(.NET Core C#) 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 .NET Downloads Chilkat .NET Assemblies Chilkat for .NET Core Chilkat for Mono

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

Chilkat.Mime mime = new Chilkat.Mime();
bool success;

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.
Chilkat.Mime jpgPart = mime.GetPart(1);
jpgPart.Encoding = "binary";

Chilkat.Mime pdfPart = 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?
Chilkat.BinData binData = new Chilkat.BinData();
// Write the binary MIME into binData;
mime.GetMimeBd(binData);

Chilkat.Email email = 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.
Chilkat.StringBuilder sb = 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");