That's genius :) It's like a huge cake of abstraction! I love it - this way
front-end developers can concentrate on what's important to them! This
modular approach also means the team can be so much more efficient!
Great work everyone who worked on this, it's looking good for the future!
Tom
2008/6/12 Youness Alaoui <[EMAIL PROTECTED]>:
> Hi All,
>
> This email is to explain a bit the design and structure of aMSN2.. so it's
> leaning more towards developers than towards users...
> As I explained in my previous mail, the design is simle :
> 1 - three layers : protocol, core, gui
> 2 - the protocol is taken care of by pymsn
> 3 - the gui is abstracted and any front end can be used (multi-front end
> client)
> 4 - the programming language is python...
>
> So for the technical details, first, download the source code. I've now
> imported it into our public SVN, and you can get it from the SVN URL :
> https://amsn.svn.sourceforge.net/svnroot/amsn/trunk/amsn2
> You will see the three layers in the amsn2 subdir, we have :
> gui/
> core/
> protocol/
>
> The idea is that the protocol layer will be the glue between pymsn and the
> core, it will receive events from the core and notify pymsn, and it will
> receive events from pymsn and notify the core.
> This allows for one thing : modularity! I do not want to have code mixed
> everywhere again like we had with aMSN 0.x... This would also 'in theory'
> allow for switching to a different protocol or to a different library, BUT
> we do NOT want to do this. It was decided that aMSN is an MSN clone and if
> you want a multi protocol client, there are many good ones out there.. we
> want to concentrate on the MSN protocol so users can have a fully featured
> client, we want all our efforts to go into MSN compatibility. End of the
> discussion!
>
> The GUI layer takes care of all our GUI needs, we have a 'manager' that
> basically stores which front ends we have installed and allows us to access
> their classes... a front end can register itself from anywhere by calling
> the guiManager.registerFrontEnd, and giving it its module
> (sys.modules[__name__] ).
> Alen has maybe a different idea about this and we'll see what he comes up
> with, so this design can change a little...
> NOTE that everything so far is in proof of concept mode and anything can
> change at any time!
> The way I see the front ends is a bit like a set of mega widgets... or an
> 'abstracted toolkit API' but higher level...
> I will talk again about front ends once I explain the core a bit...
>
> The core.. the most important thing out there.. that's the heart of aMSN2,
> we want every front end to act the same, to have the same features, and this
> will be accomplished thanks to the core! The core is the glue between the
> protocol and the UI, it will take care of profiles, configuration, options,
> non-protocol/ui features, etc...
> The most important part of the Core in terms of the other layers is the
> 'views' concept. This design will allow us to have a really nice client,
> easy to build new front ends, and a consistent feature set amongst all the
> front ends...
> What is a View? Well it's simple, it's how we want the user to 'view' our
> UI. For example, the GUI doesn't need to know if a contact is online, away
> or busy.. the UI doesn't need to know a contact's nickname or psm, or a
> group's "count/total".... the UI only needs to know *what* to show the
> user... If we tell the UI to show a specific icon (depending on the state)
> for a contact, as well as what 'name' to give the contact (including the
> PSM.. or not, depending on the user's options)... and if we tell the UI that
> the group's name is "X (count/total)".. that's all it really needs to
> know...right ?
> well, that's what the views are all about, they tell the UI how to display
> an object...
>
> So there's this magical thing that I called 'StringView'... it's a 'view'
> on a 'string'... basically, it's a list of elements specifying how the
> string should be displayed... A StringView can be something like this :
> list : color red text "my nickname" image <img> text "<-- that was a
> smiley" color grey text "(away)" color red text "\n" italic true text
> "psm" italic false
> (the stringview can also contains tags...)
>
> With a StringView we can represent anything we want.. the nickname of a
> user, including smileys, including status, including the psm, etc..
> The reason why we do it like this is because :
> 1 - we don't want every front end to have code for parsing the smileys
> (what about custom smileys)
> 2 - we don't want every front to need to access the user's preferences like
> "show psm beside the nickname"/"show psm under nickname"/"don't show the
> psm"
> 3 - the UI doesn't need to know the status/whatever of a user, it just
> needs to know *how* to display it.. because that's what the user will see in
> the end...
>
>
> So.. now that you know about the StingView, let's talk about ContactView..
> as you can see every ContactView has a unique identifier representing the
> contact.. an 'icon', which will be an Image that gets built by the core
> (using the front end Image class API).. it can be a buddy icon depending on
> the status or the display picture (depends on the user's options), it can
> also contain 'emblems' like 'blocked', or 'away' emblem on top of the
> display picture, or a 'alarm' emblem if the user has one...
> We do not want the front end to need to look through the options, or to
> query the core for whether a contact has an alarm or not, or query
> the protocol to see if the contact is blocked or not....
> The ContactView also has a 'name'.. that's a StringView to represent the
> contact.. it will contain the nickname (or custom nickname), parsed smileys,
> the psm (depends on option)... the color of the nickname will depend on the
> status of the contact, or depends if the user sets a 'custom color' on the
> user.. etc... You now understand that we don't want every UI to start
> checking if the user has set a custom nickname for the user, or if there's a
> global custom nickname (or psm), or if he has a custom color for the user,
> etc...
> The ContactView also contains a 'dp' attribute which is an Image with the
> display picture of the user... the reason why this is different from the
> 'icon' attribute is because we might want to show them both.. for example :
> [icon] nickname [ display ]
> psm [ picture ]
>
> Like pidgin does for example... whether that attribute contains the DP or
> nothing will depend on the user's options again...
> Finally, we have a 'menu' which is the contextual menu when you right click
> on the user (it's a MenuView item describing what the menu contains) and a
> 'tooltip' which is a TooltipView on what to show in the tooltip...
>
> Now, I'll expain what the GroupView class is... it's a view on a group..
> hehe.. it's the same thing again, the unique id, the icon (will change from
> collapsed to expanded icon), the name (StringView containing the name of
> the group + the count/total), menu and tooltip.. but we have one more item :
> 'contacts'.. it's an ordered list of the contacts contained inside
> that group...
>
> The other view classes are pretty much self explanatory...
> Now, we move the front end.. the front end is given to the core as a module
> object, the module contains all the classes we want/need and the core
> creates them as he needs...
> Any front end should implement the amsn2.gui.base.* classes, we have a few
> classes in there, it's not that complicated :
> mainloop : this is just an abstraction over the main loop.... pymsn needs
> the glib mainloop (hopefully removed soon), but you might want to run the
> qt/gtk/efl main loop, depending on what toolkit you use.. you implement this
> here...
> main : the main window, this window will contain the login screen or
> contact list... the login window and contact list windows will need to use
> this window to show themselves inside of it.. why.. because we don't want to
> have a window appear/disappear when you start logging in...
> image : simple class to abstract an image.. use whatever library you want
> to represent an image.. (QImage? gdkpixbug... etc...)
> login : this is the login window... the base classe has documentation on
> each function.. it should be straight forward... this implementation is not
> yet finished, as we need a way to feed the login window the list of profiles
> as well as the list of "sign in as " statuses for each profile (if a profile
> has a saved custom state)....
> contact_list : this is the interesting one... the base classes functions
> are documented so it should be simple but I still want to explain this a bit
> :
> When you look at the api, you will notice something, there are only 4
> functions :
> contactUpdated, groupAdded, groupRemoved, groupUpdated...
> You might be asking "humm.. why isn't there a contactAdded, contactRemoved,
> etc...", well, it's simple... here's how it would work, on initial connect,
> you get a bunch of calls to groupAdded with the groups of your contact list,
> in each of those groups, you have the contacts (remember,
> GroupView.contacts), so the front end gets this, and displays the group with
> its contacts...
> in every possible scenario of the contact list getting modified, the 4
> functions are enough to make the UI sync with the protocol...
> nickname changed : groupUpdated + contactUpdated ( the groupUpdated is
> called if the sorting is done by nickname, so the front end gets the new
> ordered list of contacts and it reorders the contacts in the UI)
> psm changed : contactUpdated
> status changed : groupUpdated + contactUpdated (the groupUpdated because
> the sorting can be done on status, or if the user goes offline (if we group
> offline contacts together, then we get groupUpdated for both groups) the
> 'name' (count/total) of the group might also change, and contactUpdated
> because the '(status)' or color might change)
> new user : groupUpdated (the list of contacts has one more, the UI adds it
> when it synchronizes the UI list with the groupview.contacts list)
> deleted user : groupUpdated (same as above)
> contact blocked, unblocked, etc... whatever : contactUpdated
> sorting changed (ascending/descending/alphabetically, etc..) : groupUpdated
>
> etc...
> What this means is that the sorting is of course left to the Core.. the
> core decides on how to sort the contacts, etc.. it's not the UI's job.. but
> it also means that the UI must keep on each group widget, the ordered list
> of contacts that are shown with their unique id, so it can resynchronize
> itself when it gets a groupUpdated... of course, you can just delete all
> contacts from the UI and rebuild them.. but try to be optimal in terms of
> performance please... thanks...
> This also means that.. I know, you won't like it.. but! it is necessary...
> when a user clicks on a group, you must NOT collapse/expand it.. you must
> tell the core about that event and let the core decide... sending you a
> groupUpdated() with an empty list of contacts in the GroupView...
> The reason is simple :
> 1 - the GroupView gives you the 'icon' for the group.. and that's what's
> deciding if the icon is expanded/collapsed...
> 2 - imagine an option 'never collapse groups'... we don't want a UI that
> ignores that option...
> 3 - imagine the option on a contact "always show this contact"... so we
> would want a 'collapsed' group.. but still showing a contact...
> 4 - what about 'collapse/expand' on double-click only...
>
> to be able to do all that, we need the UI to work this way! I know that for
> some toolkits it will be easy/intuitive but for others (like gtk with its
> treeview) it will actually involve more work... sorry about that!
>
> Also please note that *for now*, we don't have all that working... humm..
> yeah.. there's not much done with the icons.. the protocol doesn't do much..
> there is no "group_clicked" or anything like that yet.. so be patient and
> we'll try to make the core evolve as fast as possible...
>
> any comments are appreciated!
>
> Thanks for reading!
> KaKaRoTo
>
>
>
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