MQHeader

Package: @opra/common

MQHeader is the runtime class that represents a message header declared on an MQController or MQOperation. Headers carry metadata alongside a message — correlation IDs, routing keys, content-type hints, and similar transport-level values.

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Inheritance

DocumentElement
└── Value
    └── MQHeader

Value contributes the core name/type pair. MQHeader adds lifecycle and validation metadata.

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Properties

Properties inherited from Value:

Property	Type	Description
name	string | RegExp	Header name. May be a RegExp to match multiple headers with a single declaration.
type	DataType | undefined	The data type used for encoding and decoding the header value.
description	string | undefined	Human-readable description.
isArray	boolean | undefined	Whether the header holds an array of values.
examples	any[] | undefined	Example values for documentation.

Properties on MQHeader:

Property	Type	Description
required	boolean | undefined	Header must be present in the message.
deprecated	boolean | string | undefined	Marks the header as deprecated. Pass a string for a deprecation message.
designType	Type | undefined	TypeScript constructor type from design:type metadata.

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Methods

generateCodec(codec, options?)

Compiles a validation/transformation function for encoding (output) or decoding (input) the header value according to its declared type.

const decoder = header.generateCodec('decode');
const encoder = header.generateCodec('encode');

generateCodec(
  codec: 'encode' | 'decode',
  options?: DataType.GenerateCodecOptions,
): Validator

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toJSON(options?)

Returns a plain OpraSchema.MQHeader object for schema export.

toJSON(options?: ApiDocument.ExportOptions): OpraSchema.MQHeader

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Obtaining an MQHeader instance

Headers are retrieved via MQController.findHeader() or MQOperation.findHeader().

const ctrl = document.api.findController('CustomerQueue');
const header = ctrl?.findHeader('x-correlation-id');

if (header) {
  console.log(header.name);      // 'x-correlation-id'
  console.log(header.required);  // true | false | undefined
  const decoder = header.generateCodec('decode');
}

→ MQController · MQOperation