Получение XML аттрибута без исключений

add no exception methods
commit_hash:245a52ca795a16ad57a9ac642b0cd00ca0122a32

3 files changed, 52 insertions, 0 deletions

diff --git a/library/cpp/xml/document/node-attr.h b/library/cpp/xml/document/node-attr.h
index 1378ffdfbff..6f5445d4c2d 100644
--- a/library/cpp/xml/document/node-attr.h
+++ b/library/cpp/xml/document/node-attr.h
@@ -45,6 +45,18 @@ namespace NXml {
     }
 
     template <class T>
+    TMaybe<T> TNode::TryAttr(TZtStringBuf name) const {
+        TCharPtr value(xmlGetProp(NodePointer, XMLCHAR(name.c_str())));
+        if (!value) {
+            return Nothing();
+        }
+
+        T t;
+        AttrInternal(value, t, name);
+        return t;
+    }
+
+    template <class T>
     T TNode::Attr(TZtStringBuf name, const T& defvalue) const {
         TCharPtr attr(xmlGetProp(NodePointer, XMLCHAR(name.c_str())));
         if (!attr) {
diff --git a/library/cpp/xml/document/xml-document-decl.h b/library/cpp/xml/document/xml-document-decl.h
index bfda1fb7e6e..643ba664680 100644
--- a/library/cpp/xml/document/xml-document-decl.h
+++ b/library/cpp/xml/document/xml-document-decl.h
@@ -328,6 +328,14 @@ namespace NXml {
         /**
         * get node attribute
         * @param name: attribute name
+        * returns value if exists
+        */
+        template <class T>
+        TMaybe<T> TryAttr(TZtStringBuf name) const;
+
+        /**
+        * get node attribute
+        * @param name: attribute name
         * returns default value if attribute not found
         */
         template <class T>
@@ -600,6 +608,16 @@ namespace NXml {
         /**
         * get node attribute
         * @param name: attribute name
+        * returns value if exists
+        */
+        template <class T>
+        TMaybe<T> TryAttr(TZtStringBuf name) const {
+            return ActualNode.TryAttr<T>(name);
+        }
+
+        /**
+        * get node attribute
+        * @param name: attribute name
         * throws exception if attribute not found
         */
         template <class T>
diff --git a/library/cpp/xml/document/xml-document_ut.cpp b/library/cpp/xml/document/xml-document_ut.cpp
index 9f537b75c4c..0ec1fc60838 100644
--- a/library/cpp/xml/document/xml-document_ut.cpp
+++ b/library/cpp/xml/document/xml-document_ut.cpp
@@ -1,5 +1,6 @@
 #include <library/cpp/testing/unittest/registar.h>
 #include <util/generic/map.h>
+#include <util/generic/yexception.h>
 
 #include "xml-document.h"
 
@@ -35,6 +36,27 @@ Y_UNIT_TEST_SUITE(TestXmlDocument) {
         NXml::TConstNode text = root.Node("text");
         UNIT_ASSERT_EQUAL(text.Value<TString>(), "Некоторый текст");
     }
+    Y_UNIT_TEST(GetAttributes) {
+        NXml::TDocument xml(R"(<?xml version="1.0"?>
+                            <root>
+                                <a><b len="15" correct="1">hello world</b></a>
+                                <text>Некоторый текст</text>
+                            </root>
+                            )",
+                            NXml::TDocument::String);
+
+        NXml::TConstNode root = xml.Root();
+        NXml::TConstNode b = root.Node("a/b");
+
+        UNIT_ASSERT_EXCEPTION_CONTAINS(b.Attr<int>("unknown attrib"), yexception, "@unknown attrib");
+
+        const auto unknownAttr = b.TryAttr<int>("unknown attrib");
+        UNIT_ASSERT(unknownAttr.Empty());
+
+        const auto knownAttr = b.TryAttr<int>("len");
+        UNIT_ASSERT(knownAttr.Defined());
+        UNIT_ASSERT_EQUAL(knownAttr.GetRef(), 15);
+    }
     Y_UNIT_TEST(SerializeString) {
         NXml::TDocument xml("frob", NXml::TDocument::RootName);
         xml.Root().SetAttr("xyzzy", "Frobozz");