bwilliams
465358609a
Short and single-letter names in application code become full words (tests keep theirs). Wrapped calls, signatures and composite literals put one item per line, and one-line function bodies are expanded. Exported names and groups of constants get doc comments, and comments refer to the renamed identifiers.
73 lines
2.3 KiB
Go
73 lines
2.3 KiB
Go
// Package websocket implements the hub that pushes messages to connected
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// clients: WebSocket clients upgraded by Hub.ServeHTTP (the /ws endpoint) and
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// plain TCP clients run by Hub.ServeTCP, which send the same messages as
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// newline-delimited JSON (see tcp.go). Package tcpserver runs a TCP server
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// for those clients.
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//
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// Every message is a JSON Envelope: a WebSocket text frame, or one line on
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// TCP.
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//
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// Client -> server:
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//
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// {"type":"ping","id":"1"}
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// {"type":"echo","id":"2","payload":{...}}
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//
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// Server -> client:
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//
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// {"type":"welcome","payload":{"clientId":"..."}}
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// {"type":"pong","id":"1","payload":{"time":"..."}}
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// {"type":"echo","id":"2","payload":{...}}
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// {"type":"error","id":"3","error":"..."}
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// {"type":"item.created","payload":{...}}
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//
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// Any other type from a client gets an "unknown message type" error. The last
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// message is one sent by Hub.Push: its type is the pushed message type.
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package websocket
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import "encoding/json"
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// Envelope is the wire format for every message in both directions.
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type Envelope struct {
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Type string `json:"type"`
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ID string `json:"id,omitempty"`
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Payload json.RawMessage `json:"payload,omitempty"`
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Error string `json:"error,omitempty"`
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}
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// Envelope types. TypeEvent, TypeRequest and TypeAck are reserved: nothing
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// sends or handles them yet.
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const (
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// TypeWelcome is sent to a client when it connects, with its client ID.
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TypeWelcome = "welcome"
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// TypePing asks the server for a TypePong.
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TypePing = "ping"
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// TypePong answers a TypePing, with the server's time.
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TypePong = "pong"
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// TypeEcho is sent back to the client with the same ID and payload.
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TypeEcho = "echo"
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// TypeEvent is reserved for events pushed to clients.
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TypeEvent = "event"
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// TypeRequest is reserved for requests from clients.
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TypeRequest = "request"
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// TypeAck is reserved for acknowledging a request.
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TypeAck = "ack"
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// TypeError reports an error, with the ID of the message it answers.
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TypeError = "error"
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)
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// mustRaw returns value as raw JSON: value itself if it is already
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// json.RawMessage, nil if value is nil or can't be marshalled.
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func mustRaw(value any) json.RawMessage {
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if value == nil {
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return nil
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}
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if raw, ok := value.(json.RawMessage); ok {
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return raw
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}
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encoded, err := json.Marshal(value)
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if err != nil {
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return nil
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}
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return encoded
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}
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