CPop3Connection v1.19

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Welcome to CPop3Connection, a freeware MFC class to support the POP3 protocol. POP3 for those not familiar with all the internet protocols is the protocol used to retrieve internet email.

For detailed information about the Post Office Protocol Version 3 you should read RFC 1725. You should also refer to RFC 822 which contains details on the layout of messages.

You can find numerous Web Servers which carry these documents by going to www.yahoo.com and look for RFC and 1725 or 822.

Features

Usage

History

API Reference

Planned Enhancements

Contacting the Author

Features

• Simple and clean C++ interface.
• The interface provided is synchronous which provides an easier programming model than using asynchronous sockets.
• The code does not rely on the MFC socket classes. These classes have a number of shortcomings, one of which causes problems when they are used in NT services.
• The code can be used in a console application without any problems (Again this is not the case for the MFC socket classes).
• A configurable timeout for the connection can be set through the class API.

Usage

• To use the class in your code simple include pop3.cpp in your project and #include pop3.h in which ever of your modules needs to make calls to the class.
• To see the class in action, have a look at the code in InitInstance in the module "main.cpp".
• Your code will need to include MFC either statically or dynamically.
• You will need to have a functioning Winsock stack installed and correctly initialized prior to calling any functions in CPop3Connection. Depending on your application, this will involve calling either WSAStartup or AfxSocketInit at startup of your application.
• You will also need to have afxtempl.h and winsock.h or afxsock.h in your precompiled header. The code will work just aswell in a GUI or console app. The code should also work in a multithreaded application, although it has not be explicitly tested in this scenario.

History

V1.0 (18th May 1998)

• Initial public release.

V1.1 (28th June 1998)

• Fixed a potential buffer overflow problem in Delete and Retrieve functions when a large message number was specified.
• Improve the ReadResponse code by
•     a) passing the readability check onto the socket class and
•     b) Sleeping for 100 ms prior to looping around waiting for new response data
• Classes are now fully Unicode compliant. Unicode build configurations are also now included.
• Now supports the TOP POP3 command which can be issued using the GetHeader function.
• Fixed a few typos in the documentation.

V1.11 (4th January 1999 )

• Minor update to the documentation.
• Now includes VC 5 workspace files as standard.
• Properly Unicode enabled all the code as previously the code exposes an Ascii(LPSTR/LPCSTR) API instead of a TCHAR / CString API.

V1.12 (22nd February 1999 )

• Default timeout for the code when a debug build is built has now been set to 60 seconds.
• Improved the reading of responses back from the server by implementing a growable receive buffer.
• Updated instructions on how the relevant RFC documents can be retrieved.

V1.13 (25th March 1999)

• Fixed a memory leak in the CPop3Connection::ReadReturnResponse function.
• Now sleeps for 250 ms instead of yielding the time slice. This helps reduce CPU usage when waiting for data to arrive in the socket

V1.14 (15th June 1999)

• Added functions to return the message body, header or a particular header field of a message.
• Tidied up some of the TRACE messages which the code generates.
• Fixed some typos and spelling mistakes in this file.

V1.15 (16th June 1999)

• Fixed a bug in the GetHeaderItem function which was causing a header item which appeared at the beginning of the header fields to fail to be parsed incorrectly.

V1.16 (27th June 1999)

• Fixed a bug in the GetHeaderItem function when a header spanned multiple lines as is allowed by RFC 822.

V1.17 (29th June 1999)

• Another improvement to GetHeaderItem. When will it end <g>. Originally this was reported as a bug but upon further investigation it turns out that the message which was causing the problems had embedded tabs in the header. This is discouraged by the RFC which refers to mail headers (RFC 822). The code has been enhanced to handle this case. Thanks to Chris Bishop for spotting this.
• Fix for a bug in GetHeaderItem where I accidentally was using "=" instead of "==". Thanks to Angelini Fabio for spotting this.
• Updated documentation to refer to RFC 822.

V1.18 (5th July 1999)

• Addition of the following functions:
  i) CPop3Message::GetReplyTo()
  ii) CPop3Message::GetRawBody 
  iii) CPop3Message::GetSubject 
  iv) CPop3Message::GetFrom 
  v) CPop3Message::GetDate 
• GetHeaderItem function now uses case insensitive searching.
• GetHeaderItem now allows you to search for the "n'th" header of a specified type.

V1.19 (24th August 1999)

• Fixed a bug whereby the function GetHeader was sometimes failing when it was called when the message was retrieved using the "TOP" command.

API Reference

The API consists of the public member functions of the class CPop3Connection & CPop3Message

CPop3Connection::Connect
CPop3Connection::Disconnect
CPop3Connection::Statistics
CPop3Connection::Delete
CPop3Connection::GetMessageSize
CPop3Connection::GetMessageID
CPop3Connection::Retrieve
CPop3Connection::Reset
CPop3Connection::UIDL
CPop3Connection::GetMessageHeader
CPop3Connection::Noop
CPop3Connection::GetLastCommandResponse
CPop3Connection::GetTimeout
CPop3Connection::SetTimeout
CPop3Message::GetMessageText
CPop3Message::GetHeader
CPop3Message::GetHeaderItem
CPop3Message::GetBody
CPop3Message::GetReplyTo
CPop3Message::GetRawBody
CPop3Message::GetSubject
CPop3Message::GetFrom
CPop3Message::GetDate

 

 

CPop3Connection::Connect

BOOL CPop3Connection::Connect(LPCSTR pszHostName, LPCSTR pszUser,   LPCSTR pszPassword, int nPort = 110);

Return Value

If the function succeeds, the return value is TRUE. If the function fails, the return value is FALSE. To get extended error information, call ::GetLastError.

Parameters

pszHostName The network address of the socket to connect to: a machine name such as “mail.yourisp.com”, or a dotted number such as “128.56.22.8”.

pszUser This is the POP3 user name of the mailbox.

pszPassword This is the password for the POP3 mailbox.

nPort This is the port number on which to connect. The default value is 110 which is the default POP3 port number.

Remarks

Call this member function to establish a connection to a POP3 mailbox.

See Also

CPop3Connection::Disconnect

 

CPop3Connection::Disconnect

BOOL CPop3Connection::Disconnect();

Return Value

If the function succeeds, the return value is TRUE. If the function fails, the return value is FALSE. To get extended error information, call ::GetLastError.

Parameters

None.

Remarks

The corollary function of Connect.

See Also

CPop3Connection::Connect

 

CPop3Connection::Statistics

BOOL CPop3Connection::Statistics(int& nNumberOfMails, int& nTotalMailSize);

Return Value

If the function succeeds, the return value is TRUE. If the function fails, the return value is FALSE. To get extended error information, call ::GetLastError.

Parameters

nNumberOfMails Upon a successful return this will contain the number of mails waiting in the mailbox.

nTotalMailSize Upon a successful return this will contain the size in bytes (aka Octets) of all mails waiting in the mailbox.

Remarks

Retrieves the statistics for the Mailbox by issuing the "STAT" command.

See Also

CPop3Connection::GetMessageSize

 

CPop3Connection::Delete

BOOL CPop3Connection::Delete(int nMsg);

Return Value

If the function succeeds, the return value is TRUE. If the function fails, the return value is FALSE. To get extended error information, call ::GetLastError.

Parameters

nMsg The message number of the message to delete. This value starts at 1.

Remarks

Marks a message as "to be deleted" by issuing the "DELE" command.

See Also

CPop3Connection::Reset

 

CPop3Connection::GetMessageSize

BOOL CPop3Connection::GetMessageSize(int nMsg, DWORD& dwSize);

Return Value

If the function succeeds, the return value is TRUE. If the function fails, the return value is FALSE. To get extended error information, call ::GetLastError.

Parameters

nMsg The message number of the message to retrieve the size of.

dwSize Upon a successful return this will contain the size in bytes of the specified message.

Remarks

Retrieves the size of a specified message. Internally this will issue the "LIST" command if required.

See Also

CPop3Connection::Retrieve

 

CPop3Connection::GetMessageID

BOOL CPop3Connection::GetMessageID(int nMsg, CString& sID);

Return Value

If the function succeeds, the return value is TRUE. If the function fails, the return value is FALSE. To get extended error information, call ::GetLastError.

Parameters

nMsg The message number of the message to retrieve the ID of.

sID Upon a successful return this will contain the ID of the specified message as a string.

Remarks

Retrieves the ID of a specified message. Internally this will issue the "UIDL" command if required. As "UIDL" is an optional POP3 command, your client app should handle the return value if it is to correctly work on all POP3 servers.

See Also

CPop3Connection::UIDL

 

CPop3Connection::Retrieve

BOOL CPop3Connection::Retrieve(int nMsg, CPop3Message& message);

Return Value

If the function succeeds, the return value is TRUE. If the function fails, the return value is FALSE. To get extended error information, call ::GetLastError.

Parameters

nMsg The message number of the message to retrieve the size of.

message Upon a successful return this will contain the POP3 messages.

Remarks

Retrieves the specified message by issuing the "RETR" command.

See Also

CPop3Connection::GetMessageSize

 

CPop3Connection::GetMessageHeader

BOOL CPop3Connection::GetMessageHeader(int nMsg, CPop3Message& message);

Return Value

If the function succeeds, the return value is TRUE. If the function fails, the return value is FALSE. To get extended error information, call ::GetLastError.

Parameters

nMsg The message number of the message to retrieve the header of.

sID Upon a successful return this will contain the POP3 messages.

Remarks

Retrieves the header of a specified message. Internally this will issue the "TOP" command if required. As "TOP" is an optional POP3 command, your client app should handle the return value if it is to correctly work on all POP3 servers.

See Also

CPop3Connection::GetMessage

 

CPop3Connection::Reset

BOOL CPop3Connection::Reset();

Return Value

If the function succeeds, the return value is TRUE. If the function fails, the return value is FALSE. To get extended error information, call ::GetLastError.

Parameters

None.

Remarks

Resets all messages which were previously marked as deleted. i.e. it undoes the work of all the DELE commands in this session. For further information about how messages are deleted in POP3, please refer to the RFC.

See Also

CPop3Connection::Delete

 

CPop3Connection::UIDL

BOOL CPop3Connection::UIDL();

Return Value

If the function succeeds, the return value is TRUE. If the function fails, the return value is FALSE. To get extended error information, call ::GetLastError.

Parameters

None.

Remarks

Sends the "UIDL" command which retrieves the ID for a specified message. As "UIDL" is an optional POP3 command, your client app should handle the return value if it is to correctly work on all POP3 servers.

See Also

CPop3Connection::GetMessageID

 

CPop3Connection::Noop

BOOL CPop3Connection::Noop();

Return Value

If the function succeeds, the return value is TRUE. If the function fails, the return value is FALSE. To get extended error information, call ::GetLastError.

Parameters

None.

Remarks

Issues a "NOOP" command to the server.

 

CPop3Connection::GetLastCommandResponse

CString CPop3Connection::GetLastCommandResponse() const;

Return Value

The last command response from the server as a CString.

Parameters

None.

Remarks

The CPop3Connection class can return additional text information along with most errors. This extended error information can be retrieved by using the GetLastCommandResponse function after an unsuccessful function call. An example of this is if the Connect function failed because of a validation problem, GetLastCommandResponse could return something like "-ERR Access is denied". GetLastCommandResponse can be called multiple times until another CPop3Connection function is called which sends a POP3 command.

 

CPop3Connection::GetTimeout

DWORD CPop3Connection::GetTimeout() const;

Return Value

The timeout in milliseconds which the code will wait for responses from the POP3 server.

Parameters

None.

Remarks

Since CPop3Connection provides a synchronous API, a timeout mechanism is provided. By default the value is 2 seconds in release mode and 20 seconds in debug mode. The value is larger in debug mode so that the code does not time out when you are debugging it.

See Also

CPop3Connection::SetTimeout

 

CPop3Connection::SetTimeout

void CPop3Connection::SetTimeout(DWORD dwTimeout) const;

Return Value

None.

Parameters

dwTimeout The new timeout value in milliseconds.

Remarks

Sets the timeout to use for connections to the POP3 server.

See Also

CPop3Connection::GetTimeout

 

 

CPop3Message::GetMessageText

LPCSTR CPop3Message::GetMessageText() const;

Return Value

A character pointer to the actual message text this class instance represents.

Parameters

None.

Remarks

Upon a successful call to CPop3Connection::Retrieve, the message class will contain a message. This function allows the text to of the message to be accessed.

See Also

CPop3Connection::Retrieve

 

CPop3Message::GetHeader

CString CPop3Message::GetHeader() const;

Return Value

A CString containing the header of this message

 

CPop3Message::GetBody

CString CPop3Message::GetBody() const;

Return Value

A CString containing the body of this message

 

CPop3Message::GetHeaderItem

CString CPop3Message::GetHeaderItem(const CString& sName, int nItem = 0) const;

Return Value

A CString containing the header body of the header field

Remarks

This function allows a specific message header line to be retrieved e.g you could call the function with sName set to "Date" to find the date the mail message was sent at. The return value is a CString which follows the internet convention for that particular header. The nItem parameter allows you to specify that the n'th occurrence of the header field be returned.

 

CPop3Message::GetReplyTo

CString CPop3Message::GetReplyTo() const;

Return Value

A CString containing the Reply to field

Remarks

Returns the most appropriate address for replies. Looks first for Reply-To, then From, then Sender, then Return-Path as a last resort, returns the first one of the above that is non-empty.

 

CPop3Message::GetRawBody

LPCSTR CPop3Message::GetRawBody() const;

Return Value

A const char pointer to the raw message body

 

CPop3Message::GetSubject

CString CPop3Message::GetSubject() const;

Return Value

A CString containing the subject of the message

Remarks

Returns the subject of the message.

 

CPop3Message::GetFrom

CString CPop3Message::GetFrom() const;

Return Value

A CString containing the sender of the message

Remarks

Returns the sender of the message.

 

CPop3Message::GetDate

CString CPop3Message::GetDate() const;

Return Value

A CString containing the "Date:" header of the message

Remarks

Returns the "Date:" header of the message.

Planned Enhancements

• Implement support for the APOP command.
• Package the code up into an OCX, COM Interface or DLL to allow non MFC apps to use the code.
• Provide a better sample app. At the moment, it's very much a test program which tests all of the functions.
• If you have any other suggested improvements, please let me know so that I can incorporate them into the next release.

Please send any comments or bug reports to me via email. For any updates to this article, check my site here.