问题描述
如何将下面的代码转换为使用流/管道,以便我不需要将全部内容读入内存?
类似于:
http.Get(http://example.com/).Pipe(./data.txt)
包主
导入(net / http;io / ioutil)
func main(){
resp,err:= http.Get(http://example.com/)
check(err)
defer resp.Body.Close( )
body,err:= ioutil.ReadAll(resp.Body)
check(err)
err = ioutil.WriteFile(./ data.txt,body,0666)
$ check(err)
}
func check(e error){
if e!= nil {
panic(e)
}
}
> io.Copy ()?其文档可在以下网址找到: http://golang.org/pkg/io/#Copy
尽管这很简单。给它一个 io.Reader 和一个 io.Writer ,它将数据复制一次,一次一个小块(例如,不是所有的内存在一次)。
所以你可以尝试写如下:
func main(){
resp,err:= http.Get(...)
check(err)
defer resp.Body.Close( )
out,err:= os.Create(filename.ext)
if err!= nil {
// panic?
推迟出.Close()
io.Copy(out,resp.Body)
}
我没有测试过以上;我刚刚从上面的例子中快速入侵了它,但它应该接近,如果不是钱的话。
How do I convert the below code to use streams/pipes so that I don't need to read the full content into memory?Something like:http.Get("http://example.com/").Pipe("./data.txt")
package main import ("net/http";"io/ioutil") func main() { resp, err := http.Get("http://example.com/") check(err) defer resp.Body.Close() body, err := ioutil.ReadAll(resp.Body) check(err) err = ioutil.WriteFile("./data.txt", body, 0666) check(err) } func check(e error) { if e != nil { panic(e) } }
How about io.Copy()? Its documentation can be found at: http://golang.org/pkg/io/#Copy
It's pretty simple, though. Give it an io.Reader and an io.Writer and it copies the data over, one small chunk at a time (e.g. not all in memory at once).
So you might try writing something like:
func main() { resp, err := http.Get("...") check(err) defer resp.Body.Close() out, err := os.Create("filename.ext") if err != nil { // panic? } defer out.Close() io.Copy(out, resp.Body) }
I haven't tested the above; I just hacked it together quickly from your above example, but it should be close if not on the money.
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