// Copyright 2020 The Gitea Authors. All rights reserved. // Use of this source code is governed by a MIT-style // license that can be found in the LICENSE file. package eventsource import ( "bytes" "fmt" "io" "strings" "time" jsoniter "github.com/json-iterator/go" ) func wrapNewlines(w io.Writer, prefix []byte, value []byte) (sum int64, err error) { if len(value) == 0 { return } n := 0 last := 0 for j := bytes.IndexByte(value, '\n'); j > -1; j = bytes.IndexByte(value[last:], '\n') { n, err = w.Write(prefix) sum += int64(n) if err != nil { return } n, err = w.Write(value[last : last+j+1]) sum += int64(n) if err != nil { return } last += j + 1 } n, err = w.Write(prefix) sum += int64(n) if err != nil { return } n, err = w.Write(value[last:]) sum += int64(n) if err != nil { return } n, err = w.Write([]byte("\n")) sum += int64(n) return } // Event is an eventsource event, not all fields need to be set type Event struct { // Name represents the value of the event: tag in the stream Name string // Data is either JSONified []byte or interface{} that can be JSONd Data interface{} // ID represents the ID of an event ID string // Retry tells the receiver only to attempt to reconnect to the source after this time Retry time.Duration } // WriteTo writes data to w until there's no more data to write or when an error occurs. // The return value n is the number of bytes written. Any error encountered during the write is also returned. func (e *Event) WriteTo(w io.Writer) (int64, error) { sum := int64(0) nint := 0 n, err := wrapNewlines(w, []byte("event: "), []byte(e.Name)) sum += n if err != nil { return sum, err } if e.Data != nil { var data []byte switch v := e.Data.(type) { case []byte: data = v case string: data = []byte(v) default: var err error json := jsoniter.ConfigCompatibleWithStandardLibrary data, err = json.Marshal(e.Data) if err != nil { return sum, err } } n, err := wrapNewlines(w, []byte("data: "), data) sum += n if err != nil { return sum, err } } n, err = wrapNewlines(w, []byte("id: "), []byte(e.ID)) sum += n if err != nil { return sum, err } if e.Retry != 0 { nint, err = fmt.Fprintf(w, "retry: %d\n", int64(e.Retry/time.Millisecond)) sum += int64(nint) if err != nil { return sum, err } } nint, err = w.Write([]byte("\n")) sum += int64(nint) return sum, err } func (e *Event) String() string { buf := new(strings.Builder) _, _ = e.WriteTo(buf) return buf.String() }