LIS654 lecture 3
omeka installation and system
overview start
Thomas Krichel
2011-10-05
this lecture
• Introduction to the Internet.
• Introduction to wotan.
• Introduction to omeka.
Internet application protocols
• Most of the time in digital libraries, we
assume that Internet access works.
• What we need are protocols that make the
Internet do something useful.
• Such protocols are called Internet application
protocols.
• The most important one of them is the
domain name system.
Domain Name System
• Domain Name System allows us to associate humanfriendly names with IP addresses. These names are
called domains names.
• Domain names can be leased from domain nate
registrars.
• A machine with a domain name on the Internet is
called a host.
• When we know the domain name of the host, we can
communicate with the host.
protocols to communicate with hosts
• There are two protocol we use in this class.
– We use http to work with the omeka web
interface
– We use ssh for some special operations.
• Both protocols are client/server protocols.
• You run as ssh or http client on your local
machine.
• You communicate with a machine that runs
ssh or http server software.
the ssh protocol
• ssh is protocol that uses public key
cryptography to encrypt a stream of
communication between client and server.
• This allows us to privately manipulate the
server. Or “manipulations” are really just
changes to files on the server that contain our
web pages.
• The ssh client software we use on the PC is
called WinSCP. It is a file transfer program.
the host key
• When an ssh client opens a connection with a
host, it requests its key.
• If you have not connected to the host before,
you get a warning that your ssh client does not
know the host with that key. When you accept,
your ssh client remembers the key.
• If you connect to the a host you have a key
stored for and the key changes, your ssh client
will warn you. This may be a host controlled by a
mafioso.
our server
• Is the machine wotan.liu.edu
• We also say it is a “host” on the Internet.
• wotan is the head of the gods in the Germanic
legend. The name has nothing to do with
Chinese food.
• It is a humble PC.
• It runs the testing version of Debian/GNU Linux.
• It runs both http and ssh server software.
• It is maintained by Thomas Krichel.
user name & password
• To open a meaningful ssh session on wotan,
you need a use name and a password.
• You can choose your user name as a short form
of your own name.
• It should be all lowercases and can not have
spaces.
• Please don't choose an insecure password.
the web site
• As part of the course, you are being provided
with web space on the server wotan.liu.edu, at
the URL
http://wotan.liu.edu/home/user
where user is a user name that you have chosen.
• This shows a list of available fails as prepared by
the web server at wotan.
• This is a page that Thomas has prepared for you.
omeka
• Omeka is an open-source software for imagebased repositories.
• Each of you gets a complete installation of
omeka installed in your home directory.
• Omeka uses PHP [2 slides].
• Omeka uses mySQL [2 slides].
PHP
• Omeka is written in PHP. PHP is the PHP
Hypertext Processor, a high level scripting
language.
• PHP code is interpreted by the web server.
• On wotan we run the Apache web server.
• Apache on wotan is configured in such a way
as to interpret PHP.
Apache interprets PHP
• When Apache on wotan finds a file that has
the ending .php, it does not send it to the web
client directly.
• Instead it scans the page for special processing
instructions, <?php … ?> and sends these
processing instructions to a PHP interpreter.
• Then it sends the processed code (usually in
HTML) to the client.
• This verry slow and inefficient.
mySQL
• Omeka uses the mySQL database system to store
data. It keeps as set of databases.
• Your database has the same name as your user
name.
• The database was created by Thomas before
today’s class by running the mySQL commands
CREATE DATABASE user;
GRANT ALL ON user.* to 'user'@'localhost' IDENTIFIED
BY 'secret' WITH GRANT OPTION;
where user is your username and secret is your
secret word.
the PHPmyadmin site
• At http://wotan.liu.edu/phpmyadmin we have
the PHPmyadmin installation.
• PHPmyadmin is a web interface, written for
the administration of mySQL, written in PHP.
Thus you don’t have to learn mySQL
commands.
• You gain access to the interface by login with
your user name and your secret word.
the omeka site
• As part of the course, you are being provided
with web space on the server wotan.liu.edu,
at the URL
http://wotan.liu.edu/omeka/user
where user is a user name that you have
chosen.
• This URL will initially redirect to an
initialization screen. Fill it out.
filling out the form
• Things to note
– “Superuser Account Username”
– “Email” for password reminders to the superuser.
Note that wotan can not send out non-local email
;-(
– “Administrator Email” will be noted on the site
• All other settings can be left at the default
and/or can be changed in the “general
settings” later.
omeka’s mySQL tables
• Each database has a set of tables inside.
• The tables that omeka creates, and then uses,
all have a name starting with “omeka_”.
• You can create other tables in your mySQL
database but choose names that don’t start
with “omeka_”.
• You can see the tables created once you have
filled out the installation form.
some generalities about Debian
• Debian is an open-source computer operating
system developed and maintained by a large
group of volunteer.
• Debian packages together a very large set of
pieces of software into a coherent system.
• Wotan runs the testing version.
• It provides a version of the UNIX operating
system using Linux.
files, directories and links
• Files are continuous chunks data on disks
that are required for software applications.
• Directories are files that contain other files.
Microsoft calls them folders.
• In UNIX, the directory separator is “/”
• The top directory is “/” on its own.
users and groups
• “root” is the user name of the superuser.
• The superuser has all privileges.
• There are other physical users, i.e. persons
using the machine
• There are users that are virtual, usually
created to run a daemon. For example, the
web sever in run by a user www-data.
• Arbitrary users can be put together in
groups.
permission model
• Permission of files are given
– to the owner of the file
– to the group of the file
– and to the rest of the world
• A group is a grouping of users. Unix allows
to define any number of groups and make
users a member of it.
• The rest of the world are all other users
who have access to the system. That
includes www-data!
winscp
• In winscp, the client that we use here most of
the time, we don't make advanced use of public
keys, we simply give a password.
• Note that winscp does not establish a
connection to wotan. It simply uses ssh as a
means to transfer files.
• When winscp saves a file, it may require to open
a new connection and will ask you the password
again. This request may be in a window you
can't immediately see.
ssh and mac os/x
• In the past I told Mac users to investigate investigate a
software called fugu:
http://rsug.itd.umich.edu/software/fugu/
• A student made me aware of TextWrangler at
http://www.barebones.com/products/textwrangler/
– This is an editor, not an ssh client but
– It has support for remote file storing via ssh.
– I think it also has a HTML editing mode.
– My student was pleased with it.
open a wotan session with winscp
• If you see a list of session, click on “new session”.
– The host name is “wotan.liu.edu”.
– Give your user name.
– Click on “save”, this will save the session, after “ok”.
• You will be lead to the list of saved sessions, doubleclick to open a session.
• At initial connection, you will be shown a warning
message that you can ignore.
• When saving or duplicating files, you may be asked to
enter your password again. Watch out for that.
home directory
• When your connection with wotan, and you
have authenticated as a certain user, you will
be shown your home directory.
• On wotan this is /home/user where user is
your user name.
• There you see a bunch of files starting with a
dot. Leave them alone.
• And you see a bunch of directories.
initial files on wotan
• A directory called public_html. This is your web
site.
• A directory called omeka-version where version
is a version number.
• A symbolic link (aka symlink, aka shortcut)
called omeka leading to omeka-version. This
there for updating the installation later.
web home directory
• The web home directory is /var/www.
• There you see a directory home, with a series
of links
– they have a user name as file name
– they go to your home/public_html directory
• There you see a directory omeka with a series
of links
– they have a user name as file name
– they go to your omeka directory
web site address
• http://wotan.liu.edu/ goes to the /var/www
directory. There it shows the file index.html.
• http://wotan.liu.edu/home/user goes to the
/var/www/home directory, where it finds the
link to the public_html directory of the user
user.
• http://wotan.liu.edu/omeka/user goes to the
/var/www/omeka directory, where it finds the
link to the omeka directory. There it shows
index.php.
the admin interface
• The admin interface for your omeka site is at
http://wotan.liu.edu/omeka/user/admin.
• You simply add ‘admin’ to your omeka
address. For trivial security, there is no link to
this place. Bookmark it in your browser.
omeka/db.ini
• This contains the instructions that allow to
connect to your database.
• Since PHP is executed by the web server as
www-data, and that is not a member of a
group with you, the file has to be readable by
all.
• Security of omeka is not Fort Knox.
omeka/themes
• There we have themes. Each theme is in a
directory.
• You can install a new theme by downloading a
theme from the omeka theme web site
http://omeka.org/add-ons/themes/, upload it
and then selected it from the admin interface.
• Let us try this out now.
http://openlib.org/home/krichel
Please shutdown the computers when
you are done.
Thank you for your attention!