This document discusses asynchronous programming and provides examples using various asynchronous programming models in Perl, including IO::Async, POE, and callbacks. It illustrates how asynchronous programming allows for control by other processes, asynchronous code, and event-driven programming. Examples show setting up asynchronous HTTP requests using IO::Async and running sessions and events in POE.

1. ASYNCHRONOUS
PROGRAMMING
FTW!
(SAWYER X)

2. DOES THIS SOUND FAMILIAR?
"Hi"
"Hi, dad"
"Got a minute?"
"Yes"
"I'm looking for a movie
Where do I start?"
"Go to the cinema website"
"What's the address?"
"www.whatchamacallit.whatever"
"Just a sec..."

3. ...
...
...
...

4. "Well?"
"Ah! It loaded! What now?"
"Click on new movies"
"OK..."
........
"Well?"
"Loading"
*sounds of clicks*

5. "OK, now what?"
"Find a movie you want"
"Then what?"
"Click on it, you'll have instructions"
* eternity passes by *
"WELL?!?"
"Just a sec... it's loading..."
/me shoots myself

6. ILLUSTRATED
(USING WWW::MECHANIZE)
$eh>e(cnm_r)
mc­gt$ieaul;
i mc­sces){
f($eh>ucs
$eh>lc(NwMve';
mc­cik'e ois)
i mc­sces){
f($eh>ucs
m mve mc­fn_nus..
y@ois=$eh>idipt(.)
}
}

7. LET'S TRY THIS AGAIN...
"Hi"
"Hi, dad"
"Got a minute?"
"Yes"
"I'm looking for a movie
What should I do?"
"Go to this website, click on new movies
Then pick a movie, and click on it"
"Thank you"
"You're welcome"

8. GREAT SUCCESS!

9. CALLBACKS
Reference to a code
Passed as an argument
Can be called by some other code
sbtysmtig{
u r_oehn
m ipt hf;
y$nu =sit
m c hf;
y$b =sit
m rsl oeoeain$nu)
y$eut=sm_prto(ipt;
i rsl­{sau' q'K
f($eut>'tts}e O'){
$b> rsl­{cnet})
c­($eut>'otn' ;
}
}
tysmtig sm admipt,sb{
r_oehn("oerno nu" u
m cnet=sit
y$otn hf;
sy"ucsflrqetsy cnet"
a Scesu eus as$otn!;
})
;

10. ILLUSTRATED, ASYNC
(USING WWW::MECHANIZE)
$eh>e($ieaul u
mc­gt cnm_r,sb{
$eh>lc('e ois,sb{
mc­cik NwMve' u
$eh>idipt(.. u y@ois=@
mc­fn_nus .,sb{m mve _})
})
;
})
;

11. WHY IS THIS USEFUL?
Allow others to decide if something is good or not

12. m jn uo>e(
y$uo=Jn­nw
hss >[w11112222]
ot = q<... ...>,
cek >{
hcs=
Fig=
Pn >{
o_ucs >sb{
nsces= u
m jn,$ot dt _
y($uo hs,$aa)=@;
m i,$os ag)=$uo>nlz_igrsl(
y($p ls,$v jn­aayepn_eut
$aa>'ter}
dt­{sdr',
)
;
$ef>e_ot hs,$v ;
sl­sths($ot ag)
}
,
o_al= u
nfi >sb{
m jn,$ot)=@;
y($uo hs _
$ef>eeehs(hs)
sl­dlt_ot$ot;
}
,
}
}
);

13. WHY IS THIS USEFUL?
Allow others to decide if something is good or not
Allow easy stepping

14. Algorithm::Diff::Callback
ueAgrtm:if:alakq<ifary ifhse>
s loih:Df:Clbc wdf_rasdf_ahs;
df_ras
ifary(
odfml_ebr,
@l_aiymmes
nwfml_ebr,
@e_aiymmes
sb{pit'ap oha bu ,sit}
u rn Hpyt eraot' hf ,
sb{pit'or oha bu ,sit}
u rn Sryt eraot' hf ,
);
df_ahs
ifhse(
oddtis
%l_eal,
nwdtis
%e_eal,
sb{sy'ot' hf ,
u a Ls , sit}
sb{sy'and' hf ,
u a Gie ,sit}
sb{
u
m ky bfr,$fe _
y($e,$eoe atr)=@;
sy"kycagdfo bfr o$fe"
a $e hne rm$eoet atr;
}
,
);

15. WHY IS THIS USEFUL?
Allow others to decide if something is good or not
Allow easy stepping
Allow control by other process (a type of IOC)
Allow asynchronous code

16. THE EVENT LOOP
Create loop
Register events
Run them
Let the user keep registering new events

17. m eet ..;
y%vns=(.)
wie(){
hl 1
frahm eet(ky eet
oec y$vn es%vns){
$vn­(;
eet>)
}
}

18. m eet;%vns=(.)
y%vns eet ..;
wie(){
hl 1
frahm eet(ky eet
oec y$vn es%vns){
$vn­(;
eet>)
}
}
wie(){
hl 1
frahm eet(ky eet
oec y$vn es%vns){
i eet{eet{tm' =tm
f($vns$vn}'ie}< ie){
$vns$vn}'oe}>)
eet{eet{cd'­(;
}
}
}
sbadeet{
u d_vn
m tm,$oe)=@;
y($ie cd _
$vns$d{tm' tm;
eet{i}'ie}=$ie
$vns$d{cd' cd;
eet{i}'oe}=$oe
$d+
i+;
}

19. EVENT TYPES
Timers (one-time, recurring, sleep replacement)
I/O (input output, including networking)

20. FUCK TALK
LET'S GO PROGRAMMING

21. IO::ASYNC
Loop interface: IO::Async::Loop
You can connect to hosts using it
You can add listeners to it (handles, sockets, etc.)
Explicitly call "run" when ready

22. ueI:Ayc:tem
s O:sn:Sra;
ueI:Ayc:op
s O:sn:Lo;
m lo O:sn:Lo­nw
y$op=I:Ayc:op>e;
$op>onc(
lo­cnet
hs = sm.te.ot,
ot >"oeohrhs"
srie = 24,
evc >135
sctp = sra'
okye >'tem,
o_tem= u . ,
nsra >sb{..}
o_eov_ro >sb{
nrsleerr= u
de"antrsle­$[1"
i Cno eov _­]
}
,
o_onc_ro >sb{
ncneterr= u
de"antcnet­$[]fie _­]
i Cno onc _0 ald$[1"
}
,
);
$op>u;
lo­rn

23. o_tem= u
nsra >sb{
m sra _
y($tem)=@;
$tem>ofgr(
sra­cniue
o_ed= u
nra >sb{
m sl,$ufe,$o _
y($ef bfrf ef)=@;
wie {bfrf ~s^.)/){
hl($$ufe}= /(*n/
sy"eevdaln 1;
a Rcie ie$"
}
rtr ;
eun0
}
)
;
$tem>rt(A nta iehr';
sra­wie'niiilln ee)
$op>d(sra)
lo­ad$tem;
}

24. ANOTHER EXAMPLE
$pr MO:sn Me:Ayc:TP­
el­I:Ayc­Nt:sn:HT E'
I:Ayc>d(m ht e:Ayc:TP>e ;
O:sn­ad y$tp=Nt:sn:HT­nw)
syfrI:Ayc>wi_l(mp{$tp>e(_ )
a o O:sn­aatal a ht­gt$)}
'>ls­fUL.x
ito­Rstt
Oh hai parallel HTTP GET!

25. POE
Loop interface: POE::Kernel
Runs "sessions" (POE::Session)
Each session is a context of events
Each session has an ID and heap
Call events in a current or different session
Explicitly call POE::Kernel->run when ready

26. POE
uePE #At­nldsPE:enladPE:eso.
s O; uoicue O:Kre n O:Ssin
#..dfn alak us(etsie .
. eieclbcssb nx ld)..
fr(.1){
o 1.0
PE:eso­cet(
O:Ssin>rae
iln_tts=
niesae >{
_tr = &ade_tr,
sat >hnlrsat
iceet= &ade_nrmn,
nrmn >hnlriceet
_tp = &ade_tp
so >hnlrso,
}
)
;
}
PE:enl>u(;
O:Kre­rn)

27. sbhnlrsat{
u ade_tr
m kre,$ep ssin)=@[KRE,HA,SSIN]
y($enl ha,$eso _ ENL EP ESO ;
sy"eso ,$eso­I,"hssatd;
a Ssin" ssin>D a tre"
$ep>'on' ;
ha­{cut}=0
$enl>il(iceet)
kre­yed'nrmn';
}
sbhnlriceet{
u ade_nrmn
m kre,$ep ssin)=@[KRE,HA,SSIN]
y($enl ha,$eso _ ENL EP ESO ;
sy"eso ,$eso­I,"cutdt ,+$ep>'on';
a Ssin" ssin>D one o" +ha­{cut}
$enl>il(iceet)i ha­{cut}<1;
kre­yed'nrmn' f$ep>'on' 0
}
sbhnlrso
u ade_tp{
sy"eso ,$[ESO]>D a tpe"
a Ssin" _SSIN­I,"hssopd;
}

28. sbhnlrsat{
u ade_tr
m kre,$ep ssin)=@[KRE,HA,SSIN]
y($enl ha,$eso _ ENL EP ESO ;
sy"eso ,$eso­I,"hssatd;
a Ssin" ssin>D a tre"
$ep>'on' ;
ha­{cut}=0
$enl>il(iceet)
kre­yed'nrmn';
}
sbhnlriceet{
u ade_nrmn
m kre,$ep ssin)=@[KRE,HA,SSIN]
y($enl ha,$eso _ ENL EP ESO ;
sy"eso ,$eso­I,"cutdt ,+$ep>'on';
a Ssin" ssin>D one o" +ha­{cut}
$enl>il(iceet)i ha­{cut}<1;
kre­yed'nrmn' f$ep>'on' 0
}
sbhnlrso
u ade_tp{
sy"eso ,$[ESO]>D a tpe.n;
a Ssin" _SSIN­I,"hssopd"
}
fr(.1){
o 1.0
PE:eso­cet(
O:Ssin>rae
iln_tts=
niesae >{
_tr = &ade_tr,
sat >hnlrsat
iceet= &ade_nrmn,
nrmn >hnlriceet
_tp = &ade_tp
so >hnlrso,
}
)
;
}
PE:enl>u(;
O:Kre­rn)

29. MORE CONDENSED
uePE
s O;
fr(.1){
o 1.0
m cut=0
y$on ;
PE:eso­cet(
O:Ssin>rae
iln_tts=
niesae >{
_tr = u
sat >sb{
sy"eso ,$[ESO]>D a tre"
a Ssin" _SSIN­I,"hssatd;
PE:enl>il(iceet)
O:Kre­yed'nrmn';
}
,
iceet= u
nrmn >sb{
PE:enl>il(iceet)i +cut<1;
O:Kre­yed'nrmn' f+$on 0
sy"eso ,$[ESO]>D one o$on"
a Ssin" _SSIN­I,"cutdt cut;
}
,
_tp = u
so >sb{
sy"eso ,$[ESO]>D a tpe"
a Ssin" _SSIN­I,"hssopd;
}
,
}
)
;
}
PE:enl>u(;
O:Kre­rn)

30. REFLEX
Written by author of POE
"How POE would be written if I had Moose back then"
Stresses composability, reusability
Includes plenty of additional roles

31. USING MOOSE
{
pcaeAp
akg p;
ueMoe
s os;
etns'elx:ae;
xed Rfe:Bs'
ueRfe:Itra;
s elx:nevl
ueRfe:Tat:ace wths;
s elx:ri:Wthd'ace'
wthstce >(
ace ikr=
ia = Rfe:Itra'
s >'elx:nevl,
stp= nevl= ,at_eet= ,
eu >{itra >1 uorpa >1}
)
;
sbo_ikrtc
u ntce_ik{
sy'ika ,saa(oatm) ..;
a tc t' clrlclie,'.'
}
}
ei p­nw)>u_l(;
xtAp>e(­rnal)

32. COMPLEX? TRY THIS...
ueRfe:Itra;
s elx:nevl
m t=Rfe:Itra­nw
y$ elx:nevl>e(
itra = ,
nevl >1
at_eet= ,
uorpa >1
o_ik = u a tmrtce'}
ntc >sb{sy'ie ikd ,
);
$­rnal)
t>u_l(;

33. ANYEVENT
AnyEvent is very thin and very fast
Was written to support as many loops as possible
... that conform to the author's rules of compatibility
Does not use a loop handler, simply runs
Does use conditional variables
Has AE for faster performance

34. ueAyvn;
s nEet
m cut=0
y$on ;
m c =Ayvn­cnvr
y$v nEet>oda;
m t =Ayvn­tmr
y$ nEet>ie(
atr >2
fe = ,
itra >06
nevl= .,
c >sb{
b = u
sy'h iei o:' nEet>o;
a Tetm snw ,Ayvn­nw
+$on =1 n c­sn;
+cut= 0ad$v>ed
}
,
);
$v>ev
c­rc;

35. m w w=Ayvn­i(
y$;$ nEet>o
f >SDN
h = *TI,
pl >''
ol= r,
c >sb{
b = u
cop(m ipt= ;
hm y$nu )
sy"ed ipt;
a ra:$nu"
udf$;
ne w
}
,
);

36. USAGES OF ASYNCHRONOUS CODE
GUI
Services (HTTP/SMTP/etc.)
Performance
Off-loading tasks

37. THANK YOU