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Qt-based LiveConnect Plugins

The Qt-based Netscape Plugin software makes it easy to write plugins such that they can be used on both Unix/Linux and Windows/95/NT, in Netscape and Internet Explorer, and any other web browser supporting the same protocol.

How-to

1. Download the Plugin SDK from Netscape, and copy the following files from there to $QTDIR/extensions/nsplugin/src :
   • common/npwin.cpp
   • common/npunix.c
   • include/npapi.h
   • include/npupp.h
   • include/jri.h
   • include/jri_md.h
   • include/jritypes.h
2. Build the Netscape Plugin extension library, found in the extensions/nsplugin/src directory of your Qt distribution. This produces a static library to be linked with your plugin code.
3. Read the plugin class documentation, and examine the example plugins.
4. Do most of your development as a stand-alone Qt application - debugging Netscape Plugins is cumbersome. You may want to use signal(2) in your plugin to enable core-dumps if your browser disables them.
5. Note the platform-specific build steps below.
6. Read about the raw plugin interface in Netscape's handbook.
7. If files viewed by a plugin are provided by an HTTP server (using a http://... URL) then the server must be configured to send the correct MIME type for the file, such as by editing the mime.types file of Apache. If the files are viewed via a file://... URL, then the browser will use the filename extension to decide the file type (and hence the plugin to load) - the user may need to set the filename extension in the Helpers or Applications section of their browser preferences.

We are working on streamlining the build process for Qt-based Netscape Plugins.

Building under X11

• The Makefiles in the examples are appropriate for UNIX/X11.
• The user must install the resulting Shared Object in the Plugins directory of the browser.

Building under Windows

• Qt needs to be built as a static library when building Netscape plugins, we are looking into the problem of making it work with Qt as a dynamic library.
• Plugins must be named npname.dll, or the browser will ignore them.
• The link step must include:
  • /def:name.def
  • /dll
  • a compiled resource file defining the file/MIME types accepted by the plugin.
• The user must install the resulting DLL in the Plugins directory of the browser.

Known Bugs

The Qt-based LiveConnect Plugin binding code has a number of minor bugs, but is sufficiently stable for most production applications.

• MSIE 4.0 support is poor.
• Crashes on X11 if window is closed via window manager.
• Keyboard problems on Windows.