Notes for developers

These notes are collected by Heikki, mostly from skype chats with Wolfram
and Mike. I collected them for my own use, but I hope they will turn out
to be helpful to anyone who needs to get started with mkws.


Libraries
---------

* We are using jquery as a browser indepent layer to access the dom, so we
don't have to worry about IE bugs.  Wolfram looked why we are using
jquery.json-2.4.js ... it turns out we needed it because the standard functions
in IE8 are broken.

* jasmine is a test framework (mkws dev). you will not use jasmine in a
production site.  the nice thing with the jasmine test framework is that it
will work with any browser. I can start a virtual machine with IE8, open the
test page, wait 3 seconds for success and shutdown windows.

* handlebar is a template engine



Include files
-------------

The whitepaper says to include mkws-complete.js. This file is made by concatenating
a number of files (see Makefile). For us developers, it is easier to include the
raw files, as in

    <script type="text/javascript" src="tools/htdocs/jquery-1.10.0.min.js"></script>
    <script type="text/javascript" src="tools/htdocs/pz2.js"></script>
    <script type="text/javascript" src="tools/htdocs/handlebars-v1.1.2.js"></script>
    <script type="text/javascript" src="tools/htdocs/jquery.json-2.4.js"></script>
    <script type="text/javascript" src="tools/htdocs/mkws.js"></script>

You can also include the css directly in your test page:
    <style type="text/css">
      #mkwsTermlists div.facet {
      float:left;
      width: 30%;
      margin: 0.3em;
      }
      #mkwsStat {
      text-align: right;
      }
    </style>


Most (all?) code work happens in mkws.js.


Unit tests
----------

if you want understand the test than you can look at mkws/test/spec/mkws-config.js
and mkws/test/spec/mkws-pazpar2.js . See also mkws/test/README.txt


Structure of mkws.js
--------------------
(This will soon be out of date, but should provide some kind of starting
point even then)

First page is just helper functions for the Handlebars template library, which we
use to generate some of the HTML output. (Down the line, we will use this more
heavilty -- right now it's only used for records).

Then we define the mkws object, which contains all global state -- which hopefully
there is not much of. It is one of only two objects we place in the global namespace:
the other is mkws_config, which is a hash supplied by the application if it wants
to override default configs.

Next is a very short function defined to allow us to publish and subscribe events.
That is not yet used: shifting much of the code to do so is a big part of what I
am working on right now.

Next, a very short stanza of code that just makes sure mkws_config is defined:
simple applications won't bother to define it at all since they override node
of the defaults.

Next, a factory method for making widget objects. At present this is trivial
because we are only now starting to need a representation of individual widgets
as JS objects. More of the functionality will get moved into these objects over
the next week.

Next, a factory method for making widget-team objects. This is where all the
awesomeness is at the moment. A team is a bunch of widgets that work together
to achieve a common goal, e.g. the search-box, search-button and results-pane
widgets.

HTML elements are defined as belonging to the same team if they have an
mkwsTeam_NAME class for the same NAME. You can have multiple teams (as in
two-teams.html that I linked to earlier) which are completely independent of
each other.

I guess you're familiar with the JS idiom where the factory function for a kind
of object also acts as a namespace where all the object's member-variables live,
invisible to the outside world? That's what we do here. All the member variables
have names of the form m_NAME.

Now I sugges you skip over all the team-object code for now -- we'll return to it
later. For now, page down to "// wrapper to call team() after page load" which is
the next thing after the end of that function (or class, if you like).

You're familiar with this JS idiom?
  (function() { code ... })();
 Runs the code immediately, but within its own namespace. That's what we do for
all the remaining code in mkws.js. In this case, we pass the jQuery object into
that namespace under the name `j' for reasons that are frankly opaque to me.

There's still a few places in the code where oddities live on, either from jsdemo
or from work Wolfram's done, where I don't really understand why it's that way
but I'm scared to change it. In this case, IIRC, it's something to do with
protecting our copy of the jQuery object, or something.

Aaanyway, within that namespaced area, where's what we do.

First, we set up the mkws.debug() function, which just logs to the console in a
form that doesn't explode IE. I have plans for this function, make it understand
debugging levels a bit like log4j or maybe more like yaz-log where there are
named logging types that are not in a sequence.

(You will notice that the teams have a debug() function which delegates to this
but adds some other useful team-specific stuff.)

 Next up: the utility function mkws.handle_node_with_team(). We use a LOT of nodes
that have their team-name in a class (as in "mkwsTeam_NAME" outlined above).
All the utility does is parse out that team-name, and the widget-type, from the
classes, and pass them through to the callback.

mkws.resize_page() does what it says. Gets called when window-size changes, and
allows us to move the facers to the side or the bottom as the screen is wide or
narrow (e.g. when you turn your iPad 90 degrees)

(Aside: I thought we'd have to iterate over all teams to move their facet lists
but it turns out we don't: jQuery just Does The Right Thing if you call
   $(".mkwsTermlistContainer1").hide();
or similar and there are multiple hits.)

Next come a bunch of JS functions that are invoked from the MKWS UIs --
swithching between target and record views, stepping through pages of results,
etc. All of these are team-specific, but the global code in the HTML can't
invoke a team's member function directly. So these stub functions just invoke
the relevant member of the appropriate team.

default_mkws_config() fills in the mkws_config structure from hardwired defaults.
This is the wrong way round: instead, whenever we want to find a config value, we
should default our way up a tree, starting with the individual widget's config,
falling back to the team's config if the widget doesn't define that value, then
the global config, and finally the default. I'll make that change once widget
objects are fully real.

authenticate_session() authenticates onto the SP when we're using it (rather
than raw pp2). It's a bit sellotape-and-string, to be honest, just does a wget.
It would be better if this was supported by pz2.js

run_auto_searches() is what makes pages like
  http://example.indexdata.com/auto3.html
work. THere are two places it's invoked from. Either directly when all the HTML
has been set up if we're using raw pp2; or when SP authentication has been
completed if we're using that. As with the UI functions, it just delegates down
into the teams.

Finally, code that runs when the page has finished loading -- this is really
the main() function

The first thing it does is patch up the HTML so that old-style MKWS apps work
using new-style elements. This is the code you just fixed.

Straight after that, more fixup: elements that have an mkws* class but no
team are given an extra class kwsTeam_AUTO. This is the ONLY thing that's special
about the team "AUTO" -- it has no other privileges.

 Very near the end now: we walk through all nodes with an mkws* class, and create
the team and widget objects using the factories we described earlier. Jason is
worried this will be slow, hence the instrumentation. It's not :-)

Last of all: start things off! SP-auth if used, otherwise straight to the
auto-searches.