From 81e1f75b628e0b2e097ddc1c8029baf973b53d60 Mon Sep 17 00:00:00 2001
From: Michael Lumish <mlumish@google.com>
Date: Thu, 1 Jun 2023 17:16:24 -0700
Subject: [PATCH] grpc-js-xds: Support string_match in header matching

---
 packages/grpc-js-xds/src/matcher.ts           | 48 +++++++++++++++----
 packages/grpc-js-xds/src/resolver-xds.ts      | 28 +++++++++--
 .../src/xds-stream-state/rds-state.ts         |  3 +-
 3 files changed, 65 insertions(+), 14 deletions(-)

diff --git a/packages/grpc-js-xds/src/matcher.ts b/packages/grpc-js-xds/src/matcher.ts
index b173c30e..148df7f8 100644
--- a/packages/grpc-js-xds/src/matcher.ts
+++ b/packages/grpc-js-xds/src/matcher.ts
@@ -37,14 +37,19 @@ export interface ValueMatcher {
 }
 
 export class ExactValueMatcher implements ValueMatcher {
-  constructor(private targetValue: string) {}
+  constructor(private targetValue: string, private ignoreCase: boolean) {
+  }
 
   apply(value: string) {
-    return value === this.targetValue;
+    if (this.ignoreCase) {
+      return value.toLowerCase() === this.targetValue.toLowerCase();
+    } else {
+      return value === this.targetValue;
+    }
   }
 
   toString() {
-    return 'Exact(' + this.targetValue + ')';
+    return 'Exact(' + this.targetValue + ', ignore_case=' + this.ignoreCase + ')';
   }
 }
 
@@ -94,26 +99,51 @@ export class PresentValueMatcher implements ValueMatcher {
 }
 
 export class PrefixValueMatcher implements ValueMatcher {
-  constructor(private prefix: string) {}
+  constructor(private prefix: string, private ignoreCase: boolean) {
+  }
 
   apply(value: string) {
-    return value.startsWith(this.prefix);
+    if (this.ignoreCase) {
+      return value.toLowerCase().startsWith(this.prefix.toLowerCase());
+    } else {
+      return value.startsWith(this.prefix);
+    }
   }
 
   toString() {
-    return 'Prefix(' + this.prefix + ')';
+    return 'Prefix(' + this.prefix + ', ignore_case=' + this.ignoreCase + ')';
   }
 }
 
 export class SuffixValueMatcher implements ValueMatcher {
-  constructor(private suffix: string) {}
+  constructor(private suffix: string, private ignoreCase: boolean) {}
 
   apply(value: string) {
-    return value.endsWith(this.suffix);
+    if (this.ignoreCase) {
+      return value.toLowerCase().endsWith(this.suffix.toLowerCase());
+    } else {
+      return value.endsWith(this.suffix);
+    }
   }
 
   toString() {
-    return 'Suffix(' + this.suffix + ')';
+    return 'Suffix(' + this.suffix + ', ignore_case=' + this.ignoreCase + ')';
+  }
+}
+
+export class ContainsValueMatcher implements ValueMatcher {
+  constructor(private contains: string, private ignoreCase: boolean) {}
+
+  apply(value: string) {
+    if (this.ignoreCase) {
+      return value.toLowerCase().includes(this.contains.toLowerCase());
+    } else {
+      return value.includes(this.contains);
+    }
+  }
+
+  toString() {
+    return 'Contains(' + this.contains + + ', ignore_case=' + this.ignoreCase + ')';
   }
 }
 
diff --git a/packages/grpc-js-xds/src/resolver-xds.ts b/packages/grpc-js-xds/src/resolver-xds.ts
index 9879a2c6..6c2ba432 100644
--- a/packages/grpc-js-xds/src/resolver-xds.ts
+++ b/packages/grpc-js-xds/src/resolver-xds.ts
@@ -37,7 +37,7 @@ import { HeaderMatcher__Output } from './generated/envoy/config/route/v3/HeaderM
 import ConfigSelector = experimental.ConfigSelector;
 import LoadBalancingConfig = experimental.LoadBalancingConfig;
 import { XdsClusterManagerLoadBalancingConfig } from './load-balancer-xds-cluster-manager';
-import { ExactValueMatcher, FullMatcher, HeaderMatcher, Matcher, PathExactValueMatcher, PathPrefixValueMatcher, PathSafeRegexValueMatcher, PrefixValueMatcher, PresentValueMatcher, RangeValueMatcher, RejectValueMatcher, SafeRegexValueMatcher, SuffixValueMatcher, ValueMatcher } from './matcher';
+import { ContainsValueMatcher, ExactValueMatcher, FullMatcher, HeaderMatcher, Matcher, PathExactValueMatcher, PathPrefixValueMatcher, PathSafeRegexValueMatcher, PrefixValueMatcher, PresentValueMatcher, RangeValueMatcher, RejectValueMatcher, SafeRegexValueMatcher, SuffixValueMatcher, ValueMatcher } from './matcher';
 import { envoyFractionToFraction, Fraction } from "./fraction";
 import { RouteAction, SingleClusterRouteAction, WeightedCluster, WeightedClusterRouteAction } from './route-action';
 import { decodeSingleResource, HTTP_CONNECTION_MANGER_TYPE_URL } from './resources';
@@ -136,7 +136,7 @@ function getPredicateForHeaderMatcher(headerMatch: HeaderMatcher__Output): Match
   let valueChecker: ValueMatcher;
   switch (headerMatch.header_match_specifier) {
     case 'exact_match':
-      valueChecker = new ExactValueMatcher(headerMatch.exact_match!);
+      valueChecker = new ExactValueMatcher(headerMatch.exact_match!, false);
       break;
     case 'safe_regex_match':
       valueChecker = new SafeRegexValueMatcher(headerMatch.safe_regex_match!.regex);
@@ -150,10 +150,30 @@ function getPredicateForHeaderMatcher(headerMatch: HeaderMatcher__Output): Match
       valueChecker = new PresentValueMatcher();
       break;
     case 'prefix_match':
-      valueChecker = new PrefixValueMatcher(headerMatch.prefix_match!);
+      valueChecker = new PrefixValueMatcher(headerMatch.prefix_match!, false);
       break;
     case 'suffix_match':
-      valueChecker = new SuffixValueMatcher(headerMatch.suffix_match!);
+      valueChecker = new SuffixValueMatcher(headerMatch.suffix_match!, false);
+      break;
+    case 'string_match':
+      const stringMatch = headerMatch.string_match!
+      switch (stringMatch.match_pattern) {
+        case 'exact':
+          valueChecker = new ExactValueMatcher(stringMatch.exact!, stringMatch.ignore_case);
+          break;
+        case 'safe_regex':
+          valueChecker = new SafeRegexValueMatcher(stringMatch.safe_regex!.regex);
+          break;
+        case 'prefix':
+          valueChecker = new PrefixValueMatcher(stringMatch.prefix!, stringMatch.ignore_case);
+          break;
+        case 'suffix':
+          valueChecker = new SuffixValueMatcher(stringMatch.suffix!, stringMatch.ignore_case);
+          break;
+        case 'contains':
+          valueChecker = new ContainsValueMatcher(stringMatch.contains!, stringMatch.ignore_case);
+          break;
+      }
       break;
     default:
       valueChecker = new RejectValueMatcher();
diff --git a/packages/grpc-js-xds/src/xds-stream-state/rds-state.ts b/packages/grpc-js-xds/src/xds-stream-state/rds-state.ts
index fef69451..57e25edd 100644
--- a/packages/grpc-js-xds/src/xds-stream-state/rds-state.ts
+++ b/packages/grpc-js-xds/src/xds-stream-state/rds-state.ts
@@ -29,7 +29,8 @@ const SUPPPORTED_HEADER_MATCH_SPECIFIERS = [
   'range_match',
   'present_match',
   'prefix_match',
-  'suffix_match'];
+  'suffix_match',
+  'string_match'];
 const SUPPORTED_CLUSTER_SPECIFIERS = ['cluster', 'weighted_clusters', 'cluster_header'];
 
 const UINT32_MAX = 0xFFFFFFFF;