Is there a way in Go to combine URL paths similarly as we can do with filepaths using path.Join()?
For example see e.g. Combine absolute path and relative path to get a new absolute path.
When I use path.Join("http://foo", "bar"), I get http:/foo/bar.
See in Golang Playground.
The function path.Join expects a path, not a URL. Parse the URL to get a path and join with that path:
u, err := url.Parse("http://foo")
u.Path = path.Join(u.Path, "bar.html")
s := u.String() // prints http://foo/bar.html
If you are combining more than the path (scheme or host for example) or the string is more than the path (it includes a query string for example), then use ResolveReference.
ResolveReference() in net/url package
The accepted answer will not work for relative url paths containing file endings like .html or .img. The ResolveReference() function is the correct way to join url paths in go.
package main
import (
"fmt"
"log"
"net/url"
)
func main() {
u, err := url.Parse("../../..//search?q=dotnet")
if err != nil {
log.Fatal(err)
}
base, err := url.Parse("http://example.com/directory/")
if err != nil {
log.Fatal(err)
}
fmt.Println(base.ResolveReference(u))
}
I wrote this utility function that works for my purposes:
func Join(basePath string, paths ...string) (*url.URL, error) {
u, err := url.Parse(basePath)
if err != nil {
return nil, fmt.Errorf("invalid url")
}
p2 := append([]string{u.Path}, paths...)
result := path.Join(p2...)
u.Path = result
return u, nil
}
A simple approach to this would be to trim the /'s you don't want and join. Here is an example func
func JoinURL(base string, paths ...string) string {
p := path.Join(paths...)
return fmt.Sprintf("%s/%s", strings.TrimRight(base, "/"), strings.TrimLeft(p, "/"))
}
Usage would be
b := "http://my.domain.com/api/"
u := JoinURL(b, "/foo", "bar/", "baz")
fmt.Println(u)
This removes the need for checking/returning errors