That sounds reasonable.
But, for your facebook example, there is another problem. If we
don't want to get these 4000 thousand friends,
we have 2 choices：
1. don't use relationship of SA to use the default encode mechanism of
turbojson
2. write a customized "__json__"
I think, the 1st choice is not acceptable in most cases, but the 2nd
one is also annoying when we have more than 40 tables.
So, how about this :
Find a way to mark fields of an object that should be skimmed when
encode it to JSON.
On 7月24日, 下午5时34分, "Diez B. Roggisch" <[email protected]> wrote:
> 一首诗 schrieb:
>
>
>
>
>
> > I'm very glad to know that turbojson could automatic convert
> > SQLAlchemy object to JSON. But unfortunately, it can not handle SA
> > object circuit.
>
> > For example, there are 2 of SA mapped class, User and Role. User has
> > more than 1 role and a role could be given to many user. This is a
> > very common M:N relationship in relational database.
>
> > But turbojson can not convert an instance of User to JSON
> > automatically, because there is a reference loop. What now we can do
> > is add a "__json__" method to manually convert an object json, which
> > is very tedious.
>
> > So my suggestion is : why not just skipped there objects referenced
> > more than one time? This will be a behavior easily undertood and will
> > save a lot of time writing "__json__".
>
> There are two big problems with this:
>
> - JSON has no concept of refernces, it's a purely algrebraic
> structure. As a consequence, you can't serialize graph-structures with
> it. So you need to come up with a special key/value pair that denotes a
> reference. This is purely to your own design.
>
> - if that behavior would be default, it would mean that e.g. returning
> a user in facebook would return all his 4000 friends. Which is a rather
> dumb thing to do if all you want is a user's primary attributes, don't
> you agree?
>
> So I'm afraid this can't be implemented the way you wish. I'm not sure
> how this is dealt with in TG2, but in TG1 it was very easy to declare a
> special rendering for specific objects, based on rules dispatch. You
> should try & do that.
>
> Diez
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