PENGANTAR TEKNOLOGI WEB 1

PENGANTAR TEKNOLOGI WEB

Pengantar Internet (HTTP)
Antonius Rachmat C

LAN
• LAN consists of the following components:
– LAN file server is a repository of various software and data files for the network (optional)
– Nodes are the client machines on the LAN
– Wired or wireless communication media that connects the devices
• LAN network interface card (NIC) is a special adapter that links an individual device to the communication medium and specifies:
– The rate of data transmission;
– The size of the message units;
– Addressing information attached to each message
– The network topology

WAN + Wireless
• Wide area networks (WANs) are networks that cover large geographic areas.
– WANs typically connect multiple LANs
– WANs have large capacity and combine multiple channels (fiber optic, satellite, microwave, etc.)
– WANs are provided by common carriers, such as telephone companies (Sprint, AT&T, etc.)
• Wireless:
– Wifi - simple wireless networks
– WLAN - expanding the wireless connection
– WiMax - Long-range wireless
What is Internet?


Intranet vs Extranet
• Intranet: is a private enterprise network for information gathering and distribution within an organization.
• Extranet: is a community of interest created by extending an intranet to selected entities external to an organization.

Internet
• Inter-connections network
√ Memiliki bnyk sub network
√ Komputer yg berbeda-beda, media penghubung yg berbeda-beda = heterogen
• Internet = hardware, WWW (web) = software
• Beberapa komponen:
√ Router, client, server, modem, DNS, protocol, TCP/IP


Internet
• Router: hardware yang mengatur jalur data sebuah paket (message)
• Client: bagian yg meminta layanan ke server
• Server: bagian yg melayani client (response)
• Modem (modulator/demodulator):
– Modulator merupakan bagian yang mengubah sinyal informasi kedalam sinyal pembawa (Carrier) dan siap untuk dikirimkan.
– Demodulator adalah bagian yang memisahkan sinyal informasi (yang berisi data atau pesan) dari sinyal pembawa (carrier) yang diterima sehingga informasi tersebut dapat diterima dengan baik.

• DNS : Domain Name Services
– Mengasosiasikan setiap node (komputer) yg terhubung ke Internet dengan sebuah nama yg “human readable”
– Mis: 202.134.201.137 => google.com
• Protocol: aturan komunikasi data
• TCP/IP: Transmission Control Protocol / Internet Protocol
– Protocol untuk Internet

• TCP: mengatur transmisi data
– Data dibagi menjadi paket2 kecil (~1.5kb)
– Paket tsb dikirim lwt router
• IP: menerjemahkan aturan dari satu network ke network yg lain
– Memungkinkan antar jaringan berbeda saling berkomunikasi





Penjelasan
• Protokol application layer: bertanggung jawab untuk menyediakan akses kepada aplikasi terhadap layanan jaringan TCP/IP.
• Protokol host to network: berguna untuk membuat komunikasi menggunakan sesi koneksi yang bersifat connection-oriented atau broadcast yang bersifat connectionless.

Penjelasan
• Protokol lapisan network: bertanggung jawab untuk melakukan pemetaan (routing) dan enkapsulasi paket-paket data jaringan menjadi paket-paket IP.
• Protokol lapisan physical: bertanggung jawab untuk meletakkan frame-frame jaringan di atas media jaringan yang digunakan.




Sejarah Internet

Internet di Indonesia

Domain
• Adalah alamat permanen situs di dunia internet
• Identifikasi sebuah situs Istilah yang umum digunakan adalah URL.
http://www.fppti.or.id
http://www.ipi.or.id
http://www.iwapi-jabar.or.id

Generic Domains
Tata Nama

• xxx.com : commercial
http://www.kompas.com
• xxx.edu : dunia pendidikan
http://www.upi.edu
• xxx.ac.id : pendidikan
• xxx.go.id : pemerintahan
http://www.bandung.go.id
• xxx.or.id :organisasi non profit
http://www.ipi.or.id

Country-Specific Domains
• Berektensi dua huruf second level domain)
- Indonesia berekstensi id
http://www.itb.ac.id
- Australia au
http://nla.gov.au
- Jepang berekstensi .jp
http://www.jla.or.jp
• Di Indonesia: dikenal dengan domain-co.id, .ac.id, .go.id, .mil.id, .or.id

Types of Websites
• Portal Web site- www.yahoo.com
• News Web site- www.cnn.com
• Informational web site- www.smidec.gov.my
• Business/ Marketing web site- www.kraft.com
• Educational website- www.resepi.mesra.net
• Entertainment web site- www.shockwave.com
• Advocacy web site- www.hsus.org
• Personal web site- www.ukm.my/radzuan
• Blog

HTTP
• Hypertext Transport Protocol (RFC 1945)
• Tim Berners-Lee, 1991
• Language of the Web
– Protocol yang digunakan untuk komunikasi antara web browsers dan web servers
– Since 1990
• TCP port 80
• Penyempurnaan HTTP 1.0 menjadi versi 1.1 dispesifikasikan oleh IETF dengan RFC 2616
• HTTP merupakan implementasi dari protokol TCP
• Bersifat “Stateless”
– Tidak ada informasi yang disimpan
– Solusi? Cookies & Session

HTTP (2)
• HTTP bersifat request – response:
– HTTP client (user agent misalnya) mengirimkan permintaan (request) ke HTTP server dan server meresponse sesuai request tersebut
• User agent: Mozilla, Netscape, Microsoft Internet Explorer atau browser berbasis teks, Lynx atau links
• Perbedaan mendasar antara HTTP/1.1 dengan HTTP/1.0 adalah penggunaan hubungan persistent.
• HTTP/1.0 membuka satu koneksi untuk tiap permintaan URI
– header = Connection: close
• HTTP/1.1 dapat menggunakan sebuah koneksi TCP untuk beberapa permintaan URI (persistent)
– header = Connection: Keep-Alive
– kecuali jika client menyatakan tidak hendak menggunakan hubungan persistent (header = Connection: close).

HTTP Client (Browser)
• NCSA Mosaic (M. Andreesen)
• Netscape Navigator (M. Andreesen)
• Microsoft Internet Explorer
• Browser Wars of the 1990's
• Mozilla (Netscape Open Sourced)
• Now Mozilla Firefox
• Apple Safari (from Konqueror)
• Others (Opera, Lynx)

Universal Resource Location (URL)

Universal Resource Location (URL)


Universal Resource Location (URL)


Universal Resource Location (URL)

URL Path = File System Path
• URL Path “/” maps to Document Root
• Let’s say Document Root is C:\htdocs\
/ => C:\htdocs\
/images/ => C:\htdocs\images\
/a/X.html => C:\htdocs\a\X.html
HTTP 1.0 is Stateless
• Each request/response pair uses its own connection; doesn't know about other pairs
• "One-Shot"
– Server Fulfills Request, and closes connection
+ Simple
─ Hard to design pages that are "logically connected" (e.g. Amazon checkout)

What is the URL path?
• http://foo.com:8080/a/b/bar.html?hello.there#binky
• query begins with ?
– hello.there
• fragment begins with #
– binky
• So, path is between host and query/fragment
– /a/b/bar.html
• But Request-Line includes Query

Fragment
• Used by client side to scroll to named anchors
• ...
• http://foo.com/b.html#Chapter1

Request String
• The path & query part of the URL
• NOT the fragment part
• http://foo.com/dir/b.html?info=extra&hello
– /dir/b.html?info=extra&hello is the Request String

HTTP Request Messages
• GET – retrieve document specified by URL
• PUT – store specified document under given URL
• HEAD – retrieve info. about document specified by URL
• POST – give information (eg. annotation) to the server
• DELETE – remove document specified by URL
• CONNECT – for use by caches

Example Request / Response
• Client requests
http://solaria.stanford.edu/food/index.html
• Client sends
GET /food/index.html HTTP/1.0\r\n\r\n
• Server sees request with path /food/index.html
• Server maps onto Document Root
G:/webroot + /food/index.html
• Server sends back file over HTTP (e.g. HTML file)

Method: Head
• Gunakan Tantlet

Hasil

Method: GET
• Buat file cobaget.php

GET
• Ketik perintah berikut:

Method : POST


Hasil POST


HTTP Response Codes
• 1xx – Informational – request received, processing
• 2xx – Success – action received, understood, accepted
• 3xx – Redirection – further action necessary
• 4xx – Client Error – bad syntax or cannot be fulfilled
• 5xx – Server Error – server failed