Documentation
¶
Overview ¶
Package hub provides a transport agnostic connection hub.
Index ¶
Constants ¶
const ( Signon = "_signon" Signoff = "_signoff" )
Variables ¶
This section is empty.
Functions ¶
Types ¶
type ChanConn ¶
type ChanConn struct {
// contains filtered or unexported fields
}
ChanConn is a channel based connection used for simple in-process hub participants.
func NewChanConn ¶
NewChanConn returns a new channel connection with the given id and channel.
type Conn ¶
type Conn interface {
// Ctx returns the connection context.
Ctx() context.Context
// ID is an internal connection identifier, the hub has id 0, transient connections have a
// negative and normal connections positive ids.
ID() int64
// User is an external user identifier
User() string
// Chan returns an unchanging receiver channel. The hub sends a nil message to this
// channel after a signoff message from this conn was received.
Chan() chan<- *Msg
}
Conn is a connection abstraction providing a ID, user field and a channel to send messages. Connections can represent one-off calls, connected clients of any kind, or the hub itself.
type Hub ¶
type Hub struct {
// contains filtered or unexported fields
}
Hub is the central message server that manages connection. Hub itself represents conn id 0. Connection creators are also responsible for sending the signon message and validating messages. One-off connections used for a simple request-response round trips can be used without signon and must use id -1. These connections can only be responded to directly and must not be stored.
type MatchFilter ¶
MatchFilter only routes messages, that match one of a list of subjects.
type Msg ¶
type Msg struct {
// From is the origin connection of this message or nil for server internal messages.
From Conn
// Subj is the required message header used for routing and determining the data type.
Subj string
// Tok is a client token that is used in replies, so they can be matched to a request.
Tok string
// Raw is the message body as bytes usually encoded as JSON.
Raw []byte
// Data is the typed body data and can be used to avoid serialization of internal messages.
Data interface{}
}
Msg is the central structure passed between connections. The optional body is represented by raw bytes or typed data. If raw bytes are required but not set, non nil data is encoded as JSON.
func RawMsg ¶
RawMsg returns a new message with subj and v encoded as JSON or an error. This is helpful encode the message body immediately to not hand off ownership of v.
func Read ¶
Read parses input bytes and returns a message or an error. The byte slice is then owned by the message and cannot be reused.
func Req ¶
Req sends req to the hub from a newly created transient connection and returns the first response or an error if the timeout was reached.
func (*Msg) Reply ¶
Reply returns a new message with the same subj and tok and a new data. The message body will be encoded directly and data will not set.
func (*Msg) ReplyErr ¶
ReplyErr returns a new reply with the error encoded as the single json object field err
func (*Msg) ReplyRes ¶
ReplyRes returns a new reply with result encoded as the single json object field res
type RouterFunc ¶
type RouterFunc func(*Msg)
RouterFunc implements Router for simple route functions.
func NewMatchFilter ¶
func NewMatchFilter(r Router, match ...string) RouterFunc
NewMatchFilter returns a new router that matches message subject and calls r.
func NewPrefixFilter ¶
func NewPrefixFilter(r Router, match ...string) RouterFunc
NewMatchFilter returns a new router that matches message subject prefixes and calls r.
func NewRegexpFilter ¶
func NewRegexpFilter(r Router, pat *regexp.Regexp) RouterFunc
NewRegexpFilter returns a new router that matches message subjects with regexp and calls r.
func (RouterFunc) Route ¶
func (r RouterFunc) Route(m *Msg)
type Routers ¶
type Routers []Router
Routers is a slice of routers, all of them are called with incoming messages.
type Service ¶
type Service interface {
// Serve handles the message and returns the response or nil, or an error.
Serve(*Msg) (*Msg, error)
}
A service is a common interface for the last message processor in line. It usually is used by wrappers, that handles request parsing and delegate.
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