Development/Tutorials/KIO Slaves/Hello World
Parts to be reviewed:
Port to KF5Understanding
A kioslave allows you to represent any kind of storage in a way you want. As an example, the kio_http kioslave loads data from the network over the http (protocol) and shows it rendered as html. Technically, a kioslave is a shared object plus its description. E.g. the imap4 kioslave consist of the following files:
tweedleburg:/usr/local # find -iname "*imap4*"
./lib/kde4/kio_imap4.so
./share/kde4/services/imap4.protocol
The files
We want to write a "hello world" kioslave here. This can be seen as a learning exercise and as a template for future programming projects.
CMakeLists.txt
PROJECT( tutorial )
FIND_PACKAGE(KDE4 REQUIRED)
INCLUDE_DIRECTORIES( ${KDE4_INCLUDES} . )
set(kio_hello_PART_SRCS
hello.cpp)
kde4_add_plugin(kio_hello ${kio_hello_PART_SRCS})
target_link_libraries(kio_hello ${KDE4_KIO_LIBS})
install(TARGETS kio_hello DESTINATION ${PLUGIN_INSTALL_DIR})
########### install files ###############
install(FILES hello.protocol DESTINATION ${SERVICES_INSTALL_DIR})
hello.h
#ifndef HELLO_H
#define HELLO_H
#include <kio/slavebase.h>
/**
This class implements a hello-world kioslave
*/
class hello : public KIO::SlaveBase
{
public:
hello( const QByteArray &pool, const QByteArray &app );
void get( const KUrl &url );
};
#endif
hello.cpp
#include "hello.h"
#include <kdebug.h>
#include <kcomponentdata.h>
extern "C" int KDE_EXPORT kdemain( int argc, char **argv )
{
kDebug(7000) << "Entering function";
KComponentData instance( "kio_hello" );
if (argc != 4)
{
fprintf( stderr, "Usage: kio_hello protocol domain-socket1 domain-socket2\n");
exit( -1 );
}
hello slave( argv[2], argv[3] );
slave.dispatchLoop();
return 0;
}
void hello::get( const KUrl &url )
{
kDebug(7000) << "Entering function";
mimeType( "text/plain" );
QByteArray str( "Hello_world" );
data( str );
finished();
kDebug(7000) << "Leaving function";
}
hello::hello( const QByteArray &pool, const QByteArray &app )
: SlaveBase( "hello", pool, app ) {}
hello.protocol
[Protocol]
DocPath=kioslave/kio_hello.html
exec=kio_hello
input=none
output=filesystem
protocol=hello
reading=true
Compile the stuff
Create a new Folder "build":
mkdir build
cd build
Run cmake and make
cmake ..
make
now you can install it (maybe you should use an experimental setup?)
make install
If you want to do this by hand:
g++ -shared -lkdeui -lkio -lkdecore -fPIC -I$(qmake -query QT_INSTALL_HEADERS) hello.cpp -o kio_hello.so
Install the stuff
Now you can install it (maybe you should use an experimental setup?):
make install
or if you want to install it to your system:
sudo make install
Of course you can also do this by hand.
Find out where your protocols are lying:
kde4-config --path services
/usr/share/kde4/services/
kde4-config --path module
/usr/lib64/kde4/
cp kio_hello.so /usr/local/lib/kde4/
cp kio_hello.so /usr/lib64/kde4/
cp kio_hello.protocol /usr/share/kde4/services/
Test it
In Konqueror
Start kinfocenter, choose hello as protocol. If this is possible, start konqueror, type hello:/// into the URL bar.
On the command line
kioclient 'cat' 'hello:///'