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Plone addon to reserve stuff in a calendar.

Project description

Not a replacement for Outlook or Google Calendar, but a system to manage reservations on the backend and to provide them on the frontend.

Introduction

Originally developed together with the municipality of Zug, Switzerland this Addon aims to combine differing reservation systems into one flexible solution.

It does so by providing a way to deal with the following usecases:

  • Manage meeting rooms in a company. Users reserve the rooms themselves without an authority confirming/denying their reservations.

  • Manage nursery spots. Parents apply for a spot in the nursery for their kid. Someone at the nursery goes through the applicants and decides who gets the spot. Parents may add an application to the waitinglist.

  • Manage community facilities. Citizens see the availability of facilities online and call the municipality to reserve a facility. The management is done internally (maybe through an already existing software). The addon is only used for display.

Screenshots

overview example calendar example reserve example confirm example

Build Status

Build Status

Requirements

  • Python 2.7

  • Plone 4.3+ ( Plone 4.1 and 4.2 had to be dropped, sorry )

  • Linux / Posix ( Windows may or may not work )

  • Postgresql 9.1+ ( Older versions DO NOT work! )

  • 1024MB+ RAM

seantis.reservation is tested using IE8+, Chrome, Firefox. IE7 is not supported! Note also that IE8 and IE9 only work right if the Plone site is in production mode. The reason for it is that those browsers ignore every stylesheet after the 32th. In production these stylesheets are merged.

Note that we also rely heavily on javascript as the calendar shown for reservations is rendered through javascript. If your requirement is to run without javascript then this is not the droid you are looking for.

Limitations

These are the things seantis.reservation currently doesn’t do, or doesn’t do well:

  • Multilanguage. It is perfectly fine to run seantis.reservation in the language of your choice, though you might have to do some translations for yourself. However, you might find the ability to run the site in multiple languages (where the language is set on a per-request basis) to be lacking or with rough edges. It should mostly work but we cannot guarantee it or tell you that we tested this well.

  • Timezones. We currently do not store a timezone with the resource. Therefore comparing different resources of different timezones is a no go.

  • Recurrence. Though it is possible to create reservations with simple daily recurrence, it is not possible to modify them, so if you create 1000 recurrences and you make a mistake you have to delete all or adjust them each.

Installation

The setup instructions assume an Ubuntu / Debian Server installation as well as basic knowledge of Plone.

Install required packages

sudo apt-get install git-core
sudo apt-get install libxml2 libxml2-dev
sudo apt-get install libxslt1.1 libxslt1-dev
sudo apt-get install python2.7 python2.7-dev

Install Postgresql

Run the installer

sudo apt-get install postgresql-9.1
sudo apt-get install postgresql-9.1-dev

If the dev package cannot be found try

sudo apt-get install postgresql-server-dev-all

Create a database user (replace your_password with your own). This password is needed later!

sudo -u postgres psql -c "CREATE USER reservation WITH PASSWORD 'your_password'"

Create the reservations database

sudo -u postgres psql -c "CREATE DATABASE reservations ENCODING 'UTF8' TEMPLATE template0"

Grant the required privileges to the reservation user

sudo -u postgres psql -c "GRANT ALL PRIVILEGES ON DATABASE reservations to reservation"

Install Plone

Download the buildout configs to the folder which will hold your Plone installation.

wget -qO - https://raw.github.com/seantis/seantis.reservation/master/buildout/buildouts.sh | bash

Or if you don’t have wget (like on OSX):

curl https://raw.github.com/seantis/seantis.reservation/master/buildout/buildouts.sh | bash

Edit your database connection settings in the database.cfg file.

nano database.cfg

Download the boostrap script

wget http://downloads.buildout.org/1/bootstrap.py

Again, alternatively with curl

curl http://downloads.buildout.org/1/bootstrap.py > bootstrap.py

Bootstrap your environment

python2.7 bootstrap.py

Run the installation (and get that coffee machine cracking)

bin/buildout

If everything went well you may now start your instance

bin/instance fg

Creating a Reservation Plone Site

Create the Site

Having started your instance, navigate to the plone root:

http://localhost:8080

It should say ‘Plone is up and running’. On this site click “Create new Plone site” If you used the develop.cfg the username and password are “admin” and “admin”.

Obviously you do not want to use develop.cfg in production!

On the “Create a Plone site” form, you should enter name and title of your plone site, followed by checking the box of the following Add-On:

Seantis Reservation - for default plone theme

Having done that, click “Create Plone Site”

Create Resource Folder

On your freshly minted Plone Site, click on “Add new…” and choose “Folder”. Use any name you like.

Add a Resource

In the newly created folder, click on “Display” and choose “Resource Listing”.

This will turn the folder into a view designed for displaying Resources.

After changing the view click on “Add new…” and choose “Resource”. Enter any name you like.

You should now see a calendar in which you can create allocations that may be reserved. One level up, in the folder view, you may add more resources and compare them. Of course there is more to learn, but this is the basic setup of the Seantis Reservation module.

Data Structure

To really understand seantis.reservation it is important to understand a few core concepts:

Resource

Resources are Dxterity content types who display a calendar and interact with the core of seantis.reservation. They are heavy on the UI side of things, while being nothing more than a foreign key in the database.

Allocations

Everyone familiar with Outlook or Google Calendar knows that one can just click on an empty spot and add a new reservation.

In seantis.reservation this is not the case. In this module, a spot that may be reserved must be marked as such first. This is called an allocation.

The idea is to allocate time which may be reserved. It is like declaring time that should be managed by reservations. Outlook and Google Calendar implicitly see all time as allocated and under their management.

One reason for this is the fact that only through limiting the available time we can calculate meaningful utilization numbers. Another reason is that some periods of time may be overbooked, other times may not, or generally speaking: some timeperiods are different than others.

Allocations therefore define how periods of time may be reserved. They may not overlap for any given resource and they are independent of Plone and part of the SQL database model.

Reserved Slots

When reserving an allocation or a part of an allocation, reserved slots are generated. They ensure that no reservation is ever granted twice by accident.

Reserved slots may start every 5 minutes. At 5.35 or 5.40 for example, but not at 5.36 or 5.39. When reserving 45 minutes of an allocation, many reserved slots are spawned and aligned. Their primary keys then ensure on a low level basis that no overlaps occur.

For a much needed example:

Resource: 1234
Allocation: 09:00 - 10:00

=> reserve 1234, 09:30 - 10:00

Reserved Slots:
    1234 09:30
    1234 09:35
    1234 09:40
    1234 09:45
    1234 09:50
    1234 09:55

=> try to reserve 1234, 09:30 - 10:00 again

Reserved Slot 1234, 09:30 already exists

Of course there are a number of optimizations to ensure that we don’t generated millions of reserved slots. But this is basically it.

Reservations

Reservations exist in two states: Pending and Approved.

Pending reservations are reservations on a waitinglist. Users have submitted them, but nobody has confirmed them. They have therefore no reserved slot associated with them.

Approved reservations are reservations who are associated with reserved slots and are therefore confirmed and binding.

Note that it is possible in the UI side of seantis.reservation to go from pending to confirmed automatically. This is called auto-approval.

FAQ

Why is Database X not an option? / Why does Postgresql < 9.1 not work?

seantis.reservation relies on a Postgresql feature introduced in 9.1 called “Serialized Transactions”. Serialized transactions are transactions that, run on multiuser systems, are guaranteed to behave like they are run on a singleuser system.

In other words, serialized transactions make it much easier to ensure that the data stays sane even when multiple write transactions are run concurrently.

Other databases, like Oracle, also support this feature and it would be possible to support those databases as well. Patches welcome.

Note that MySQL has serialized transactions with InnoDB, but the documentation does not make any clear guarantees and there is a debate going on:

http://stackoverflow.com/questions/6269471/does-mysql-innodb-implement-true-serializable-isolation

Why did you choose SQL anyway? Why not use the ZODB? Why not insert your favorite NoSQL DB here?

  • If a reservation is granted to you, noone else must get the same grant. Primary keys and transactions are a natural fit to ensure that.

  • Our data model is heavily structured and needs to be validated against a schema.

  • All clients must have the same data at all time. Not just eventually.

  • Complicated queries must be easy to develop as reporting matters.

  • The core of seantis.reservation should eventually be independent of Zope/Plone.

Why / How is my allocation colored? My allocation is green, but it should be orange/red!

Basically colors are assigned to events based on their availability:

75-100% : Green / Available

1-74% : Orange / Partly Available

0% : Unavailable

The availability is calculated by taking the total time available and dividing it by the time reserved. If an allocation is set to be approved automatically (the default) a 0% availability also means that no new reservations can be made.

If an allcation is set to be approved manually, there’s automatically an unlimited waitinglist. Reservations to that waitinglist can be made at any time - unless the allocation setting is changed - and the number of people in the waitinglist is shown on the allcation itself.

Changelog

1.0.1

  • Fixes some tiny issues

1.0

  • Initial release

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