bug of RapidXML when the value of a xml node is null - c++

If the value of node in the xml is null, when we print the xml node, the node has no start tag, but only the end tag. For example:
xml_document<char> doc;
doc.append_node(doc.allocate_node(rapidxml::node_element, "mynode", ""));
ofstream ofs("test.xml");
ofs<<doc;
the content of test.xml is:
</mynode>
the expected content of test.xml is
<mynode></mynode>
Is this a bug of rapidxml

I do not know what version of RapidXml you're using. I've used few days ago the latest and works fine... this problem was fixed or it was a particular case of yours :)

Related

How to create a xml node using rapidxml

Hi I want to create the following xml file in C++ using rapidxml on Linux.
How to add an element which is of type name.
<wrapit>
<mainNode>
<name>something1</name>
</mainNode>
</wrapit>
what my code generates looks like following which I don't want.
<wrapit>
<mainNode>
<name something1=""/>
</mainNode>
</wrapit>
I could not find much information for this. Few on wordpress but the xml formats are different.
Code snippet
xml_node<>* root = doc.allocate_node(node_element, "mainNode");
doc.append_node(root);
xml_node<>* child = doc.allocate_node(node_element,"name");
child->append_attribute(doc.allocate_attribute("something1"));
root->append_node(child);
ugg....
xml_node<>* child = doc.allocate_node(node_element,"name","something1");
does it.

Add XML contained in string as XML nodes to existing pugixml tree

I have a configuration file saver/loader. In addition to the expected data, there is a <CustomData> node. When saving the node, we'd simply have a std::string _customData and add it to the node, like this:
pugi::xml_document doc;
pugi::xml_node config = doc.append_child("OurConfig");
// save custom data
pugi::xml_node customData = config.append_child("CustomData");
customData.append_child(pugi::node_pcdata).set_value(_customData);
Our _customData was base64 encoded XML. It is provided from another part of the application. It must be a string, since the other part of the application uses different programming language (C#). As you can imagine, that became annoying, because it wasn't human readable. First step to fix this was simply to get rid of base64 in the app that provides _customData. So now we have readable version, which looks like this:
<?xml version="1.0"?>
<OurConfig>
<CustomData><CfgRoot>
<SomeValue name="External setting for foo" value="Foo"/>
<SomeValue name="External setting for bar" value="Bar"/>
</CfgRoot></CustomData>
</OurConfig>
But it could probably improve if the custom data was directly appended to XML tree instead of as string value. How can I append XML string as XML and not as string to pugixml tree?
Ie. the output I'd like:
<?xml version="1.0"?>
<OurConfig>
<CustomData>
<CfgRoot>
<SomeValue name="External setting for foo" value="Foo"/>
<SomeValue name="External setting for bar" value="Bar"/>
</CfgRoot>
</CustomData>
</OurConfig>
In the docs, there are three methods listed. I used the first one, making a convenience function like this:
bool AppendXMLString(pugi::xml_node target, const std::string& srcString)
{
// parse XML string as document
pugi::xml_document doc;
if (!doc.load_buffer(srcString.c_str(), srcString.length()))
return false;
for (pugi::xml_node child = doc.first_child(); child; child = child.next_sibling())
target.append_copy(child);
return true;
}

Tinyxml2 append function

I have been looking for a way to append my xml file using tinyxml2 but couldn't find anything. I would appreciate any help.
Here is my code:
function savedata() {
XMLNode * pRoot = xmlDoc.NewElement("Cars");
xmlDoc.InsertFirstChild(pRoot);
XMLElement * pElement = xmlDoc.NewElement("Brand");
pElement->SetText("Audi");
pRoot->InsertEndChild(pElement);
pElement = xmlDoc.NewElement("type");
pElement->SetText("4x4");
pRoot->InsertEndChild(pElement);
pElement = xmlDoc.NewElement("Date");
pElement->SetAttribute("day", 26);
pElement->SetAttribute("month", "April");
pElement->SetAttribute("Year", 2015);
pElement->SetAttribute("dateFormat", "26/04/2015");
pRoot->InsertEndChild(pElement);
XMLError eResult = xmlDoc.SaveFile("SavedData1.xml");
XMLCheckResult(eResult);
}
Everytime I run the function, the xml is overwritten and I want to append to the existing file.
My xml file:
<Cars>
<Brand>Audi</Brand>
<Whatever>anothercrap</Whatever>
<Date day="26" month="April" Year="2015" dateFormat="26/04/2015"/>
</Cars>
My root is and I want to append to the existing file. For example,
<Cars>
<Brand>Audi</Brand>
<type>4x4</type>
<Date day="26" month="April" Year="2015" dateFormat="26/04/2015"/>
<Brand>BMWM</Brand>
<type>truck</type>
<Date day="26" month="April" Year="2015" dateFormat="26/04/2015"/>
</Cars>
XML is structured data so a textual append would be tricky and possibly error-prone, as you would have to make sure you don't add the root node twice, and that you maintain indentation etc.
What might be easier is to load the XML, parse it with TinyXML, and write it back.
You can append if you use the FILE overload for xmldoc.Save.
FILE* file = fopen("myfile.xml","a");
xmlDoc.Save(file);
fclose(file);
You just have to be careful when doing this since it will mess up the doc if you're printing multiple root nodes. If you're doing this for logging purposes I would just leave out the root node entirely and just have whatever is reading the log back know to append them or just not even care about proper xml format.

how do i add attributes to xml using xerces?

i have currently generated some XML using xercer in C++, using the following code:
XMLCh tempAttribute[100];
XMLString::transcode("ad", tempStr, 99);
doc = impl->createDocument(0,tempStr ,0);
root = doc->getDocumentElement();
XMLString::transcode("imageAd", tempStr, 99);
element = doc->createElement(tempStr);
root->appendChild(element);
However i am attempting to get the attributes within the top "ad" element (as below), however i have had little luck in doing so, can someone with experience using xerces please advise.
Thanks in advance!
<ad xsi:noNamespaceSchemaLocation="smaato_ad_v0.9.xsd" modelVersion="0.9">
<imageAd>
maybe you didn't saw the call to setAttribute in my previous answer but you can set any attribute for any element with calls like
root->setAttribute(L"modelVersion", L"0.9");
root->setAttribute(L"xsi:noNamespaceSchemaLocation", L"xsi:noNamespaceSchemaLocation");
Where root is the pointer to your root element.

XML Getting attibute value of a Node

I am using XML DOM API in C++ to parse an XML file. I can't find any method to get the attribute value in a node element.
For example, in the following xml
<test>
<fruit count="10">
...
...
</fruit>
<test>
I need to get the count string("10") using XML APIs. Can anybody help me with some code snippets.
Use DOM Parser API to get attribute value count.
Refer below sample code:
//code to perform some process for parsing the input file and get rootElement
DOMNodeList* fruitNodes= rootElement->getElementsByTagName(XMLString::transcode("fruit"));
DOMNode* node = fruitNodes->item(0);
DOMElement* fruitElement = dynamic_cast <xercesc::DOMElement*>(node);
const XMLCh* attrValue = fruitElement->getAttribute(XMLString::transcode("count"));
you can get value 10 from attrValue using: string(XMLString::transcode(attrValue))
Based on http://msdn.microsoft.com/en-us/library/windows/desktop/ms754523(v=vs.85).aspx
Try something like:
pXMLDomNodeList = pXMLDocElement->selectNodes("/test/fruit/#count");