Re: Application roles

[Raffael Herzog]

On Sun, 15 Feb 2004 19:21:57 +0100, Stefan Urbanek <stefan@agentfarms.net> 
wrote:

> Today on #gnustep was a discussion about presenting applications to the 
> users in some nicer way. Besides idea of providing 'Display name' in 
> application information plists, I had an idea of 'Application Roles' 
> that I would like to share and hear your comments.
>
> What is an application role? Nothing more and nothing less than a short 
> (one-two words) description what application does: 'Mailer', 'Web 
> Browser', 'Text Editor'. Each developer should provide this role in a 
> .plist and Workplace.app (GWorkspace) should display all application in 
> one of the following ways:
>
> Mozilla.app, Firebird.app, Opera.app (as it does currently) - honestly, 
> would you know what those applications do? So what about using 'role' 
> definition when displaying application name:
> Web Browser - Mozilla
> Web Browser - Firebird
> ...
> Or for users with single variant just: 'Web Browser'

I see a problem with such roles: How do we standardise them? Currently, 
GNUstep has a simple but well working concept of file types. In 
Info-gnustep you can also list three roles: NSViewer or NSEditor. NSNone 
is used for non-file-based tools like e.g. an IRC client. I think this is 
basically enough, although there definitely are cases where it gets 
difficult. Let's take three examples and see whether we can solve it with 
what we already have:

1. Text Editor

The user might want to use his default text editor for something, e.g. in 
GNUMail, when composing a message, he might want to use some menu 
Edit->Open in Text Editor.

Now we know the GNUstep type of plain text which is ".txt" and we also 
know the preferred application to handle these files. So this scenario can 
be solved by saving a temporary txt file and ask the Workspace to open it 
with the default application. Scenario solved without extending GNUstep.

2. URLs

A difficult one. :) Let's assume the user clicks a URL in GNUMail to open 
it with whatever can handle that URL. for a http://... URL this would be 
the web browser, for a ftp:// URL, it would be GWNet.

GWorkspace 0.6.3 introduced a concept that can be used to solve this 
scenario: There are URL handlers, i.e. GWNet determines the application to 
be used to open a URL by it's protocol part. Two handlers are already 
provided: FTP and SMB. More possible handlers are HTTP and HTTPS.

Here we need to extend GNUstep by not only mapping file types to 
applications but also mapping protocols to applications. Basically the 
same thing as with file types, just for protocols. In Info-gnustep.plist:

GSProtocols = (
  {
    GSIdentifiers = ( http );
    GSName = "World Wide Web";
  },
  {
    GSIdentifiers = ( https );
    GSName = "World Wide Web (Encrypted)"
  });

Like this, protocols can be mapped to applications without any need for 
application roles. The Cocoa API already provides an interface for this: 
[[NSWorkspace sharedWorkspace] openURL: @"http://www.gnustep.org/";] -- it 
just needs to be implemented.

3. Mailing

Actually, I'd stick to services for this one. Standardisation is needed 
anyway, no matter whether application roles are introduced or we simply 
define some services a mail client should provide. Basically, IMO, 
services on a standardised basis are exactly the same as application roles 
as you described, just without adding anything to GNUstep. :)

cu,
   Raffi

--
The difference between theory and practice is that in theory, there is no 
difference, but in practice, there is.

Raffael Herzog - herzog@raffael.ch - www.raffael.ch - ICQ #67961355