MessageStart.head

Description

For each protocol

The content of head can vary depending on the protocol used by the message.

HTTP

The head of an HTTP request message has the following content:

• scheme - For HTTP/2 only, "http" or "https"
• authority - Equivalent to the Host header in HTTP/2
• protocol - Can be "HTTP/1.0" or "HTTP/1.1"
• method - HTTP method such as "GET" and "POST"
• path - Requested URI
• headers - Header fields

The head of an HTTP response message has the following content:

• protocol - Can be "HTTP/1.0" or "HTTP/1.1"
• status - Response status code
• statusText - Response reason phrase
• headers - Header fields

MQTT

The head of an MQTT packet has the following content:

• type - Type of the packet such as "SUBSCRIBE" and "PUBLISH"
• qos - PUBLISH Quality of Service
• dup - Duplicate delivery of a PUBLISH packet
• retain - PUBLISH retained message flag
• Other properties defined in the specification

Thrift

The head of a Thrift message has the following content:

• seqID - Sequence ID as a number
• type - Type of the message: "call", "reply", "exception" or "oneway"
• name - Name of the message
• protocol - Encoding protocol: "binary" or "compact"

Dubbo

The head of a Dubbo message has the following content:

• id - Request ID as a string
• status - Status code
• isRequest - Is it a request?
• isTwoWay - Is it 2-way?
• isEvent - Is it an event?

Syntax

messageStart.head

Example

pipy()

  .listen(8080)
  .demuxHTTP().to(
    $=>$
    .handleMessageStart(
      msg => (
        console.log('Path:', msg.head.path, 'Headers:', msg.head.headers)
      )
    )
    .replaceMessage(
      new Message('Hello!')
    )
  )

See Also

• MessageStart
• Message