如何使用Go编程语言处理并行HTTP请求？

I was playing with the go HTTP package. I wanted to process request in parallel as I do in java. But I couldn't.

I created a simple web server, put a sleep in the middle and realized that go process one request per time, so if I did a refresh on my browser, the process of the first request has to finish until the second request start processing, here is the code:

func main(){

    //Process the http commands
    fmt.Printf("Starting http Server ... ")
    http.Handle("/", http.HandlerFunc(sayHello))
    err := http.ListenAndServe("0.0.0.0:8080", nil)
    if err != nil {
        fmt.Printf("ListenAndServe Error",err)
    }
}

func sayHello(c http.ResponseWriter, req *http.Request) {
    fmt.Printf("New Request
")
    processRequest(c, req)
}

func processRequest(w http.ResponseWriter, req *http.Request){
    time.Sleep(time.Second*3)
    w.Write([]byte("Go Say’s Hello(Via http)"))
    fmt.Println("End")
}

As I wanted to process both request in parallel I added the "go" command before "processRequest(c, req)" in "sayHello" function in order to process each request in a different gorutine. But... it doesn't work.... I don't know why. I know that both request are processed because I see the printed line at the console but the browser keep waiting for information..... and don't show my response.

So... my questions,

Does each request create a new http.ResponseWriter? or it's use the same? Do you know how to indicate the web server to process each request with different threads?

Any help is welcomed....

Fersca

All connections are automatically handled concurrently. Each TCP connection (not request) gets its own goroutine.

In a world with http pipelining and browsers that reuse connections, this may not always work out well. Most likely your browser is reusing a connection which stalls it until the current request being processed by the goroutine finishes.

To allow the run-time support to utilize more than one OS thread you might want to set that number via:

 runtime.GOMAXPROCS(n)

or set the GOMAXPROCS environment variable.

To get the number of available cores, use

 runtime.NumCPU()

So you often end up with

 runtime.GOMAXPROCS(runtime.NumCPU())

I think your browser is waiting because you did not sent a response back to it Your browser made a request to sayHello and sayHello also made a request to processRequest, from your code processRequest sent back a response to sayHello but sayHello did not send back a response to the browser.

you can use http.Get or http.Post to call processRequest