Go by Example: Url Parsing

URLs provide a uniform way to locate resources. Here’s how to parse URLs in Go.

 
package main

import (
    "fmt"
    "net"
    "net/url"
)

func main() {

We’ll parse this example URL, which includes a scheme, authentication info, host, port, path, query params, and query fragment.

 
    s := "postgres://user:pass@host.com:5432/path?k=v#f"

Parse the URL and ensure there are no errors.

 
    u, err := url.Parse(s)
    if err != nil {
        panic(err)
    }

Accessing the scheme is straightforward.

 
    fmt.Println(u.Scheme)

User contains all authentication info; call Username and Password on this for individual values.

 
    fmt.Println(u.User)
    fmt.Println(u.User.Username())
    p, _ := u.User.Password()
    fmt.Println(p)

The Host contains both the hostname and the port, if present. Use SplitHostPort to extract them.

 
    fmt.Println(u.Host)
    host, port, _ := net.SplitHostPort(u.Host)
    fmt.Println(host)
    fmt.Println(port)

Here we extract the path and the fragment after the #.

 
    fmt.Println(u.Path)
    fmt.Println(u.Fragment)

To get query params in a string of k=v format, use RawQuery. You can also parse query params into a map. The parsed query param maps are from strings to slices of strings, so index into [0] if you only want the first value.

 
    fmt.Println(u.RawQuery)
    m, _ := url.ParseQuery(u.RawQuery)
    fmt.Println(m)
    fmt.Println(m["k"][0])
}

Running our URL parsing program shows all the different pieces that we extracted.

 
$ go run url-parsing.go 
postgres
user:pass
user
pass
host.com:5432
host.com
5432
/path
f
k=v
map[k:[v]]
v

Next example: http Request.

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