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Maybe I am missing something, but why not just be more semantically
explici=
t and if the state of the resources is "on", return a "off" link
relation w=
ith a POST method and if the state is "off" return an "on" link
relation wi=
th a POST method. You have a semantic understanding of what is
going on and=
could implement a toggle button in a UI that represented the
state, etc. D=
id I miss something in the definition of the problem?
On Tue, Jul 8, 2014=
at 2:28 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: /stat=
e , where state can
> be "On" or "Off."
>
> One can PUT to /state , changin=
g /state to either "On" or "Off."
> Similarly, a GET to /state will tell yo=
u if the light is currently "On" or
> "Off."
>
> Where I'm struggling is wi=
th a safe "Toggle" mechanism. That is, if
> /state is "On", change it to "O=
ff" and vice versa.
>
> I understand that one solution would be to simply p=
erform 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 princ=
iples,
> particularly regarding idempotency. In short, can one safely toggl=
e?
>
> Any suggestions?
>
> Thanks,
> Robby
>
>
>
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<p><div dir=3D"ltr">Maybe I am missing something, but why not just be=
more semantically explicit and if the state of the resources is "on&q=
uot;, return a "off" link relation with a POST method and if the =
state is "off" return an "on" link relation with a POST=
method. You have a semantic understanding of what is going on and could im=
plement a toggle button in a UI that represented the state, etc. Did I miss=
something in the definition of the problem?<br>
</div><div class=3D"gmail_extra"><br><br><div class=3D"gmail_quote">On Tue,=
Jul 8, 2014 at 2:28 PM, 'Simpson, Robby (GE Energy Management)' <a=
href=3D"mailto:[email protected]">[email protected]</a> [rest-discus=
s] <span dir=3D"ltr"><<a href=3D"mailto:rest-discuss-noreply@yahoogroups=
.com" target=3D"_blank">[email protected]</a>></span>=
wrote:<br>
<blockquote class=3D"gmail_quote" style=3D"border-left:1px #ccc solid;">
<u></u>
=20
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<span>=C2=A0</span>
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<div>
<div>
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=20=20=20=20=20=20
<p>Hi,<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>
Imagine a light switch with one simple resource: /state , where state can<b=
r>
be "On" or "Off."<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>
Where I'm struggling is with a safe "Toggle" mechanism. That=
is, if<br>
/state is "On", change it to "Off" and vice versa.<br>
<br>
I understand that one solution would be to simply perform a GET on /state<b=
r>
and then PUT the opposite. However, I am concerned with both the overhead<=
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>
Any solution I've looked at thus far seems to violate RESTful principle=
s,<br>
particularly regarding idempotency. In short, can one safely toggle?<br>
<br>
Any suggestions?<br>
<br>
Thanks,<br>
Robby<br>
<br>
</p>
</div>
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