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it sounds like you want to implement "toggle" and i doubt "toggle" would
ever be idempotent since idempotent requests will contain the state that
you want to write ("on" or "off").
FWIW, you could use a non-idempotent write (HTTP.POST) to implement
"toggle" -- that would be consistent at the *network level* -- but i'm not
sure if that's what you need.
mamund
+1.859.757.1449
skype: mca.amundsen
http://amundsen.com/blog/
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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">it sounds like you want to implement "toggle=
" and i doubt "toggle" would ever be idempotent since idempo=
tent requests will contain the state that you want to write ("on"=
or "off").<div>
<br></div><div>FWIW, you could use a non-idempotent write (HTTP.POST) to im=
plement "toggle" -- that would be consistent at the *network leve=
l* -- but i'm not sure if that's what you need.</div><div><br>
</div>
<div><br></div></div><div class=3D"gmail_extra"><br clear=3D"all"><div><div=
dir=3D"ltr"><div><br></div>mamund<div><span><span title=3D"Call with Googl=
e Voice"><span title=3D"Call with Google Voice">+1.859.757.1449</span><=
/span></span><br>
skype: mca.amundsen<br><a href=3D"http://amundsen.com/blog/" target=3D"_bla=
nk">http://amundsen.com/blog/</a><br><a href=3D"http://twitter.com/mamund" =
target=3D"_blank">http://twitter.com/mamund</a><br><a href=3D"https://githu=
b.com/mamund" target=3D"_blank">https://github.com/mamund</a><br>
<a href=3D"http://linkedin.com/in/mamund" target=3D"_blank">http://linkedin=
.com/in/mamund</a></div></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>
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