man page for yaws apiWord文件下载.docx

man page for yaws apiWord文件下载.docx

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Theout（Arg）functionissuppliedoneargument,an#arg{}structure.

Wehavethefollowingrelevantrecorddefinitions:

-record（arg,{

clisock,%%thesocketleadingtothepeerclient

client_ip_port,%%{ClientIp,ClientPort}tuple

headers,%%headers

req,%%request

clidata,%%Theclientdata（asabinaryinPOSTrequests）

server_path,%%Thenormalizedserverpath

querydata,%%WastheURLontheformof...?

query（GETreqs）

appmoddata,%%theremainderofthepathuptothequery

docroot,%%where'

sthedata

fullpath,%%fullpathtoyawsfile

cont,%%Continuationforchunkedmultipartuploads

state,%%Stateforusebyusersoftheout/1callback

pid,%%pidoftheyawsworkerprocess

opaque,%%usefultopassstaticdata

appmod_prepath,%%pathinfrontof:

appmod>

appmoddata>

pathinfo%%Setto'

d/e'

whencallingc.yawsfortherequest

%%http:

//some.host/a/b/c.yaws/d/e

}）.

Theheadersargumentisalsoarecord:

-record（headers,{

connection,

accept,

host,

if_modified_since,

if_match,

if_none_match,

if_range,

if_unmodified_since,

range,

referer,

user_agent,

accept_ranges,

cookie=[],

keep_alive,

content_length,

authorization,

other=[]%%miscotherheaders

itlikes.Wehavethefollowingfunctionstoaidthatgeneration.

API

ssi（DocRoot,ListOfFiles）

Serversideinclude.Justincludethefilesasisinthedocu-

ment.Thefileswillnotbeparsedandsearchedfor<

tags.

pre_ssi_files（DocRoot,ListOfFiles）->

Serversideincludeofpreindentedcode.ThedatainFiles

willbeincludedbutcontainedina<

pre>

tag.Thedatawillbe

htmlized.

pre_ssi_string（String）

IncludehtmlizedcontentfromString.

f（Fmt,Args）

Theequivalentofio_lib:

format/2.Thisfunctionisautomati-

cally-includedinallerlangcodewhichisapartofayaws

page.

htmlize（Binary|List|Char）

HtmlizeanIOlistobject.

setcookie（Name,Value,[Path,[Expire,[Domain,[Secure]]]]）

Setsacookietothebrowser.

find_cookie_val（Cookie,Header）

Thisfunctioncanbeusedtosearchforacookiethatwasprevi-

ouslysetbysetcookie/2-6.Forexampleifwesetacookieas

setcookie（"

sid"

SomeRandomSid）,thenonsubsequent

requestsfromthebrowserwecancall:

find_cookie（"

（Arg#arg.headers）#headers.cookie）

Thefunctionreturns[]ifnocookiewasfound,otherwisethe

actualcookieisreturnedasastring.

redirect（Url

Thisfunctiongeneratesaredirecttothebrowser.Itwill

clearanypreviouslysetheaders.Sotogeneratearedirectand

setacookie,weneedtosetthecookieaftertheredirectas

in:

...dosomestuff

Ret=[{redirect,"

"

},

setcookie（"

Random）

].

redirect_self（Arg）

Ifwewanttoissuearedirecttoourselves,thisfunctionis

useful.Itreturnsarecord#redir_self{}definedin

yaws_api.hrl.TherecordcontainsfieldstoconstructaURLto

ourselves.

-record（redir_self,{

host,%%string（）-ourownhost

scheme,%%http|https

scheme_str,%%"

https:

//"

|"

http:

port,%%integer（）-ourownport

port_str%%"

:

int>

-theoptionalportpart

%%toappendtotheurl

get_line（String）

Thisfunctionisconvenientwhengetting\r\nterminatedlines

fromastreamofdata.Itreturns:

{line,Line,Tail}or{lastline,Line,Tail}

Thefunctionhandlesmultilinesasdefinedine.g.SMTPorHTTP

mime_type（FileName）

ReturnsthemimetypeasdefinedbytheextensionofFileName

stream_chunk_deliver（YawsPid,Data）

Whenayawsfunctionneedstodeliverchunksofdatawhichitgets

fromaprocess.Theotherprocesscancallthisfunctiontodeliver

thesechunks.Itrequirestheout/1functiontoreturnthe

value{streamcontent,MimeType,FirstChunk}towork.

YawsPidistheprocessidentifieroftheyawsprocessdeliveringtheoriginal

ThePidmusttypicallybepassed（somehow）totheproducerofthestream.

stream_chunk_deliver_blocking（YawsPid,Data）

Asynchronousversionoftheabovefunction.Thissynchronousversion

mustalwaysbeusedwhentheproducerofthestreamisfasterthanthe

consumer.ThisisusuallythecasesincetheclientistheWWWbrowser.

stream_chunk_end（YawsPid）

Whentheprocessdiscussedaboveisdonedeliveringdata,itmustcall

thisfunctiontolettheyawscontentdeliveringprocessfinishup

theHTTPtransaction.

stream_process_deliver（Socket,IoList）

Yawsallowsapplicationprocessestodeliverdatadirectlytothe

client.Theapplicationtellsyawsaboutsuchaprocessbyreturning

{streamcontent_from_pid,MimeType,Pid}fromitsout/1

function.Inthiscase,Pidusesthe

stream_process_deliver/2functiontodeliverdatatothe

client.TheapplicationgetsSocketfromArg#arg.clisock,

andIoLististhedatatobesenttotheclient.

stream_process_deliver_chunk（Socket,IoList）

SameasabovebutdeliversIoListusingHTTPchunkedtransfer

format.IoListmusthaveasizegreaterthanzero.The

applicationprocessdeliveringthedatawillhavehadtohavemake

surethattheHTTPheadersoftheresponseindicatechunkedtransfer

mode,eitherbyensuringnoContent-Lengthheaderissetorby

specificallysettingtheTransfer-Encodingheadertochunked.

stream_process_deliver_final_chunk（Socket,IoList）

Iftheapplicationprocessdeliveringdatatotheclientuseschunked

transfermode,itmustcallthistodeliverthefinalchunkofthe

transfer.Thistellsyawstocreateaspecialfinalchunkinthe

formatrequiredbytheHTTPspecification（RFC2616）.IoListmay

beempty,butifitssizeisgreaterthanzero,thatdatawillbe

sentasaseparatechunkbeforethefinalchunk.

stream_process_end（Socket,YawsPid）

Applicationprocessesdeliveringdatadirectlytoclientsmustcall

thisfunctiontoinformyawsthatthey'

vefinishedusing

Socket.TheYawsPidargumentwillhavebeenpassedtothe

processearlierwhenyawssentitamessagetellingittoproceedwith

datadelivery.YawsexpectsSockettobeopen.

stream_process_end（closed,YawsPid）

Sameasthepreviousfunctionbuttheapplicationcallsthisifit

closestheclientsocketaspartofitsdatadeliveryprocess.This

allowsyawstocontinuewithoutassumingthesocketisstillopenand

encounteringerrorsduetothatassumption.TheYawsPidargument

willhavebeenpassedtotheapplicationprocessearlierwhenyaws

sentitamessagetellingittoproceedwithdatadelivery.

parse_query（Arg）

ThisfunctionwillparsethequerypartoftheURL.

Itwillreturna{Key,Value}listoftheitemssuppliedinthequery

partoftheURL.

queryvar（Arg,VarName）

Thisfunctionisautomaticallyincludedfromyaws_apiinall

.yawspages.Itisusedtosearchforavariableinthe

querypartoftheurl.Returns{ok,Val}orundefined.

Ifavariableisdefinedmultipletimes,thefunctionmayalso

return{Val1,....}.

parse_post（Arg）

ThisfunctionwillparsethePOSTdataassuppliedfromthebrowser.

Itwillreturna{Key,Value}listoftheitemssetbythebrowser.

postvar（Arg,VarName）

POSTeddatafromtheclient.Returns{ok,Val}orundefined.

getvar（Arg,VarName）

ThisfunctionlooksattheHTTPrequestmethodfromthe

clientandinvokespostvar/2ifitisaPOSTfromtheclient

andqueryvar/2ifitisaGETrequestfromtheclient.

parse_multipart_post（Arg）

IfthebrowserhassettheContent-Typeheadertothevalue

"

multipart/form-data"

whichisthecasewhenthebrowser

wantstouploadafiletotheserverthefollowinghappens:

Ifthefunctionreturns{result,Res}nomoredata

willcomefromthebrowser.

Ifthefunctionreturns{cont,Cont,Res}thebrowser

willsupplymoredata.（Thefilewastobigtocomeinoneread）

Thisindicatesthatthereismoredatatocomeandtheout/1function

shouldreturn{get_more,Cont,User_state}whereUser_statemight

usefullybeaFileDescriptor.

TheResvalueisalistofeither:

{header,Header}|{part_body,Binary}|{body,Binary}

Exampleusagecouldbe:

out（A）->

caseyaws_api:

parse_multipart_post（A）of

{cont,Cont,Res}->

St=handle_res（A,Res）,

{get_more,Cont,St};

{result,Res}->

handle_res（A,Res）,

{html,f（"

Done<

/pre>

[]）}

end.

handle_res（A,[{head,Name}|T]）->

io:

format（"

head:

~p~n"

[Name]）,

handle_res（A,T）;

handle_res（A,[{part_body,Data}|T]）->

part_body:

[Data]）,

handle_res（A,[{body,Data}|T]）->

body:

handle_res（A,[]）->

End_res~n"

）.

new_cookie_session（Opaque）

Createanewcookiebasedsession,theyawssystemwillsetthe

cookie.Thenewrandomgeneratedcookieisreturnedfromthis

function.TheOpaqueargumentwilltypicallycontainuserdata

suchasusernameandpa