
|
|
kFailNoResources = 9
|
|
};
|
|
|
|
enum Error {
|
|
kErrNoError = 0,
|
|
kErrUnknownError = 0x4000,
|
|
kErrBadParameter = 0x4001,
|
|
kErrBadUsage = 0x4002,
|
|
kErrNoWinsock = 0x4003, // Win32
|
|
kErrHostNotFound = 0x5000, // UNIX
|
|
kErrTryAgain = 0x5001, // UNIX
|
|
kErrNoRecovery = 0x5002, // UNIX
|
|
kErrNoData = 0x5003, // UNIX
|
|
kErrNoAddress = 0x5004, // UNIX
|
|
};
|
|
|
|
protected:
|
|
|
|
<A HREF="protocol.html#DwProtocolClient">DwProtocolClient</A>();
|
|
|
|
public:
|
|
|
|
virtual <A HREF="protocol.html#~DwProtocolClient">~DwProtocolClient</A>();
|
|
virtual int <A HREF="protocol.html#Open">Open</A>(const char* aServer, DwUint16 aPort);
|
|
DwBool <A HREF="protocol.html#IsOpen">IsOpen</A>() const;
|
|
int <A HREF="protocol.html#Close">Close</A>();
|
|
int <A HREF="protocol.html#SetReceiveTimeout">SetReceiveTimeout</A>(int aSecs);
|
|
int <A HREF="protocol.html#LastCommand">LastCommand</A>() const;
|
|
int <A HREF="protocol.html#LastFailure">LastFailure</A>() const;
|
|
const char* <A HREF="protocol.html#LastFailureStr">LastFailureStr</A>() const;
|
|
int <A HREF="protocol.html#LastError">LastError</A>() const;
|
|
const char* <A HREF="protocol.html#LastErrorStr">LastErrorStr</A>() const;
|
|
|
|
protected:
|
|
|
|
enum {
|
|
kWSAStartup=1, // Win32
|
|
kgethostbyname,
|
|
tdesocket,
|
|
ksetsockopt,
|
|
kconnect,
|
|
ksend,
|
|
krecv,
|
|
kclose, // UNIX
|
|
kclosesocket, // Win32
|
|
tdeselect
|
|
};
|
|
DwBool mIsDllOpen;
|
|
DwBool mIsOpen;
|
|
SOCKET mSocket;
|
|
DwUint16 mPort;
|
|
char* mServerName;
|
|
int mReceiveTimeout;
|
|
int mLastCommand;
|
|
int mFailureCode;
|
|
const char* mFailureStr;
|
|
int mErrorCode;
|
|
const char* mErrorStr;
|
|
virtual void <A HREF="protocol.html#HandleError">HandleError</A>(int aErrorCode, int aSystemCall);
|
|
int <A HREF="protocol.html#PSend">PSend</A>(const char* aBuf, int aBufLen);
|
|
int <A HREF="protocol.html#PReceive">PReceive</A>(char* aBuf, int aBufSize);
|
|
};
|
|
</PRE>
|
|
<H2>
|
|
<FONT COLOR="navy"> DESCRIPTION </FONT>
|
|
</H2>
|
|
<P>
|
|
<B><TT>DwProtocolClient</TT></B> is the base class for other classes that
|
|
implement specific protocols, such as SMTP, POP, and NNTP.
|
|
<B><TT>DwProtocolClient</TT></B> serves two purposes. First, It combines
|
|
operations common to all its derived classes, such as opening a TCP connection
|
|
to the server. Second, it provides a platform-independent interface to the
|
|
network services required by its subclasses.
|
|
<P>
|
|
There are two separate implementations of
|
|
<B><TT>DwProtocolClient</TT></B>: one for Berkeley sockets under UNIX, and
|
|
one for Winsock under Win32. The interface is the same for both implementations,
|
|
thus providing platform independence.
|
|
<P>
|
|
There are two platform-specific details that you should be aware of. First,
|
|
if you are writing a UNIX program, you should be sure to handle the SIGPIPE
|
|
signal. This signal is raised when a program tries to write to a TCP connection
|
|
that was shutdown by the remote host. The default action for this signal
|
|
is to terminate the program. To prevent this from happening in your program,
|
|
you should either catch the signal or tell the operating system to ignore
|
|
it. Second, if you are writing a Win32 application for Windows NT or Windows95,
|
|
you should be aware of the fact that the constructor calls the Winsock function
|
|
<B><TT>WSAStartup()</TT></B> to initialize the Winsock DLL. (The destructor
|
|
calls <B><TT>WSACleanup()</TT></B>.) Because it is possible for
|
|
<B><TT>WSAStartup()</TT></B> to fail, it is also possible that the constructor
|
|
may fail. To verify that the constructor has succeeded, call the member function
|
|
<B><TT>LastError()</TT></B> and check that it returns zero.
|
|
<P>
|
|
To open a connection to a server, call <B><TT>Open()</TT></B> with the server
|
|
name and TCP port number as arguments. <B><TT>Open()</TT></B> is declared
|
|
virtual; derived classes may override this member function.
|
|
<B><TT>Open()</TT></B> may fail, so you should check the return value to
|
|
verify that it succeeded. To close the connection, call
|
|
<B><TT>Close()</TT></B>. To check if a connection is open, call
|
|
<B><TT>IsOpen()</TT></B>. <B><TT>IsOpen()</TT></B> returns a value that indicates
|
|
whether or not a call to <B><TT>Open()</TT></B> was successful; it will not
|
|
detect failure in the network or a close operation by the remote host.
|
|
<P>
|
|
<B><TT>DwProtocolClient</TT></B> sets a timeout on receive operations on
|
|
the TCP connection. The default value of the timeout period is 90 seconds.
|
|
To change the default value, call <B><TT>SetReceiveTimeout()</TT></B> and
|
|
pass the new value as an argument.
|
|
<P>
|
|
Whenever <B><TT>DwProtocolClient</TT></B> cannot complete an operation, it
|
|
is because an error has occurred. Most member functions indicate that an
|
|
error has occurred via their return values. For most member functions, a
|
|
return value of -1 indicates an error. To get the specific error that has
|
|
occurred, call <B><TT>LastError()</TT></B>, which returns either the system
|
|
error code or a MIME++ defined error code. To get a text string that describes
|
|
the error, call <B><TT>LastErrorStr()</TT></B>.
|
|
<P>
|
|
Some errors are also considered "failures." A failure occurs when an operation
|
|
cannot be completed because of conditions external to the program. For example,
|
|
a failure occurs when the network is down or when an application's user enters
|
|
bad input. Errors that occur because of programmer error are not considered
|
|
failures. If an error occurs, you should call <B><TT>LastError()</TT></B>
|
|
to determine the error, but you should also call
|
|
<B><TT>LastFailure()</TT></B> to determine if a failure occurred. In interactive
|
|
applications, failures should always be reported to the application's user.
|
|
To get a text string that describes a failure, call
|
|
<B><TT>LastFailureStr()</TT></B>.
|
|
<P>
|
|
It is possible to translate the error and failure message strings to a language
|
|
other than English. To do this, you may override the virtual function
|
|
<B><TT>HandleError()</TT></B>.
|
|
<H2>
|
|
<FONT COLOR="navy"> Public Member Functions </FONT>
|
|
</H2>
|
|
<P>
|
|
<FONT COLOR="teal"><B> virtual
|
|
<A NAME="~DwProtocolClient">~DwProtocolClient</A>() </B></FONT>
|
|
<P>
|
|
Frees the resources used by this object. In a Win32 environment, the destructor
|
|
calls <B><TT>WSACleanup()</TT></B>.
|
|
<P>
|
|
<FONT COLOR="teal"><B> virtual int <A NAME="Open">Open</A>(const char* aServer,
|
|
DwUint16 aPort) </B></FONT>
|
|
<P>
|
|
Opens a TCP connection to the server <B><TT>aServer</TT></B> at port
|
|
<B><TT>aPort</TT></B>. <B><TT>aServer</TT></B> may be either a host name,
|
|
such as "smtp.acme.com" or an IP number in dotted decimal format, such as
|
|
"147.81.64.59". If the connection attempt succeeds,
|
|
<B><TT>Open()</TT></B> returns 0; othewise, it returns -1. To determine what
|
|
error occurred when the connection attempt fails, call the member function
|
|
<B><TT>LastError()</TT></B>. To determine if a failure also occurred, call
|
|
the member function <B><TT>LastFailure()</TT></B>.
|
|
<P>
|
|
<FONT COLOR="teal"><B> DwBool <A NAME="IsOpen">IsOpen</A>() const </B></FONT>
|
|
<P>
|
|
Returns true value if a connection to the server is open.
|
|
<B><TT>IsOpen()</TT></B> will return a true value if a call to
|
|
<B><TT>Open()</TT></B> was successful; it will not detect failure in the
|
|
network or a close operation by the remote host.
|
|
<P>
|
|
<FONT COLOR="teal"><B> int <A NAME="Close">Close</A>() </B></FONT>
|
|
<P>
|
|
Closes the connection to the server. Returns 0 if successful, or returns
|
|
-1 if unsuccessful.
|
|
<P>
|
|
<FONT COLOR="teal"><B> int
|
|
<A NAME="SetReceiveTimeout">SetReceiveTimeout</A>(int aSecs) </B></FONT>
|
|
<P>
|
|
Changes the default timeout for receive operations on the socket to
|
|
<B><TT>aSecs</TT></B> seconds. The default value is 90 seconds.
|
|
<P>
|
|
<FONT COLOR="teal"><B> int <A NAME="LastCommand">LastCommand</A>() const
|
|
</B></FONT>
|
|
<P>
|
|
Returns an enumerated value indicating the last command sent to the server.
|
|
Enumerated values are defined in subclasses of
|
|
<B><TT>DwProtocolClient</TT></B>.
|
|
<P>
|
|
<FONT COLOR="teal"><B> int <A NAME="LastFailure">LastFailure</A>() const
|
|
</B></FONT>
|
|
<P>
|
|
Returns an enumerated value indicating what failure last occurred.
|
|
<P>
|
|
<FONT COLOR="teal"><B> const char*
|
|
<A NAME="LastFailureStr">LastFailureStr</A>() const </B></FONT>
|
|
<P>
|
|
Returns a failure message string associated with the failure code returned
|
|
by <B><TT>LastFailure()</TT></B>.
|
|
<P>
|
|
<FONT COLOR="teal"><B> int <A NAME="LastError">LastError</A>() const
|
|
</B></FONT>
|
|
<P>
|
|
Returns an error code for the last error that occurred. Normally, the error
|
|
code returned is an error code returned by a system call;
|
|
<B><TT>DwProtocolClient</TT></B> does no translation of error codes returned
|
|
by system calls. In some cases, an error code defined by MIME++ may returned
|
|
to indicate improper use of the <B><TT>DwProtocolClient</TT></B> class.
|
|
<P>
|
|
<FONT COLOR="teal"><B> const char* <A NAME="LastErrorStr">LastErrorStr</A>()
|
|
const </B></FONT>
|
|
<P>
|
|
Returns an error message string associated with the error code returned by
|
|
<B><TT>LastError()</TT></B>.
|
|
<H2>
|
|
<FONT COLOR="navy"> Protected Member Functions </FONT>
|
|
</H2>
|
|
<P>
|
|
<B><FONT COLOR="teal"> <A NAME="DwProtocolClient">DwProtocolClient</A>()
|
|
</FONT></B>
|
|
<P>
|
|
Initializes the <B><TT>DwProtocolClient</TT></B> object. In a Win32 environment,
|
|
this constructor calls <B><TT>WSAStartup()</TT></B> to initialize the Winsock
|
|
DLL. To verify that the DLL was initialized successfully, call the member
|
|
function <B><TT>LastError()</TT></B> and verify that it returns zero.
|
|
<P>
|
|
<B><FONT COLOR="teal"> virtual void <A NAME="HandleError">HandleError</A>(int
|
|
aErrorCode, int aSystemCall) </FONT></B>
|
|
<P>
|
|
Interprets error codes. <B><TT>aErrorCode</TT></B> is an error code, which
|
|
may be a system error code, or an error code defined by
|
|
<B><TT>DwProtocolClient</TT></B>. <B><TT>aSystemCall</TT></B> is an enumerated
|
|
value defined by <B><TT>DwProtocolClient</TT></B> that indicates the last
|
|
system call made, which should be the system call that set the error code.
|
|
<B><TT>HandleError()</TT></B> sets values for <B><TT>mErrorStr</TT></B>,
|
|
<B><TT>mFailureCode</TT></B>, and <B><TT>mFailureStr</TT></B>.
|
|
<P>
|
|
<B><FONT COLOR="teal"> int <A NAME="PSend">PSend</A>(const char* aBuf, int
|
|
aBufLen) </FONT></B>
|
|
<P>
|
|
Sends <B><TT>aBufLen</TT></B> characters from the buffer
|
|
<B><TT>aBuf</TT></B>. Returns the number of characters sent. If the number
|
|
of characters sent is less than the number of characters specified in
|
|
<B><TT>aBufLen</TT></B>, the caller should call
|
|
<B><TT>LastError()</TT></B> to determine what, if any, error occurred. To
|
|
determine if a failure also occurred, call the member function
|
|
<B><TT>LastFailure()</TT></B>.
|
|
<P>
|
|
<B><FONT COLOR="teal"> int <A NAME="PReceive">PReceive</A>(char* aBuf, int
|
|
aBufSize) </FONT></B>
|
|
<P>
|
|
Receives up to <B><TT>aBufSize</TT></B> characters into the buffer
|
|
<B><TT>aBuf</TT></B>. Returns the number of characters received. If zero
|
|
is returned, the caller should call the member function
|
|
<B><TT>LastError()</TT></B> to determine what, if any, error occurred. To
|
|
determine if a failure also occurred, call the member function
|
|
<B><TT>LastFailure()</TT></B>.
|
|
</BODY></HTML>
|