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Robby, I'd like to know more about the real world need for such an API.
Sure, mechanical light switches DID work this way, but do home automation
systems really offer a "toggle"? I'm trying to imagine why I would ever
want to simply change the state of the lighting in my room, without caring
if the result was lights on or lights off. I can't.
So are you programming a home automation system? If so, do you really need
toggle, given my observation above?
Or is this just a hypothetical question about the generic behavior of
toggle and how it maps to REST? If so, then it kind of feels like the
perennial, "Can REST do THIS?" questions that skeptics of REST would lob
from time to time in the good old REST v WS-STAR WARS days. It kind of
reminds me of the old chestnut, "How can I do two-phase commit in REST?"
Or is your need for toggle behavior truly needed in some other actual
domain? If so, could you please tell us a bit more about the domain and
it's REAL need for toggle behavior. With such context in mind, we can
perhaps help you better map it into a RESTful API.
Thanks.
-- Nick
Nick Gall
Phone: +1.781.325.8370
Other Contact Info: http://bit.ly/nickgall
On Tue, Jul 8, 2014 at 5:28 PM, 'Simpson, Robby (GE Energy Management)'
[email protected] [rest-discuss] <[email protected]>
wrote:
> Hi,
>
>
> I've been scratching my head over this one for a while and am hoping I can
> get some help.
>
>
> Imagine a light switch with one simple resource: /state , where state can
> be "On" or "Off."
>
>
> One can PUT to /state , changing /state to either "On" or "Off."
> Similarly, a GET to /state will tell you if the light is currently "On" or
> "Off."
>
>
> Where I'm struggling is with a safe "Toggle" mechanism. That is, if
> /state is "On", change it to "Off" and vice versa.
>
>
> I understand that one solution would be to simply perform a GET on /state
> and then PUT the opposite. However, I am concerned with both the overhead
> and latency this entails as well as the potential for a race condition
> (what if /state changes between the GET and the PUT?).
>
>
> Any solution I've looked at thus far seems to violate RESTful principles,
> particularly regarding idempotency. In short, can one safely toggle?
>
>
> Any suggestions?
>
>
> Thanks,
> Robby
>
>
>
>
> ------------------------------------
> Posted by: "Simpson, Robby (GE Energy Management)" <[email protected]>
> ------------------------------------
>
>
> ------------------------------------
>
> Yahoo Groups Links
>
>
>
>
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<p><div dir=3D"ltr">Robby, I'd like to know more about the real w=
orld need for such an API. Sure, mechanical light switches DID work this wa=
y, but do home automation systems really offer a "toggle"? I'=
m trying to imagine why I would ever want to simply change the state of the=
lighting in my room, without caring if the result was lights on or lights =
off. I can't.<div>
<br></div><div>So are you programming a home automation system? If so, do y=
ou really need toggle, given my observation above?</div><div><br></div><div=
>Or is this just a hypothetical question about the generic behavior of togg=
le and how it maps to REST? If so, then it kind of feels like the perennial=
, "Can REST do THIS?" questions that skeptics of REST would lob f=
rom time to time in the good old REST v WS-STAR WARS days. It kind of remin=
ds me of the old chestnut, "How can I do two-phase commit in REST?&quo=
t;</div>
<div><br></div><div>Or is your need for toggle behavior truly needed in som=
e other actual domain? If so, could you please tell us a bit more about the=
domain and it's REAL need for toggle behavior. With such context in mi=
nd, we can perhaps help you better map it into a RESTful API.</div>
<div><br></div><div>Thanks.</div><div><br></div><div>-- Nick</div></div><di=
v class=3D"gmail_extra"><br clear=3D"all"><div><div dir=3D"ltr">Nick Gall<b=
r>Phone: +1.781.325.8370<br>Other Contact Info: <a href=3D"http://bit.l=
y/nickgall" target=3D"_blank">http://bit.ly/nickgall</a></div>
</div>
<br><br><div class=3D"gmail_quote">On Tue, Jul 8, 2014 at 5:28 PM, 'Sim=
pson, Robby (GE Energy Management)' <a href=3D"mailto:robby.simpson@ge.=
com">[email protected]</a> [rest-discuss] <span dir=3D"ltr"><<a href=
=3D"mailto:[email protected]" target=3D"_blank">rest-dis=
[email protected]</a>></span> wrote:<br>
<blockquote class=3D"gmail_quote" style=3D"border-left:1px #ccc solid;">Hi,=
<br>
<br>
<br>
I've been scratching my head over this one for a while and am hoping I =
can<br>
get some help.<br>
<br>
<br>
Imagine a light switch with one simple resource: /state , where state can<b=
r>
be "On" or "Off."<br>
<br>
<br>
One can PUT to /state , changing /state to either "On" or "O=
ff."<br>
Similarly, a GET to /state will tell you if the light is currently "On=
" or<br>
"Off."<br>
<br>
<br>
Where I'm struggling is with a safe "Toggle" mechanism. =C2=
=A0That is, if<br>
/state is "On", change it to "Off" and vice versa.<br>
<br>
<br>
I understand that one solution would be to simply perform a GET on /state<b=
r>
and then PUT the opposite. =C2=A0However, I am concerned with both the over=
head<br>
and latency this entails as well as the potential for a race condition<br>
(what if /state changes between the GET and the PUT?).<br>
<br>
<br>
Any solution I've looked at thus far seems to violate RESTful principle=
s,<br>
particularly regarding idempotency. =C2=A0In short, can one safely toggle?<=
br>
<br>
<br>
Any suggestions?<br>
<br>
<br>
Thanks,<br>
Robby<br>
<br>
<br>
<br>
<br>
------------------------------------<br>
Posted by: "Simpson, Robby (GE Energy Management)" <<a href=3D=
"mailto:[email protected]">[email protected]</a>><br>
------------------------------------<br>
<br>
<br>
------------------------------------<br>
<br>
Yahoo Groups Links<br>
<br>
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