gpce 2003, erfurt dynamic generation of xml september 22, 2003 domain specific languages for...

GPCE 2003, Erfurt Dynamic Generation of XML September 22, 2003GPCE 2003, Erfurt Dynamic Generation of XML September 22, 2003

Domain Specific LanguagesDomain Specific Languagesfor Interactive Web for Interactive Web

ServicesServices

Claus BrabrandClaus Brabrand[ Joint work with Anders Møller, Michael Schwartzbach, BRICS, [ Joint work with Anders Møller, Michael Schwartzbach, BRICS,

Denmark ]Denmark ]

Compose Research GroupCompose Research Group

INRIA/LaBRI, University of Bordeaux IINRIA/LaBRI, University of Bordeaux I


OutlineOutline

• Introduction (Program Family)Introduction (Program Family)

• Session ManagementSession Management•State ManagementState Management

• Document ConstructionDocument Construction•Domain Specific VerificationsDomain Specific Verifications

•Domain Specific OptimizationDomain Specific Optimization

• Form-Field ValidationForm-Field Validation

• ConclusionConclusion


Program FamilyProgram Family

””Web servers on which clients can initiate sessions Web servers on which clients can initiate sessions that involve several exchanges of information that involve several exchanges of information mediated by HTML forms”.mediated by HTML forms”.

serverserverclientclient InternetInternet

Interactive (Form-Based) Web Services:Interactive (Form-Based) Web Services:


public class SessionServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { ServletContext context = getServletContext(); HttpSession session = request.getSession(true); response.setContentType("text/html"); PrintWriter out = response.getWriter(); out.println("<HTML><HEAD><TITLE>Servlet Demo</TITLE></HEAD><BODY>"); if (session.isNew()) { out.println("<FORM ACTION=SessionServlet>" + "Enter your name: <INPUT NAME=handle>" + "<INPUT TYPE=SUBMIT></FORM>"); session.putValue("state", "1"); } else { String state = (String) session.getValue("state"); if (state.equals("1")) { String name = (String) request.getParameter("handle"); int users = ((Integer) context.getAttribute("users")).intValue() + 1; context.setAttribute("users", new Integer(users)); session.putValue("name", name); out.println("Hello " + name + ", you are user number " + users); session.putValue("state", "2"); } else /* state.equals("2") */ { String name = (String) session.getValue("name"); out.println("Goodbye " + name); session.invalidate(); } } out.println("</BODY></HTML>"); }}

A Program from the Program A Program from the Program FamilyFamily Java Servlet


A Program from the Program A Program from the Program FamilyFamily

WebWebServiceService

CLIENCLIENTT INTERNET SERVER INTERNET SERVER




session management

Java Servlet




state management

Java Servlet




document construction

Java Servlet



A Program from the Program A Program from the Program FamilyFamily Java Servlet

session management state management document construction





Java Servlet


The The <<bigwigbigwig>> Language/SystemLanguage/System

• A high-level domain-specific A high-level domain-specific programming language for programming language for developing interactive Web services.developing interactive Web services.

<<bigwigbigwig>><<bigwigbigwig>>

HTMLHTML

CGI ScriptsCGI Scripts

JavaScriptJavaScript

HTTP Auth.HTTP Auth.

Java AppletsJava Applets

CompleteService

Specification

CompleteService

Specification


<<bigwigbigwig>> = = a Collection oa Collection offDomain Specific LanguagesDomain Specific Languages

• C-like core language withC-like core language with•Session-based rSession-based runtime systemuntime system

•Dynamic documentsDynamic documents

•FForm-field orm-field validationvalidation

•Relational dRelational databaseatabase

•Concurrency controlConcurrency control

•Semantic sSemantic securityecurity

•Cryptographic securityCryptographic security

•Syntactic-level macrosSyntactic-level macros


OutlineOutline








Implementation ApproachesImplementation Approaches

• Traditionally 2 approaches:Traditionally 2 approaches:

– Script-centered:Script-centered:•Perl/CGI, Java Servlets, …Perl/CGI, Java Servlets, …

– Page-centered:Page-centered:•ASP, PHP, JSP, ...ASP, PHP, JSP, ...


Script-Centered:Script-Centered:Perl/CGI, Servlets, ...Perl/CGI, Servlets, ...

e





e



requestrequest



e



computecomputereplyreply



e


e


HTMLHTML



e


e


submitsubmit



e


e


computecomputereplyreply



e


e

eWebWebServiceServiceHTMLHTML


e

e

e

PagePage-Centered:-Centered:PHP, ASP, JSP, ...PHP, ASP, JSP, ...




Page-CenteredPage-Centered

• Increased level of abstractionIncreased level of abstraction::•CGI protocol details abstracted awayCGI protocol details abstracted away

• Easy to add dynamics to static pagesEasy to add dynamics to static pages::•

• ScalabilityScalability::•SpecializedSpecialized Web server Web server

““Service code embedded in tags andService code embedded in tags and interpreted by specialized Web server”interpreted by specialized Web server”

<html><body>Time: <%= Now() %></body></html><html><body>Time: <%= Now() %></body></html><%= Now() %>


Script-Centered vs. PageScript-Centered vs. Page--CenteredCentered

• As the service complexity increases:As the service complexity increases:– Page-Page-CCentered entered Script- Script-CCentered entered

•A lot of HTML is generated by script elementsA lot of HTML is generated by script elements

• Interesting dInteresting duality:uality:•Script-centered:Script-centered:

– DDefaultefault:: program programming,ming, EEscapescape:: print printinging ( (printprint))

•Page-centered:Page-centered:– DDefaultefault:: print printing,ing, EEscapescape:: programming programming (<%... (<%...

%>)%>)


Fundamental DrawbacksFundamental Drawbacks

<input name=”x”>

a_scripta_script another_scriptanother_script

<%= $y %>submitsubmit


• A service A service == a collection of a collection of scripts/pages!scripts/pages!

• Implicit control-flow:Implicit control-flow:

•No interaction correspondenceNo interaction correspondence::


SessionSession-Centered:-Centered:Mawl and Mawl and <<bigwigbigwig>>!!

e

CLIENT INTERNET SERVERCLIENT INTERNET SERVER

e

e

Web ServiceWeb Service

showshow x; x;

showshow y; y;

xx

yy

submitsubmit


SessionSession-Centered:-Centered:Mawl and Mawl and <<bigwigbigwig>>!!

e

e


showshow x; x;

showshow y; y;

xx

submitsubmit

• Domain specific abstration: Domain specific abstration: showshow

• Explicit control-flowExplicit control-flow

• Check interaction correspondenceCheck interaction correspondence


OutlineOutline








e

e

e

General Purpose General Purpose ManuallyManually




e

e

e

savesave





e

e

e

savesave

restorerestore






• Private (to each session thread):Private (to each session thread):ServletContext context = getServletContext();int p ((Integer) context.getAttribute("p")).intValue();p++;context.setAttribute("p", new Integer(var));



• Private (to each session thread):Private (to each session thread):

• Shared (among all session threads):Shared (among all session threads):HttpSession session = request.getSession(true);int s ((Integer) session.getValue("s")).intValue();s++;session.setValue("s", new Integer(var));

ServletContext context = getServletContext();int p ((Integer) context.getAttribute("p")).intValue();p++;context.setAttribute("p", new Integer(var));


Domain Specific: Domain Specific: sharedshared modifiermodifier

• Private (to each session thread):Private (to each session thread):int p;

...p++;...


Domain Specific: Domain Specific: sharedshared modifiermodifier

• Private (to each session thread):Private (to each session thread):

• Shared (among all session threads):Shared (among all session threads):shared int s;

...s++;...

int p;

...p++;...


Domain Specific Domain Specific AutomaticallyAutomatically

e

CLIENT INTERNET SERVERCLIENT INTERNET SERVER

e

e


[ save ][ save ][ restore ][ restore ]

showshow x; x;

showshow y; y;

xx

yy

submitsubmit


OutlineOutline








Dynamically Generated Dynamically Generated XMXML:L:Current ProblemsCurrent Problems

• Traditionally:Traditionally:• print(...)print(...) in Perl/CGI, ...in Perl/CGI, ...• <% print(...) %><% print(...) %> in PHP, ASP, JSP, ...in PHP, ASP, JSP, ...

• ProblemsProblems::•ForcesForces linear linear document document constructionconstruction• Intermixes pIntermixes programmerrogrammer // d designer esigner aspectsaspects•No interaction cNo interaction correspondenceorrespondence•No static XML validationNo static XML validation•No common fragments cachingNo common fragments caching


Our Solution:Our Solution:HTML documents in HTML documents in <<bigwigbigwig>>• Templates (1Templates (1stst class, class, higherhigher--orderorder

valuesvalues):):•XML fragments with XML fragments with named gapsnamed gaps::

• OperationsOperations::•plug:plug: for document constructionfor document construction

•show:show: for client interactionfor client interaction

[[[[ Hello Hello <[<[whatwhat]>]>!!]]]]


PlugPlug

• Plug:Plug: expexp <[<[ idid == expexp ]]


PlugPlug

• Plug:Plug: expexp <[<[ idid == expexp ]]

• Example:Example:htmlhtml hello = hello = [[ Hello [[ Hello <[<[whatwhat]>]>! ]]! ]];;htmlhtml world = world = [[ <b>World</b> ]][[ <b>World</b> ]];;

htmlhtml h = hello <[ h = hello <[whatwhat = world]; = world];...;...;


ShowShow

• Show:Show: showshow expexp ;;

xx

CLIENT CLIENT INTERNET INTERNET SERVER SERVER

eshowshow xx;;

submitsubmitsuspendsuspendresumeresume


ShowShow

• Show:Show: showshow expexp ;;

• Example:Example:

xx


eshowshow xx;;

submitsubmitsuspendsuspendresumeresume

htmlhtml hello = hello = [[ Hello [[ Hello <[<[whatwhat]>]>! ]]! ]];;htmlhtml world = world = [[ <b>World</b> ]][[ <b>World</b> ]];;

htmlhtml hh = hello <[ = hello <[whatwhat = world]; = world];showshow h h;;


Show-ReceiveShow-Receive

• SShowhow:: showshow expexp receivereceive[[vv

==ff, ..., ...];]; xx


e

ff, ..., ...submitsubmitshowshow x x receivereceive[v=f,..][v=f,..];;


Show-ReceiveShow-Receive

• SShowhow:: showshow expexp receivereceive[[vv

==ff, ..., ...];];

• Example:Example:stringstring s; s;htmlhtml inputinput = = [[[[ Enter email: Enter email: <input type=”text” name=”<input type=”text” name=”emailemail”>”>]]]];;

showshow input input receivereceive[s = [s = emailemail];];

xx


eshowshow x x receivereceive[v=f,..][v=f,..];;

ff, ..., ...submitsubmit


Example: ”Welcome”Example: ”Welcome”

htmlhtml greeting = greeting = [[[[ Hello Hello <[<[whowho]>]>, welcome to , welcome to <[<[whatwhat]>]>..]]]];;

htmlhtml cover = cover = [[[[ <head><title>Welcome</title></head><head><title>Welcome</title></head> <body><body><[<[contentscontents]>]></body></body>]]]];;

htmlhtml h; h;h = greeting <[h = greeting <[whowho = = ”Stranger””Stranger”];];h = h <[h = h <[whatwhat = = [[ <b>GPCE</b> ]][[ <b>GPCE</b> ]]];];showshow cover <[ cover <[contentscontents = h]; = h];


Flexibility: PHP/ASP/JSPFlexibility: PHP/ASP/JSP

• List of results (e.g. “List of results (e.g. “search enginesearch engine”)”)::•One template with 10,20,30, One template with 10,20,30,

or 40 or 40 hardwiredhardwired server-sideserver-sidescript elements: script elements:

•One template with one big One template with one big ””generate-allgenerate-all”” server-side server-side script element:script element:

script-centeredscript-centered

<% ..1.. %><% ..1.. %>

...or......or...

<% ..2.. %><% ..2.. %>

<% ..20.. %><% ..20.. %> :

<% <% for for i=1 to N doi=1 to N do { ..i.. } { ..i.. } %>%>


Flexibility:Flexibility: <<bigwigbigwig>>

• List of results (e.g. “List of results (e.g. “search enginesearch engine”)”)::

<ul> <li>1 <li>2 : <li>N</ul>

<ul> <li>1 <li>2 : <li>N</ul>



• List of results (e.g. “List of results (e.g. “search enginesearch engine”)”)::•Two templates: “Two templates: “layoutlayout” and “” and “entryentry”...”...

<ul> <li>1 <li>2 : <li>N</ul>

<ul> <li>1 <li>2 : <li>N</ul>

htmlhtml layoutlayout = = [[ <ul>[[ <ul><[<[itemsitems]>]></ul> ]]</ul> ]];;htmlhtml entry = entry = [[ <li>[[ <li><[<[numnum]><[]><[itemsitems]>]> ]] ]];;




•...and o...and one recursive function: ne recursive function: ““ff””htmlhtml f( f(intint n) { n) { ifif (n (n === 0) = 0) returnreturn layoutlayout;; returnreturn f(n-1) <[ f(n-1) <[itemitemss = entry <[ = entry <[numnum = n]]; = n]];}}


<ul> <li>1 <li>2 : <li>N</ul>

<ul> <li>1 <li>2 : <li>N</ul>




•...and o...and one recursive function: ne recursive function: ““ff””

•Example usage:Example usage:

htmlhtml f( f(intint n) { n) { ifif (n (n === 0) = 0) returnreturn layoutlayout;; returnreturn f(n-1) <[ f(n-1) <[itemitemss = entry <[ = entry <[numnum = n]]; = n]];}}

<ul> <li>1 <li>2 : <li>27</ul>

<ul> <li>1 <li>2 : <li>27</ul>


showshow f(27);f(27);




Flexibility: Separates Flexibility: Separates Designer / Programmer Designer / Programmer AspectsAspects



htmlhtml layoutlayout = = [[ <table>[[ <table><[<[itemsitems]>]></table> ]]</table> ]];;htmlhtml entry = entry = [[[[ <tr><td><tr><td><[<[numnum]>]></td></tr></td></tr> <[<[itemsitems]>]>]]]];;


Flexibility: Separates Flexibility: Separates Designer / Programmer Designer / Programmer AspectsAspects


Problems?Problems?

• ““DynDoc”:DynDoc”:•Templates with Templates with named gapsnamed gaps•Plug and showPlug and show



Problems?Problems?


<input name=”x”>

a_scripta_script another_scriptanother_script

<%= $y %>submitsubmit


OutlineOutline








Type SafetyType Safety(in terms of (in terms of <<bigwigbigwig>>))

• Show/Receive correspondenceShow/Receive correspondence::

• Gap presenGap presencece::

htmlhtml dd = = [[[[ Enter email: Enter email: <<input type=“text” name=“input type=“text” name=“emailemail”>”>]]]];;

showshow d d receivereceive[s = [s = ageage];];

htmlhtml hellohello = = [[ [[ Hello Hello <[<[whatwhat]>]>!! ]] ]];;htmlhtml world = world = [[ <b>World</b> ]][[ <b>World</b> ]];;htmlhtml h; h;

h = hello <[h = hello <[contentscontents = world]; = world];


Static Analysis!Static Analysis!

Apply standard, Apply standard, data-flow analysisdata-flow analysis techniques, techniques,but with highly but with highly domain-specific latticesdomain-specific lattices


Static Analysis!Static Analysis!

• Conservatively approximateConservatively approximatefor all HTML variables & program for all HTML variables & program points:points:

• Their Their gaps and fields (and their kinds)gaps and fields (and their kinds) all possible runtime values all possible runtime values

• Forward data-flow analysis:Forward data-flow analysis:1.1. Control-flow graph (trivial for Control-flow graph (trivial for <<bigwigbigwig>>))

2.2. Finite lattice: Finite lattice: Gap-and-FieldGap-and-Field

3.3. Monotone transfer functions: plug, assign, ...Monotone transfer functions: plug, assign, ...


Gap-and-Field LatticeGap-and-Field LatticeGKindGKind

nogap

string

html

error

FKindFKind

error

text

nofield

checkboxradio

tup(F1)

rel(F1) rel(Fn)

tup(Fn)

..

..

• An An abstract documentabstract document is: is:

((GNameGName GKindGKind) x () x (FNameFName FKindFKind))

FNameFName FKindFKind

aa htmlhtml

gg htmlhtml

nn nogapnogap

GNameGName GKindGKind

aa htmlhtml

gg htmlhtml

nn nogapnogap


Monotone Transfer Monotone Transfer FunctionsFunctions

• Plug:Plug: xx11 <[ <[gg = = xx22]]



• Plug:Plug: xx11 <[ <[gg = = xx22]]


aa htmlhtml

gg htmlhtml

nn nogapnogap


aa htmlhtml

gg htmlhtml

nn nogapnogap


aa nogapnogap

gg nogapnogap

nn htmlhtml


aa htmlhtml

gg htmlhtml

nn nogapnogap



• Plug:Plug: xx11 <[ <[gg = = xx22]]

<[g = ]


aa htmlhtml

gg htmlhtml

nn nogapnogap


aa htmlhtml

gg htmlhtml

nn nogapnogap


aa htmlhtml

gg htmlhtml

nn nogapnogap


aa nogapnogap

gg nogapnogap

nn htmlhtml


aa htmlhtml

gg htmlhtml

nn nogapnogap


aa

gg

nn

GG : : GKindGKind x x GKindGKind GKindGKind



• Plug:Plug: xx11 <[ <[gg = = xx22]]

<[g = ]


aa htmlhtml

gg htmlhtml

nn nogapnogap


aa htmlhtml

gg htmlhtml

nn nogapnogap


aa htmlhtml

gg htmlhtml

nn nogapnogap


aa nogapnogap

gg nogapnogap

nn htmlhtml


aa htmlhtml

gg htmlhtml

nn nogapnogap


aa htmlhtml

gg

nn




• Plug:Plug: xx11 <[ <[gg = = xx22]]

<[g = ]


aa htmlhtml

gg htmlhtml

nn nogapnogap


aa htmlhtml

gg htmlhtml

nn nogapnogap


aa htmlhtml

gg htmlhtml

nn nogapnogap


aa htmlhtml

gg htmlhtml

nn nogapnogap


aa nogapnogap

gg nogapnogap

nn htmlhtml


aa htmlhtml

gg nogapnogap

nn




• Plug:Plug: xx11 <[ <[gg = = xx22]]

<[g = ]


aa htmlhtml

gg htmlhtml

nn nogapnogap


aa htmlhtml

gg htmlhtml

nn nogapnogap


aa htmlhtml

gg htmlhtml

nn nogapnogap


aa htmlhtml

gg htmlhtml

nn nogapnogap


aa nogapnogap

gg nogapnogap

nn htmlhtml


aa htmlhtml

gg nogapnogap

nn htmlhtml



Then: Check SolutionThen: Check Solution

• Traverse solution: intercept Traverse solution: intercept errorerrorss




gap presentgap present

EE11 <[ <[gg = E = E22]]FNameFName FKindFKind

aa htmlhtml

gg htmlhtml

nn nogapnogap


aa htmlhtml

gg htmlhtml

nn nogapnogap




gap presentgap present

field presentfield present

type check:type check: v ~ v ~ texttext

EE11 <[ <[gg = E = E22]]

showshow E E receivereceive[v=[v=ff, , ......];];


aa htmlhtml

gg htmlhtml

nn nogapnogap


aa htmlhtml

gg htmlhtml

nn nogapnogap


aa htmlhtml

gg htmlhtml

nn nogapnogap


ee radioradio

ff texttext

tt texttext


Type SafetyType Safety??

• Show/Receive interaction Show/Receive interaction correspondencecorrespondence::







Type SafetyType Safety!!

• Show/Receive interaction Show/Receive interaction correspondencecorrespondence::






*** receive.wig:5: input field ‘email’ not received no such input field ‘age’

*** receive.wig:5: input field ‘email’ not received no such input field ‘age’

*** plug.wig:5: no such gap ‘contents’*** plug.wig:5: no such gap ‘contents’


Problems?Problems?




Problems?Problems?


• ProblemsProblems::•ForcesForces linear linear document document constructionconstruction• Intermixes pIntermixes programmerrogrammer // d designer esigner aspectaspectss•No interaction cNo interaction correspondenceorrespondence•No static XML validationNo static XML validation•No common fragments cachingNo common fragments caching


Problems?Problems?








Valid HTML !?Valid HTML !?


Static AnalysisStatic Analysis (again)! (again)!

• Conservatively approximateConservatively approximatefor allfor all HTML variables & program points HTML variables & program points::

• A A summary graphsummary graph all possible runtime values all possible runtime values

• Forward data-flow analysis:Forward data-flow analysis:1.1. Control-flow graph: (Control-flow graph: (trivial for trivial for <<bigwigbigwig>>))

2.2. Finite lattice: Finite lattice: summary graphssummary graphs

3.3. Monotone transfer functions: plug, assign, ...Monotone transfer functions: plug, assign, ...


Summary GraphSummary Graph

htmlhtml greeting = greeting = ...;...;

htmlhtml cover = ...; cover = ...;




””Stranger”Stranger”greetinggreeting

whowho






””Stranger”Stranger”greetinggreeting

gpcegpce

whowho

whatwhat






””Stranger”Stranger”

covercover

greetinggreeting

gpcegpce

contentscontents whowho

whatwhat





Monotone Transfer FunctionMonotone Transfer Function

• Plug:Plug: xx11 <[ <[gg = = xx22]]



• Plug:Plug:

gg

gg

gggg

xx11 <[ <[gg = = xx22]]



• Plug:Plug:

<[<[gg = ]= ]

xx11 <[ <[gg = = xx22]]

gg

gg

gggg



• Plug:Plug:

<[<[gg = ]= ]

xx11 <[ <[gg = = xx22]]

gg

gg

gggg

gg

gg

gggg



• Plug:Plug:

<[<[gg = ]= ]

xx11 <[ <[gg = = xx22]]

gg

gg

gggg

gg

gg

gggg

However, too imprecise...!However, too imprecise...!



<[<[gg = ]= ]

• Plug:Plug:

open gapsopen gaps

xx11 <[ <[gg = = xx22]]

gg

gg

gggg

gg

gg

gggg



• Plug:Plug: xx11 <[ <[gg = = xx22]]

<[<[gg = ]= ]

open gapsopen gaps

gg

gg

gggg

gg

gg

gggg


GapTrack AnalysisGapTrack Analysis

• GapTrack data-flow analysis:GapTrack data-flow analysis:– program points compute:program points compute:

•““Tracks the origins (templates) of open Tracks the origins (templates) of open gaps”gaps”

((gg )) ’’

: : GNameGName 22TEMPLATESTEMPLATES

<[<[gg = ]= ]

gg

gg

gggg

gg

gg

gggg


...;...;h = greeting <[h = greeting <[who who = = ”Stranger””Stranger”];];h = h <[h = h <[what what = = [[ <b>GPCE</b> ]][[ <b>GPCE</b> ]]];];showshow cover <[ cover <[contentscontents = h]; = h];

• Now: Now: summary graphsummary graph show show statementsstatements

•Then what...?Then what...?

Validation?Validation?

””Stranger”Stranger”

covercover

greetinggreeting

bricsbrics

contentscontents whowho

whatwhat



a set of a set of hopefulhopeful

XML docs XML docs


XML docs XML docs

A A summary graphsummary graphdescribes:describes:




XML docs XML docs


XML docs XML docs

a set of a set of validvalid

XML docs XML docs


XML docs XML docs


A DTD describesA DTD describes(e.g. XHTML 1.0):(e.g. XHTML 1.0):


Validation!Validation!


XML docs XML docs


XML docs XML docs


XML docs XML docs


XML docs XML docs

validation!validation!


A DTD describesA DTD describes(e.g. XHTML 1.0):(e.g. XHTML 1.0):


Validation!Validation!


XML docs XML docs


XML docs XML docs


XML docs XML docs


XML docs XML docs

validationvalidation!

• Decidable!:• Summary graph traversal (parsing vs. DTD)• Memoization termination• Sound and complete!

• Decidable!:• Summary graph traversal (parsing vs. DTD)• Memoization termination• Sound and complete!


Compiler Compiler VValalidation Recipeidation Recipe

• Step-by-Step:Step-by-Step:1. 1. Extract control-flow graphExtract control-flow graph2. 2. Gap-and-FieldGap-and-Field data-flow analysisdata-flow analysis3. 3. GapGapTrackTrack data-flow analysisdata-flow analysis4. 4. Summary GraphSummary Graph data-flow data-flow analysisanalysis55. . ValidationValidation ((shows)shows) graphgraph analysi analysiss


Experiments Experiments 800MHz Pentium III / Linux800MHz Pentium III / Linux

Program # Lines # Templates

Time (sec.)

chat 65 3 0.1guess 75 6 0.1calendar 77 5 0.1xbiff 561 18 0.1webboard 1132 37 0.6cdshop 1709 36 0.5jaoo 1941 73 2.4bachelor 2535 137 8.2courses 4465 57 1.3eatcs 5345 133 6.7

Many validation errors found, Many validation errors found, no spurious errorsno spurious errors


ExampleExample Revisited Revisited

html greeting = [[ Hello <[who]>, welcome to <[what]>.]];

html cover = [[ <head><title>Welcome</title></head> <body><[contents]></body>]];

html h;h = greeting <[who = ”Stranger”];h = h <[what = [[ <b>GPCE</b> ]]];show cover <[contents = h];

html greeting = [[ Hello <[who]>, welcome to <[what]>.]];

html cover = [[ <head><title>Welcome</title></head> <body><[contents]></body>]];



Planting an ErrorPlanting an Error

html greeting = [[ <td>Hello <[who]>, welcome to <[what]>.</td>]];

html cover = [[ <head><title>Welcome</title></head> <body><table><[contents]></table></body>]];






ExampleExample Revisited Revisited--- welcome.wig:13 HTML Validation:welcome.wig:7 warning: possible illegal subelement ‘td’ of ‘table’ template: <table><[contents]></table> contents: td plugs: contents:{welcome.wig:13}

--- welcome.wig:13 HTML Validation:welcome.wig:7 warning: possible illegal subelement ‘td’ of ‘table’ template: <table><[contents]></table> contents: td plugs: contents:{welcome.wig:13}

112233445566778899

1010111112121313








Problems?Problems?




OutlineOutline








Domain Specific Domain Specific RepresentationRepresentation



• Constant:Constant:• O O (1)(1)

• Plug:Plug:• O O (1)(1)

• Show:Show:• OO (|d|) (|d|)

[[ hello <[what]>! ]]

x <[g = y]

show d;



document structure



document structure

string



document structure

string templates



dynamic



static

dynamic



static

dynamic“Transmit JavaScript recipe for client-side doc. reconstruction”

“Transmit JavaScript recipe for client-side doc. reconstruction”



static

dynamic“Transmit JavaScript recipe for client-side doc. reconstruction”

“Transmit JavaScript recipe for client-side doc. reconstruction”

“Write each template to a separate file so that it can be cached”

“Write each template to a separate file so that it can be cached”


ExperimentsExperiments

• Size of HTML:Size of HTML: original HTML

JavaScript reconstruction

...all templates cached

Cut to 2.6% – 25% sizeCut to 2.6% – 25% size


Experiments Experiments (700MHz, 28.8 Modem)(700MHz, 28.8 Modem)

• TimeTime (download+render):(download+render): original HTML

...all templates cached

2.2x – 10x faster2.2x – 10x faster


Problems?Problems?




OutlineOutline








Example: ”EnterEmail”Example: ”EnterEmail”

htmlhtml input = input = [[[[ Please enter your email:<br>Please enter your email:<br> <input type=”text” name=”<input type=”text” name=”emailemail”>”>]]]];;

htmlhtml output = output = [[ Your email is: [[ Your email is: <[<[emailemail]>]> ]] ]];;

stringstring s; s; showshow input input receivereceive[s = [s = emailemail];];showshow output <[ output <[emailemail = s];= s];



formatformat EmailEmail = = regexpregexp(”<(”<wordword>@<>@<wordword>(>(\\.<.<wordword>)+”);>)+”);

htmlhtml input = input = [[[[ Please enter your email:<br>Please enter your email:<br> <input type=”text” name=”<input type=”text” name=”emailemail”>”>]]]];;






htmlhtml input = input = [[[[ Please enter your email:<br>Please enter your email:<br> <input type=”text” name=”<input type=”text” name=”emailemail” ” format=”format=”EmailEmail””>>]]]];;






htmlhtml input = input = [[[[ Please enter your email:<br>Please enter your email:<br> <input type=”text” name=”<input type=”text” name=”emailemail” ” format=”format=”EmailEmail””>>]]]];;


stringstring s; s;show input input receivereceive[s = [s = emailemail];];showshow output <[ output <[emailemail = s];= s];


Form Field Validation: Form Field Validation: ““PowerForms”PowerForms”• Domain specific languageDomain specific language::

•uniquely for uniquely for form-fieldform-field validation validation

• Declarative Declarative specification (regexps)specification (regexps)::•AAbstracts away operational detailsbstracts away operational details

• PowerForms also available as PowerForms also available as stand-alone toolstand-alone tool

PowerFormsPowerFormsPowerFormsPowerFormsHTMLHTML

JavaScript

(subset)

JavaScript

(subset)

HTMLHTML

RegexpsRegexps


Form-Form-Field InterdependencyField Interdependency

• ““Favorite LetterFavorite Letter””•Select filteringSelect filtering

• ““NYC OfficeNYC Office””•Complex interdependencyComplex interdependency


OutlineOutline








Domain Specific Language Domain Specific Language Design and Analyses:Design and Analyses:

• Yield:Yield:Flexible, Safe, and EfficientFlexible, Safe, and EfficientDynamic Generation of XMLDynamic Generation of XML


Domain Specific Language Domain Specific Language Design and Analyses:Design and Analyses:

• Yield:Yield:

• AND:AND:•Non-linear Non-linear document document constructionconstruction

•SeparatesSeparates p programmerrogrammer // d designer esigner aspectsaspects

•Guaranteed Guaranteed interaction cinteraction correspondenceorrespondence

•SStatic XML validationtatic XML validation

•CCommon fragments cachingommon fragments caching

Flexible, Safe, and EfficientFlexible, Safe, and EfficientDynamic Generation of XMLDynamic Generation of XML


Objective AssessmentsObjective Assessments

• Robustness:Robustness:•Session integritySession integrity

•State integrityState integrity

• Interaction correspondenceInteraction correspondence

•XML validityXML validity

• PerformancePerformance•Well...Well...

• ConcisenessConciseness•1/5 code (compared to Java Servlets)1/5 code (compared to Java Servlets)




Conciseness (Servlets)Conciseness (Servlets)


Conciseness (Conciseness (<<bigwigbigwig>>))service { shared int users = 0;

session Hello() { string name; show [[Enter your name: <input name=handle>]] receive[name=handle]; users++; show [[Hello <[who]>, you are user number <[count]>]] <[who=name,count=users]; show [[Goodbye <[who]>]] <[who=name]; }}


0

100

200

300

400

Servlets <bigwig>

Conciseness (Conciseness (<<bigwigbigwig>>))service { shared int users = 0;

session Hello() { string name; show [[Enter your name: <input name=handle>]] receive[name=handle]; users++; show [[Hello <[who]>, you are user number <[count]>]] <[who=name,count=users]; show [[Goodbye <[who]>]] <[who=name]; }}

session management state management document construction misc.

Overall: 1/5 code


The The <<bigwigbigwig>> Compiler Compiler

• Version 2.0:Version 2.0:• Implemented in CImplemented in C (f (for or UNIXUNIX // Linux)Linux)

•Complete source code availableComplete source code available– Approximately 2.5 MB sourceApproximately 2.5 MB source

• LicenLicenssee:: GPL (GPL (Gnu Public LicenGnu Public Licenssee))

<<bigwigbigwig>><<bigwigbigwig>>

HTMLHTML

CGI ScriptsCGI Scripts

JavaScriptJavaScript

HTTP Auth.HTTP Auth.

Java AppletsJava Applets

CompleteService

Specification

CompleteService

Specification


• Homepage:Homepage:– IntroductionIntroduction– ExamplesExamples– Ref. manualRef. manual– TutorialsTutorials– PapersPapers– PresentationsPresentations– Downloads:Downloads:

•src / binsrc / bin

– 2 Recorded Presentations (MS & IBM 2 Recorded Presentations (MS & IBM Research)Research)

http://www.brics.dk/bigwig/http://www.brics.dk/bigwig/


<<bigwigbigwig>> Publications Publications

• Concurrency ControlConcurrency Control ETAPS/FASE,ETAPS/FASE, 19981998• Runtime SystemRuntime System Computer Networks J.Computer Networks J., , 19991999• Dynamic DocumentsDynamic Documents POPL, POPL, 20002000• Form-Field ValidationForm-Field Validation WWW Journal, WWW Journal, 20002000• HTML ValidationHTML Validation PASTE, PASTE, 20012001• The The <<bigwigbigwig>> Project Project TOIT Journal,TOIT Journal, 20022002• Syntax MacrosSyntax Macros PEPM, PEPM, 20022002• Document CachingDocument Caching WWW Journal, WWW Journal, 20022002


<<bigwigbigwig>> JWIG (Java) JWIG (Java)

http://www.brics.dk/JWIG/


Thank you!Thank you!