(MFC) 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 C/C++ Library Downloads MS Visual C/C++ Libs

See Also: Using MFC CString in Chilkat

#include <CkMime.h>
#include <CkBinData.h>
#include <CkEmail.h>
#include <CkStringBuilder.h>

void ChilkatSample(void)
    {
    CkString strOut;

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

    CkMime 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.
    CkMime *jpgPart = mime.GetPart(1);
    jpgPart->put_Encoding("binary");
    delete jpgPart;

    CkMime *pdfPart = mime.GetPart(2);
    pdfPart->put_Encoding("binary");
    delete pdfPart;

    // 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?
    CkBinData binData;
    // Write the binary MIME into binData;
    mime.GetMimeBd(binData);

    CkEmail 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.put_Subject("Binary MIME Email");
    email.put_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.
    CkStringBuilder sb;
    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");


    SetDlgItemText(IDC_EDIT1,strOut.getUnicode());

    }