运行此代码时,我必须等待 10 秒才能打印 s.Locations 并等待 60 秒以上才能打印 n.Titles。这是什么原因造成的?
有关如何解决此问题的提示会很有帮助,即查看完成某些代码行需要多长时间。 Go 的新手,所以不确定如何准确地执行此操作。
我已确保关闭连接。由于我计算机上的其他所有内容加载速度都非常快,我不认为通过 http.Get 访问互联网应该很慢。
package main
import (
"encoding/xml"
"fmt"
"io/ioutil"
"net/http"
"strings"
)
// SitemapIndex is the root xml
type SitemapIndex struct {
Locations []string `xml:"sitemap>loc"`
}
// News is the individual categories
type News struct {
Titles []string `xml:"url>news>title"`
Keywords []string `xml:"url>news>keywords"`
Locations []string `xml:"url>loc"`
}
// NewsMap is the
type NewsMap struct {
Keywords string
Location string
}
func main() {
var s SitemapIndex
var n News
// np := make(map[string]NewsMap)
resp, _ := http.Get("https://www.washingtonpost.com/news-sitemaps/index.xml")
bytes, _ := ioutil.ReadAll(resp.Body)
xml.Unmarshal(bytes, &s)
resp.Body.Close()
for i := range s.Locations {
s.Locations[i] = strings.TrimSpace(s.Locations[i])
}
fmt.Println(s.Locations) // slice of data
for _, Location := range s.Locations {
resp, _ := http.Get(Location)
bytes, _ := ioutil.ReadAll(resp.Body)
xml.Unmarshal(bytes, &n)
resp.Body.Close()
}
fmt.Println(n.Titles)
}
我得到了输出,但我必须为 s.Locations 等待 10 秒,为 n.Titles 等待 60 秒以上
最佳答案
Tips on how to troubleshoot this would be helpful.
从简单的事情开始,一次测量一件事情,一个科学实验。
使用 curl
测量基本响应时间。
$ curl https://www.google.com/robots.txt -o /dev/null
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 7246 0 7246 0 0 94103 0 --:--:-- --:--:-- --:--:-- 94103
$ curl https://www.nytimes.com/robots.txt -o /dev/null
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 934 100 934 0 0 61 0 0:00:15 0:00:15 --:--:-- 230
$ curl https://www.washingtonpost.com/robots.txt -o /dev/null
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 3360 100 3360 0 0 133 0 0:00:25 0:00:25 --:--:-- 869
$
谷歌没有延迟。纽约时报有 15 秒的延迟。华盛顿邮报有 25 秒的延迟。
在 Go 中,确认华盛顿邮报有 25 秒的延迟。
$ go run wapo.go
25.174366651s
$ cat wapo.go
package main
import (
"fmt"
"io/ioutil"
"net/http"
"os"
"time"
)
func main() {
start := time.Now()
resp, err := http.Get("https://www.washingtonpost.com/news-sitemaps/index.xml")
if err != nil {
fmt.Fprintln(os.Stderr, err)
return
}
_, err = ioutil.ReadAll(resp.Body)
if err != nil {
fmt.Fprintln(os.Stderr, err)
return
}
resp.Body.Close()
fmt.Fprintln(os.Stderr, time.Since(start))
}
$
接下来,从另一台计算机尝试不同的 ISP。
$ curl https://www.google.com/robots.txt -o /dev/null
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 7246 0 7246 0 0 27343 0 --:--:-- --:--:-- --:--:-- 27343
$ curl https://www.nytimes.com/robots.txt -o /dev/null
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 934 100 934 0 0 2017 0 --:--:-- --:--:-- --:--:-- 2017
$ curl https://www.washingtonpost.com/robots.txt -o /dev/null
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 3360 100 3360 0 0 356 0 0:00:09 0:00:09 --:--:-- 840
$ curl https://www.washingtonpost.com/news-sitemaps/index.xml -o /dev/null
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 1101 100 1101 0 0 104 0 0:00:10 0:00:10 --:--:-- 266
$
$ go run wapo.go
8.378458882s
$
谷歌没有延迟。 《纽约时报》稍有延迟。华盛顿邮报有 9 秒的延迟。
Go 代码和编译器是一样的:
$ go version
go version devel +a25c2878c7 Sat Jul 27 23:29:18 2019 +0000 linux/amd64
$ cat wapo.go
package main
import (
"fmt"
"net/http"
"os"
"time"
)
func main() {
start := time.Now()
resp, err := http.Get("https://www.washingtonpost.com/news-sitemaps/index.xml")
if err != nil {
fmt.Fprintln(os.Stderr, err)
return
}
resp.Body.Close()
fmt.Fprintln(os.Stderr, time.Since(start))
}
$
因此,关注网络和站点因素。
关于http - 为什么我的代码需要这么长时间才能返回结果?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/57246203/