From d93b763226c97eaf9128f643fb56c756e2ba7560 Mon Sep 17 00:00:00 2001
From: AnandWalvekar <anand.walvekar@gmail.com>
Date: Wed, 1 Nov 2017 00:54:22 +0530
Subject: [PATCH] Expose whether a result was served from cache or fetched from
 the server (#176)

Closes #170.
---
 Sources/Apollo/ApolloStore.swift     |  2 +-
 Sources/Apollo/GraphQLResponse.swift |  4 ++--
 Sources/Apollo/GraphQLResult.swift   | 15 ++++++++++++---
 3 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/Sources/Apollo/ApolloStore.swift b/Sources/Apollo/ApolloStore.swift
index d2e8d21e74..a8ba6b5778 100644
--- a/Sources/Apollo/ApolloStore.swift
+++ b/Sources/Apollo/ApolloStore.swift
@@ -98,7 +98,7 @@ public final class ApolloStore {
 
       return try transaction.execute(selections: Query.Data.selections, onObjectWithKey: Query.rootCacheKey, variables: query.variables, accumulator: zip(mapper, dependencyTracker))
     }.map { (data: Query.Data, dependentKeys: Set<CacheKey>) in
-      GraphQLResult(data: data, errors: nil, dependentKeys: dependentKeys)
+      GraphQLResult(data: data, errors: nil, source:.cache, dependentKeys: dependentKeys)
     }
   }
 
diff --git a/Sources/Apollo/GraphQLResponse.swift b/Sources/Apollo/GraphQLResponse.swift
index c9695d9ba9..fc1332f074 100644
--- a/Sources/Apollo/GraphQLResponse.swift
+++ b/Sources/Apollo/GraphQLResponse.swift
@@ -31,10 +31,10 @@ public final class GraphQLResponse<Operation: GraphQLOperation> {
       return firstly {
         try executor.execute(selections: Operation.Data.selections, on: dataEntry, withKey: Operation.rootCacheKey, variables: operation.variables, accumulator: zip(mapper, normalizer, dependencyTracker))
       }.map { (data, records, dependentKeys) in
-        (GraphQLResult(data: data, errors: errors, dependentKeys: dependentKeys), records)
+        (GraphQLResult(data: data, errors: errors, source: .server, dependentKeys: dependentKeys), records)
       }
     } else {
-      return Promise(fulfilled: (GraphQLResult(data: nil, errors: errors, dependentKeys: nil), nil))
+      return Promise(fulfilled: (GraphQLResult(data: nil, errors: errors, source: .server, dependentKeys: nil), nil))
     }
   }
 }
diff --git a/Sources/Apollo/GraphQLResult.swift b/Sources/Apollo/GraphQLResult.swift
index 8398cd778e..21f72b4262 100644
--- a/Sources/Apollo/GraphQLResult.swift
+++ b/Sources/Apollo/GraphQLResult.swift
@@ -1,15 +1,24 @@
 /// Represents the result of a GraphQL operation.
 public struct GraphQLResult<Data> {
+    /// Represents source of data
+    public enum Source {
+        case cache
+        case server
+    }
+
   /// The typed result data, or `nil` if an error was encountered that prevented a valid response.
   public let data: Data?
   /// A list of errors, or `nil` if the operation completed without encountering any errors.
   public let errors: [GraphQLError]?
-  
+  /// Source of data
+  public let source:Source
+    
   let dependentKeys: Set<CacheKey>?
   
-  init(data: Data?, errors: [GraphQLError]?, dependentKeys: Set<CacheKey>?) {
+  init(data: Data?, errors: [GraphQLError]?, source:Source, dependentKeys: Set<CacheKey>?) {
     self.data = data
     self.errors = errors
-    self.dependentKeys = dependentKeys
+    self.dependentKeys = dependentKeys     
+    self.source = source
   }
 }