Parse Retry-After header responses that include decimal points (OpenF…

…eign#980)

rfc7231 section 7.1.3 states that the Retry-After header can return delay-seconds value
that is a non-negative decimal integer, representing time in seconds.

Some servers return the second delay with a decimal point.  Eg instead of 2 they return 2.0
This patch handles this case where the server has included a decimal point in their response.

core/src/main/java/feign/codec/ErrorDecoder.java

@@ -13,21 +13,22 @@
  */
 package feign.codec;
 
+import static feign.FeignException.errorStatus;
+import static feign.Util.RETRY_AFTER;
+import static feign.Util.checkNotNull;
+import static java.util.Locale.US;
+import static java.util.concurrent.TimeUnit.SECONDS;
+
+import feign.FeignException;
+import feign.Response;
+import feign.RetryableException;
+
 import java.text.DateFormat;
 import java.text.ParseException;
 import java.text.SimpleDateFormat;
 import java.util.Collection;
 import java.util.Date;
 import java.util.Map;
-import feign.FeignException;
-import feign.Response;
-import feign.RetryableException;
-import static feign.FeignException.errorStatus;
-import static feign.Util.RETRY_AFTER;
-import static feign.Util.checkNotNull;
-import static java.util.Locale.US;
-import static java.util.concurrent.TimeUnit.NANOSECONDS;
-import static java.util.concurrent.TimeUnit.SECONDS;
 
 /**
  * Allows you to massage an exception into a application-specific one. Converting out to a throttle
@@ -143,7 +144,8 @@ public Date apply(String retryAfter) {
       if (retryAfter == null) {
         return null;
       }
-      if (retryAfter.matches("^[0-9]+$")) {
+      if (retryAfter.matches("^[0-9]+\\.?0*$")) {
+        retryAfter = retryAfter.replaceAll("\\.0*$", "");
         long deltaMillis = SECONDS.toMillis(Long.parseLong(retryAfter));
         return new Date(currentTimeMillis() + deltaMillis);
       }

core/src/test/java/feign/codec/RetryAfterDecoderTest.java

@@ -13,14 +13,16 @@
  */
 package feign.codec;
 
-import org.junit.Test;
-import java.text.ParseException;
-import feign.codec.ErrorDecoder.RetryAfterDecoder;
 import static feign.codec.ErrorDecoder.RetryAfterDecoder.RFC822_FORMAT;
-import static java.util.concurrent.TimeUnit.MILLISECONDS;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 
+import feign.codec.ErrorDecoder.RetryAfterDecoder;
+
+import java.text.ParseException;
+
+import org.junit.Test;
+
 public class RetryAfterDecoderTest {
 
   private RetryAfterDecoder decoder = new RetryAfterDecoder(RFC822_FORMAT) {
@@ -48,4 +50,9 @@ public void rfc822Parses() throws ParseException {
   public void relativeSecondsParses() throws ParseException {
     assertEquals(RFC822_FORMAT.parse("Sun, 2 Jan 2000 00:00:00 GMT"), decoder.apply("86400"));
   }
+
+  @Test
+  public void relativeSecondsParseDecimalIntegers() throws ParseException {
+    assertEquals(RFC822_FORMAT.parse("Sun, 2 Jan 2000 00:00:00 GMT"), decoder.apply("86400.0"));
+  }
 }