Media Types Reference

TMediaType (MARS.Core.MediaType) defines constants for the common MIME types used in [Produces] / [Consumes] and content negotiation. Prefer these constants over string literals.

[GET, Produces(TMediaType.APPLICATION_JSON)]
function GetData: TData;

Constants

Constant	Value
TMediaType.TEXT_PLAIN	text/plain
TMediaType.TEXT_XML	text/xml
TMediaType.TEXT_HTML	text/html
TMediaType.TEXT_YAML	text/yaml
TMediaType.TEXT_EVENT_STREAM	text/event-stream
TMediaType.APPLICATION_XML	application/xml
TMediaType.APPLICATION_XML_FireDAC	application/xml-firedac
TMediaType.APPLICATION_JSON	application/json
TMediaType.APPLICATION_JSON_FireDAC	application/json-firedac
TMediaType.APPLICATION_XHTML_XML	application/xhtml+xml
TMediaType.APPLICATION_SVG_XML	application/svg+xml
TMediaType.APPLICATION_ATOM_XML	application/atom+xml
TMediaType.APPLICATION_OCTET_STREAM	application/octet-stream
TMediaType.APPLICATION_FORM_URLENCODED_TYPE	application/x-www-form-urlencoded
TMediaType.APPLICATION_YAML	application/x-yaml
TMediaType.APPLICATION_PDF	application/pdf
TMediaType.MULTIPART_FORM_DATA	multipart/form-data
TMediaType.WILDCARD	*/*

Notes

• */* (WILDCARD) matches any type; writers/readers registered for it act as fallbacks (lowest affinity).
• FireDAC variants (…-firedac) carry datasets in a compact Delphi-native format; plain application/json carries them as an interoperable array of objects. See FireDAC & Datasets.
• text/event-stream is used by Server-Sent Events.
• application/x-yaml requires MARS.YAML.ReadersAndWriters to be registered (used by the OpenAPI endpoint).

Parsing and matching

TMediaType.Create('application/json;charset=utf-8') parses a header value (type, subtype and parameters such as charset and quality factor q). Matches performs content-type negotiation, honoring wildcards and q priorities — this is what the content-negotiation layer uses to pick a reader/writer against the request's Accept/Content-Type.