Lua Requires Chilkat v11.0.0+

Create Binary MIME

See more MIME Examples

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. Lua

local chilkat = require("chilkat")

local success = false

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

local mime = chilkat.Mime.new()

mime:set_body_from_plain_text("This is the plain text body.")
mime:convert_to_multipart_mixed()
mime:append_part_from_file("qa_data/jpg/penguins.jpg")
mime:append_part_from_file("qa_data/pdf/fishing.pdf")

-- At this point, when saved, the MIME bodies will be base64 encoded.
mime:save_mime("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.

local jpgPart = chilkat.Mime.new()
mime:part_at(1, jpgPart)

jpgPart.encoding = "binary"

local pdfPart = chilkat.Mime.new()
mime:part_at(2, pdfPart)

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:save_mime("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?
local binData = chilkat.BinData.new()
-- Write the binary MIME into binData;
mime:get_mime_bd(binData)

local email = chilkat.Email.new()
-- Load the email from the binData.
email:set_from_mime_bd(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:add_to("Chilkat", "support@chilkatsoft.com")
email:save_eml("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.
local sb = chilkat.StringBuilder.new()
email:get_mime_sb(sb)
sb:write_file("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:get_mime_sb(sb)
sb:write_file("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:save_mime("qa_output/mime_binary.mime")