fixed NullRef exception if BodyHtml is null/Nothing

CompuMaster.Net.Smtp/AssemblyInfo.vb

@@ -0,0 +1 @@
+<Assembly: Runtime.CompilerServices.InternalsVisibleTo("CompuMaster.Net.Smtp.Tests")>

CompuMaster.Net.Smtp/CompuMaster.Net.Smtp.vbproj

@@ -3,7 +3,7 @@
   <PropertyGroup>
     <RootNamespace>CompuMaster.Net.Smtp</RootNamespace>
     <TargetFrameworks>netstandard2.0;netcoreapp3.1;net6.0;net48;net45</TargetFrameworks>
-	  <Version>2024.11.04.100</Version>
+	  <Version>2024.12.03.100</Version>
 	  <Authors>Jochen Wezel</Authors>
 	  <Company>CompuMaster GmbH</Company>
 	  <Copyright>2010-2024 CompuMaster GmbH</Copyright>

CompuMaster.Net.Smtp/Messaging/EMailAttachment.vb

@@ -2,23 +2,49 @@ Option Explicit On
 Option Strict On
 
 ''' <summary>
-'''     An e-mail attachment
+''' An e-mail attachment
 ''' </summary>
 Public Class EMailAttachment
     Public Sub New()
         'Do nothing
     End Sub
+
+    ''' <summary>
+    ''' Create an attachment from local file path
+    ''' </summary>
+    ''' <param name="filepath"></param>
     Public Sub New(filepath As String)
         Me.FilePath = filepath
     End Sub
+
+    ''' <summary>
+    ''' Create an attachment from local file path for reference by placeholder ID in HtmlBody
+    ''' - WARNING: Attachments with placeholder ID and without reference in BodyHtml will be removed from message before sending
+    ''' </summary>
+    ''' <param name="filepath"></param>
+    ''' <param name="placeholderName">A placeholder ID</param>
     Public Sub New(filepath As String, placeholderName As String)
         Me.FilePath = filepath
         Me.PlaceholderInMhtmlToBeReplacedByContentID = placeholderName
     End Sub
+
+    ''' <summary>
+    ''' Create an attachment from in-memory data
+    ''' </summary>
+    ''' <param name="data"></param>
+    ''' <param name="filename"></param>
     Public Sub New(data As Byte(), filename As String)
         Me.RawData = data
         Me.RawDataFilename = filename
     End Sub
+
+    ''' <summary>
+    ''' Create an attachment from in-memory data for reference by placeholder ID in HtmlBody
+    ''' - WARNING: Attachments with placeholder ID and without reference in BodyHtml will be removed from message before sending
+    ''' </summary>
+    ''' <param name="data"></param>
+    ''' <param name="filename"></param>
+    ''' <param name="placeholderName"></param>
     Public Sub New(data As Byte(), filename As String, placeholderName As String)
         Me.RawData = data
         Me.RawDataFilename = filename
@@ -92,7 +118,8 @@ Public Class EMailAttachment
 
     Private _PlaceholderInMHTML_ToReplaceWithCID As String ' <Obsolete("Use ContentID instead", False), System.ComponentModel.EditorBrowsable(ComponentModel.EditorBrowsableState.Never)> _
     ''' <summary>
-    '''     A placeholder string (without prefix "cid:") in the HTML code of the message (there it must be with prefix "cid:") which shall be replaced by the CID code of the attachment
+    ''' A placeholder string (without prefix "cid:") in the HTML code of the message (there it must be with prefix "cid:") which shall be replaced by the CID code of the attachment 
+    ''' - WARNING: Attachments with placeholder ID and without reference in BodyHtml will be removed from message before sending
     ''' </summary>
     ''' <remarks>
     ''' <para>Define the placeholder which shall be replaced by the Content-ID for the contents of a file to the email. Emails formatted in HTML can include images with this information and internally reference the image through a "cid" hyperlink.</para>
@@ -136,7 +163,7 @@ Public Class EMailAttachment
 #Disable Warning CA2249 ' Erwägen Sie die Verwendung von "string.Contains" anstelle von "string.IndexOf"
             'remove attachments with missing references
             For MyCounter As Integer = attachments.Count - 1 To 0 Step -1
-                If attachments(MyCounter).PlaceholderInMhtmlToBeReplacedByContentID <> Nothing AndAlso htmlBody.IndexOf(attachments(MyCounter).PlaceholderInMhtmlToBeReplacedByContentID) = -1 Then
+                If attachments(MyCounter).PlaceholderInMhtmlToBeReplacedByContentID <> Nothing AndAlso If(htmlBody, "").IndexOf(attachments(MyCounter).PlaceholderInMhtmlToBeReplacedByContentID) = -1 Then
                     'html doesn't contain any reference to the embedded object - removing attachment
                     attachments.RemoveAt(MyCounter)
                 End If

CompuMaster.Net.Smtp/Messaging/EMailMessage.vb

@@ -248,9 +248,9 @@ Public Class EMailMessage
     End Function
 
     ''' <summary>
-    ''' Prepare HTML and attachments for embedded images feature, initialize all list fields if null/Nothing
+    ''' Prepare HTML and attachments for embedded images feature, cleanup attachments with placeholder but without reference from BodyHtml, initialize all list fields if null/Nothing
     ''' </summary>
-    Friend Sub PrepareForSending()
+    Public Sub PrepareForSending()
         'Fix HTML and attachments
         EMailAttachment.FixHtmlContentIDs(Me.BodyHtml, Me.EMailAttachments)
         'Init missing list instances

Tests/EMailMessageTest.vb

@@ -63,4 +63,104 @@ Imports CompuMaster.Net.Smtp
         Assert.Pass()
     End Sub
 
+    <Test> Public Sub FixHtmlContentIDs()
+        Dim Attachments As List(Of CompuMaster.Net.Smtp.EMailAttachment)
+
+        EMailAttachment.FixHtmlContentIDs("", Nothing)
+
+        Attachments = New List(Of CompuMaster.Net.Smtp.EMailAttachment)
+        EMailAttachment.FixHtmlContentIDs("", Attachments)
+        Assert.That(Attachments.Count, [Is].EqualTo(0))
+
+        Attachments = New List(Of CompuMaster.Net.Smtp.EMailAttachment)
+        Attachments.Add(New CompuMaster.Net.Smtp.EMailAttachment())
+        EMailAttachment.FixHtmlContentIDs(Nothing, Attachments)
+        Assert.That(Attachments.Count, [Is].EqualTo(1))
+
+        Attachments = CreateEMailAttachmentsSample1()
+        EMailAttachment.FixHtmlContentIDs(Nothing, Attachments)
+        Assert.That(Attachments.Count, [Is].EqualTo(0))
+
+        Attachments = CreateEMailAttachmentsSample1()
+        EMailAttachment.FixHtmlContentIDs("<html>" &
+                                          "<img src=""cid:" & Attachments(0).PlaceholderInMhtmlToBeReplacedByContentID & """/>" &
+                                          "<img src=""cid:" & Attachments(1).PlaceholderInMhtmlToBeReplacedByContentID & """/>" &
+                                          "<img src=""cid:" & Attachments(2).PlaceholderInMhtmlToBeReplacedByContentID & """/>" &
+                                          "<img src=""cid:" & Attachments(3).PlaceholderInMhtmlToBeReplacedByContentID & """/>" &
+                                          "<img src=""cid:" & Attachments(4).PlaceholderInMhtmlToBeReplacedByContentID & """/>" &
+                                          "</html>", Attachments)
+        Assert.That(Attachments.Count, [Is].EqualTo(5))
+
+        Attachments = CreateEMailAttachmentsSample1()
+        EMailAttachment.FixHtmlContentIDs("<html>" &
+                                          "<img src=""cid:" & Attachments(0).PlaceholderInMhtmlToBeReplacedByContentID & """/>" &
+                                          "</html>", Attachments)
+        Assert.That(Attachments.Count, [Is].EqualTo(1))
+
+        Attachments = CreateEMailAttachmentsSample2()
+        EMailAttachment.FixHtmlContentIDs("<html>" &
+                                          "</html>", Attachments)
+        Assert.That(Attachments.Count, [Is].EqualTo(2))
+
+        Attachments = CreateEMailAttachmentsSample2()
+        EMailAttachment.FixHtmlContentIDs("<html>" &
+                                          "<img src=""cid:" & Attachments(0).PlaceholderInMhtmlToBeReplacedByContentID & """/>" &
+                                          "<img src=""cid:" & Attachments(3).PlaceholderInMhtmlToBeReplacedByContentID & """/>" &
+                                          "</html>", Attachments)
+        Assert.That(Attachments.Count, [Is].EqualTo(4))
+    End Sub
+
+    Private Function CreateEMailAttachmentsSample1() As List(Of CompuMaster.Net.Smtp.EMailAttachment)
+        Dim Attachments As New List(Of CompuMaster.Net.Smtp.EMailAttachment)
+        Attachments.Add(New CompuMaster.Net.Smtp.EMailAttachment() With {
+            .FilePath = Nothing,
+            .RawDataFilename = "ProjectDetails_CM-4825_Fachhandwerk360 Dreier+Herber GbR (DEB300336) _ Helpdesk _ IT Management + Support.pdf.pdf",
+            .RawDataOriginFilename = "ProjectDetails_CM-4825_Fachhandwerk360 Dreier+Herber GbR (DEB300336) _ Helpdesk _ IT Management + Support.pdf.pdf",
+            .RawData = New Byte() {1, 2, 3},
+            .PlaceholderInMhtmlToBeReplacedByContentID = "ed642552-3e6c-41ac-8984-85b24ff2ba0c"
+        })
+        Attachments.Add(New CompuMaster.Net.Smtp.EMailAttachment() With {
+            .FilePath = Nothing,
+            .RawDataFilename = "ProjectDetails_CM-4825_Overview_Fachhandwerk360 Dreier+Herber GbR (DEB300336) _ Helpdesk _ IT Management + Support.pdf.pdf",
+            .RawDataOriginFilename = "ProjectDetails_CM-4825_Overview_Fachhandwerk360 Dreier+Herber GbR (DEB300336) _ Helpdesk _ IT Management + Support.pdf.pdf",
+            .RawData = New Byte() {1, 2, 3},
+            .PlaceholderInMhtmlToBeReplacedByContentID = "62ac3106-82c2-44dd-bc03-cc29f674fc0b"
+        })
+        Attachments.Add(New CompuMaster.Net.Smtp.EMailAttachment() With {
+            .FilePath = Nothing,
+            .RawDataFilename = "ProjectDetails_CM-4825_MainCategories_Fachhandwerk360 Dreier+Herber GbR (DEB300336) _ Helpdesk _ IT Management + Support.pdf.pdf",
+            .RawDataOriginFilename = "ProjectDetails_CM-4825_MainCategories_Fachhandwerk360 Dreier+Herber GbR (DEB300336) _ Helpdesk _ IT Management + Support.pdf.pdf",
+            .RawData = New Byte() {1, 2, 3},
+            .PlaceholderInMhtmlToBeReplacedByContentID = "4ff43e11-fa0a-49f7-984c-7bd2869d87f2"
+        })
+        Attachments.Add(New CompuMaster.Net.Smtp.EMailAttachment() With {
+            .FilePath = "RE559902886.pdf",
+            .RawDataFilename = Nothing,
+            .RawDataOriginFilename = Nothing,
+            .RawData = Nothing,
+            .PlaceholderInMhtmlToBeReplacedByContentID = "4b38e763-79b0-470f-80bd-d493c6b2eb9f"
+        })
+        Attachments.Add(New CompuMaster.Net.Smtp.EMailAttachment() With {
+            .FilePath = "RE559902886_printer.pdf",
+            .RawDataFilename = Nothing,
+            .RawDataOriginFilename = Nothing,
+            .RawData = Nothing,
+            .PlaceholderInMhtmlToBeReplacedByContentID = "676fdb55-af32-4c13-b70a-933e4d20dedf"
+        })
+        Return Attachments
+    End Function
+
+    ''' <summary>
+    ''' Sample attachments: 2 with placeholder + 2 without placeholder
+    ''' </summary>
+    ''' <returns></returns>
+    Private Function CreateEMailAttachmentsSample2() As List(Of CompuMaster.Net.Smtp.EMailAttachment)
+        Dim Attachments As New List(Of CompuMaster.Net.Smtp.EMailAttachment)
+        Attachments.Add(New CompuMaster.Net.Smtp.EMailAttachment(New Byte() {1, 2, 3}, "ProjectDetails_CM-4825_Fachhandwerk360 Dreier+Herber GbR (DEB300336) _ Helpdesk _ IT Management + Support.pdf.pdf", "ed642552-3e6c-41ac-8984-85b24ff2ba0c"))
+        Attachments.Add(New CompuMaster.Net.Smtp.EMailAttachment(New Byte() {1, 2, 3}, "ProjectDetails_CM-4825_Overview_Fachhandwerk360 Dreier+Herber GbR (DEB300336) _ Helpdesk _ IT Management + Support.pdf.pdf"))
+        Attachments.Add(New CompuMaster.Net.Smtp.EMailAttachment("RE559902886.pdf"))
+        Attachments.Add(New CompuMaster.Net.Smtp.EMailAttachment("RE559902886_printer.pdf", "676fdb55-af32-4c13-b70a-933e4d20dedf"))
+        Return Attachments
+    End Function
+
 End Class