(VB.NET UWP/WinRT) Create Binary MIME

Demonstrates how to create and save a multipart/mixed MIME document where the parts (a JPG and a PDF) are NOT base64 encoded, but are instead binary.

Note: This example requires Chilkat v9.5.0.62 or greater.

Chilkat Universal Windows Platform (UWP) / WinRT Downloads Chilkat for the Universal Windows Platform (UWP)

' This example requires the Chilkat API to have been previously unlocked.
' See Global Unlock Sample for sample code.

Dim mime As New Chilkat.Mime
Dim success As Boolean

mime.SetBodyFromPlainText("This is the plain text body.")
mime.ConvertToMultipartMixed()
mime.AppendPartFromFile("qa_data/jpg/penguins.jpg")
mime.AppendPartFromFile("qa_data/pdf/fishing.pdf")

' At this point, when saved, the MIME bodies will be base64 encoded.
mime.SaveMime("qa_output/sample.txt")

' We now have the following MIME where everything is base64 encoded:
' The code that follows shows how to eliminate the base64 to make this binary MIME.

' 	Content-Type: multipart/mixed; boundary="------------000207060703080505060404"
' 
' 	--------------000207060703080505060404
' 	Content-Type: text/plain
' 	Content-Transfer-Encoding: 7bit
' 
' 	This is the plain text body.
' 	--------------000207060703080505060404
' 	Content-Disposition: attachment; filename="penguins.jpg"
' 	Content-Type: image/jpeg; name="penguins.jpg"
' 	Content-Transfer-Encoding: base64
' 
' 	/9j/4AAQSkZJRgABAgEAYABgAAD/7gAOQWRvYmUAZAAAAAAB/+ESCEV4aWYAAE1NACoAAAAIAAcB
' 	MgACAAAAFAAAAGIBOwACAAAABwAAAHZHRgADAAAAAQAEAABHSQADAAAAAQA/AACcnQABAAAADgAA
' 	...
' 	800a1MlLipJHlyU9en7sqVPkBK+gBj+o+1E91Ld7iJk0pJDO5PmDk4FOGOHy6S3JW120W1uCJ5M0
' 	PBa54edOFAc8ePX/2Q==
' 
' 	--------------000207060703080505060404
' 	Content-Disposition: attachment; filename="fishing.pdf"
' 	Content-Type: application/pdf; name="fishing.pdf"
' 	Content-Transfer-Encoding: base64
' 
' 	JVBERi0xLjMKJcfsj6IKNSAwIG9iago8PC9MZW5ndGggNiAwIFIvRmlsdGVyIC9GbGF0ZURlY29k
' 	ZT4+CnN0cmVhbQp4nM1c288cNxVX09A0myq35tom7bSl8E1hp76P/YpASIiXlEg8tDwVKEJfilIe
' 	...
' 	MDRGMT48OTlENkRFQzExQjkzNjA0Mjc1RUFCNzIyMjI4RjA0RjE+XQo+PgpzdGFydHhyZWYKMjk0
' 	MzY5CiUlRU9GCg==
' 
' 	--------------000207060703080505060404--
' 


' To make it binary MIME (getting rid of the base64), set the Encoding property to "binary"
' for the JPG and PDF parts.
Dim jpgPart As Chilkat.Mime = mime.GetPart(1)
jpgPart.Encoding = "binary"


Dim pdfPart As Chilkat.Mime = mime.GetPart(2)
pdfPart.Encoding = "binary"


' Now save it.  If you try to view this MIME in a text editor,
' the JPG and PDF parts will be garbled and unintelligible. That's because
' the bytes do not represent characters.
mime.SaveMime("qa_output/sampleBinary.mim")

' The MIME now contains this:

' 	Content-Type: multipart/mixed; boundary="------------000207060703080505060404"
' 
' 	--------------000207060703080505060404
' 	Content-Type: text/plain
' 	Content-Transfer-Encoding: 7bit
' 
' 	This is the plain text body.
' 	--------------000207060703080505060404
' 	Content-Disposition: attachment; filename="penguins.jpg"
' 	Content-Type: image/jpeg; name="penguins.jpg"
' 	Content-Transfer-Encoding: binary
' 
' 	<Binary Data Here>
' 
' 	--------------000207060703080505060404
' 	Content-Disposition: attachment; filename="fishing.pdf"
' 	Content-Type: application/pdf; name="fishing.pdf"
' 	Content-Transfer-Encoding: binary
' 
' 	<Binary Data Here>
' 
' 	--------------000207060703080505060404--
' 


' Can we load this binary MIME into an Email object?
Dim binData As New Chilkat.BinData
' Write the binary MIME into binData;
mime.GetMimeBd(binData)

Dim email As New Chilkat.Email
' Load the email from the binData.
email.SetFromMimeBd(binData)

' Note: Many email clients may not be able to correctly process emails
' using the binary encoding.  Thunderbird has trouble.  Windows Live Mail
' worked OK.
email.Subject = "Binary MIME Email"
email.From = "admin@chilkatsoft.com"
email.AddTo("Chilkat","support@chilkatsoft.com")
email.SaveEml("qa_output/binaryEmail.eml")

' Chilkat does not recommend trying to use binary MIME for email.
' Binary MIME is typically used in HTTP for uploads and downloads.
' 


' Also, binary MIME is not representable in a string.  
' If we try to get the MIME as a string, then it must be encoded
' using base64.

' Chilkat automatically changes binary encodings to base64
' when there's an attempt to get the MIME as a string.
Dim sb As New Chilkat.StringBuilder
email.GetMimeSb(sb)
sb.WriteFile("qa_output/email_fromSb.eml","utf-8",False)


' Likewise, if we try to get the MIME as a string from the Mime object, 
' it cannot contain non-character data in a binary encoding.  The binary
' bytes MUST be in base64.  The act of trying to retrieve the MIME in string
' format will force Chilkat to convert binary encodings (for non-text parts)
' to base64.
mime.GetMimeSb(sb)
sb.WriteFile("qa_output/mime_fromSb.eml","utf-8",False)

' However, the above use of base64 is just for the purpose of making the MIME
' string friendly.  If we save the MIME to a file, it's still binary:
mime.SaveMime("qa_output/mime_binary.mime")