Go URL Read

Introduction

Here is an example program that uses goroutines and channels.

It fetches several web pages simultaneously using the net/http package, and prints the URL of the biggest home page. 


package main /*from w  w w.  j a  v a 2s .  com*/

import ( 
    "fmt" 
    "io/ioutil" 
    "net/http" 
) 

type HomePageSize struct { 
    URL  string 
    Size int 
} 

func main() { 
    urls  := []string{ 
        "http://www.apple.com", 
        "http://www.amazon.com", 
        "http://www.google.com", 
        "http://www.microsoft.com", 
    } 

    results  := make(chan HomePageSize) 

    for _, url  := range urls { 
        go func(url string) { 
            res, err  := http.Get(url) 
            if err  != nil { 
                panic(err) 
            } 
            defer res.Body.Close() 

            bs, err  := ioutil.ReadAll(res.Body) 
            if err  != nil { 
                panic(err) 
            } 

            results <- HomePageSize{ 
                URL:  url, 
                Size: len(bs), 
            } 
        }(url) 
    } 

    var biggest HomePageSize 

    for range urls { 
        result  := <-results 
        if result.Size > biggest.Size { 
            biggest = result 
        } 
    } 

    fmt.Println("The biggest home page:", biggest.URL) 
}



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