github.com/google/martian/v3@v3.3.3/martianurl/url_filter.go (about)

     1  // Copyright 2015 Google Inc. All rights reserved.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package martianurl
    16  
    17  import (
    18  	"encoding/json"
    19  	"net/url"
    20  
    21  	"github.com/google/martian/v3"
    22  	"github.com/google/martian/v3/filter"
    23  	"github.com/google/martian/v3/log"
    24  	"github.com/google/martian/v3/parse"
    25  )
    26  
    27  var noop = martian.Noop("url.Filter")
    28  
    29  func init() {
    30  	parse.Register("url.Filter", filterFromJSON)
    31  }
    32  
    33  // Filter runs modifiers iff the request URL matches all of the segments in url.
    34  type Filter struct {
    35  	*filter.Filter
    36  }
    37  
    38  type filterJSON struct {
    39  	Scheme       string               `json:"scheme"`
    40  	Host         string               `json:"host"`
    41  	Path         string               `json:"path"`
    42  	Query        string               `json:"query"`
    43  	Modifier     json.RawMessage      `json:"modifier"`
    44  	ElseModifier json.RawMessage      `json:"else"`
    45  	Scope        []parse.ModifierType `json:"scope"`
    46  }
    47  
    48  // NewFilter constructs a filter that applies the modifer when the
    49  // request URL matches all of the provided URL segments.
    50  func NewFilter(u *url.URL) *Filter {
    51  	log.Debugf("martianurl.NewFilter: %s", u)
    52  	m := NewMatcher(u)
    53  	f := filter.New()
    54  	f.SetRequestCondition(m)
    55  	f.SetResponseCondition(m)
    56  	return &Filter{f}
    57  }
    58  
    59  // filterFromJSON takes a JSON message as a byte slice and returns a
    60  // parse.Result that contains a URLFilter and a bitmask that represents the
    61  // type of modifier.
    62  //
    63  // Example JSON configuration message:
    64  // {
    65  //   "scheme": "https",
    66  //   "host": "example.com",
    67  //   "path": "/foo/bar",
    68  //   "query": "q=value",
    69  //   "scope": ["request", "response"],
    70  //   "modifier": { ... }
    71  //   "else": { ... }
    72  // }
    73  func filterFromJSON(b []byte) (*parse.Result, error) {
    74  	msg := &filterJSON{}
    75  	if err := json.Unmarshal(b, msg); err != nil {
    76  		return nil, err
    77  	}
    78  
    79  	filter := NewFilter(&url.URL{
    80  		Scheme:   msg.Scheme,
    81  		Host:     msg.Host,
    82  		Path:     msg.Path,
    83  		RawQuery: msg.Query,
    84  	})
    85  
    86  	m, err := parse.FromJSON(msg.Modifier)
    87  	if err != nil {
    88  		return nil, err
    89  	}
    90  
    91  	filter.RequestWhenTrue(m.RequestModifier())
    92  	filter.ResponseWhenTrue(m.ResponseModifier())
    93  
    94  	if len(msg.ElseModifier) > 0 {
    95  		em, err := parse.FromJSON(msg.ElseModifier)
    96  		if err != nil {
    97  			return nil, err
    98  		}
    99  
   100  		if em != nil {
   101  			filter.RequestWhenFalse(em.RequestModifier())
   102  			filter.ResponseWhenFalse(em.ResponseModifier())
   103  		}
   104  	}
   105  
   106  	return parse.NewResult(filter, msg.Scope)
   107  }