http: add Location method to Response

Fixes #2300

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/5117041

diff --git a/src/pkg/http/response.go b/src/pkg/http/response.go
index b01a303a1283b7cd8befaa55e2d82f21625a81c2..56c65b53c7a0330f0d11aee4c5046cc14075ccc5 100644 (file)
--- a/src/pkg/http/response.go
+++ b/src/pkg/http/response.go
@@ -13,6 +13,7 @@ import (
        "os"
        "strconv"
        "strings"
+       "url"
 )
 
 var respExcludeHeader = map[string]bool{
@@ -77,6 +78,23 @@ func (r *Response) Cookies() []*Cookie {
        return readSetCookies(r.Header)
 }
 
+var ErrNoLocation = os.NewError("http: no Location header in response")
+
+// Location returns the URL of the response's "Location" header,
+// if present.  Relative redirects are resolved relative to
+// the Response's Request.  ErrNoLocation is returned if no
+// Location header is present.
+func (r *Response) Location() (*url.URL, os.Error) {
+       lv := r.Header.Get("Location")
+       if lv == "" {
+               return nil, ErrNoLocation
+       }
+       if r.Request != nil && r.Request.URL != nil {
+               return r.Request.URL.Parse(lv)
+       }
+       return url.Parse(lv)
+}
+
 // ReadResponse reads and returns an HTTP response from r.  The
 // req parameter specifies the Request that corresponds to
 // this Response.  Clients must call resp.Body.Close when finished

diff --git a/src/pkg/http/response_test.go b/src/pkg/http/response_test.go
index 1d4a23423582fa6d6c94da28e5ef81b3b8c0ee0d..86494bf4ae9bd80aad89c0f024bcb5d6458933d5 100644 (file)
--- a/src/pkg/http/response_test.go
+++ b/src/pkg/http/response_test.go
@@ -15,6 +15,7 @@ import (
        "io/ioutil"
        "reflect"
        "testing"
+       "url"
 )
 
 type respTest struct {
@@ -395,3 +396,52 @@ func diff(t *testing.T, prefix string, have, want interface{}) {
                }
        }
 }
+
+type responseLocationTest struct {
+       location string // Response's Location header or ""
+       requrl   string // Response.Request.URL or ""
+       want     string
+       wantErr  os.Error
+}
+
+var responseLocationTests = []responseLocationTest{
+       {"/foo", "http://bar.com/baz", "http://bar.com/foo", nil},
+       {"http://foo.com/", "http://bar.com/baz", "http://foo.com/", nil},
+       {"", "http://bar.com/baz", "", ErrNoLocation},
+}
+
+func TestLocationResponse(t *testing.T) {
+       for i, tt := range responseLocationTests {
+               res := new(Response)
+               res.Header = make(Header)
+               res.Header.Set("Location", tt.location)
+               if tt.requrl != "" {
+                       res.Request = &Request{}
+                       var err os.Error
+                       res.Request.URL, err = url.Parse(tt.requrl)
+                       if err != nil {
+                               t.Fatalf("bad test URL %q: %v", tt.requrl, err)
+                       }
+               }
+
+               got, err := res.Location()
+               if tt.wantErr != nil {
+                       if err == nil {
+                               t.Errorf("%d. err=nil; want %q", i, tt.wantErr)
+                               continue
+                       }
+                       if g, e := err.String(), tt.wantErr.String(); g != e {
+                               t.Errorf("%d. err=%q; want %q", i, g, e)
+                               continue
+                       }
+                       continue
+               }
+               if err != nil {
+                       t.Errorf("%d. err=%q", i, err)
+                       continue
+               }
+               if g, e := got.String(), tt.want; g != e {
+                       t.Errorf("%d. Location=%q; want %q", i, g, e)
+               }
+       }
+}