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vegetax
vegeta.z at gmail.com
Sun Mar 20 20:02:10 EST 2005
Graham Dumpleton wrote: > vegetax wrote .. >> Graham Dumpleton wrote: >> >> >> - Where do i set a database connection pool to load at server >> >> initialization ,so that all request can access it? is the pythonImport >> >> directive the best place? where do i set a clean up function for the >> >> pool >> >> at server finalization ? >> > >> > Cleanup function registration for stuff that should be done at time of >> > child >> > termination can only be done with req.server.register_cleanup(). There >> > probably should be an apache.register_cleanup() method which would be >> > available from a module imported using PythonImport. This would then >> be >> > the >> > best way of doing it. >> > >> > It seems that the best one could do now is import the module when >> > required >> > but don't do anything at the time of import which would require a >> > cleanup >> > function to be registered. Then, when the first handler calls in to the >> > actual module, require that the "req" object be passed into the pool, >> > with >> > those resources which need to be cleaned up later being created then >> > with a >> > cleanup function being registered through >> > req.server.register_cleanup(). >> > >> > I have added a bug report suggesting that apache.register_cleanup() be >> > added to allow it to be used from module imported using PythonImport. >> >> But is to problematic to clean resources at request level, i think in the >> midtime i will be cleaning up resources like connections with an external >> script which i run after apache exits. > > I perhaps didn't explain it properly or I don't understand what you are > saying. > >>From a request object there are two ways of registering a cleanup > function. The first is: > > req.register_cleanup() > > The register function in this case will be called when the handler for > that specific request is finished. > > The other which I referenced was: > > req.server.register_cleanup() > > This registers a function which will only be called when the Apache > process itself terminates. Ie., when one does apachectl stop or > restart. > > Thus, wasn't talking about cleaning up resources at request level. > The unfortunate bit was that since apache.register_cleanup() doesn't > exist, one has to defer registration of cleanup function for process > termination until one has access to req.server, which is at point of > first request that needs pool. > >> > FWIW, in Vampire, when Vampire's module importing mechanism is used a >> > stripped down request object is available in the set of global >> > variables during import as __req__. Thus in Vampire one could actually >> > register a cleanup function during import by using: >> > >> > __req__.server.register_cleanup(....) >> > >> > This would save each handler having to pass the req object into a pool >> > and >> > means one wouldn't have to delay creation of resources which needed the >> > cleanup function to be registered. >> >> Looks like a good solution when the clean up is needed per request,and >> is >> also posible that the pool component was made by someone else,and cant >> take >> req as parameter. > > Again, not talking per request here as am registering cleanup handler > via the server object and not the actual request object. Sorry about the missunderstanding,i see the irony of the req.server.register_cleanup, maybe adding a PythonCleanUp directive ? >> > BTW, have you considered other page templating solutions besides PSP? >> > In terms >> > of best separation between model, view and controller, or at least >> > between the >> > HTML that represents a page and the code that populates it, I would >> > recommend >> > using HTMLTemplate. >> > >> > http://freespace.virgin.net/hamish.sanderson/htmltemplate.html >> > >> > Why I prefer it over PSP is that in PSP you are effectively still >> > embedding >> > Python code in the template itself and to render the template you are >> > actually >> > executing it, with there being call outs from the template to collect >> > data. >> > In HTMLTemplate, the template object is distinct, with your controller >> > code >> > making calls into the template object when desired to set fields within >> > it. >> > Ie., DOM like but not having the overhead of a DOM because only >> > fillable parts >> > of the template are indexed. >> > >> > What this means is that with HTMLTemplate you aren't forced to prepare >> > all your >> > data up front before filling in the template, instead you can fill it >> > in bit >> > by bit. >> > >> > I can supply references to example of using HTMLTemplate from Vampire >> > later if >> > you are interested. >> > Graham >> >> Thanks for the advice graham,but i dont share the philosophy kind of >> those templates engines, first and last it uses its own tag language, i >> HATE that. > > Huh. PSP also defines its own language within HTML so I don't really > see the difference. I personally find the PSP syntax more confusing, > more complicated and more error prone especially if embedding actual > Python code. Please don't confuse HTMLTemplate with systems like > TAL and Metal. It is different and much simpler, with the manner in > which pages are constructed and then rendered being different as well. > >> I like psp because it lets you embed python code, so that i can >> generate complex dynamic views,but the code inside the psp is only for >> content displaying, 100% of the form processing is done by the controler >> calling domain object's methods! in extremely exceptional situations the >> psp code will have a litle processing or data gathering, but those are >> only >> exceptions, the key here is that the team respect the rules. >> >> I work with web designers,you simply cant let them touch the dynamic >> parts,those parts tend to be complex,they should work in the static parts >> and coordinate with the programmer in charge of the dynamic view >> generation,and then plug dynamic and static parts together, in order to >> coordinate they MUST have some programming knowledge ,anyway i use >> javascript a lot and i dont take a person who doesnt know javascript as >> a >> web designer.Thats my point of view. > > When using HTMLTemplate the web designers don't need to touch > any Python code at all and thus don't go anywhere near the controller > aspects of the application. Because HTMLTemplate is standard XHTML > the web designer can even use high level web design tools. All they > need to do is add the appropriate namespace designated attributes > in the XHTML as per Python coders directions as to what data will be > filled in. The web designer can even put in dummy data in the template > as place holders so the pages look correct for some set of data when > they are designing it, with the dummy content being replaced by the > controller code when it runs. > Anyway, there is probably no point continuing this particular discussion. I also agree with you =) in that ,is just that we have different methodologies and/or requirements,which need different tools to work well.
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