Parsing and creating MIME messages with Hyperlambda

magic.lambda.mime gives you the ability to parse and create MIME messages from Hyperlambda. The project contains the following slots.

• [mime.parse] - Parses a MIME message, and returns it as a lambda object
• [mime.create] - Creates a MIME message for you, and returns the entire message as text, being the MIME entity
• [.mime.parse] - Parses a native MimeEntity for you, and returns it as a lambda object (not for usage directly from Hyperlambda code)
• [.mime.create] - Creates a MIME message for you, and returns it as a native MimeEntity object (not for usage directly from Hyperlambda code)

Parsing MIME messages

Below is an example of how parsing a MIME message might look like.

// Actual message
.msg:"Content-Type: multipart/mixed; boundary=\"=-3O9TzEjuVDwt7d5uGDkV/Q==\"\n\n--=-3O9TzEjuVDwt7d5uGDkV/Q==\nContent-Type: text/plain\nContent-Disposition: attachment; filename=README.md\n\n# Your dynamic files folder\n\nSome README.md file\n\n--=-3O9TzEjuVDwt7d5uGDkV/Q==\nContent-Type: text/plain\n\nBar\n--=-3O9TzEjuVDwt7d5uGDkV/Q==--\n"

// Parsing the above message
mime.parse:x:@.msg

After evaluating the above, you’ll end up with something resembling the following.

mime.parse:multipart/mixed
   entity:text/plain
      headers
         Content-Disposition:attachment; filename=README.md
      content:"# Your dynamic files folder\n\nSome README.md file\n"
   entity:text/plain
      content:Bar

Notice how the slot creates a tree structure, perfectly resembling your original MIME message. It will also take care of MIME headers for you, adding these into a [headers] collection, on a per MIME entity basis, depending upon whether or not your message actually contains headers or not. The [.mime.parse] semantically works identically, except it requires as its input a raw MimeEntity object from MimeKit. The [.mime.parse] slot can only be invoked from C#, since it starts with a ”.”.

Creating a mime message

The [mime.create] slot is logically the exact opposite of the [mime.parse] slot, and can take (almost) the exact same input as its sibling produces as output. Below is an example.

mime.create:multipart/mixed
   structured:false

   entity:text/plain
      content:this is the body text
      
   entity:text/plain
      content:this is another body text

Which of course wil result in something resembling the following after evaluation.

mime.create:"Content-Type: multipart/mixed; boundary=\"=-7+NI+p6PuOyQUzW5ihnXvw==\"\n\n--=-7+NI+p6PuOyQUzW5ihnXvw==\nContent-Type: text/plain\n\nthis is the body text\n--=-7+NI+p6PuOyQUzW5ihnXvw==\nContent-Type: text/plain\n\nthis is another body text\n--=-7+NI+p6PuOyQUzW5ihnXvw==--\n"

Notice - If you set its [structured] argument to boolean true, the slot will return the MIME envelope headers for the outermost MIME entity “detached” from the rest of the message. This is useful when you for some reasons don’t want the headers for the outermost entity to be a part of the actual message, such as for instance when creating multipart/form-data types of messages you need to transmit to some HTTP endpoint. If you do this, the return after executing the slot will resemble the following.

mime.create
   Content-Type:"multipart/mixed; boundary=\"=-EbMBZ3eHrSrMqtB2KHSv+A==\""
   content:"--=-EbMBZ3eHrSrMqtB2KHSv+A==\nContent-Type: text/plain\n\nthis is the body text\n--=-EbMBZ3eHrSrMqtB2KHSv+A==\nContent-Type: text/plain\n\nthis is another body text\n--=-EbMBZ3eHrSrMqtB2KHSv+A==--\n"

The [.mime.create] slot, will semantically do the exact same thing, but instead of returning a piece of text, being the MIME message, it will produce a raw MimeEntity that it returns to caller. This slot is used internally when the “magic.lambda.mail” project constructs emails to send over an SMTP connection for instance, and when the “magic.lambda.http” project transmits multipart/form-data types of requests. This slot can only be invoked from C# since it starts with a period (.) as its name.

Project website

The source code for this repository can be found at github.com/polterguy/magic.lambda.mime, and you can provide feedback, provide bug reports, etc at the same place.

Quality gates