Working with XML, anyone knows a nice guide?

Morgawr · Post by **Morgawr** » Wed Jan 30, 2008 4:50 pm

Hello everyone, I just realized I need to learn some XML for my program because that would make it easier so, since I have some time, I wanted to flick through a nice guide/manual on the net before buying a real book (maybe).

Does anyone know a very nice guide on the net for XML? A complete guide with maybe examples and easy-tips and anything that makes a guide "nice"

I've already checked the search feature in this forums but didn't find anything in here and I am already browsing google as we speak, looking for a nice guide, but surely some help from you professional programmers would be awesome

very very thanks again

Acki · Post by **Acki** » Wed Jan 30, 2008 6:40 pm

Google is amazing !!!

just if you're to dump to use google:

http://www.google.de/search?hl=de&q=%2B ... uche&meta=

Morgawr · Post by **Morgawr** » Wed Jan 30, 2008 6:54 pm

Acki wrote:Google is amazing !!!
just if you're to dump to use google:
http://www.google.de/search?hl=de&q=%2B ... uche&meta=

heh yeah

I found http://www.w3schools.com/xml/xml_view.asp this page right after I posted that message and read it (most of it) and now I can understand the basics behind XML... so well, I made a test program to see if it worked but I'm having problems because I don't really know how to start reading from an XML file... this is my program (the important part):

Code: Select all

...
    IrrXMLReader* read = createIrrXMLReader("texting.xml");
    if(read==0)
     cout << "not loaded\n";

    u32 var1;
    u32 var2;
    while(read->read())
    {
        if(read->getNodeName()=="var1")
         var1 = (u32)read->getAttributeValue(read->getNodeName());
    }
    cout << var1 << "\n";// << var2 << "\n";
...

(nevermind the commented out part, it was part of a test)
and this is my XML file:

Code: Select all

<?xml version="1.0" encoding="ISO-8859-1"?>
<body>
    <var1 ID="1">3</var1>
    <var2 ID="2">4</var2>
    <body2>
        <var3 ID="3">5</var3>
        <stringa ID="4">ciao a tutti</stringa>
    </body2>
</body>

I don't know if the reading process is correct or not, I don't think so since it's not working properly, I get an int number like "3086andsomeotherdigits" instead of "3"... I also tried getAttributeValueAsInt but I get the same results... can somebody give me a brief explanation or tell me what's the wrong part in that code? thanks a lot

MasterGod · Post by **MasterGod** » Wed Jan 30, 2008 6:54 pm

http://www.w3schools.com/xml/default.asp

MasterGod · Post by **MasterGod** » Wed Jan 30, 2008 6:54 pm

http://www.w3schools.com/xml/default.asp

Morgawr · Post by **Morgawr** » Wed Jan 30, 2008 6:55 pm

MasterGod wrote:http://www.w3schools.com/xml/default.asp

As I said in the post above, already found that guide

thanks

Morgawr · Post by **Morgawr** » Wed Jan 30, 2008 7:44 pm

Sorry for double posting but I updated my code with something like this just to see if it works:

Code: Select all

    while(read->read())
    {
        if((read->getNodeType()==EXN_ELEMENT))
        {
         cout << "\n inside exn_element \n" << read->getNodeName();
         if(read->getNodeName()=="var1")
         {
          cout << read->getNodeName()<<"\n";
          cout << "\n inside getnodename() \n";
         }
        }
    }

and it's totally screwed up o.o
I mean, I don't understand how it's possible that it NEVER enters into the second if but inside the first if when I print all the getNodeName() I DO get a "var1" node name, which doesn't get passed into the following if condition... I really don't understand this, can somebody enlighten me very please?

Acki · Post by **Acki** » Wed Jan 30, 2008 7:56 pm

I'm not sure, because I use tinyXML (it's realy easy to use)...

but you get a char_type* as return value of getNodeName so you can't compare it with ==, or am I wrong ???

maybe try something like this:

Code: Select all

         stringc test = read->getNodeName();
         if(test.equals_ignore_case("var1"))

or try tinyXML...

Morgawr · Post by **Morgawr** » Wed Jan 30, 2008 8:04 pm

Acki wrote:I'm not sure, because I use tinyXML (it's realy easy to use)...

but you get a char_type* as return value of getNodeName so you can't compare it with ==, or am I wrong ???

maybe try something like this:
Code: Select all
         stringc test = read->getNodeName();
         if(test.equals_ignore_case("var1"))
or try tinyXML...

Wow it works

I guess it was a lower/upper case problem, thanks a lot

anyways what's tinyXML? It might be interesting and, if as you said it's easier, might want to try it out before I build all my program on IrrXML just to get screwed later

Acki · Post by **Acki** » Wed Jan 30, 2008 9:11 pm

and again, google is your friend...

http://sourceforge.net/projects/tinyxml

dlangdev · Post by **dlangdev** » Wed Jan 30, 2008 9:27 pm

wow, thanks acki for the tinyxml link.

i'm currently reading the docs at the moment...

http://www.grinninglizard.com/tinyxmldo ... rial0.html

i've started coding using msxml 6.0 api and it looks pretty solid so far as it fits with the design spec. but tinyxml could bring more stuff in shorter time. although it seems that it doesn't load from a string, as most that i found load from a file.

Acki · Post by **Acki** » Wed Jan 30, 2008 10:38 pm

I love tinyXML, I also used it with my IrrExtensions...

small examples:

reading:

Code: Select all

TiXmlDocument doc("./defaults.dat");
if(doc.LoadFile()){
  TiXmlElement* root = doc.RootElement();
  if(root){
    TiXmlElement* grp = root->FirstChildElement("Tools");
    if(grp){
      for(TiXmlElement* itm = grp->FirstChildElement("set"); itm != NULL; itm = itm->NextSiblingElement("set")){
        int id;
        if(itm->Attribute("ID", &id)){
          cCheckButton* o = getToolWidget(id)->chkWidget;
          if(o){
            int i;
            if(itm->Attribute("Value", &i))  o->value((bool)i);
          }
        }
      }
    }
  }
}

writing:

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TiXmlDocument doc;
TiXmlDeclaration* decl = new TiXmlDeclaration("1.0", "", "");
doc.LinkEndChild(decl);
TiXmlElement* root = new TiXmlElement("IrrExt13_Defaults");
TiXmlElement* tools = new TiXmlElement("Tools");
for(int t = 0; t < lstTools.size(); t++){
  TiXmlElement* elm = new TiXmlElement("set");
  elm->SetAttribute("ID", (int)lstTools[t].ID);
  elm->SetAttribute("Value", (int)lstTools[t].chkWidget->value());
  tools->LinkEndChild(elm);
}
root->LinkEndChild(tools);
doc.LinkEndChild(root);
doc.SaveFile("./defaults.dat");

and the XML file:

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<?xml version="1.0" ?>
<IrrExt13_Defaults>
    <Tools>
        <set ID="0" Value="1" />
        <set ID="2" Value="1" />
        <set ID="4" Value="1" />
        <set ID="5" Value="0" />
        <set ID="6" Value="0" />
        <set ID="7" Value="0" />
        <set ID="8" Value="0" />
        <set ID="10" Value="0" />
        <set ID="12" Value="0" />
        <set ID="14" Value="1" />
        <set ID="100" Value="0" />
        <set ID="102" Value="0" />
        <set ID="103" Value="0" />
        <set ID="104" Value="0" />
        <set ID="105" Value="0" />
        <set ID="1" Value="0" />
        <set ID="3" Value="0" />
        <set ID="9" Value="0" />
        <set ID="11" Value="0" />
        <set ID="13" Value="0" />
        <set ID="101" Value="0" />
    </Tools>
</IrrExt13_Defaults>

dlangdev · Post by **dlangdev** » Fri Feb 01, 2008 9:11 am

acki: that code looks beautiful, i like it.

i've got demo #1 for msxml coded and tested, what i found out using msxml sdk is the following:

1) xmldoc object can load from file or string, pretty much covering the two important feature of loading from a file and getting xml data from a remote machine, typically a soap call return data.

2) once loaded, i can walk the dom and pick the elements with corresponding attribs. though i still don't like dealing with LPCSTR and BSTR, though. they're nasty.

anyway, i still have many steps to take, including one demo using tinyxml.

thanks for the code, really appreciate it.

hybrid · Post by **hybrid** » Fri Feb 01, 2008 10:22 am

Ok, then let's check about irrXML

Code: Select all

io::IXMLReader* reader = FileSystem->createXMLReader(file);
if (reader)
{
  while(reader->read())
  {
    if (reader->getNodeType() == io::EXN_ELEMENT)
    {
      if (core::stringc("set") == reader->getNodeName())
      {
        s32 id;
        if (reader->getAttributeValue(L"ID").size())
        {
          id = reader->getAttributeValueAsInt(L"ID");
          cCheckButton* o = getToolWidget(id)->chkWidget;
          if(o)
          {
             if (reader->getAttributeValue(L"Value").size())
               o->value(reader->getAttributeValueAsInt(L"Value"));
          }
        }
      }
    }
  }
}

and writing

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Writer = FileSystem->createXMLWriter(file);
if (Writer)
{
  Writer->writeXMLHeader();
  Writer->writeElement(L"IrrExt13_Defaults", false);
  Writer->writeLineBreak();
  Writer->writeElement(L"Tools", false);
  Writer->writeLineBreak();
  for(int t = 0; t < lstTools.size(); t++)
  {
    Writer->writeElement(L"set", true,
      L"ID", core::stringw(lstTools[t].ID).c_str(),
      L"Value", core::stringw(lstTools[t].chkWidget->value()).c_str());
  }
  Writer->writeClosingTag(L"Tools");
  Writer->writeLineBreak();
  Writer->writeClosingTag(L"IrrExt13_Defaults");
  Writer->drop();
}

I don't think that these approaches are really different in code size or programming complexity. Of course, irrXML is doing a SAX style, while tinyXML seems to have a DOM. But for the presented purpose using SAX is pretty straight.

CuteAlien · Post by **CuteAlien** » Fri Feb 01, 2008 12:45 pm

The main problem with irrXML for me is that it writes 32-bit chars in linux and I still have not found a single editor on Linux which can handle this. Which means that every time I write something with it in Linux I have to switch to windows whenever I need to modify the xml's. And that just sucks.

edit: And yeah, sorry, that doesn't really belong in the thread. Seeing tinyXml and irrXML compared on the level of reading/writing was just getting on my nerves, as this is so far from the biggest problem I have to fight when using irrXML.

edit2: Also tinyXml and irrXML do different jobs anyway. With tinyXml you work with xml-structures in c++. Mainly in memory! Additionally it offers you the functions to load & save those structures (with a single command!). irrXML is a pure xml reader/writer.