Improve error handling

Author: lahirumaramba

src/main/java/com/google/firebase/remoteconfig/FirebaseRemoteConfigClientImpl.java

@@ -18,6 +18,7 @@
 
 import static com.google.common.base.Preconditions.checkArgument;
 import static com.google.common.base.Preconditions.checkNotNull;
+import static com.google.common.base.Preconditions.checkState;
 
 import com.google.api.client.http.HttpRequestFactory;
 import com.google.api.client.http.HttpResponseInterceptor;
@@ -49,7 +50,6 @@ final class FirebaseRemoteConfigClientImpl implements FirebaseRemoteConfigClient
 
   private static final Map<String, String> COMMON_HEADERS =
           ImmutableMap.of(
-                  "X-GOOG-API-FORMAT-VERSION", "2",
                   "X-Firebase-Client", "fire-admin-java/" + SdkUtils.getVersion(),
                   // There is a known issue in which the ETag is not properly returned in cases
                   // where the request does not specify a compression type. Currently, it is
@@ -95,17 +95,20 @@ public RemoteConfigTemplate getTemplate() throws FirebaseRemoteConfigException {
             .addAllHeaders(COMMON_HEADERS);
     IncomingHttpResponse response = httpClient.send(request);
     RemoteConfigTemplate parsed = httpClient.parse(response, RemoteConfigTemplate.class);
+    parsed.setETag(getETag(response));
+    return parsed;
+  }
 
+  private String getETag(IncomingHttpResponse response) {
     List<String> etagList = (List<String>) response.getHeaders().get("etag");
-    checkArgument(!(etagList == null || etagList.isEmpty()),
+    checkState(etagList != null && !etagList.isEmpty(),
             "ETag header is not available in the server response.");
 
     String etag = etagList.get(0);
-    checkArgument(!Strings.isNullOrEmpty(etag),
+    checkState(!Strings.isNullOrEmpty(etag),
             "ETag header is not available in the server response.");
 
-    parsed.setETag(etag);
-    return parsed;
+    return etag;
   }
 
   static FirebaseRemoteConfigClientImpl fromApp(FirebaseApp app) {

src/main/java/com/google/firebase/remoteconfig/internal/RemoteConfigServiceErrorResponse.java

@@ -24,6 +24,8 @@
 import com.google.firebase.remoteconfig.RemoteConfigErrorCode;
 
 import java.util.Map;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 
 /**
  * The DTO for parsing error responses from the Remote Config service.
@@ -41,14 +43,6 @@ public final class RemoteConfigServiceErrorResponse extends GenericJson {
   @Key("error")
   private Map<String, Object> error;
 
-  public String getStatus() {
-    if (error == null) {
-      return null;
-    }
-
-    return (String) error.get("status");
-  }
-
   @Nullable
   public RemoteConfigErrorCode getRemoteConfigErrorCode() {
     if (error == null) {
@@ -60,9 +54,9 @@ public RemoteConfigErrorCode getRemoteConfigErrorCode() {
       return null;
     }
 
-    int separator = message.indexOf(':');
-    if (separator != -1) {
-      String errorCode = message.substring(0, separator).replaceAll("\\[|\\]", "");
+    Matcher errorMatcher = Pattern.compile("^\\[(\\w+)\\]:.*$").matcher(message);
+    if (errorMatcher.find()) {
+      String errorCode = errorMatcher.group(1);
       return RC_ERROR_CODES.get(errorCode);
     }
 

src/test/java/com/google/firebase/remoteconfig/FirebaseRemoteConfigClientImplTest.java

@@ -89,7 +89,7 @@ public void testGetTemplate() throws Exception {
     checkGetRequestHeader(interceptor.getLastRequest());
   }
 
-  @Test(expected = IllegalArgumentException.class)
+  @Test(expected = IllegalStateException.class)
   public void testGetTemplateWithInvalidEtags() throws FirebaseRemoteConfigException {
     // ETag does not exist
     response.setContent(MOCK_TEMPLATE_RESPONSE);
@@ -290,7 +290,6 @@ private void checkGetRequestHeader(HttpRequest request) {
     assertEquals("GET", request.getRequestMethod());
     assertEquals(TEST_REMOTE_CONFIG_URL, request.getUrl().toString());
     HttpHeaders headers = request.getHeaders();
-    assertEquals("2", headers.get("X-GOOG-API-FORMAT-VERSION"));
     assertEquals("fire-admin-java/" + SdkUtils.getVersion(), headers.get("X-Firebase-Client"));
     assertEquals("gzip", headers.getAcceptEncoding());
   }