Web Clients

Programming for Bioinformatics
HTTP
Perl
Ralf Zimmer, Institut für Informatik, Lehrstuhl für Praktische Informatik und Bioinformatik, WS 2010/2011: Bioinformatics Programming Course 1
Web Clients with Perl
HTML
document
with links
Click
Web
browser
User
Web
server
some
application
Web
client
(Perl)
Ralf Zimmer, Institut für Informatik, Lehrstuhl für Praktische Informatik und Bioinformatik, WS 2010/2011: Bioinformatics Programming Course 2
Web Clients with Perl and also Web Servers ...
HTML
document
with links
Click
Web
browser
User
Web
client
(Perl)
Web
server
some
application
Web
server
(Perl)
Ralf Zimmer, Institut für Informatik, Lehrstuhl für Praktische Informatik und Bioinformatik, WS 2010/2011: Bioinformatics Programming Course 3
Web Clients with Perl and also Web applications ...
HTML
document
with links
Click
Web
browser
User
Web
client
(Perl)
Web
server
some
application
CGI
script
(Perl)
Application
(Perl, ...)
Ralf Zimmer, Institut für Informatik, Lehrstuhl für Praktische Informatik und Bioinformatik, WS 2010/2011: Bioinformatics Programming Course 4
Web Clients: Introduction
HTML
document
with links
Click
Web
browser
User
Web
client
(Perl)
HyperText
Transfer
Protocol
Web
server
some
application
CGI
script
(Perl)
Application
(Perl, ...)
Ralf Zimmer, Institut für Informatik, Lehrstuhl für Praktische Informatik und Bioinformatik, WS 2010/2011: Bioinformatics Programming Course 5
Web Clients: Introduction
•
•
HTTP = Hyper-Text Transfer Protocol
protocol to specify data transfer for the WWW (i.e. data transmitted when
clicking a hyperlink (URL) or submitting a form)
•
URL = Uniform Resource Locator (http://<host>/<path_to_document>)
•
HTTP-client = program communicating via the HTTP protocol (with a
Web/HTTP server)
•
Why writing web client programs?
– automating tedious clicking
– downloading many pages, many data items
– schedule tasks at certain times
– ...
History:
– Tim Berners-Lee (CERN, CH): WWW
– 1993 U.Illinois, Urbana-Champaign: Mosaic Browser
– 1994 Netscape Navigator
•
Ralf Zimmer, Institut für Informatik, Lehrstuhl für Praktische Informatik und Bioinformatik, WS 2010/2011: Bioinformatics Programming Course 6
Web Clients: Introduction
HTML
document
with links
Click
Web
browser
User
Web
client
(Perl)
Web
server
some
application
CGI
script
(Perl)
Application
(Perl, ...)
Ralf Zimmer, Institut für Informatik, Lehrstuhl für Praktische Informatik und Bioinformatik, WS 2010/2011: Bioinformatics Programming Course 7
Web Clients: Introduction
HTML
document
with links
Click
Web
browser
User
Web
client
(Perl)
listen to a port
of the network
Request
Web
server
some
application
CGI
script
(Perl)
Application
(Perl, ...)
Ralf Zimmer, Institut für Informatik, Lehrstuhl für Praktische Informatik und Bioinformatik, WS 2010/2011: Bioinformatics Programming Course 8
Web Clients: Introduction
Web
browser
listen to a port
of the network
Request
Berkeley
Sockets
Web
server
Berkeley
Sockets
TCP/IP
Ralf Zimmer, Institut für Informatik, Lehrstuhl für Praktische Informatik und Bioinformatik, WS 2010/2011: Bioinformatics Programming Course 9
Web Clients: Sample Session
Web
browser
Web
server
http://www.lmu.de/
Use http, hypertext
transfer protocol
... and this
document
contact this host
Ralf Zimmer, Institut für Informatik, Lehrstuhl für Praktische Informatik und Bioinformatik, WS 2010/2011: Bioinformatics Programming Course 10
http://www.lmu.de/
Ralf Zimmer, Institut für Informatik, Lehrstuhl für Praktische Informatik und Bioinformatik, WS 2010/2011: Bioinformatics Programming Course 11
Web Clients: Sample Session
Web
browser
Web
server
http://www.lmu.de/
Use http, hypertext
transfer protocol
... and this
document
contact this host
a GET Request
Don‘t close the
connection
after
Client software
server
answer
revision
server
name
used
in request
client
can
GET / HTTP/1.0
accept these
Connection: Keep-Alive
documents
User-Agent: Mozilla/3.0
Host: www.lmu.de
Accept: image/gif, image/jpeg, */*
Ralf Zimmer, Institut für Informatik, Lehrstuhl für Praktische Informatik und Bioinformatik, WS 2010/2011: Bioinformatics Programming Course 12
Web Clients: Sample Session
Web
browser
Web
server
Request
http://www.lmu.de/
Response
GET / HTTP/1.0
Connection: Keep-Alive
User-Agent: Mozilla/3.0
Host: www.lmu.de
Accept: image/gif, image/jpeg, */*
HTTP/1.0 200 Ok
Date: Tue, 01 Jan 2002, 10:00 GMT
Server: Apache/1.1.1
Content-type: text/html
Content-length: ...
Last-modified: ...
<title>Example</title>
[HTML text ...]
Ralf Zimmer, Institut für Informatik, Lehrstuhl für Praktische Informatik und Bioinformatik, WS 2010/2011: Bioinformatics Programming Course 13
<img src=„images/lmu.gif“>
Web Clients: Sample Session
> telnet www.lmu.de 80
Trying 141.84.120.25...
Connected to www.lmu.de.
Escape character is '^]'.
GET / HTTP/1.0
host:www.lmu.de
HTTP/1.1 200 OK
Server: Microsoft-IIS/4.0
Content-Location: http://141.84.120.25/index.htm
Date: Wed, 16 Jan 2002 19:41:36 GMT
Content-Type: text/html
Accept-Ranges: bytes
Last-Modified: Thu, 10 Jan 2002 18:17:39 GMT
ETag: "632921639ac11:1a6f4"
Content-Length: 9811
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
...
Ralf Zimmer, Institut für Informatik, Lehrstuhl für Praktische Informatik und Bioinformatik, WS 2010/2011: Bioinformatics Programming Course 14
Web Clients: Sample Session
Web
browser
Web
server
Request
http://www.lmu.de/
Response
GET /images/lmu.gif HTTP/1.0
Connection: Keep-Alive
User-Agent: Mozilla/3.0
Host: www.lmu.de
Accept: image/gif, image/jpeg, */*
HTTP/1.0 200 Ok
Date: Tue, 01 Jan 2002, 10:00 GMT
Server: Apache/1.1.1
Content-type: text/html
Content-length: ...
Last-modified: ...
[GIF-Data]
Ralf Zimmer, Institut für Informatik, Lehrstuhl für Praktische Informatik und Bioinformatik, WS 2010/2011: Bioinformatics Programming Course 15
Web Clients: Sample Session
Web
browser
Web
server
Request
http://www.lmu.de/
Response
GET /example.html HTTP/1.0
Connection: Keep-Alive
User-Agent: Mozilla/3.0
Host: www.lmu.de
Accept: image/gif, image/jpeg, */*
HTTP/1.0 200 Ok
Date: Tue, 01 Jan 2002, 10:00 GMT
Server: Apache/1.1.1
Content-type: text/html
Content-length: ...
Last-modified: ...
[HTML Data]
Ralf Zimmer, Institut für Informatik, Lehrstuhl für Praktische Informatik und Bioinformatik, WS 2010/2011: Bioinformatics Programming Course 16
HTTP log
GET / HTTP/1.1
Host: darwin.bio.informatik.uni-muenchen.de:6419
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; de-DE; rv:0.9.2) Gecko/20010726 Netscape6/6.1
Accept: text/xml, application/xml, application/xhtml+xml, text/html;q=0.9, image/png, image/jpeg,
image/gif;q=0.2, text/plain;q=0.8, text/css, */*;q=0.1
Accept-Language: de-DE
Accept-Encoding: gzip,deflate,compress,identity
Accept-Charset: ISO-8859-1, utf-8;q=0.66, *;q=0.66
Keep-Alive: 300
Connection: keep-alive
If-Modified-Since: Wed, 09 Jan 2002 19:13:01 GMT
Cache-Control: max-age=0
HTTP/1.1 200 OK
Date: Wed, 09 Jan 2002 19:13:37 GMT
Server: Apache/1.3.20 (Linux/SuSE)
Content-Location: index.html.de
Vary: negotiate,accept-language
TCN: choice
Keep-Alive: timeout=15, max=100
Connection: Keep-Alive
Transfer-Encoding: chunked
Content-Type: text/html
Content-Language: de
879
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
<HEAD>
<TITLE>Webserver Testseite</TITLE>
...
Ralf Zimmer, Institut für Informatik, Lehrstuhl für Praktische Informatik und Bioinformatik, WS 2010/2011: Bioinformatics Programming Course 17
Schedule WS 2010/11
9 ct
10:00
10:45
11:15
Monday
Tuesday
Wednesday
Thursday
Friday
Groups &
Organisation
(Zimmer)
Perl Intro
(Küffner)
Tools &
Databases
(Petri)
Alignment
(Erhard)
SSP (Secondary
Introduction
(Zimmer)
Perl Intro
(Küffner)
Tools &
Databases
(Petri)
Alignment
(Erhard)
SSP (Secondary
Assignments I Assignments
/ Surfing
II / Skripting
Assignments
III / Skripting
Assignments
Programming
Assignments
Programming
Tools (Unix/
cvs/Make/...)
(Zimmer)
HTML/HTTP
(Küffner)
Databases/
SQL
(Windhager)
Alignment
(Erhard)
Validation
(Petri)
Unix/Shell
(Petri)
Practical Perl
Perl/CGI
(Küffner)
Java/JDBC
Packages
(Windhager)
Programming
Programming
Programming
structure prediction)
(Zimmer)
structure prediction)
(Zimmer)
Validation
(Petri)
Programming
Programming
12:45
18:00
24:00
Ralf Zimmer, Institut für Informatik, Lehrstuhl für Praktische Informatik und Bioinformatik, WS 2010/2011: Bioinformatics Programming Course 18