Adds a method.Filter to package method (#291)

* add new method.Filter

* add method to debug log line

*  fix import spacing

* fix json parsing test by registering header package

* remove stray newline

* address comments in review

method/method_filter.go

@@ -0,0 +1,121 @@
+// Copyright 2015 Google Inc. All rights reserved.
+//
+// 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 method
+
+import (
+	"encoding/json"
+	"net/http"
+	"strings"
+
+	"github.com/google/martian"
+	"github.com/google/martian/filter"
+	"github.com/google/martian/log"
+	"github.com/google/martian/parse"
+)
+
+var noop = martian.Noop("method.Filter")
+
+func init() {
+	parse.Register("method.Filter", filterFromJSON)
+}
+
+// Filter runs modifier iff the request method matches the specified method.
+type Filter struct {
+	*filter.Filter
+}
+
+type filterJSON struct {
+	Method       string               `json:"method"`
+	Modifier     json.RawMessage      `json:"modifier"`
+	ElseModifier json.RawMessage      `json:"else"`
+	Scope        []parse.ModifierType `json:"scope"`
+}
+
+func filterFromJSON(b []byte) (*parse.Result, error) {
+	msg := &filterJSON{}
+	if err := json.Unmarshal(b, msg); err != nil {
+		return nil, err
+	}
+
+	filter := NewFilter(msg.Method)
+
+	m, err := parse.FromJSON(msg.Modifier)
+	if err != nil {
+		return nil, err
+	}
+
+	filter.RequestWhenTrue(m.RequestModifier())
+	filter.ResponseWhenTrue(m.ResponseModifier())
+
+	if len(msg.ElseModifier) > 0 {
+		em, err := parse.FromJSON(msg.ElseModifier)
+		if err != nil {
+			return nil, err
+		}
+
+		if em != nil {
+			filter.RequestWhenFalse(em.RequestModifier())
+			filter.ResponseWhenFalse(em.ResponseModifier())
+		}
+	}
+
+	return parse.NewResult(filter, msg.Scope)
+}
+
+// NewFilter constructs a filter that applies the modifer when the
+// request method matches meth.
+func NewFilter(meth string) *Filter {
+	log.Debugf("method.NewFilter(%q)", meth)
+	m := NewMatcher(meth)
+	f := filter.New()
+	f.SetRequestCondition(m)
+	f.SetResponseCondition(m)
+	return &Filter{f}
+}
+
+// Matcher is a conditional evaluator of request methods to be used in
+// filters that take conditionals.
+type Matcher struct {
+	method string
+}
+
+// NewMatcher builds a new method matcher.
+func NewMatcher(method string) *Matcher {
+	return &Matcher{
+		method: method,
+	}
+}
+
+// MatchRequest retuns true if m.method matches the request method.
+func (m *Matcher) MatchRequest(req *http.Request) bool {
+	matched := m.matches(req.Method)
+	if matched {
+		log.Debugf("method.MatchRequest: matched %s request: %s", req.Method, req.URL)
+	}
+	return matched
+}
+
+// MatchResponse retuns true if m.method matches res.Request.Method.
+func (m *Matcher) MatchResponse(res *http.Response) bool {
+	matched := m.matches(res.Request.Method)
+	if matched {
+		log.Debugf("method.MatchResponse: matched %s request: %s", res.Request.Method, res.Request.URL)
+	}
+	return matched
+}
+
+func (m *Matcher) matches(method string) bool {
+	return strings.ToUpper(method) == strings.ToUpper(m.method)
+}

method/method_filter_test.go

@@ -0,0 +1,213 @@
+// Copyright 2015 Google Inc. All rights reserved.
+//
+// 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 method
+
+import (
+	"net/http"
+	"testing"
+
+	_ "github.com/google/martian/header"
+	"github.com/google/martian/martiantest"
+	"github.com/google/martian/parse"
+	"github.com/google/martian/proxyutil"
+)
+
+func TestFilterModifyRequest(t *testing.T) {
+	tt := []struct {
+		method string
+		want   bool
+	}{
+		{
+			method: "GET",
+			want:   true,
+		},
+		{
+			method: "get",
+			want:   true,
+		},
+		{
+			method: "POST",
+			want:   false,
+		},
+		{
+			method: "DELETE",
+			want:   false,
+		},
+		{
+			method: "CONNECT",
+			want:   false,
+		},
+		{
+			method: "connect",
+			want:   false,
+		},
+	}
+
+	for i, tc := range tt {
+		req, err := http.NewRequest("GET", "http://example.com", nil)
+		if err != nil {
+			t.Fatalf("%d. NewRequest(): got %v, want no error", i, err)
+		}
+
+		mod := NewFilter(tc.method)
+		tm := martiantest.NewModifier()
+		mod.SetRequestModifier(tm)
+
+		if err := mod.ModifyRequest(req); err != nil {
+			t.Fatalf("%d. ModifyRequest(): got %q, want no error", i, err)
+		}
+
+		if tm.RequestModified() != tc.want {
+			t.Errorf("%d. tm.RequestModified(): got %t, want %t", i, tm.RequestModified(), tc.want)
+		}
+	}
+}
+
+func TestFilterModifyResponse(t *testing.T) {
+	tt := []struct {
+		method string
+		want   bool
+	}{
+		{
+			method: "GET",
+			want:   true,
+		},
+		{
+			method: "get",
+			want:   true,
+		},
+		{
+			method: "POST",
+			want:   false,
+		},
+		{
+			method: "DELETE",
+			want:   false,
+		},
+		{
+			method: "CONNECT",
+			want:   false,
+		},
+		{
+			method: "connect",
+			want:   false,
+		},
+	}
+
+	for i, tc := range tt {
+		req, err := http.NewRequest("GET", "http://example.com", nil)
+		if err != nil {
+			t.Fatalf("%d. NewRequest(): got %v, want no error", i, err)
+		}
+		res := proxyutil.NewResponse(200, nil, req)
+
+		mod := NewFilter(tc.method)
+		tm := martiantest.NewModifier()
+		mod.SetResponseModifier(tm)
+
+		if err := mod.ModifyResponse(res); err != nil {
+			t.Fatalf("%d. ModifyResponse(): got %q, want no error", i, err)
+		}
+
+		if tm.ResponseModified() != tc.want {
+			t.Errorf("%d. tm.ResponseModified(): got %t, want %t", i, tm.ResponseModified(), tc.want)
+		}
+	}
+
+}
+
+func TestFilterFromJSON(t *testing.T) {
+	j := `{
+		    "method.Filter": {
+              "scope": ["request", "response"],
+              "method": "GET",
+              "modifier": {
+                "header.Modifier": {
+                  "scope": ["request", "response"],
+                  "name": "Mod-Run",
+                  "value": "true"
+                } 
+		      },
+		      "else": {
+                "header.Modifier": {
+                  "scope": ["request", "response"],
+                  "name": "Else-Run",
+                  "value": "true"
+                } 
+              }
+            }
+	      }`
+
+	msg := []byte(j)
+
+	r, err := parse.FromJSON(msg)
+	if err != nil {
+		t.Fatalf("FilterFromJSON(): got %v, want no error", err)
+	}
+
+	reqmod := r.RequestModifier()
+	if reqmod == nil {
+		t.Fatal("reqmod: got nil, want not nil")
+	}
+
+	req, err := http.NewRequest("GET", "https://example.com", nil)
+	if err != nil {
+		t.Fatalf("http.NewRequest(): got %v, want no error", err)
+	}
+
+	if err := reqmod.ModifyRequest(req); err != nil {
+		t.Fatalf("reqmod.ModifyRequest(): got %v, want no error", err)
+	}
+
+	if got, want := req.Header.Get("Mod-Run"), "true"; got != want {
+		t.Errorf("req.Header.Get(%q): got %q, want %q", "Mod-Run", got, want)
+	}
+
+	if got, want := req.Header.Get("Else-Run"), ""; got != want {
+		t.Errorf("req.Header.Get(%q): got %q, want %q", "Else-Run", got, want)
+	}
+
+	resmod := r.ResponseModifier()
+	if resmod == nil {
+		t.Fatalf("resmod: got nil, want not nil")
+	}
+
+	res := proxyutil.NewResponse(200, nil, req)
+	if err := resmod.ModifyResponse(res); err != nil {
+		t.Fatalf("resmod.ModifyResponse(): got %v, want no error", err)
+	}
+
+	if got, want := res.Header.Get("Mod-Run"), "true"; got != want {
+		t.Errorf("res.Header.Get(%q): got %q, want %q", "Mod-Run", got, want)
+	}
+
+	// test else conditional modifier with POST
+	req, err = http.NewRequest("POST", "http://example.com", nil)
+	if err != nil {
+		t.Fatalf("http.NewRequest(): got %v, want no error", err)
+	}
+
+	if err := reqmod.ModifyRequest(req); err != nil {
+		t.Fatalf("reqmod.ModifyRequest(): got %v, want no error", err)
+	}
+
+	if got, want := req.Header.Get("Mod-Run"), ""; got != want {
+		t.Errorf("req.Header.Get(%q): got %q, want %q", "Mod-Run", got, want)
+	}
+
+	if got, want := req.Header.Get("Else-Run"), "true"; got != want {
+		t.Errorf("req.Header.Get(%q): got %q, want %q", "Else-Run", got, want)
+	}
+}

method/method_verifier.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// Package method provides utilities for verifying method type in martian.Proxy.
+// Package method provides utilities for working with request methods.
 package method
 
 import (