net/http: implement path value methods on Request

[gostls13.git] / src / net / http / request.go

diff --git a/src/net/http/request.go b/src/net/http/request.go
index 12039c9ae2388bc7c979127886f8750707763445..b66e6853f66f8d4b173fb390e0b8d10bf17ad380 100644 (file)
--- a/src/net/http/request.go
+++ b/src/net/http/request.go
@@ -329,6 +329,11 @@ type Request struct {
        // It is unexported to prevent people from using Context wrong
        // and mutating the contexts held by callers of the same request.
        ctx context.Context
+
+       // The following fields are for requests matched by ServeMux.
+       pat         *pattern          // the pattern that matched
+       matches     []string          // values for the matching wildcards in pat
+       otherValues map[string]string // for calls to SetPathValue that don't match a wildcard
 }
 
 // Context returns the request's context. To change the context, use
@@ -1415,6 +1420,48 @@ func (r *Request) FormFile(key string) (multipart.File, *multipart.FileHeader, e
        return nil, nil, ErrMissingFile
 }
 
+// PathValue returns the value for the named path wildcard in the ServeMux pattern
+// that matched the request.
+// It returns the empty string if the request was not matched against a pattern
+// or there is no such wildcard in the pattern.
+func (r *Request) PathValue(name string) string {
+       if i := r.patIndex(name); i >= 0 {
+               return r.matches[i]
+       }
+       return r.otherValues[name]
+}
+
+func (r *Request) SetPathValue(name, value string) {
+       if i := r.patIndex(name); i >= 0 {
+               r.matches[i] = value
+       } else {
+               if r.otherValues == nil {
+                       r.otherValues = map[string]string{}
+               }
+               r.otherValues[name] = value
+       }
+}
+
+// patIndex returns the index of name in the list of named wildcards of the
+// request's pattern, or -1 if there is no such name.
+func (r *Request) patIndex(name string) int {
+       // The linear search seems expensive compared to a map, but just creating the map
+       // takes a lot of time, and most patterns will just have a couple of wildcards.
+       if r.pat == nil {
+               return -1
+       }
+       i := 0
+       for _, seg := range r.pat.segments {
+               if seg.wild && seg.s != "" {
+                       if name == seg.s {
+                               return i
+                       }
+                       i++
+               }
+       }
+       return -1
+}
+
 func (r *Request) expectsContinue() bool {
        return hasToken(r.Header.get("Expect"), "100-continue")
 }