feat(DynamicStruct): toString() escaping #3833

Foundation/include/Poco/Dynamic/Struct.h

@@ -32,6 +32,37 @@ namespace Poco {
 namespace Dynamic {
 
 
+template <typename S, typename I = typename S::ConstIterator>
+std::string structToString(const S& data, bool wrap = true)
+	/// Utility function for converting DynamicStruct to std::string.
+	/// Set wrap to false in order to prevent string values wrapping
+	/// (useful to prevent JSON fragments from being treated as strings).
+{
+	std::string val;
+	val.append("{ ");
+	I it = data.begin();
+	I itEnd = data.end();
+	if (!data.empty())
+	{
+		Var key(it->first);
+		Impl::appendJSONKey(val, key);
+		val.append(": ");
+		Impl::appendJSONValue(val, it->second, wrap);
+		++it;
+	}
+	for (; it != itEnd; ++it)
+	{
+		val.append(", ");
+		Var key(it->first);
+		Impl::appendJSONKey(val, key);
+		val.append(": ");
+		Impl::appendJSONValue(val, it->second, wrap);
+	}
+	val.append(" }");
+	return val;
+}
+
+
 template <typename K, typename M = std::map<K, Var>, typename S = std::set<K>>
 class Struct
 	/// Struct allows to define a named collection of Var objects.
@@ -226,11 +257,20 @@ public:
 		return it->second;
 	}
 
-	std::string toString() const
+	std::string toString(bool wrap = true) const
+		/// Returns the DynamicStruct as string.
+		///
+		/// To prevent unwanted string wrapping
+		/// (eg. when a value is JSON string),
+		/// `wrap` should be false. Note, however,
+		/// that wrap argument is of a limited utility
+		/// because it applies to the entire Struct,
+		/// so it should not be relied on when mixed content
+		/// (ie. plain string, which should be wrapped,
+		/// and JSON-as-string entries, which shouldn't)
+		/// is held.
 	{
-		std::string str;
+		return structToString<Data, ConstIterator>(_data, wrap);
-		Var(*this).template convert<std::string>(str);
-		return str;
 	}
 
 private:
@@ -332,26 +372,7 @@ public:
 
 	void convert(std::string& val) const
 	{
-		val.append("{ ");
+		val = structToString(_val);
-		ValueType::ConstIterator it = _val.begin();
-		ValueType::ConstIterator itEnd = _val.end();
-		if (!_val.empty())
-		{
-			Var key(it->first);
-			Impl::appendJSONKey(val, key);
-			val.append(": ");
-			Impl::appendJSONValue(val, it->second);
-			++it;
-		}
-		for (; it != itEnd; ++it)
-		{
-			val.append(", ");
-			Var key(it->first);
-			Impl::appendJSONKey(val, key);
-			val.append(": ");
-			Impl::appendJSONValue(val, it->second);
-		}
-		val.append(" }");
 	}
 
 	void convert(Poco::DateTime&) const
@@ -518,26 +539,7 @@ public:
 
 	void convert(std::string& val) const
 	{
-		val.append("{ ");
+		val = structToString(_val);
-		ValueType::ConstIterator it = _val.begin();
-		ValueType::ConstIterator itEnd = _val.end();
-		if (!_val.empty())
-		{
-			Var key(it->first);
-			Impl::appendJSONKey(val, key);
-			val.append(": ");
-			Impl::appendJSONValue(val, it->second);
-			++it;
-		}
-		for (; it != itEnd; ++it)
-		{
-			val.append(", ");
-			Var key(it->first);
-			Impl::appendJSONKey(val, key);
-			val.append(": ");
-			Impl::appendJSONValue(val, it->second);
-		}
-		val.append(" }");
 	}
 
 	void convert(Poco::DateTime&) const
@@ -704,26 +706,7 @@ public:
 
 	void convert(std::string& val) const
 	{
-		val.append("{ ");
+		val = structToString(_val);
-		ValueType::ConstIterator it = _val.begin();
-		ValueType::ConstIterator itEnd = _val.end();
-		if (!_val.empty())
-		{
-			Var key(it->first);
-			Impl::appendJSONKey(val, key);
-			val.append(": ");
-			Impl::appendJSONValue(val, it->second);
-			++it;
-		}
-		for (; it != itEnd; ++it)
-		{
-			val.append(", ");
-			Var key(it->first);
-			Impl::appendJSONKey(val, key);
-			val.append(": ");
-			Impl::appendJSONValue(val, it->second);
-		}
-		val.append(" }");
 	}
 
 	void convert(Poco::DateTime&) const
@@ -890,26 +873,7 @@ public:
 
 	void convert(std::string& val) const
 	{
-		val.append("{ ");
+		val = structToString(_val);
-		ValueType::ConstIterator it = _val.begin();
-		ValueType::ConstIterator itEnd = _val.end();
-		if (!_val.empty())
-		{
-			Var key(it->first);
-			Impl::appendJSONKey(val, key);
-			val.append(": ");
-			Impl::appendJSONValue(val, it->second);
-			++it;
-		}
-		for (; it != itEnd; ++it)
-		{
-			val.append(", ");
-			Var key(it->first);
-			Impl::appendJSONKey(val, key);
-			val.append(": ");
-			Impl::appendJSONValue(val, it->second);
-		}
-		val.append(" }");
 	}
 
 	void convert(Poco::DateTime&) const

Foundation/include/Poco/Dynamic/VarHolder.h

@@ -67,10 +67,12 @@ void Foundation_API appendJSONString(std::string& val, const Var& any);
 	/// regardless of the underlying type) and appends it to val.
 
 
-void Foundation_API appendJSONValue(std::string& val, const Var& any);
+void Foundation_API appendJSONValue(std::string& val, const Var& any, bool wrap = true);
 	/// Converts the any to a JSON value (if underlying type qualifies
-	/// as string - see isJSONString() - , it is wrapped into double quotes)
+	/// as string - see isJSONString() - it is wrapped into double quotes)
-	/// and appends it to val
+	/// and appends it to val.
+	/// Wrapping can be prevented (useful for appending JSON fragments) by setting
+	/// the wrap argument to false.
 
 
 template <typename C>

Foundation/src/VarHolder.cpp

@@ -66,7 +66,7 @@ void appendJSONKey(std::string& val, const Var& any)
 }
 
 
-void appendJSONValue(std::string& val, const Var& any)
+void appendJSONValue(std::string& val, const Var& any, bool wrap)
 {
 	if (any.isEmpty())
 	{
@@ -74,7 +74,7 @@ void appendJSONValue(std::string& val, const Var& any)
 	}
 	else
 	{
-		bool isStr = isJSONString(any);
+		bool isStr = wrap && isJSONString(any);
 		if (isStr)
 		{
 			appendJSONString(val, any.convert<std::string>());

Foundation/testsuite/src/VarTest.cpp

@@ -2286,6 +2286,14 @@ void VarTest::testOrderedDynamicStructBasics()
 }
 
 
+void VarTest::testDynamicStructNoEscapeString()
+{
+	DynamicStruct aStruct;
+	aStruct["Birthday"] = "{ \"Day\": 12, \"Month\": \"May\", \"Year\": 2005 }";
+	assertEqual(aStruct.toString(false), "{ \"Birthday\": { \"Day\": 12, \"Month\": \"May\", \"Year\": 2005 } }");
+}
+
+
 void VarTest::testDynamicStructString()
 {
 	DynamicStruct aStruct;
@@ -3131,6 +3139,7 @@ CppUnit::Test* VarTest::suite()
 	CppUnit_addTest(pSuite, VarTest, testDynamicPair);
 	CppUnit_addTest(pSuite, VarTest, testDynamicStructBasics);
 	CppUnit_addTest(pSuite, VarTest, testOrderedDynamicStructBasics);
+	CppUnit_addTest(pSuite, VarTest, testDynamicStructNoEscapeString);
 	CppUnit_addTest(pSuite, VarTest, testDynamicStructString);
 	CppUnit_addTest(pSuite, VarTest, testOrderedDynamicStructString);
 	CppUnit_addTest(pSuite, VarTest, testDynamicStructInt);

Foundation/testsuite/src/VarTest.h

@@ -57,6 +57,7 @@ public:
 	void testDynamicStructBasics();
 	void testOrderedDynamicStructBasics();
 	void testDynamicStructString();
+	void testDynamicStructNoEscapeString();
 	void testOrderedDynamicStructString();
 	void testDynamicStructInt();
 	void testOrderedDynamicStructInt();