37 lines
998 B
Go
37 lines
998 B
Go
package webutils
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import (
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"errors"
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"fmt"
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"net/http"
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)
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var (
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ErrWriterNotFlushable = errors.New("response writer not flushable")
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)
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// SseWriter provides a simple implementation for sending data via Server Side Events
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// to the client. The function runs until the dataStream channel is closed.
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// The ResponseWriter must not be used after calling this function
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//
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// Inspired by and partially copied from https://medium.com/@rian.eka.cahya/server-sent-event-sse-with-go-10592d9c2aa1
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func SseWriter(w http.ResponseWriter, dataStream chan []byte) error {
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w.Header().Set("Access-Control-Expose-Headers", "Content-Type")
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w.Header().Set("Content-Type", "text/event-stream")
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w.Header().Set("Cache-Control", "no-cache")
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w.Header().Set("Connection", "keep-alive")
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flusher, ok := w.(http.Flusher)
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if !ok {
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return ErrWriterNotFlushable
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}
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for data := range dataStream {
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_, err := fmt.Fprintf(w, "%s\n\n", string(data))
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if err != nil {
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return err
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}
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flusher.Flush()
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}
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return nil
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}
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