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urisearch.go
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/
urisearch.go
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package urisearch
import (
"go.aporeto.io/enforcerd/trireme-lib/policy"
)
type node struct {
children map[string]*node
leaf bool
data interface{}
}
// APICache represents an API cache.
type APICache struct {
methodRoots map[string]*node
ID string
External bool
}
type scopeRule struct {
rule *policy.HTTPRule
}
// NewAPICache creates a new API cache
func NewAPICache(rules []*policy.HTTPRule, id string, external bool) *APICache {
a := &APICache{
methodRoots: map[string]*node{},
ID: id,
External: external,
}
for _, rule := range rules {
sc := &scopeRule{
rule: rule,
}
for _, method := range rule.Methods {
if _, ok := a.methodRoots[method]; !ok {
a.methodRoots[method] = &node{}
}
for _, uri := range rule.URIs {
insert(a.methodRoots[method], uri, sc)
}
}
}
return a
}
// FindRule finds a rule in the APICache without validating scopes
func (c *APICache) FindRule(verb, uri string) (bool, *policy.HTTPRule) {
found, rule := c.Find(verb, uri)
if rule == nil {
return found, nil
}
if policyRule, ok := rule.(*scopeRule); ok {
return found, policyRule.rule
}
return false, nil
}
// FindAndMatchScope finds the rule and returns true only if the scope matches
// as well. It also returns true of this was a public rule, allowing the callers
// to decide how to present the data or potentially what to do if authorization
// fails.
func (c *APICache) FindAndMatchScope(verb, uri string, attributes []string) (bool, bool) {
found, rule := c.Find(verb, uri)
if !found || rule == nil {
return false, false
}
policyRule, ok := rule.(*scopeRule)
if !ok {
return false, false
}
if policyRule.rule.Public {
return true, true
}
return c.MatchClaims(policyRule.rule.ClaimMatchingRules, attributes), false
}
// MatchClaims receives a set of claim matchibg rules and a set of claims
// and returns true of the claims match the rules.
func (c *APICache) MatchClaims(rules [][]string, claims []string) bool {
claimsMap := map[string]struct{}{}
for _, claim := range claims {
claimsMap[claim] = struct{}{}
}
var matched int
for _, clause := range rules {
matched = len(clause)
for _, claim := range clause {
if _, ok := claimsMap[claim]; ok {
matched--
}
if matched == 0 {
return true
}
}
}
return false
}
// Find finds a URI in the cache and returns true and the data if found.
// If not found it returns false.
func (c *APICache) Find(verb, uri string) (bool, interface{}) {
root, ok := c.methodRoots[verb]
if !ok {
return false, nil
}
return search(root, uri)
}
// parse parses a URI and splits into prefix, suffix
func parse(s string) (string, string) {
if s == "/" {
return s, ""
}
for i := 1; i < len(s); i++ {
if s[i] == '/' {
return s[0:i], s[i:]
}
}
return s, ""
}
// insert adds an api to the api cache
func insert(n *node, api string, data interface{}) {
if len(api) == 0 {
n.data = data
n.leaf = true
return
}
prefix, suffix := parse(api)
// root node or terminal node
if prefix == "/" {
n.data = data
n.leaf = true
return
}
if n.children == nil {
n.children = map[string]*node{}
}
// If there is no child, add the new child.
next, ok := n.children[prefix]
if !ok {
next = &node{}
n.children[prefix] = next
}
insert(next, suffix, data)
}
func search(n *node, api string) (found bool, data interface{}) {
prefix, suffix := parse(api)
if prefix == "/" {
if n.leaf {
return true, n.data
}
}
next, foundPrefix := n.children[prefix]
// We found either an exact match or a * match
if foundPrefix {
matchedChildren, data := search(next, suffix)
if matchedChildren {
return true, data
}
}
// If not found, try the ignore operator.
next, foundPrefix = n.children["/?"]
if foundPrefix {
matchedChildren, data := search(next, suffix)
if matchedChildren {
return true, data
}
}
// If not found, try the * operator and ignore the rest of path.
next, foundPrefix = n.children["/*"]
if foundPrefix {
for len(suffix) > 0 {
matchedChildren, data := search(next, suffix)
if matchedChildren {
return true, data
}
prefix, suffix = parse(suffix)
}
matchedChildren, data := search(next, "/")
if matchedChildren {
return true, data
}
}
if n.leaf && len(prefix) == 0 {
return true, n.data
}
return false, nil
}