Parsing XML File with Boost C++ - c++

Question

I have to parse one xml file using boost c++, I have written one test code which is working for this xml.
a.xml
<a>
<modules>
<module>abc</module>
<module>def</module>
<module>ghi</module>
</modules>
</a>
Output is coming
abc
def
ghi
but for this a.xml file, my test code is not showing any output, 3 blank lines are coming as output.
<a>
<modules>
<module value = "abc"/>
<module value = "def"/>
<module value = "abc"/>
</modules>
</a>
here is the test code:
#include <boost/property_tree/ptree.hpp>
#include <boost/property_tree/xml_parser.hpp>
#include <boost/foreach.hpp>
#include <iostream>
int main()
{
using boost::property_tree::ptree;
ptree pt;
read_xml("a.xml",pt);
BOOST_FOREACH(ptree::value_type &v, pt.get_child("a.modules"))
std::cout<<v.second.data()<<std::endl;
return 0;
}
My Problem is I am having a large xml file which contains the mixture of patterns from both the files and I have to parse it.
File is b.xml and I have to get message subtag from each tag.
<MultiMessage>
<Message structID="1710" msgID="0" length="50">
<structure type="AppHeader">
</structure>
</Message>
<Message structID="27057" msgID="27266" length="315">
<structure type="Container">
<productID value="166"/>
<publishTo value="xyz"/>
<templateID value="97845"/>
<sendingTime value="1421320622367060444"/>
<message value="092374NMKLA90U345N09832LJKN0A9845JHKLASDF09U8426LJAKLJDGF09845U6KLJSDGP89U45LJSDFP9GU4569078LJK"/>
</structure>
</Message>
</MultiMessage>
<MultiMessage>
<Message structID="1710" msgID="0" length="50">
<structure type="AppHeader">
</structure>
</Message>
<Message structID="27057" msgID="27266" length="315">
<structure type="Container">
<productID value="166"/>
<publishTo value="xyz"/>
<templateID value="97845"/>
<sendingTime value="1421320622367060444"/>
<message value="092374NMKLA90U345N09832LJKN0A9845JHKLASDF09U8426LJAKLJDGF09845U6KLJSDGP89U45LJSDFP9GU4569078LJK"/>
</structure>
</Message>
</MultiMessage>
<MultiMessage>
<Message structID="1710" msgID="0" length="50">
<structure type="AppHeader">
</structure>
</Message>
<Message structID="27057" msgID="27266" length="315">
<structure type="Container">
<productID value="166"/>
<publishTo value="xyz"/>
<templateID value="97845"/>
<sendingTime value="1421320622367060444"/>
<message value="092374NMKLA90U345N09832LJKN0A9845JHKLASDF09U8426LJAKLJDGF09845U6KLJSDGP89U45LJSDFP9GU4569078LJK"/>
</structure>
</Message>
</MultiMessage>
and output should be :
092374NMKLA90U345N09832LJKN0A9845JHKLASDF09U8426LJAKLJDGF09845U6KLJSDGP89U45LJSDFP9GU4569078LJK
092374NMKLA90U345N09832LJKN0A9845JHKLASDF09U8426LJAKLJDGF09845U6KLJSDGP89U45LJSDFP9GU4569078LJK
092374NMKLA90U345N09832LJKN0A9845JHKLASDF09U8426LJAKLJDGF09845U6KLJSDGP89U45LJSDFP9GU4569078LJK
Thank You
Regards

Answer 1

Boost Documentation:
The attributes of an XML element are stored in the subkey . There is one child node per attribute in the attribute node. Existence of the node is not guaranteed or necessary when there are no attributes.
<module value = "abc"/>
//One way would be this:
boost::get<std::string>("module.<xmlattr>.value");
One more way (untested), which appears to be better:
BOOST_FOREACH(boost::property_tree::ptree::value_type &v, pt.get_child("a.modules"))
{
std::cout << v.second.get_child("<xmlattr>.type").data() << std::endl;
std::cout << v.second.get_child("<xmlattr>.Reference").data() << std::endl;
}
One more taken from here.
//Parse XML...
BOOST_FOREACH(boost::property_tree::ptree::value_type &v, pt.get_child("a.modules"))
{
const boost::property_tree::ptree &attributes = v.second.get_child("<xmlattr>", boost::property_tree::ptree());
BOOST_FOREACH(const boost::property_tree::ptree::value_type &v, attributes)
{
std::cout << v.first.data() << std::endl;
std::cout << v.second.data() << std::endl;
}
}