JumpStart to the Web technologies tutorial: Universal = Resource Locator

From: Subject: JumpStart to the Web technologies tutorial: Universal Resource Locator Date: Thu, 14 Nov 2002 10:48:10 +0100 MIME-Version: 1.0 Content-Type: multipart/related; boundary="----=_NextPart_000_0019_01C28BCB.52BF0EB0"; type="text/html" X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 This is a multi-part message in MIME format. ------=_NextPart_000_0019_01C28BCB.52BF0EB0 Content-Type: text/html; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable Content-Location: http://www.sergey.com/web_course/part_3.html JumpStart to the Web technologies tutorial: Universal = Resource Locator

Jumpstart into=20 the Web technologies:	<- Prev.	Start	Contents	References	Home	Next=20 ->

URL=20 - Universal Resource Locator

How do you give an address to some resource on the Internet?=20 URL.
Universal Resource Locator (URL) is basically the unique address = for a=20 resource on the Internet. General structure of the URL is the following: =

scheme://hostname[:port]/path/filename=20
Where scheme is basically protocol, by = which=20 resource should be accessed. Depends on the scheme the URL can = look a=20 differently, here is the list of the most commonly used schemes:=20

http - HyperText Transfer Protocol (WWW server protocol), = the=20 most used one.=20

The format of this type of URL=20 = is:
http://[user:password]@hostname[:port]/path/filename[#label= |parameters],=20 where:=20

user & password - Username and password for http=20 authentication. They are optional and in most cases are not used. = It's also=20 not a good idea to use them in the URL because of security problems = it may=20 cause. If omitted and resource requires authentication, user will be = prompted.=20
hostname - Hostname of the computer where resource is = residing.=20 If ommited, the current hostname is used (the one of the current = URL).=20
port - port number, by default 80 for http.=20
path - path to resource inside the computer. If = omitted,=20 current path is used. Note, that if hostname is omitted you can use = the=20 relative path instead of the full path, which is very usefull = feature if you=20 need to build the documents and need easily move them to other=20 place.
e.g.: in document http://www.company.com/misc/main.html = you need=20 to link to http://www.company.com/misc/part1/chapter1.html, so = instead of=20 using the full URL you can use just "part1/chapter1.html".=20
filename - filename of the resource, if omitted, = index.html is=20 used (it's actually configurable in httpd config files)=20
label - label inside the file, used to position the = browser=20 inside the file=20
parameters - CGI parameters that can be specified (GET = method).=20

All of these fields are actually optional, in case if = field is=20 omitted default is used.
Note: That it's better to use URLs = with as=20 fewer fields as possible, because it allows you to build much more = portable=20 documents. For example if you put in you document the full path and = you need=20 to move it some place else, you'll have to change all the URLs inside = your=20 documents. But if you use the relative path (without hostname & = and with=20 relative path instead of the absolute one, most likely you = won't need=20 to change anything.=20

ftp - File Transfer protocol=20 =

ftp://[user:password]@hostname[:port]/path/filename, = where=20 the meaning of the fields is similar to the http protocol.=20

mailto - Send e-mail=20

mailto:address - this will open new message in = your e-mail=20 composer (netscape).=20

news - Usenet news protocol=20

news://server-name/groupname, where:=20

server-name - hostname of the news server=20
groupname - name of the newsgroup

e.g.:=20 news://news.ne.mediaone.net/alt.os.unix

More info on URLs can be found here<= /I>=20

Jumpstart into=20 the Web technologies: <- Prev. Start Contents References Home Next=20 ->

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