Re: Using Browser as Front End

Dear Haitao,

On 12/14/2013 02:26 AM, Haitao Zhang wrote:
> I know using browser as a front end is not a new idea but I found out
> recently that WebSocket makes pushing data to browser very easy to do.
> 
> My personal interest is to use the javascript libraries supported by
> browsers (D3 in my case) for visualization, while retaining control in a
> Prolog console -- so I don't have to write a web server. This turns out
> fairly straightforward. I know that SWI does not yet support WebSocket,
> but one can write a simple man-in-the-middle server easily in anything
> that supports WS. My first try was with nodejs. Then I tried with
> Emacs/Elisp since I access SWI from Emacs with ediprolog. Both worked
> out well in my simple use case, where it is just one way traffic from
> Prolog to the browser. But as a proof of concept I see it as a good sign
> for more ambitious undertakings.

You'd almost think it is easier to add WS to SWI-Prolog :-)

> My setup is like this: start servers (WS and TCP) in the host platform.
> I use emacs but nodejs also works with little coding. Connect the
> browser to the WS server (through embedded javascript in a local html
> file). Connect Prolog to the TCP server. The host platform then simply
> copies any data coming in through the TCP socket over to the outgoing
> WebSocket. As I said I only implemented the half duplex part for my
> personal use, but servers should be neutral on the direction of flow. I
> would have to set up my Prolog client to handle async data and have not
> got around to it as I am happy with running things from my ediprolog
> console, which runs synchronously. Above the data layer I wrote some js
> client code to display data, and I then send over data from Prolog
> (encoded in json with embedded dispatching information) and have the
> data rendered in the browser. I also use the same websocket to update my
> js client code whenever I have a need to (like after creating a new
> display function). So the REPL is complete for both js and Prolog.
> 
> My primary intention is just to share the idea and hopefully someone
> will find it helpful.
> 
> On a more tentative note, Carlo Capelli  has recently ported the Prolog
> console to Qt. Is there an interest in creating a javascript based
> frontend for SWI? There are a lot of UI and graphics libraries available
> through js. With Websocket async two way communication is easy as well.
> 
> Just a thought,

Good to see other people also think this is the way to go.  There has
been some discussion on the list about this.  I suspect it will move
in that direction.  When and to what level is unclear.  A considerable
amount of resources is needed to get anywhere near the tools that
exist now.

	Cheers --- Jan