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112 lines
1.9 KiB
Go

package path
import (
"fmt"
"regexp"
"strings"
"github.com/alecthomas/participle/v2"
"github.com/alecthomas/participle/v2/lexer"
)
type PathPart interface {
regex() string
}
type PathSlash struct {
Value string `"/"`
}
func (p PathSlash) regex() string {
return "/"
}
type PathShortPattern struct {
Name string `"{" @Ident "}"`
}
func (p PathShortPattern) regex() string {
return fmt.Sprintf("(?P<%s>[^/]+?)", p.Name)
}
type PathLongPattern struct {
Name string `"{{" @Ident "}}"`
}
func (p PathLongPattern) regex() string {
return fmt.Sprintf("(?P<%s>.+?)", p.Name)
}
type PathString struct {
Value string `@Ident`
}
func (p PathString) regex() string {
return regexp.QuoteMeta(p.Value)
}
type PathPattern struct {
Parts []PathPart `@@+`
}
func (pp PathPattern) regex() string {
sb := &strings.Builder{}
for _, p := range pp.Parts {
sb.WriteString(p.regex())
}
return sb.String()
}
func (pp PathPattern) Match(s string) (bool, map[string]string, error) {
r, err := regexp.Compile("^" + pp.regex() + "$")
if err != nil {
return false, nil, err
}
ms := r.FindStringSubmatch(s)
if ms == nil {
return false, nil, nil
}
ctx := map[string]string{}
for i, name := range r.SubexpNames() {
ctx[name] = ms[i]
}
return true, ctx, nil
}
var parser = participle.MustBuild[PathPattern](
participle.Union[PathPart](
&PathSlash{},
&PathLongPattern{},
&PathShortPattern{},
&PathString{},
),
participle.Lexer(
lexer.MustSimple([]lexer.SimpleRule{
{Name: "Slash", Pattern: `/`},
{Name: "PatternLongOpen", Pattern: `{{`},
{Name: "PatternLongClose", Pattern: `}}`},
{Name: "PatternShortOpen", Pattern: `{`},
{Name: "PatternShortClose", Pattern: `}`},
{Name: "Ident", Pattern: `[^/{}]+`},
}),
),
)
func ParsePattern(path string) (*PathPattern, error) {
return parser.ParseString("", path)
}
func MustParsePattern(path string) *PathPattern {
p, err := ParsePattern(path)
if err != nil {
panic(err)
}
return p
}