Re: RESTful Toggle

"Jonathan Ballard [email protected] [rest-discuss]" <[email protected]> Wed, 9 Jul 2014 14:44:07 -0700
Newsgroups	gmane.comp.web.services.rest
Message-ID	<CAAPAK-4ztUw7dES1XpVTSridavv8+6+XuHr35OHmhJDkNZCtyw@mail.gmail.com>
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It may require another resource. Move/Swap/Redirect the two states (on and
=
off) based on current state rather than one specific state that has no
mech=
anism itself for toggle. It depends on how persistent and concurrent
you wa=
nt the two states.


Solution:


POST /state/on
POST /state/off
PUT /state/to=
ggle
DELETE /state


Returns semantics for redirected or moved resources. Ov=
erride with new
OPTION:TOGGLE.






On Wed, Jul 9, 2014 at 6:06 AM, Keith P H=
assen [email protected]
[rest-discuss] <rest-discuss-noreply@yahoogrou=
ps.com> wrote:


>
>
> You could implement a POST operation that simply flip=
s the state, whatever
> it is.  If you implement PUT, the request should be=
 idempotent but it's
> unclear if that's what you intend here.  Protecting =
against the kind of
> race conditions you mention is usually performed with=
 conditional requests
> (If-Match, If-None-Match, etc).
>
> K
>
>
>
> On Tu=
e, Jul 8, 2014 at 5:28 PM, 'Simpson, Robby (GE Energy Management)'
> robby.=
[email protected] [rest-discuss] <[email protected]>
> wrot=
e:
>
>>
>>
>> Hi,
>>
>> I've been scratching my head over this one for a wh=
ile and am hoping I can
>> get some help.
>>
>> Imagine a light switch with=
 one simple resource: /state , where state can
>> be "On" or "Off."
>>
>> O=
ne can PUT to /state , changing /state to either "On" or "Off."
>> Similarl=
y, 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 t=
hat 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 latenc=
y this entails as well as the potential for a race condition
>> (what if /s=
tate 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
>>
>>
>  
>

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      <p><div dir=3D"ltr">It may require another resource. Move/Swap/Redire=
ct the two states (on and off) based on current state rather than one speci=
fic state that has no mechanism itself for toggle. It depends on how persis=
tent and concurrent you want the two states.<div>
<br></div><div>Solution:</div><div><br></div><div>POST /state/on</div><div>=
POST /state/off</div><div>PUT /state/toggle</div><div>DELETE /state<br><div=
><br></div></div><div>Returns semantics for redirected or moved resources. =
Override with new OPTION:TOGGLE.=C2=A0</div>
<div><br></div></div><div class=3D"gmail_extra"><br><br><div class=3D"gmail=
_quote">On Wed, Jul 9, 2014 at 6:06 AM, Keith P Hassen <a href=3D"mailto:ke=
[email protected]">[email protected]</a> [rest-discuss] <span dir=
=3D"ltr">&lt;<a href=3D"mailto:[email protected]" target=
=3D"_blank">[email protected]</a>&gt;</span> wrote:<br>
<blockquote class=3D"gmail_quote" style=3D"border-left:1px #ccc solid;">




<u></u>


















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=20=20=20=20=20=20
=20=20=20=20=20=20
      <p></p><div dir=3D"ltr"><div class=3D"gmail_default" style=3D"font-fa=
mily:trebuchet ms,sans-serif;font-size:small;color:rgb(51,51,51);">You coul=
d implement a POST operation that simply flips the state, whatever it is.=
=C2=A0 If you implement PUT, the request should be idempotent but it&#39;s =
unclear if that&#39;s what you intend here.=C2=A0 Protecting against the ki=
nd of race conditions you mention is usually performed with conditional req=
uests (If-Match, If-None-Match, etc).<br>


<br></div><div class=3D"gmail_default" style=3D"font-family:trebuchet ms,sa=
ns-serif;font-size:small;color:rgb(51,51,51);">K<br><br></div></div><div cl=
ass><div class=3D"gmail_extra"><br><br><div class=3D"gmail_quote">On Tue, J=
ul 8, 2014 at 5:28 PM, &#39;Simpson, Robby (GE Energy Management)&#39; <a h=
ref=3D"mailto:[email protected]" target=3D"_blank">[email protected]<=
/a> [rest-discuss] <span dir=3D"ltr">&lt;<a href=3D"mailto:rest-discuss-nor=
[email protected]" target=3D"_blank">[email protected]=
m</a>&gt;</span> wrote:<br>


<blockquote class=3D"gmail_quote" style=3D"border-left:1px #ccc solid;">




<u></u>


















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    <div>
=20=20=20=20=20=20
=20=20=20=20=20=20
      <p>Hi,<br>
<br>
I&#39;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 &quot;On&quot; or &quot;Off.&quot;<br>
<br>
One can PUT to /state , changing /state to either &quot;On&quot; or &quot;O=
ff.&quot;<br>
Similarly, a GET to /state will tell you if the light is currently &quot;On=
&quot; or<br>
&quot;Off.&quot;<br>
<br>
Where I&#39;m struggling is with a safe &quot;Toggle&quot; mechanism.  That=
 is, if<br>
/state is &quot;On&quot;, change it to &quot;Off&quot; 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&#39;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>


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