amfora/client/url.go
2021-12-23 00:23:06 -05:00

103 lines
2.8 KiB
Go

package client
// Functions that transform and normalize URLs
// Originally used to be in display/util.go
// Moved here for #115, so URLs in the [auth] config section could be normalized
import (
"net/url"
"strings"
"github.com/makeworld-the-better-one/go-gemini"
"golang.org/x/text/unicode/norm"
)
// See doc for NormalizeURL
func normalizeURL(u string) (*url.URL, string) {
u = norm.NFC.String(u)
tmp, err := gemini.GetPunycodeURL(u)
if err != nil {
return nil, u
}
u = tmp
parsed, _ := url.Parse(u)
if parsed.Scheme == "" {
// Always add scheme
parsed.Scheme = "gemini"
} else if parsed.Scheme != "gemini" {
// Not a gemini URL, nothing to do
return nil, u
}
parsed.User = nil // No passwords in Gemini
parsed.Fragment = "" // No fragments either
if parsed.Port() == "1965" {
// Always remove default port
hostname := parsed.Hostname()
if strings.Contains(hostname, ":") {
parsed.Host = "[" + parsed.Hostname() + "]"
} else {
parsed.Host = parsed.Hostname()
}
}
// Add slash to the end of a URL with just a domain
// gemini://example.com -> gemini://example.com/
if parsed.Path == "" {
parsed.Path = "/"
} else {
// Decode and re-encode path
// This removes needless encoding, like that of ASCII chars
// And encodes anything that wasn't but should've been
parsed.RawPath = strings.ReplaceAll(url.PathEscape(parsed.Path), "%2F", "/")
}
// Do the same to the query string
un, err := gemini.QueryUnescape(parsed.RawQuery)
if err == nil {
parsed.RawQuery = gemini.QueryEscape(un)
}
return parsed, ""
}
// NormalizeURL attempts to make URLs that are different strings
// but point to the same place all look the same.
//
// Example: gemini://gus.guru:1965/ and //gus.guru/.
// This function will take both output the same URL each time.
//
// It will also percent-encode invalid characters, and decode chars
// that don't need to be encoded. It will also apply Unicode NFC
// normalization.
//
// The string passed must already be confirmed to be a URL.
// Detection of a search string vs. a URL must happen elsewhere.
//
// It only works with absolute URLs.
func NormalizeURL(u string) string {
pu, s := normalizeURL(u)
if pu != nil {
// Could be normalized, return it
return pu.String()
}
// Return the best URL available up to that point
return s
}
// FixUserURL will take a user-typed URL and add a gemini scheme to it if
// necessary. It is not the same as normalizeURL, and that func should still
// be used, afterward.
//
// For example "example.com" will become "gemini://example.com", but
// "//example.com" will be left untouched.
func FixUserURL(u string) string {
if !strings.HasPrefix(u, "//") && !strings.HasPrefix(u, "gemini://") && !strings.Contains(u, "://") {
// Assume it's a Gemini URL
u = "gemini://" + u
}
return u
}