From 9131cd8328b96fdbf6d4cbaf2b49a800a20fe7d9 Mon Sep 17 00:00:00 2001
From: Erika Tharp <eem@momentohq.com>
Date: Fri, 1 Apr 2022 15:56:57 -0700
Subject: [PATCH] chore: Make header names that always need to be sent
 constants (#38)

---
 Momento/ControlGrpcManager.cs       |  2 +-
 Momento/DataGrpcManager.cs          |  2 +-
 Momento/HeaderInterceptor.cs        | 19 +++++++++----------
 MomentoIntegrationTest/CacheTest.cs |  5 ++++-
 4 files changed, 15 insertions(+), 13 deletions(-)

diff --git a/Momento/ControlGrpcManager.cs b/Momento/ControlGrpcManager.cs
index f8333faa..183748b9 100644
--- a/Momento/ControlGrpcManager.cs
+++ b/Momento/ControlGrpcManager.cs
@@ -17,7 +17,7 @@ internal sealed class ControlGrpcManager : IDisposable
         public ControlGrpcManager(string authToken, string endpoint)
         {
             this.channel = GrpcChannel.ForAddress(endpoint, new GrpcChannelOptions() { Credentials = ChannelCredentials.SecureSsl });
-            List<Header> headers = new List<Header>{ new Header(name: "Authorization", value: authToken), new Header(name: "Agent", value: version) };
+            List<Header> headers = new List<Header>{ new Header(name: Header.AuthorizationKey, value: authToken), new Header(name: Header.AgentKey, value: version) };
             CallInvoker invoker = channel.Intercept(new HeaderInterceptor(headers));
             this.client = new ScsControl.ScsControlClient(invoker);
         }
diff --git a/Momento/DataGrpcManager.cs b/Momento/DataGrpcManager.cs
index 9b2f546b..d97c0e3d 100644
--- a/Momento/DataGrpcManager.cs
+++ b/Momento/DataGrpcManager.cs
@@ -18,7 +18,7 @@ internal sealed class DataGrpcManager : IDisposable
         internal DataGrpcManager(string authToken, string endpoint)
         {
             this.channel = GrpcChannel.ForAddress(endpoint, new GrpcChannelOptions() { Credentials = ChannelCredentials.SecureSsl });
-            List<Header> headers = new List<Header> { new Header(name: "Authorization", value: authToken) , new Header(name: "Agent", value: version)};
+            List<Header> headers = new List<Header> { new Header(name: Header.AuthorizationKey, value: authToken) , new Header(name: Header.AgentKey, value: version)};
             CallInvoker invoker = this.channel.Intercept(new HeaderInterceptor(headers));
             this.client = new Scs.ScsClient(invoker);
         }
diff --git a/Momento/HeaderInterceptor.cs b/Momento/HeaderInterceptor.cs
index e124cd65..94a63b0d 100644
--- a/Momento/HeaderInterceptor.cs
+++ b/Momento/HeaderInterceptor.cs
@@ -2,11 +2,15 @@
 using Grpc.Core;
 using Grpc.Core.Interceptors;
 using System.Collections.Generic;
+using System.Linq;
 
 namespace MomentoSdk
 {
     class Header
     {
+        public const string AuthorizationKey = "Authorization";
+        public const string AgentKey = "Agent";
+        public readonly List<string>  onceOnlyHeaders = new List<string>{Header.AgentKey};
         public string Name;
         public string Value;
         public Header(String name, String value)
@@ -20,16 +24,11 @@ class HeaderInterceptor : Grpc.Core.Interceptors.Interceptor
     {
         private readonly List<Header> headersToAddEveryTime = new List<Header>{};
         private readonly List<Header> headersToAddOnce = new List<Header>{};
-        private volatile Boolean isUserAgentSent = false;
+        private volatile Boolean areOnlyOnceHeadersSent = false;
         public HeaderInterceptor(List<Header> headers)
         {
-            foreach(Header header in headers) {
-                if (header.Name == "Authorization") {
-                    this.headersToAddEveryTime.Add(new Header(name: header.Name, value: header.Value));
-                } else {
-                    this.headersToAddOnce.Add(new Header(name: header.Name, value: header.Value));
-                }
-            }
+            this.headersToAddOnce = headers.Where(header => header.onceOnlyHeaders.Contains(header.Name)).ToList();
+            this.headersToAddEveryTime = headers.Where(header => !header.onceOnlyHeaders.Contains(header.Name)).ToList();
         }
 
         public override TResponse BlockingUnaryCall<TRequest, TResponse>(TRequest request, ClientInterceptorContext<TRequest, TResponse> context, BlockingUnaryCallContinuation<TRequest, TResponse> continuation)
@@ -76,12 +75,12 @@ private void AddCallerMetadata<TRequest, TResponse>(ref ClientInterceptorContext
                 {
                     headers.Add(header.Name, header.Value);
                 }
-            if (!isUserAgentSent) {
+            if (!areOnlyOnceHeadersSent) {
                 foreach (Header header in this.headersToAddOnce)
                 {
                     headers.Add(header.Name, header.Value);
                 }
-                isUserAgentSent = true;
+                areOnlyOnceHeadersSent = true;
             }
         }
     }
diff --git a/MomentoIntegrationTest/CacheTest.cs b/MomentoIntegrationTest/CacheTest.cs
index 4368df79..a46aa5c4 100644
--- a/MomentoIntegrationTest/CacheTest.cs
+++ b/MomentoIntegrationTest/CacheTest.cs
@@ -19,7 +19,10 @@ public CacheTest()
         {
             uint defaultTtlSeconds = 10;
             client = new SimpleCacheClient(authKey, defaultTtlSeconds);
-            client.CreateCache(cacheName);
+            try {
+                client.CreateCache(cacheName);
+            } catch (AlreadyExistsException) {
+            }
         }
 
         // Test cleanup