Multiple changes to the validity package.

cmd/webpackager/flag_packager.go

@@ -193,7 +193,7 @@ func getPhysicalURLRuleFromFlags() (urlrewrite.Rule, error) {
 	return rule, nil
 }
 
-func getValidityURLRuleFromFlags() (validity.ValidityURLRule, error) {
+func getValidityURLRuleFromFlags() (validity.URLRule, error) {
 	return validity.AppendExtDotLastModified(*flagValidityExt), nil
 }
 

config.go

@@ -56,8 +56,9 @@ type Config struct {
 	// ValidityURLRule specifies the rule to determine the validity URL,
 	// where the validity data should be served.
 	//
-	// nil implies validity.AppendExtDotUnixTime(".validity", time.Now()).
-	ValidityURLRule validity.ValidityURLRule
+	// nil implies validity.DefaultURLRule, which appends ".validity" plus
+	// the last modified time (in UNIX time) to the document URL.
+	ValidityURLRule validity.URLRule
 
 	// Processor specifies the processor(s) applied to each HTTP response
 	// before turning it into a signed exchange. The processors make sure
@@ -109,7 +110,7 @@ func (cfg *Config) populateDefaults() {
 		cfg.PhysicalURLRule = urlrewrite.DefaultRules
 	}
 	if cfg.ValidityURLRule == nil {
-		cfg.ValidityURLRule = validity.DefaultValidityURLRule
+		cfg.ValidityURLRule = validity.DefaultURLRule
 	}
 	if cfg.Processor == nil {
 		cfg.Processor = complexproc.DefaultProcessor

validity/url.go → validity/append_ext.go

@@ -17,30 +17,14 @@ package validity
 import (
 	"fmt"
 	"log"
+	"net/http"
 	"net/url"
 	"time"
 
 	"github.com/google/webpackager/exchange"
-	"github.com/google/webpackager/internal/httpheader"
 	"github.com/google/webpackager/internal/urlutil"
 )
 
-// ValidityURLRule decides the validity URL of a resource.
-type ValidityURLRule interface {
-	// Apply returns the validity URL of a resource. physurl is the physical
-	// URL of the resource; resp is the HTTP response; vp is the period the
-	// signed exchange will be valid for. The physical URL is typically equal
-	// to the request URL but different in some cases; see package urlrewrite
-	// for more details.
-	//
-	// Note ValidityURLRule implementations can retrieve the request URL via
-	// resp.Request.URL.
-	Apply(physurl *url.URL, resp *exchange.Response, vp exchange.ValidPeriod) (*url.URL, error)
-}
-
-// DefaultValidityURLRule is the default rule used by webpackager.Packager.
-var DefaultValidityURLRule ValidityURLRule = AppendExtDotLastModified(".validity")
-
 // AppendExtDotLastModified generates the validity URL by appending ext
 // and the resource's last modified time. For example:
 //
@@ -66,7 +50,7 @@ var DefaultValidityURLRule ValidityURLRule = AppendExtDotLastModified(".validity
 //
 // The AppendExtDotLastModified rule ignores Query and Fragment in physurl.
 // The validity URLs will always have empty Query and Fragment.
-func AppendExtDotLastModified(ext string) ValidityURLRule {
+func AppendExtDotLastModified(ext string) URLRule {
 	return &appendExtDotLastModified{ext}
 }
 
@@ -79,7 +63,7 @@ func (rule *appendExtDotLastModified) Apply(physurl *url.URL, resp *exchange.Res
 	if date == "" {
 		return toValidityURL(physurl, rule.ext, vp.Date())
 	}
-	parsed, err := httpheader.ParseDate(date)
+	parsed, err := http.ParseTime(date)
 	if err != nil {
 		log.Printf("warning: failed to parse the header %q: %v", date, err)
 		return toValidityURL(physurl, rule.ext, vp.Date())
@@ -89,7 +73,7 @@ func (rule *appendExtDotLastModified) Apply(physurl *url.URL, resp *exchange.Res
 
 // AppendExtDotExchangeDate is like AppendExtDotLastModified but always
 // uses vp.Date instead of the last modified time.
-func AppendExtDotExchangeDate(ext string) ValidityURLRule {
+func AppendExtDotExchangeDate(ext string) URLRule {
 	return &appendExtDotExchangeDate{ext}
 }
 

validity/url_test.go → validity/append_ext_test.go

@@ -30,7 +30,7 @@ func TestAppendExtDotUnixTime(t *testing.T) {
 		name   string
 		url    string
 		header http.Header
-		rule   validity.ValidityURLRule
+		rule   validity.URLRule
 		vp     exchange.ValidPeriod
 		want   string
 	}{

validity/doc.go

@@ -12,5 +12,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// Package validity defines interfaces to represent validity URL rules.
+// Package validity handles the validity data of signed exchanges. It only
+// defines validity URLs at the moment though.
 package validity

validity/fixed_url.go

@@ -0,0 +1,39 @@
+// Copyright 2020 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package validity
+
+import (
+	"net/url"
+
+	"github.com/google/webpackager/exchange"
+)
+
+// FixedURL uses url as the validity URL for all resources. It is useful,
+// for example, if you plan to provide empty validity data (consisting of
+// a single byte 0xa0) for all signed exchanges and serve it on a single URL.
+//
+// url can be relative, in which case the validity URL is resolved relative
+// from the physical URL.
+func FixedURL(url *url.URL) URLRule {
+	return &fixedURL{url}
+}
+
+type fixedURL struct {
+	url *url.URL
+}
+
+func (rule *fixedURL) Apply(physurl *url.URL, resp *exchange.Response, vp exchange.ValidPeriod) (*url.URL, error) {
+	return physurl.ResolveReference(rule.url), nil
+}

validity/fixed_url_test.go

@@ -0,0 +1,67 @@
+// Copyright 2020 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package validity_test
+
+import (
+	"net/url"
+	"testing"
+
+	"github.com/google/webpackager/exchange"
+	"github.com/google/webpackager/exchange/exchangetest"
+	"github.com/google/webpackager/internal/urlutil"
+	"github.com/google/webpackager/validity"
+)
+
+func TestFixedURL(t *testing.T) {
+	tests := []struct {
+		name string
+		url  string
+		rule validity.URLRule
+		want string
+	}{
+		{
+			name: "AbsoluteURL",
+			url:  "https://example.com/index.html",
+			rule: validity.FixedURL(
+				urlutil.MustParse("https://example.com/empty.validity"),
+			),
+			want: "https://example.com/empty.validity",
+		},
+		{
+			name: "RelativeURL",
+			url:  "https://example.com/index.html",
+			rule: validity.FixedURL(
+				urlutil.MustParse("/empty.validity"),
+			),
+			want: "https://example.com/empty.validity",
+		},
+	}
+
+	for _, test := range tests {
+		arg, err := url.Parse(test.url)
+		if err != nil {
+			t.Fatal(err)
+		}
+		resp := exchangetest.MakeEmptyResponse(test.url)
+		// FixedURL does not use the ValidPeriod.
+		got, err := test.rule.Apply(arg, resp, exchange.ValidPeriod{})
+		if err != nil {
+			t.Fatalf("got error(%q), want success", err)
+		}
+		if got.String() != test.want {
+			t.Errorf("got %q, want %q", got, test.want)
+		}
+	}
+}

validity/url_rule.go

@@ -0,0 +1,36 @@
+// Copyright 2019 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package validity
+
+import (
+	"net/url"
+
+	"github.com/google/webpackager/exchange"
+)
+
+// URLRule decides the validity URL of a resource.
+type URLRule interface {
+	// Apply returns the validity URL of a resource. physurl is the physical
+	// URL of the resource; resp is the HTTP response; vp is the period the
+	// signed exchange will be valid for. The physical URL is typically equal
+	// to the request URL but different in some cases; see package urlrewrite
+	// for more details.
+	//
+	// Note implementations can retrieve the request URL via resp.Request.URL.
+	Apply(physurl *url.URL, resp *exchange.Response, vp exchange.ValidPeriod) (*url.URL, error)
+}
+
+// DefaultURLRule is the default rule used by webpackager.Packager.
+var DefaultURLRule URLRule = AppendExtDotLastModified(".validity")