英文:
The best way to set the timeout on built-in HTTP request
问题
设置内置http.NewRequest的超时时间的最佳方法是什么？目前，我正在使用http.Client的Timeout属性，它覆盖整个请求过程，但是否有更好的方法，例如使用context.WithDeadline或context.WithTimeout？如果有，它是如何工作的？如何为http.NewRequest设置context.WithDeadline解决方案？
以下是我目前的解决方案：
func (c *Client) post(resource string, data url.Values, timeout time.Duration) ([]byte, error) {
url := c.getURL(resource)
client := &http.Client{
Timeout: timeout * time.Millisecond,
}
req, err := http.NewRequest("POST", url, strings.NewReader(data.Encode()))
if err != nil {
return nil, err
}
req.Header.Add("Content-Type", "application/x-www-form-urlencoded")
resp, err := client.Do(req)
if err != nil {
return nil, err
}
return ioutil.ReadAll(resp.Body)
}
请注意，这是一个示例代码，你可以根据自己的需求进行调整。
英文:
What is the best way to setup a timeout on built-in http NewRequest? Currently, I'm using http.Client.Timeout which is cover the entire exchange, but is there something better for example context.WithDeadline or context.WithTimeout. If yes how is it working, how can I setup a context.WithDeadline solution for the http.NewRequest?
There is my current solution:
func (c *Client) post(resource string, data url.Values, timeout time.Duration) ([]byte, error) {
url := c.getURL(resource)
client := &http.Client{
Timeout: timeout * time.Millisecond,
}
req, err := http.NewRequest("POST", url, strings.NewReader(data.Encode()))
if err != nil {
return nil, err
}
req.Header.Add("Content-Type", "application/x-www-form-urlencoded")
resp, err := client.Do(req)
if err != nil {
return nil, err
}
return ioutil.ReadAll(resp.Body)
}
答案1
得分: 1
从context.WithDeadline中获取新的上下文。请参阅文档。
WithTimeout只是返回WithDeadline(parent, time.Now().Add(timeout))。
package main
import (
"context"
"io"
"log"
"net/http"
"os"
"time"
)
func getContent(ctx context.Context) {
req, err := http.NewRequest("GET", "http://example.com", nil)
if err != nil {
log.Fatal(err)
}
ctx, cancel := context.WithDeadline(ctx, time.Now().Add(3 * time.Second))
defer cancel()
req.WithContext(ctx)
resp, err := http.DefaultClient.Do(req)
if err != nil {
log.Fatal(err)
}
defer resp.Body.Close()
io.Copy(os.Stdout, resp.Body)
}
func main() {
ctx := context.Background()
getContent(ctx)
}
如果你想在main函数中触发取消操作：
func main() {
ctx := context.Background()
ctx, cancel := context.WithCancel(ctx)
sc := make(chan os.Signal, 1)
signal.Notify(sc, os.Interrupt)
go func(){
<-sc
cancel()
}()
getContent(ctx)
}
英文:
Get new context from context.WithDeadline. See documentation.
WithTimeout just returns WithDeadline(parent, time.Now().Add(timeout)).
package main
import (
"context"
"io"
"log"
"net/http"
"os"
"time"
)
func getContent(ctx context.Context) {
req, err := http.NewRequest("GET", "http://example.com", nil)
if err != nil {
log.Fatal(err)
}
ctx, cancel := context.WithDeadline(ctx, time.Now().Add(3 * time.Second))
defer cancel()
req.WithContext(ctx)
resp, err := http.DefaultClient.Do(req)
if err != nil {
log.Fatal(err)
}
defer resp.Body.Close()
io.Copy(os.Stdout, resp.Body)
}
func main() {
ctx := context.Background()
getContent(ctx)
}
If you want to make cancel trigger on main:
func main() {
ctx := context.Background()
ctx, cancel := context.WithCancel(ctx)
sc := make(chan os.Signal, 1)
signal.Notify(sc, os.Interrupt)
go func(){
<-sc
cancel()
}()
getContent(ctx)
}
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