"Bruno Desthuilliers" <[EMAIL PROTECTED]> wrote:
|H J van Rooyen a écrit : |> Hi, |> |> I want to write a small system that is transaction based. |> |> I want to split the GUI front end data entry away from the file handling and |> record keeping. |> |> Now it seems almost trivially easy using the sockets module to communicate |> between machines on the same LAN, so that I want to do the record keeping on one |> machine. |> |> I want to keep the "server" machine as simple as possible - just doing record |> keeping on a stimulus response basis - I would prefer it to do one thing at a |> time to completion because this style of operation, though limited in |> performance, keeps a lot of hassles out of life - a transaction has either |> completed, or it has not - recovery scenarios are relatively easy... | |IOW, you want a SQL DBMS. May I recommand PostgreSQL ? | Looks like the way to go - after the argy bargy here in another thread seems mySQL has no supporters left... |> Up to this point, I don't have a problem - my toy system can create a dummy |> transaction, and I can echo it from the "server" machine, with more than one |> "user" machine running - so I think it is feasible to have several tens of "data |> entry terminal" systems running, served by one not very strong machine. |> |> Now what I would really like to do is to differentiate between the 'User" |> machines, so that some can do a full range of transactions, and others a limited |> range. | |Any decent SQL DBMS is able to handle this. It's kind of builtin... Yes - if you do the whole job on the server - the architecture I have mind is more like a banking terminal scenario - please see my reply to Simon | |> And I would like to make this flexible, so that it becomes easy to introduce new |> transactions, without having to run around updating the code in all the user |> machines, with the concomitant version number hassles. | |Then you want a web front end. This seems to me to assume that the server does all the work | |> And I would like to do the whole thing in python | |You'll at least need bits of SQL (but SQLAlchemy may hide away most of |it) and HTML (but there are some python packages that knows how to build |HTML from declarative Python code). | that is good news - which packages? |> - so my question is this - is |> it possible to do the equivalent of dynamic linking? - i.e. if I keep a list of |> what a user is allowed to do | |In SQL : GRANT/REVOKE again - centric thinking - I really would like to change the bits on the client, as I explained to Simon | |> - can I somehow send him just the bits he needs to |> do the job, without having to change the static code on his machine? | |HTTP/HTML. | everybody says this - I am being dragged, kicking and screaming... |> - it seems |> to me that the eval() thingy could possibly do this for me, | |Err... I thought you wanted a reasonnably secure system, but I may have |misunderstood. | this is the guts of what I want - if eval is NFG then how do I implement such a kind of "dynamic linking" of modules on the client? |> by sending it data |> that makes it do import statements followed by calls to whatever... - will this |> work, or is there a better way? |> |> Or has all this been done already? | |Yes, it's called a web frontend for a SQL DBMS. There's no shortage of |Python frameworks to do this kind of things. | I kind of wanted to avoid the web based stuff - the application data is so small and trivial, in a sense. |> - and no I don't want a web server | |If you don't want Apache, there are Python-based application servers. |CherryPy comes to mind. | |> and php | |Why PHP ? | seems popular |> and browsers and Java | |Why Java ? | it addresses what I want - to dynamically and securely download bits of code and execute them on the remote machine... |> and html or xml... - I want to write something that works |> simply and reliably | |We do write SQL-based web apps all day long, and I can tell you they are |certainly more simple and reliable than whatever eval()-based home-made |solution we could imagine !-) Aah! but I would like you to stretch that imagination - to tell me how to do some of what Java was designed to do, but better and easier, because this is python we are talking about... I saw something in another thread here - they were talking about weave - can I use that if eval is nfg? If my original post was unclear I am sorry - the point I want answered, if possible, is how to make the client code effectively updateable on the fly - because the answer to this will influence the whole design of the rest of the system... - Hendrik -- http://mail.python.org/mailman/listinfo/python-list
