Query String URI: Add `lenient` to the URI `q` parameters, closes #1937.

src/main/java/org/elasticsearch/index/query/QueryStringQueryBuilder.java

@@ -85,6 +85,8 @@ public class QueryStringQueryBuilder extends BaseQueryBuilder {
 
     private String minimumShouldMatch;
 
+    private Boolean lenient;
+
     public QueryStringQueryBuilder(String queryString) {
         this.queryString = queryString;
     }
@@ -279,6 +281,15 @@ public class QueryStringQueryBuilder extends BaseQueryBuilder {
         return this;
     }
 
+    /**
+     * Sets the query string parser to be lenient when parsing field values, defaults to the index
+     * setting and if not set, defaults to false.
+     */
+    public QueryStringQueryBuilder lenient(Boolean lenient) {
+        this.lenient = lenient;
+        return this;
+    }
+
     @Override
     protected void doXContent(XContentBuilder builder, Params params) throws IOException {
         builder.startObject(QueryStringQueryParser.NAME);
@@ -351,6 +362,9 @@ public class QueryStringQueryBuilder extends BaseQueryBuilder {
         if (quoteFieldSuffix != null) {
             builder.field("quote_field_suffix", quoteFieldSuffix);
         }
+        if (lenient != null) {
+            builder.field("lenient", lenient);
+        }
         builder.endObject();
     }
 }

src/main/java/org/elasticsearch/rest/action/search/RestSearchAction.java

@@ -154,6 +154,7 @@ public class RestSearchAction extends BaseRestHandler {
             queryBuilder.analyzer(request.param("analyzer"));
             queryBuilder.analyzeWildcard(request.paramAsBoolean("analyze_wildcard", false));
             queryBuilder.lowercaseExpandedTerms(request.paramAsBoolean("lowercase_expanded_terms", true));
+            queryBuilder.lenient(request.paramAsBooleanOptional("lenient", null));
             String defaultOperator = request.param("default_operator");
             if (defaultOperator != null) {
                 if ("OR".equals(defaultOperator)) {