1 components in perl and soap::lite team "messengers" larry mcknight, md davis bu, md pete...
Post on 16-Dec-2015
213 Views
Preview:
TRANSCRIPT
1
Components in Perland SOAP::Lite
Team "Messengers"
Larry McKnight, MDDavis Bu, MDPete Stetson, MDMaryam Kamvar
2
Table of Contents:
Project OverviewProject DemoPerl, SOAP::Lite and Components
3
Context: PalmCIS
Project and Application.Project goal is to reduce medical errors. Improving communication (whiteboard) Timely access to patient information.
PalmCIS (the app) a wireless handheld version of the CIS.
Timely access to domain knowledge (Infobuttons).
4
Communication Example:
Nurse wants orders renewed. Nurse identifies the Intern for her patient. Nurse finds the pager number for the Intern. Nurse pages intern, waits for response. Intern interrupts his current activities to
answer page. Intern must remember task (sign orders) Intern return to previous task.
Inefficient, error prone.
5
Project:A Virtual Whiteboard
Problem: Team structure changes rapidly. Identifying and contacting providers is difficult. Problem: Interruptive work environments make errors more likely.Problem: Patients are very concerned about who looks at their data.
Solution: new system. Patient centered, asynchronous, role based (like a whiteboard).
6
Legacy: WebCIS
Web based Clinical Information System CGI based (written in C). AIX Server
farm. Patient data on mainframe. Restricted
access thru UNIX sockets (DAMs). Provider Authentication data through
LDAP server. C and Perl socket drivers available. No EJB, CORBA, or .NET
7
WebCIS
8
New Problem
We would like to take advantage of principles in this class – XP, Components, etc.We want to use Perl. Legacy Perl drivers. Convincing the system admin to install EJB,
CORBA or .NET to run the project would kill it.
Solution: Use Perl as a component model.
9
Is Perl a Component Model?
Intro to PerlPerl Objects and ModulesSOAP::LiteComponent Model definitions and satisfaction with Perl
Hold questions until end
10
Intro to Perl
In the beginning: UNIX, C, sed, awk.1986 – Larry Wall Practical Extraction and Report Language Pathologically Eclectic Rubbish Lister "So lazy he created a new computer language“
V1, 12/87 Released to Usenet V4, 3/91 The Camel book. V5, 10/94 “Everything else” - Objects, Modules. V5.6, 3/2000 V5.8, 7/2002
Today: widespread use, cgi scripts, CPAN.
11
Why Perl?
Faster development time. ~1/3 – 2/3 as much code. CPAN Common things are easy, hard things are
possible.
Most things are (or can be represented as) text. Perl has excellent string handling.Perl is and (according to Larry Wall, will always be) free. Perl is fun.
12
Common Myths about Perl
Myth:Easy to learn; Fact:Easy to use. Goal has always been power over learning. Lots of quirks, Easier ways.
Myth:Slow; Fact: Mostly Fast. C bindings, Profiling. Use of appropriate data structures. Mod_perl. Don't use it to develop a CAD app or Micro-
kernel.
13
Perl Myths continued…
Myth:Insecure; Fact: Mostly Secure Taints, warnings, use safe Security by design, not obscurity
Myth:Not scalable; Fact: Very scalable The defining problem. The best inter-platform, inter-language support I
know of. It also scales down.
Myth:Un-maintainable; Fact: It Depends “A very high-level language” Perl lets you get away with stuff.
14
Why ! Perl?
Your boss/customer wants it done in some other language.Your problem has lots of numbers in it.You need a GUI.You don't know Perl. You despise the command prompt.You don't want others to see your code.
15
Perl: Data Types
Scalarsmy $null_val=""; my $count++; my $name="Larry";my $string=$name.$count; #string is “Larry1”
Arrays, Lists my @a=();my @stooges=qw(Larry Moe Curley);
Hashesmy %treatment=(diabetes=>"insulin");my $medicine=$treatment{$disease};
16
Perl: Numbers
Type automatically set to int or floats depending on context.12345 Integer -54321 Negative integer 12345.67 Floating point 6.02E23 Scientific notation 0xffff Hexadecimal 0377 Octal 4_294_967_296 Underline for legibility
Override with int or hex functions
17
Perl: Type conversion
Hashes can be arrays%fruit=('apples',3,'oranges',6);
print $fruit{apples}; #prints 3
All arrays have scalar contexts$a=(2,4,6,8); #a is 8
$b=%c; #b is the number of items in c
($sec, $min, $hour, …)=localtime;
$now=localtime; #$now is like "Fri Aug 18,…)
18
Perl: Subroutines
Arguments Passed as a single flat list of scalars (@_) Return is evaluated in the context it is called. @c=myadd($a,$b);sub mysort { my $a=shift; my $b=shift; … return @c;}$d=mysort(@c);
19
Perl: References
@alist=("pitt", "hanks", "cage", "cruise");%treat=("headache"=>"aspirin", "cold"=>"chicken soup");sub c2f { 9/5*$ARG[0]+32 };
$stars=\@alist; $therapy=\%treat; $coldtherapy=\$treat{"cold"};$convert=\&c2f;$pi=\3.1459;
print $$coldtherapy; #prints chicken souppush @blist, $stars->[3]; #cruise is blisted
$family={dad=>"Homer", mom=>"Marge", son=>"Bart"}
22
Defining Perl Objects:
package NBC::Horse; #namespaceour @ISA=("Animal"); #inheritancesub new{ my ($class, $name)=@_; my $self={name=>"$name", #anonymous reference sound=>"neigh"}; bless $self, $class; #blessed into an object} #return implied…sub sound { my $self=shift; return $self->{sound};}
23
Instantiation of Perl Objects:
use NBC::Horse;
my $horse=NBC::Horse->new("Mr. Ed");
#is equivalent to
my $horse=NBC::Horse::new("Horse", "Mr. Ed");
print $horse->name, " says ", $horse->sound, ".\n";
#prints Mr. Ed says neigh.
24
Perl Ties
DBMuse DB_File;tie %treat, "DB_File", "treatments";
my $rx=$treat{"Diabetes"}; $treat{"PUD"}="PrevPak";
Rolling your own:User Code Executed Codetie $s, "SomeClass" SomeClass->TIESCALAR()$p = $s $p = $obj->FETCH()$s = 10 $obj->STORE(10)
25
Perl Modules
The unit of software reuse in Perl is the module, a file that has a collection of related functions designed to be used by other programs and library modules. Every module has a public interface, a set of variables and functions that outsiders are encouraged to use. From inside the module, the interface is defined by initializing certain package variables that the standard Exporter module looks at. From outside the module, the interface is accessed by importing symbols as a side effect of the use statement. … When we talk about modules in this chapter, and traditional modules in general, we mean those that use the Exporter.
26
Perl Modules
#!/usr/bin/perl –wTpackage Cards::Poker; use Exporter;use strict;use vars qw(@ISA @EXPORTS $VERSION);@ISA=qw(Exporter);@EXPORTS=(shuffle @deck);@deck=();$VERSION=0.01;1;sub new{…sub shuffle{…
27
Perl POD
The Semantic Interface pod2man, pod2text, pod2html, pod2latex…
…=head1 NAMEMyModule…=head1 SYNOPSIS use MyModule;…=item foo($bar)Foo transforms $bars and returns a $baz=cutsub foo { my $bar=shift;…
28
Modules for Distribution
CPANh2xsTest HarnessPOD
http://www.cpan.org/misc/cpan-faq.htmlman perlmodlib
29
CPAN
30
Installing Modules
Finding Modulesfind `perl –e ‘print “@INC” ’`-name “*.pm” -printpmdesc
http://search.cpan.org/
Unixtar –xzvf; perl Makefile.PL; make; make test; make installperl –MCPAN -eshell
Windows (ActiveState Perl)perl ppm.pl
31
Language Interfaces & Distributed Perl?
XSJava.pmCORBA::OrbitCOMSOAP::Lite
32
XS
XS=eXternal SubroutineSee man pages perlguts, perlxs, perlxstut,perlcall, perlapi, h2xs, Chap. 21 of the Camel.
33
Building XS
h2xs -A -n Mytest
MANIFEST, Makefile.PL,Mytest.pm, Mytest.xs, Changes
edit Mytest.xs
perl Makefile.PL
make
make test
34
Example: XS
#include "EXTERN.h" #include "perl.h" #include "XSUB.h" MODULE = Mytest PACKAGE = Mytest void round(arg) double arg CODE: if (arg > 0.0) { arg = floor(arg + 0.5); }
else if (arg < 0.0){ arg = ceil(arg - 0.5); } else { arg = 0.0; } OUTPUT: arg
35
Example:calling XS
package Mytest;
…
require Dynaloader;
…
our @ISA=(…Dynaloader…);
…
bootstrap Mytest $VERSION;
36
Example: Java.pm
use Java;
$java = new Java;
$frame = $java->create_object( "java.awt.Frame","Frame's Title");
$frame->setSize(400,400);
$frame->show();
$java->do_event( $frame,"addWindowListener",\&event_handler);
…
37
Example: CORBA::ORBit
use CORBA::ORBit idl=>[‘echo.idl’];
my $orb=CORBA::ORB_init(“orbit-local-orb”);
open IOR, “echo.ior”;
my $ior=<IOR>;
close IOR;
my $echo=$orb->string_to_object($ior);
…
$echo->echoString($mystring);
38
Example: COM
http://www.extropia.com/tutorials.misc/perl_com.html
package WebMail;
use Mail::Sender;
1;
sub send {
my($from, $replyto, $to, $cc, $bcc, $smtp, $subject, $message, $file) = @_;
…
39
Example: Perl COM cont…
PerlCtrl.pl –t
=POD =BEGIN PerlCtrl %TypeLib = ( PackageName => 'WebMail',
TypeLibGUID => '{B3C98206-C910-11D3-B450-00805F9BDE4A}', ControlGUID => '{B3C98207-C910-11D3-B450-00805F9BDE4A}',
DispInterfaceIID=>'{B3C98208-C910-11D3-B450-00805F9BDE4A}', ControlName => 'WebMail',
… Methods => { 'send' =>
{ RetType => VT_BOOL,TotalParams => 9,
40
SOAP
Simple Object Access ProtocolXML standard
<s:Envelope xmlns:s=… >
<s:Header>…</s:Header>
<s:Body>
<n:foo xmlns:n="urn:fooserv">
<symbol xsi:type="xsd:string">bar</symbol>
</n:foo>
</s:Body>
</s:Envelope>
41
SOAP::Lite Client Example
#!/usr/bin/perl -w
use SOAP::Lite;
print SOAP::Lite
->uri('http://www.soaplite.com/Demo')
->proxy('http://services.soaplite.com/hibye.cgi')
->hi()
->result;
42
SOAP::Lite Client Example2
#!/usr/bin/perl -w
use SOAP::Lite +autodispatch=>
uri=>('http://www.soaplite.com/Temper'),
proxy=>('http://services.soaplite.com/temper.cgi');
print f2c(98.6);
43
SOAP::Lite CGI Server
#!/usr/bin/perl -w
use SOAP::Transport::HTTP;
SOAP::Transport::HTTP::CGI
->dispatch_to('Temperatures')
->handle;
package Temperatures;
sub f2c{
my ($class,$f)=$_;
return 5/9*($f-32);
}
44
SOAP HTTP Daemon Server
#!/usr/bin/perl -w
use SOAP::Transport;
use Temperatures;
my $daemon=SOAP::Transport::HTTP::Daemon
->new(LocalPort=>81)
->dispatch_to('/home/soaplite/modules');
print "started SOAP daemon at ",$daemon->url, "\n";
$daemon->handle;
45
SOAP::Lite
Object methods, and exceptions.mod_perl, mod_soap serversStated support for: .NET / COM MS SOAP/ Apache SOAP interoperability HTTPS / Jabber / MQSeries / SMTP / POP3 WSDL schema
46
SOAP::Lite suds
Autodispatch doesn't always work.Talking to .Net servers requires explicitly naming and typing variables in SOAP::Lite.
47
Components
What's a component? Legally Practically
48
A component defined "Legally"
"A component model defines specific interaction and composition standards. A component model implementation is the dedicated set of executable software elements required to support the execution of components that conform to the model"
"A software component is a software element that conforms to a component model, and can be independently deployed and composed without modification according to a composition standard"
Page 7 CBSE
49
Interaction Standard
"the mandatory requirements employed and enforced to enable software elements to directly interact with other software elements"
Distributed Computing?Interfacing other languages?
50
Interaction Standard
At a bare minimum: package, useFor completeness, use Exporter.
The unit of software reuse in Perl is the module, a file that has a collection of related functions designed to be used by other programs and library modules. Every module has a public interface, a set of variables and functions that outsiders are encouraged to use. From inside the module, the interface is defined by initializing certain package variables that the standard Exporter module looks at. From outside the module, the interface is accessed by importing symbols as a side effect of the use statement. … When we talk about modules in this chapter, and traditional modules in general, we mean those that use the Exporter.
51
A component explained "Technically"
Channel
Stub Skel
Component
Client Server
InterfaceInterface
Symbol table
Module
Perl
52
Perl Interaction Standard
A Symbol tableHow does the compiler know parameter types All parameters are passed as a list of scalars.
How do I know how many parameters, ordering, expected return, etc. Smantics. Read the module documentation. Same problem in every other component
interface.
53
Semantics
String foo (String bar, int baz)
raises fooException;
float divide (float numerator, float denominator);
54
Composition Standard
Combining of two or more software components yielding a new component behavior at a different level of abstraction.Clearly separate from OS and other componentsTypically involves: Installation Configuring Instantiating
55
Practical Components
Software Reuse"you need components for complex, mission critical systems, because they are robust, scalable, flexible"
56
Practical Components
Table 3.1 Interfaces Naming Meta data Interoperability Customization Composition Evolution Support Packaging and Deployment
57
Choosing a component model
State managementScalabilityRobustnessSecurityFault toleranceDeploymentPlatform SupportEase of Development
58
Perl as a Component Model
Conclusion From the definitions in the book, Perl fulfills
the requirements of a component model. From a practical perspective, Perl modules
are used as components. Perl (+/- SOAP::Lite) fares well in criteria
used to evaluate other component models. Our project benefits from legacy support by
using Perl.
59
Whiteboard Architecture
Portal
Formatting
Data Objects
DB Driver
Database
60
Whiteboard Architecture
portal
Web_BrowserSOAP_HTTP_Daemon
Patient
Provider
Mailbox
Note
Netscape
Palm
Session
RoleC
WB
LDAP_DriverDAM_Driver
DB2 MySQL
MySQL_Driver
SLAPd
Portal_CGI_API
CGI_Session_API
palm_API
netscape_API
Patient_API
Provider_API
Mailbox_API
Note_API
SQL
Role_API
MySQL_APIDAM_API LDAP_API
LDAPsocket
WB_API
61
Whiteboard Architecture
portal
Web_Browser
MySQL_Driver
SOAP_LiteSOAP_HTTP_Daemon
MySQL
WB
Patient
Provider
Mailbox
Note
Netscape
Palm
Session
RoleC
Portal_CGI_API
CGI_Session_API
Palm_Formatting_API
Netscape_Formatting_API
WB_API_thru_SOAP
SOAP
Patient_API
Provider_API
Mailbox_API
Note_API
MySQL_API
SQL
Role_API
WB_API
LDAP_DriverDAM_Driver
DB2 SLAPd
DAM_APILDAP_API
socket LDAP
top related