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Overview
Web content is delivered to the end user's browser as follows:
| A user
requests content stored at a particular URL. |
The URL comes from another page, an email message,
even printed content.
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| The web server for
the hostname in question translates the URL into a path
and filename based on its configuration. |
The relationship between directories is not always
as simple as that described in the file and
directory management section. As an example,
the top level of our web server is stored in the
directory /scp_1/web_root. The file named
/scp_1/web_root/index.html can be requested using
the URL http://scholar.lib.vt.edu/index.html.
However, the URL
http://scholar.lib.vt.edu/theses/index.html does
not point to the file
/scp_1/web_root/theses/index.html. Rather, the web
server is configured to look for materials related
to the /theses directory in /theses_1. So, the file
is located at /theses_1/index.html instead.
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| If the requested
file must be parsed or executed (as in the case of
server side includes and PHP), the web server parses or
executes the file and delivers the content. |
If the server can't figure out where to find the
requested file, a standard but customizable message
is sent (something like "404: file not found").
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| The end user
receives the content. |
If the content is a web page containing images,
each image is loaded using the same process.
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Your job as a web author is to create and place content on
the web server such that it can be delivered to an end user when
its URL is requested.
The most important thing you'll need to know before
adding new content to a web server or editing existing
content is how to translate a URL into a path and filename
on the server (and vice versa). Here are a few examples of
the settings for our current web servers.
| URL |
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system path |
| http://scholar.lib.vt.edu/index.html |
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/scp_1/web_root/index.html |
| http://scholar.lib.vt.edu/theses/index.html |
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/theses_1/index.html |
| http://scholar.lib.vt.edu/ETD-db/index.html |
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/export/ETD-db/web_root/index.html |
| http://spec.lib.vt.edu/index.html |
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/spec_1/web_root/index.html |
| http://lumiere.lib.vt.edu/index.html |
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/home/www/lumiere.lib.vt.edu/web_root/index.html |
| http://etd.vt.edu/index.html |
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/home/www/etd.vt.edu/web_root/index.html |
Here is the overall view of the process of creating and
updating web content:
| Updating Existing
Content |
Creating New
Content |
| Download a file
from its current location using an FTP client such as
Fetch or
WS_FTP. Do not simply save the source from within your
web browser, as this may break dynamic content (see the
section on server
side includes). |
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| Edit the content
using a tool like BBedit for HTML
files, or a tool like Photoshop for
images. |
Create the content
using one of the same tools. |
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| Transfer the
updated content using an FTP client, overwriting the
existing content. |
Transfer the new
content to a desired location using an FTP client. |
Now you should be ready to move on to the sections on
HTML, and
file and directory
management.
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