I am using PugiXml library for XML related operations.
My XML File:
<CurrentStatus>
<Time Stamp= "12:30">
<price>100</price>
<amount>1</amount>
</Time>
<Time Stamp= "14:50">
<price>10</price>
<amount>5</amount>
</Time>
<Time Stamp= "16:30">
<price>10</price>
<amount>5</amount>
</Time>
</CurrentStatus>
For testing purpose, I am giving a hard-coded value that I want to delete the node Time with attribute Stamp = 14:50.
XML Node Removal Code: I used this SO Question as reference to remove a node (name = Time and Attribute = 14:50).
for (xml_node child = doc.child("CurrentStatus").first_child(); child; )
{
xml_node next = child.next_sibling();
string attributeValue = child.attribute("Stamp").as_string();
if (attributeValue == "14:50")
{
cout << "delete" << endl;
child.parent().remove_child(child);
}
child = next;
}
Question: The above code runs without any error. It even enters into the if-statement but why the original XML file remains same after the execution?
PS: I am sure that the root node and the XML document is getting read properly in General since I am able to display the XML structure on the console.
I think that the problem was in Saving.
I executed the following save statement after the if-condition and it worked.
doc.save_file("D:/myfile.xml");
Related
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;
}
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.
I want to create an XML document by building a DOM document from scratch, with syntax like:
AutoPtr<Document> doc = new Document;
AutoPtr<Element> root = doc->createElement("root");
doc->appendChild(root);
AutoPtr<Element> element1 = doc->createElementNS("http://ns1", "ns1:element1");
root->appendChild(element1);
AutoPtr<Element> element2 = doc->createElementNS("http://ns1", "ns1:element2");
root->appendChild(element2);
DOMWriter writer;
writer.setNewLine("\n");
writer.setOptions(XMLWriter::PRETTY_PRINT);
writer.writeNode(std::cout, doc);
But, when I write it, I get next result:
<root>
<ns1:element1 xmlns:ns1="http://ns1"/>
<ns1:element2 xmlns:ns1="http://ns1"/>
</root>
So namespace ns1 declared two times, and I want to declare it inside "root" element.
Is there way to get next representation:
<root xmlns:ns1="http://ns1"/>
<ns1:element1/>
<ns1:element2/>
</root>
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");
Using the MSXML2 functions from the "msxml3.dll" library, I'm trying to duplicate sections in an XML document, but it does not work as I expected.
Here is the XML:
<result>
<Target>
<Point>
<pos dimension="2">60.384005 5.333862</pos>
</Point>
</Target>
</result>
What I want is to add multiple sections. So I want to take the node, duplicate it and put it under the existing <Target> node. I'm almost convinced I should use the Clone method, but it does not seem to work.
The C++ code:
typedef MSXML2::IXMLDOMNodePtr XmlNode;
XmlNode pNode = pXMLRequest->selectSingleNode("//result");
if(pNode==NULL)
{ m_szErrorText = m_szErrorText + _T(" 'result' node not found");return FALSE;}
XmlNode pTargetNode = pNode->selectSingleNode("Target");
XmlNode pNewTargetNode = pTargetNode->cloneNode(true);
pNode->appendChild(pNewTargetNode);
But when I run this code nothing happens to the XML document. And when I inspect the XML text in pNewTargetNode I see it is '<result>' only which is just the name of the node While I would expect it to contain all the nodes in <Target>...</Target>. Is there something I am missing ?
I used the wrong kind of 'true'.
If I replace
XmlNode pNewTargetNode = pTargetNode->cloneNode(true);
with
XmlNode pNewTargetNode = pTargetNode->cloneNode(VARIANT_TRUE);
it works fine. I had already thought about this and used TRUE instead of true, but that does not work either.
So when using the msxml library alsways use VARIANT_BOOL, VARIANT_FALSE and VARIANT_TRUE.
Raymond Chen explains why there are so many variations:
http://blogs.msdn.com/b/oldnewthing/archive/2004/12/22/329884.aspx