github.com/zorawar87/trillian@v1.2.1/quota/etcd/quotaapi/name.go (about)

     1  // Copyright 2017 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 quotaapi
    16  
    17  import (
    18  	"fmt"
    19  	"regexp"
    20  	"strconv"
    21  	"strings"
    22  )
    23  
    24  const (
    25  	collectionTrees = "trees"
    26  	wildcard        = "-"
    27  )
    28  
    29  var (
    30  	// globalRE is a regex for quotas/global/ name filters.
    31  	// Wildcards ("-") are not allowed to replace "global". They could be allowed, but it's a query
    32  	// that doesn't make much sense, as if this format is used it has to be a global quota query.
    33  	globalRE *regexp.Regexp
    34  
    35  	// treeUsersRE is a broader regex for all trees/ and users/ name filters.
    36  	// It doesn't guard against the following specific situations:
    37  	// 1. quotas/trees/<id>/<kind>/config where id is not an int64
    38  	// 2. quotas/-/<id>/<kind>/config where id != "-", which is a possibly ambiguous query. It could
    39  	//    be allowed, but since the ID being queried is already known, so is the collection, so it
    40  	//    doesn't make much sense.
    41  	treesUsersRE *regexp.Regexp
    42  )
    43  
    44  func init() {
    45  	var err error
    46  	globalRE, err = regexp.Compile("^quotas/global/(-|read|write)/config$")
    47  	if err != nil {
    48  		panic(fmt.Sprintf("globalRE: %v", err))
    49  	}
    50  	treesUsersRE, err = regexp.Compile("^quotas/(-|trees|users)/[^/]+/(-|read|write)/config$")
    51  	if err != nil {
    52  		panic(fmt.Sprintf("treesUsersRE: %v", err))
    53  	}
    54  }
    55  
    56  // nameFilter represents a config name filter, as used by ListConfigs.
    57  //
    58  // A name filter is internally represented as the segments of the name, ie, the result of
    59  // strings.Split(name, "/").
    60  //
    61  // A few examples are:
    62  // * ["quotas", "global", "read", "configs"]
    63  // * ["quotas", "trees", "12345", "write", "config"]
    64  type nameFilter []string
    65  
    66  func newNameFilter(name string) (nameFilter, error) {
    67  	if !globalRE.MatchString(name) && !treesUsersRE.MatchString(name) {
    68  		return nil, fmt.Errorf("invalid name filter: %q", name)
    69  	}
    70  
    71  	nf := strings.Split(string(name), "/")
    72  
    73  	// Guard against some ambiguous / incorrect wildcards that the regexes won't protect against
    74  	switch collection := nf[1]; collection {
    75  	case collectionTrees:
    76  		id := nf[2]
    77  		if id == wildcard {
    78  			break
    79  		}
    80  		// treeID must be an int64
    81  		if _, err := strconv.ParseInt(id, 10, 64); err != nil {
    82  			return nil, fmt.Errorf("invalid name filter: %q, ID %q is not a valid 64-bit integer", name, id)
    83  		}
    84  	case wildcard:
    85  		id := nf[2]
    86  		if id != wildcard {
    87  			return nil, fmt.Errorf("invalid name filter: %q, ambiguous ID %q received", name, id)
    88  		}
    89  	}
    90  	return nf, nil
    91  }
    92  
    93  func (nf nameFilter) matches(path string) bool {
    94  	segments := strings.Split(path, "/")
    95  
    96  	l := len(nf)
    97  	if l != len(segments) {
    98  		return false
    99  	}
   100  
   101  	// Skip first and last tokens (they're always "quotas" and "config").
   102  	for i := 1; i < l-1; i++ {
   103  		if nf[i] != wildcard && nf[i] != segments[i] {
   104  			return false
   105  		}
   106  	}
   107  
   108  	return true
   109  }