Displaying HTML-formatted messages (Part 3)

Advanced topics Summary: Briefly covers usage of optional paramaters of previously discussed methods. Highlights using MessageCensor component for better e-mail security. Lists additional methods useful for embedded objects management.

Tutorial map:
Part 1 - Quickly display e-mail with inline pictures
Part 2 - Removing temporary files after use
Part 3 - Advanced topics

GetBodyWithEmbeddedObjects and RemoveMessageDirectory methods support additional parameters that may be useful for advanced applications.

Making e-mail safe and secure

Censoring of HTML content is possible through using MessageCensor component (Censor parameter). Because viruses are common example of embedded objects, censoring controlled by GetBodyWithEmbeddedObjects method not only cuts unsafe code from HTML content, but also prevents saving these objects to disk (this is important because many antivirus programs interfere with applications writing virus code to disk).

Note: MessageCensor is a separate FREE component not included in MailBee package. You may get it from MailBee web site.

Overriding defaults

By default, GetBodyWithEmbeddedObjects creates message folder in the current user's temporary folder (usually something like "C:\Documents and Settings\UserName\Local Settings\Temp", but this is OS-dependent). However, TempDirectoryPath parameter of GetBodyWithEmbeddedObjects method allows you to use any path for the temporary folder.

You can also provide custom name for message directory created by MailBee in the temporary folder (use MessageDirectoryName parameter of GetBodyWithEmbeddedObjects method). By default, message directory name is generated as MD5-digest of Message-ID. This is fine for most applications but you may override this if you need.

RemoveMessageDirectory method supports MessageDirectoryPath parameter, which overrides message directory path stored in the Message object. You may use it for deleting message directory if corresponding Message object (and the path stored inside) already gone. You may even delete any (not related to MailBee) directories. Also, there is an option to delete only the directory content but not delete the directory itself - DeleteContentOnly parameter.

Getting info on message directory path

Once GetBodyWithEmbeddedObjects was called, you may obtain path to the message directory using GetMessageDirectoryPath method. You may store this value and then pass it as a value of MessageDirectoryPath parameter of RemoveMessageDirectory method. If GetMessageDirectoryPath returns empty string, this means the message has no embedded objects (or they were censored out if censoring is used) and corresponding message directory was not created.

You may check whether message directory exists and it is a folder (not a file) using MessageDirectoryExists method.

To manually get MD5-digest of Message-ID (by default, this digest is used as a message directory name), use GetMD5Digest method. You may also use it for getting MD5 digests of any strings.

All together

The sample below displays the message on Command1_Click event and cleans-up on Form_Unload. Now the Message object is a not a global variable. Instead, only the message directory path is stored in global variable. Censoring with default rules is also used.

Code example:

' Assume objWebBrowser is a valid WebBrowser control
' (It's included in Microsoft Internet Controls type library).

' This sample is for VB only, ASP samples are discussed in another tutorial

Dim strPath

Private Sub Command1_Click()
  Dim objPOP3, objCensor, objMsg

  Set objCensor = CreateObject("MC.MessageCensor")
  ' license key is not required because MessageCensor is a free component
  objCensor.SetDefaults
  Set objPOP3 = CreateObject("MailBee.POP3")
  objPOP3.LicenseKey = "put your license key here"
  If objPOP3.Connect("pop.iforum.com", 110, "webmaildemo@iforum.com", "demo") Then
    If objPOP3.MessageCount > 0 Then
      Set objMsg = objPOP3.RetrieveSingleMessage(1)
      objWebBrowser.Document.Write objMsg.GetBodyWithEmbeddedObjects (, , objCensor)
      strPath = objMsg.GetMessageDirectoryPath
    End If
    objPOP3.Disconnect
  Else
    MsgBox objPOP3.ErrDesc
  End If
End Sub

Private Sub Form_Load()
  strPath = ""
  objWebBrowser.Navigate "about:blank"
End Sub

Private Sub Form_Unload(Cancel As Integer)
  Dim objMsg

  If strPath <> "" Then
    Set objMsg = CreateObject("MailBee.Message")
    objMsg.RemoveMessageDirectory strPath
  End If
End Sub