How to use URL from user input in Go?

Question

I am almost absolutely new to Go language and my current problem is to read URL from user input into a variable to be passed as an argument to http.Get().

The following code

package main

import (
    "bufio"
    "fmt"
    "net/http"
    "os"
    "reflect"
)

func main() {
    reader := bufio.NewReader(os.Stdin)
    fmt.Print("Enter URL: ")
    txt, _ := reader.ReadString('\n')
    fmt.Println(reflect.TypeOf(txt))   // Get object type
    //url := fmt.Sprintf("http://%s",txt)
    url := "http://google.com"
    fmt.Println(reflect.TypeOf(url))   // Get object type
    resp, err := http.Get(url)
    if err != nil {
        fmt.Printf("%s", err)
        os.Exit(1)
    } else {
        fmt.Printf("%s\n", resp.Status)
    }
}

works perfectly:

d:\Go\bin>get_status
Enter URL: google.com
string
string
200 OK

but when I uncomment line 16 of the code (while commenting out line 17)

url := fmt.Sprintf("%s",txt)
//url := "http://google.com"

to use URL from user input, I get a problem:

d:\Go\bin>get_status
Enter URL: google.com
string
string
Get http://google.com
: dial tcp: GetAddrInfoW: No such host is known.

What could be wrong with my code? Please soothe my pain! :)

Upd: import "strings" plus url := strings.TrimSpace(fmt.Sprintf("http://%s",txt)) fixed the problem.

ReadString reads until the first occurrence of delim in the input, returning a string containing the data up to and including the delimiter.

@jiang Unfortunately, I can't get it work...

Vifonius
– Vifonius

2016-01-28 06:59:25 +00:00
Commented Jan 28, 2016 at 6:59 — Vifonius
– Vifonius, Commented Jan 28, 2016 at 6:59
@Vifonius Even using TrimSpace?

jacob
– jacob

2016-01-28 07:00:44 +00:00
Commented Jan 28, 2016 at 7:00 — jacob
– jacob, Commented Jan 28, 2016 at 7:00
@jacob No, I'm on Windows.

Vifonius
– Vifonius

2016-01-28 07:05:55 +00:00
Commented Jan 28, 2016 at 7:05 — Vifonius
– Vifonius, Commented Jan 28, 2016 at 7:05

jacob · Accepted Answer · 2016-01-28 06:51:49Z

1

Alright, so it appears that ReadString includes the delimiter, so you can use TrimSpace from the strings package. This seemed to do the trick for me.

url = strings.TrimSpace(url)

answered Jan 28, 2016 at 6:51

jacob

4,9871 gold badge25 silver badges35 bronze badges

Sign up to request clarification or add additional context in comments.

5 Comments

Vifonius Over a year ago

Fascinating! Thank you very much! The problem was with '\n' at the end of the string!

Volker Over a year ago

Yeha, debugging the object types is much less useful (as Go is statically typed) than printing the actual value with %v (or even %#v).

Vifonius Over a year ago

@Volker I just wanted to be sure that I got strings in both cases. Thank you for your comment!

Volker Over a year ago

@Vifonius What else could func (*bufio.Reader) ReadString(byte) (string, error) possibly return?

Vifonius Over a year ago

@Volker Undoubtedly, I should have read the docs more thoroughly. :) I was just under fresh impression of Elixir where I had to convert URL from string to char list before passing it to :httpc.request function: url = String.to_char_list(url)

Collectives™ on Stack Overflow

How to use URL from user input in Go?

1 Answer 1

5 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

5 Comments

Your Answer

Sign up or log in

Post as a guest

Related