MIME

The MIME component implements the Multipurpose Internet Mail Extensions (RFC 2045-2049) and related standards. It provides media type parsing, MIME part construction, multipart body streaming, content sniffing, S/MIME cryptography, and DKIM signing - all without filesystem coupling or temporary files.

Media Types

MediaType is an immutable value object representing a MIME media type like application/json or text/html; charset=utf-8. Type and subtype are always lowercased. Structured syntax suffixes and registration trees are extracted automatically.

@example('protocols/mime-media-type.php')

Content Negotiation

MediaPreferences parses HTTP Accept headers and negotiates the best media type per RFC 9110.

@example('protocols/mime-negotiation.php')

Parts

Parts are the building blocks of MIME messages. Every part implements PartInterface, which exposes $mediaType, $headers, and body().

@example('protocols/mime-parts.php')

Multipart Bodies

Multipart types compose multiple parts into a single body, delimited by a boundary string. All multipart types implement MultiPartInterface (which extends PartInterface), so they nest naturally.

@example('protocols/mime-multipart.php')

Form Data

Form builds multipart/form-data bodies per RFC 7578, for HTML form submissions and file uploads.

@example('protocols/mime-form.php')

Streaming Parser

The streaming parser yields parts lazily from a read handle, with configurable limits to prevent abuse.

@example('protocols/mime-parser.php')

S/MIME Cryptography

Sign, verify, encrypt, and decrypt using CMS (RFC 5652) - entirely in-memory without temporary files or openssl_pkcs7_* functions.

@example('protocols/mime-smime.php')

DKIM Signing

Sign raw MIME messages with DKIM (RFC 6376) using RSA-SHA256 or Ed25519-SHA256 (RFC 8463). RSA keys below 1024 bits are rejected per RFC 8301.

@example('protocols/mime-dkim.php')

Content Sniffing

Detect MIME types from content bytes using magic signatures, RIFF sub-formats, ISO BMFF brands, and text heuristics. Works on raw byte strings or seekable read handles.

RFC Compliance

See src/Psl/MIME/ for the full API.