Documention for: webtitle.r
Created by: btiffin
 on: 21-Jun-2007
Format: text/editable
Downloaded on: 30-Apr-2025

[h1 Usage document for %webtitle.r
[contents
[numbering-on
[h2 Introduction to %webtitle.r

[p webtitle.r is an introduction to the ease and simplicity of accessing
the internet and parsing HTML.

[table/att/border="1px"/att/cellpadding="4px"
[row [cell **HTML** [cell Hyper Text Markup Language or Hypertext Markup Language
table]

[h2 webtitle At a Glance
[p Not setup is required, just **do** it.
[asis/style/font-size:75%
>> do %webtitle.r
>> do http://www.rebol.org/cgi-bin/cgiwrap/rebol/download-a-script.r?script-name=webtitle.r
connecting to: www.rebol.org
Script: "Web Page Title Extractor" (20-May-1999)
connecting to: www.rebol.com
REBOL Technologies
asis]
[h2 Using %webtitle.r
[p Requires REBOL/Core or REBOL/View console mode.

[h3 Running %webtitle.r
[p From the library with:
[asis/style/font-size:75%
>> do http://www.rebol.org/cgi-bin/cgiwrap/rebol/download-a-script.r?script-name=webtitle.r
asis]
or locally with:
[asis
>> do %webtitle.r
asis]

[h2 See also
[p There are other rebol.org scripts that use read http and parse.  There is more explanation of
**parse** in the scripts for weblinks.r and websplit.r
[br [link http://www.rebol.org/cgi-bin/cgiwrap/rebol/view-script.r?script=weblinks.r "%weblinks.r"
[br [link http://www.rebol.org/cgi-bin/cgiwrap/rebol/documentation.r?script=websplit.r "websplit usage doc"

[h2 What you can learn

[h3 Powerful builtin Internet Access
[p REBOL has fantastically simple builtin procedures for accessing the internet.
[br **read http://www.rebol.com** accesses and returns the HTML as text.  How cool
is that?

[h3 URLs
[p **http://www.rebol.com** is actually a value with a special datatype.  In REBOL
this is a **url!**.  Very powerful.  No quotes needed.  REBOL just **knows**.

[h3 Web Server defaults
[p Web Servers have default files that are returned.  http://www.rebol.com
is actually returned as http://www.rebol.com/index.html.  This is not always the
case.  Some sites return default.htm, or index.php, or index.cgi.  No need
to worry, the REBOL **read** function and the web server will work that all out
for you.  If REBOL Technologies ever changes its web server setup, a different file
may be returned and this script will still work.

[h3 parse
[p REBOL comes with a very powerful **parse** command.  It can parse strings or blocks.
In this example it is used to parse a web page as a string, and uses another power feature
of REBOL, the **tag!** datatype

[h4 tag!
[p One of the many REBOL builtin datatypes is the **tag!** datatype.  A tag is anything
surrounded in the ""<"" lessthan and "">"" greaterthan symbols.  HTML is based on tags,
as is XML, and a few other markup languages such as SGML.

[p **webtitle** uses parse to scan through the the web page looking for the <title> tag,
and scanning just past it.  That is a feature of the  **thru** rule of parsing, scan through the
string.  Then there is a **copy** rule, that informs parse that it has to copy all the following
scan and match data into a variable, in this case **title**.  Then the parse rules call **to**.
This rule is very similar to **thru** but it scans up to the string, not through it.  So the parser
scans past the html <title> tag, copies everthing between it right up to the ending </title>
tag.

[p Then it prints the **title** variable. 

[h3 Changing the page that is scanned
[p Changing the website or page that the title is extracted from is as easy as
changing the text after the http:// part following the **read** command.

[h3 Getting REBOL
[p Both REBOL/Core and REBOL/View are available
[br **free of charge** from [link http://www.rebol.com "www.rebol.com"

[h2 What can break

[p You will need access to the internet and rebol.com will
have to be up and running for this script to work.  Don't
worry, **http://www.rebol.com** is always up and running.

[h2 Credits

[table/att/border="1px"/att/cellpadding="4px"
[row [cell %webtitle.r [cell Author: Unknown
[row [cell REBOL/Core [cell Carl Sassenrath, REBOL Technologies
table]
[list
[li The rebol.org Library Team
[li Usage document by Brian Tiffin, Library Team Apprentice, [date
list]