muraena/core/url.go

package core

import (
	"net/url"
	"strings"
)

// Values maps a string key to a list of values.
// It is typically used for query parameters and form values.
// Unlike in the http.Header map, the keys in a Values map
// are case-sensitive.
type Values map[string][]string

// ParseQuery parses the URL-encoded query string and returns
// a map listing the values specified for each key.
// ParseQuery always returns a non-nil map containing all the
// valid query parameters found; err describes the first decoding error
// encountered, if any.
//
// Query is expected to be a list of key=value settings separated by ampersands.
// A setting without an equals sign is interpreted as a key set to an empty
// value.
// Settings containing a non-URL-encoded semicolon are considered invalid.
func ParseQuery(query string) (Values, error) {
	m := make(Values)
	err := parseQuery(m, query)
	return m, err
}

func parseQuery(m Values, query string) (err error) {
	for query != "" {
		key := query
		if i := strings.IndexAny(key, "&"); i >= 0 {
			key, query = key[:i], key[i+1:]
		} else {
			query = ""
		}
		//if strings.Contains(key, ";") {
		//	err = fmt.Errorf("invalid semicolon separator in query")
		//	continue
		//}
		if key == "" {
			continue
		}
		value := ""
		if i := strings.Index(key, "="); i >= 0 {
			key, value = key[:i], key[i+1:]
		}
		key, err1 := url.QueryUnescape(key)
		if err1 != nil {
			if err == nil {
				err = err1
			}
			continue
		}
		value, err1 = url.QueryUnescape(value)
		if err1 != nil {
			if err == nil {
				err = err1
			}
			continue
		}
		m[key] = append(m[key], value)
	}
	return err
}

// Encode encodes the values into "URL encoded" form
// ("bar=baz&foo=quux") NOT sorted by key.
func (v Values) Encode() string {
	if v == nil {
		return ""
	}
	var buf strings.Builder
	keys := make([]string, 0, len(v))
	for k := range v {
		keys = append(keys, k)
	}

	// We don't want to be sorted
	// sort.Strings(keys)
	for _, k := range keys {
		vs := v[k]
		keyEscaped := url.QueryEscape(k)
		for _, v := range vs {
			if buf.Len() > 0 {
				buf.WriteByte('&')
			}
			buf.WriteString(keyEscaped)
			buf.WriteByte('=')
			buf.WriteString(url.QueryEscape(v))
		}
	}
	return buf.String()
}