Fix parsing of timestamps in headers with ms precision. (#2609)

Author: alextwoods

build_tools/aws-sdk-code-generator/spec/protocols/output/rest-xml.json

@@ -739,6 +739,60 @@
           },
           "body": ""
         }
+      },
+      {
+        "given": {
+          "output": {
+            "shape": "OutputShape"
+          },
+          "name": "OperationName"
+        },
+        "result": {
+          "Timestamp": 1422172800
+        },
+        "response": {
+          "status_code": 200,
+          "headers": {
+            "x-timestamp": "Sun, 25 Jan 2015 08:00:00.000 GMT"
+          },
+          "body": ""
+        }
+      },
+      {
+        "given": {
+          "output": {
+            "shape": "OutputShape"
+          },
+          "name": "OperationName"
+        },
+        "result": {
+          "Timestamp": 1422172800
+        },
+        "response": {
+          "status_code": 200,
+          "headers": {
+            "x-timestamp": "1422172800"
+          },
+          "body": ""
+        }
+      },
+      {
+        "given": {
+          "output": {
+            "shape": "OutputShape"
+          },
+          "name": "OperationName"
+        },
+        "result": {
+          "Timestamp": 1422172800
+        },
+        "response": {
+          "status_code": 200,
+          "headers": {
+            "x-timestamp": "1422172800.0"
+          },
+          "body": ""
+        }
       }
     ]
   },

gems/aws-sdk-core/CHANGELOG.md

@@ -1,6 +1,8 @@
 Unreleased Changes
 ------------------
 
+* Issue - Fix parsing of ISO8601 timestamps with millisecond precision in headers.
+
 * Feature - Support modeled dualstack endpoints. It can be configured with shared configuration (`use_dualstack_endpoint`), an ENV variable (`AWS_USE_DUALSTACK_ENDPOINT`), and a constructor option (`:use_dualstack_endpoint`). Requests made to services without a dualstack endpoint will fail.
 
 * Feature - Support modeled fips endpoints. It can be configured with shared configuration (`use_fips_endpoint`), an ENV variable (`AWS_USE_FIPS_ENDPOINT`), and a constructor option (`:use_fips_endpoint`). Requests made to services without a fips endpoint will fail.

gems/aws-sdk-core/lib/aws-sdk-core/rest/response/headers.rb

@@ -41,7 +41,7 @@ def cast_value(ref, value)
           when FloatShape then value.to_f
           when BooleanShape then value == 'true'
           when TimestampShape
-            if value =~ /\d+(\.\d*)/
+            if value =~ /^\d+(\.\d*)/
               Time.at(value.to_f)
             elsif value =~ /^\d+$/
               Time.at(value.to_i)