[Seaside] Seaside Coding Pattern

Sebastian Sastre sebastian at flowingconcept.com
Fri Feb 20 16:29:00 UTC 2015

This is a great question.

And the answer I have depends a bit on what you want to optimize.

Let’s assume you want to optimize load and scale the app (I’ve answered about Seaside and scale here <http://stackoverflow.com/questions/1451989/does-seaside-scale/4717214#4717214>[1]).

Regardless of the “vendor’s" VM, when is about load, you need to think way beyond the load capacity of one image (horizontal scaling). And that influences your app design a bit. 

RESTful architectures tend to profit from this.

There is a benefit on load and parallelisation in doing things more state-less and perhaps preserving state only in some backend like a database or some cache system like Redis or memcached. It even makes you more fault tolerant since you might have not 1 database server or 1 cache server but clusters of them.

I always remember Werner Vogels saying that they learnt this lesson the hard way and that you should design things in a way that when it crashes, a quick respawn would make issues to not-disrupt the user. If you kept state in your image and it crashes (and it will) then, if that state was only in the image then is gone and your user will be disrupted. That’s why I keep as less state as I could (mostly UI/session related).

[1] http://stackoverflow.com/questions/1451989/does-seaside-scale/4717214#4717214 <http://stackoverflow.com/questions/1451989/does-seaside-scale/4717214#4717214>

> On Feb 20, 2015, at 4:20 AM, Craig <craig at hivemind.net> wrote:
> Hi All,
> A pretty-much universal pattern of coding of Web Apps in non-image based
> languages (C#, PHP, Java) is:
> 	* The incoming web request starts a process 
> 	* some objects are instantiated, usually from a SQL datastore,
> 	* some interactions occur with these objects
> 	* optionally, some database modifications are made
> 	* a response is sent to the web browser
> 	* all the temporary variables that point to the objects go
> out-of-scope
> 	* all the objects are garbage collected
> I caught myself coding a Seaside app using the same pattern and wondered if
> it's sub-optimal in an image based language.
> So, is this an acceptable way to code a Seaside app?  Should I rather be
> using long-lived image based objects? Stored in a collection hung off a
> class variable. 
> Comments would be appreciated.
> Craig
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