英文:
How to process parallel HTTP request in go programming language?
问题
我正在使用go的HTTP包进行编程。我想要像在Java中一样并行处理请求。但是我做不到。
我创建了一个简单的Web服务器，在中间加了一个延时，然后发现go一次只能处理一个请求，所以如果我在浏览器上刷新，第一个请求的处理必须完成，才能开始处理第二个请求。以下是代码：
func main(){
//处理http命令
fmt.Printf("启动http服务器...")
http.Handle("/", http.HandlerFunc(sayHello))
err := http.ListenAndServe("0.0.0.0:8080", nil)
if err != nil {
fmt.Printf("ListenAndServe错误",err)
}
}
func sayHello(c http.ResponseWriter, req *http.Request) {
fmt.Printf("新请求\n")
processRequest(c, req)
}
func processRequest(w http.ResponseWriter, req *http.Request){
time.Sleep(time.Second*3)
w.Write([]byte("Go说你好（通过http）"))
fmt.Println("结束")
}
因为我想要并行处理两个请求，所以我在"sayHello"函数的"processRequest(c, req)"之前添加了"go"命令，以便在不同的goroutine中处理每个请求。但是...它不起作用...我不知道为什么。我知道两个请求都被处理了，因为我在控制台上看到了打印的行，但是浏览器一直等待信息...并且没有显示我的响应。
所以...我的问题是，
每个请求是否创建一个新的http.ResponseWriter？还是使用同一个？
你知道如何告诉Web服务器使用不同的线程处理每个请求吗？
任何帮助都受欢迎...
Fersca
英文:
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\n")
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
答案1
得分: 22
所有连接都会自动并发处理。每个TCP连接（不是请求）都会有自己的goroutine。
在一个使用HTTP流水线和重用连接的浏览器的世界中，这种方式可能并不总是有效。很可能你的浏览器正在重用一个连接，直到当前由goroutine处理的请求完成之前，它会一直处于停滞状态。
英文:
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.
答案2
得分: 0
为了让运行时支持利用多个操作系统线程，您可以通过以下方式设置数量：
runtime.GOMAXPROCS(n)
或者设置GOMAXPROCS环境变量。
要获取可用核心数，可以使用
runtime.NumCPU()
因此，您经常会使用
runtime.GOMAXPROCS(runtime.NumCPU())
英文:
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())
答案3
得分: 0
我认为你的浏览器正在等待，因为你没有向它发送回应。你的浏览器发送了一个请求给sayHello，而sayHello也发送了一个请求给processRequest。从你的代码来看，processRequest向sayHello发送了一个回应，但是sayHello没有向浏览器发送回应。
你可以使用http.Get或http.Post来调用processRequest。
英文:
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
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