英文:
Go: Sending gob's over a pipe is hanging - UPDATE: Out-of-process http.ResponseWriter is blocking
问题
我正在编写一个使用Go语言将请求分发给外部进程的Web服务器。我正在使用gob通过管道发送ResponseWriter和Request数据类型。
问题是当接收gob时，外部进程会挂起。
更新 现在gob已成功发送到外部进程，但是外部进程在fmt.Fprintf(request.Resp, "Hello")处阻塞并停在那里。
dispreq.go
package dispreq
import (
"net/http"
)
type DispReq struct {
Resp http.ResponseWriter
Req *http.Request
}
dispatcher.go
package main
import (
"encoding/gob"
"fmt"
"net/http"
"os"
"os/exec"
"dispreq"
)
func dispatch(w http.ResponseWriter, r *http.Request) {
process := exec.Command("./hello")
pipe, piperr := process.StdinPipe()
if piperr != nil {
fmt.Fprintf(os.Stderr, piperr.Error())
return
}
encoder := gob.NewEncoder(pipe)
process.Stdout = os.Stdout
//更新：encoder.Encode(&dispreq.DispReq{w, r})
//更新：process.Start()
process.Start()
encoder.Encode(&dispreq.DispReq{w, r})
pipe.Close()
process.Wait()
}
func main() {
http.HandleFunc("/", dispatch)
http.ListenAndServe(":8080", nil)
}
hello.go
package main
import (
"dispreq"
"encoding/gob"
"os"
"fmt"
)
func main() {
gobDecoder := gob.NewDecoder(os.Stdin)
var request dispreq.DispReq
gobDecoder.Decode(&request)
fmt.Fprintf(request.Resp, "Hello")
}
英文:
I'm writing a webserver that distributes requests to out-of-process programs in Go. I'm sending the ResponseWriter and Request datatypes through Pipes using gob.
The problem is the external process is hanging when receiving the gob.
UPDATE The gob is now successfully being sent to the external process, but now the external process is blocking at fmt.Fprintf(request.Resp, "Hello") and freezes there.
dispreq.go
package dispreq
import (
"net/http"
)
type DispReq struct {
Resp http.ResponseWriter
Req *http.Request
}
dispatcher.go
package main
import (
"encoding/gob"
"fmt"
"net/http"
"os"
"os/exec"
"dispreq"
)
func dispatch(w http.ResponseWriter, r *http.Request) {
process := exec.Command("./hello")
pipe, piperr := process.StdinPipe()
if piperr != nil {
fmt.Fprintf(os.Stderr, piperr.Error())
return
}
encoder := gob.NewEncoder(pipe)
process.Stdout = os.Stdout
//UPDATE: encoder.Encode(&dispreq.DispReq{w, r})
//UPDATE: process.Start()
process.Start()
encoder.Encode(&dispreq.DispReq{w, r})
pipe.Close()
process.Wait()
}
func main() {
http.HandleFunc("/", dispatch)
http.ListenAndServe(":8080", nil)
}
hello.go
package main
import (
"dispreq"
"encoding/gob"
"os"
"fmt"
)
func main() {
gobDecoder := gob.NewDecoder(os.Stdin)
var request dispreq.DispReq
gobDecoder.Decode(&request)
fmt.Fprintf(request.Resp, "Hello")
}
答案1
得分: 2
你应该在发送数据给它之前启动进程（process.Start()）。你可能还需要通过关闭管道（pipe.Close()）或发送一个\n来刷新管道。
英文:
You should start the process (process.Start()) before sending data to it (encoder.Encode(&dispreq.DispReq{w, r})). You might also need to flush your pipe by closing it (pipe.Close()) or sending a \n.
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