f9d452ad2c
This is an example of a race-free long-poll server and client. It uses a redirection method to signal that the "Watch" is running. Other race-free methods exist.
53 lines
1.2 KiB
Go
53 lines
1.2 KiB
Go
// This is an example longpoll client. The connection to the corresponding
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// server initiates a request on a "Watch". It then waits until a redirect is
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// received from the server which indicates that the watch is ready. To signal
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// than an event on this watch has occurred, the server sends a final message.
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package main
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import (
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"bytes"
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"fmt"
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"io/ioutil"
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"log"
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"math/rand"
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"net/http"
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"time"
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)
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const (
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timeout = 15
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)
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func main() {
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log.Printf("Starting...")
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checkRedirectFunc := func(req *http.Request, via []*http.Request) error {
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log.Printf("Watch is ready!")
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return nil
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}
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client := &http.Client{
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Timeout: time.Duration(timeout) * time.Second,
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CheckRedirect: checkRedirectFunc,
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}
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id := rand.Intn(2 ^ 32 - 1)
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body := bytes.NewBufferString("hello")
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url := fmt.Sprintf("http://127.0.0.1:12345/watch?id=%d", id)
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req, err := http.NewRequest("GET", url, body)
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if err != nil {
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log.Printf("err: %+v", err)
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return
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}
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result, err := client.Do(req)
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if err != nil {
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log.Printf("err: %+v", err)
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return
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}
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log.Printf("Event received: %+v", result)
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s, err := ioutil.ReadAll(result.Body) // TODO: apparently we can stream
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result.Body.Close()
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log.Printf("Response: %+v", string(s))
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}
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