URL Builder/Query builder in Go

There's already url.URL that handles that kind of things for you.

For http handlers (incoming requests) it's a part of http.Request (access it with req.URL.Query()).

A very good example from the official docs:

u, err := url.Parse("http://bing.com/search?q=dotnet")
if err != nil {
    log.Fatal(err)
}
u.Scheme = "https"
u.Host = "google.com"
q := u.Query()
q.Set("q", "golang")
u.RawQuery = q.Encode()
fmt.Println(u)

https://github.com/golang/go/issues/17340#issuecomment-251537687

https://play.golang.org/p/XUctl_odTSb

package main

import (
    "fmt"
    "net/url"
)

func someURL() string {
    url := url.URL{
        Scheme: "https",
        Host:   "example.com",
    }
    return url.String()
}

func main() {
    fmt.Println(someURL())
}

returns:

https://example.com