RFC 2387 / START HERE
Multipart/Related, before the details
MIME Multipart/Related. MIME means Multipurpose Internet Mail Extensions; multipart/related is the name of this content type, not an acronym.
It packages several message parts as one compound object. A root part is processed first, and related parts supply content that the root needs.
Why it exists
An HTML message and its included images need more than a list of attachments. This RFC describes the package, root selection and application handoff; RFC 2392 separately defines cid links between parts.
A familiar example
A fictional picnic invitation can have an HTML root and an included photo. The application assembles the invitation from those parts. Packaging them together does not prove who sent them or make their contents safe.
Helpful background
You can start here without reading another RFC. If these ideas are unfamiliar, these short introductions may help.
What you’ll learn next
Begin with chapter one, or choose a topic.
- Treat related parts as one objectA compound object needs its related parts to be interpreted together. MIME means Multipurpose Internet Mail Extensions: a format for labeling message content.→
- Select the root and check its typeThe required type parameter describes the root; the optional start parameter selects it by Content-ID.→
- Pass parameters without executing themParameters identify the root and can carry application-specific auxiliary information. Their syntax and their interpretation are different concerns.→
- Separate disposition from application handlingContent-Disposition suggests inline or attachment presentation. A compound-object application has a different responsibility.→
- Preserve mappings, nesting and content safetyPassing and storing a compound object requires the relationships between its parts, not only their body bytes.→
This introduction explains RFC 2387 (1998). Read the original RFC ↗