Floodject

This is a project created by Ioannis Angelidis, David Nagy and Emil Møller Rasmussen.

PyPWS

Installation

Installing PyWPS can be a nightmare if trying to follow the instructions from the official documentation, as they are old and your server setup might differ. They are found in the links below:

http://pywps.wald.intevation.org/documentation/installation.html

http://pywps.wald.intevation.org/documentation/course/

Luckily, one of the developers (Luis de Sousa) working on PyWPS gave detailed instructions on how to install PyWPS on Ubuntu 14.04 in the following stackexchange thread:

http://gis.stackexchange.com/questions/83743/how-to-install-pywps-on-ubuntu

The instructions from there are partly used below, but changed to fit with the individual server setup:

Actual installation

Install dependencies, clone the project from GitHub and install it:

sudo apt-get install apache2 python-setuptools python-magic python-lxml  git-core wget

git clone https://github.com/geopython/PyWPS.git

cd ./PyWPS

sudo python setup.py install

Create folders for PyWPS assets

For convenience, in this example all PyWPS assets are stored in /var/www/html, a typical setup for a development environment. In a server setup it might be wiser to store processes in /srv and logs in /var/log.

sudo mkdir /var/www/html/pywps

sudo mkdir /var/www/html/wpsoutputs

sudo cp -R pywps/processes /var/www/html/pywps

Create log and configuration files:

sudo touch /var/www/html/pywps/pywps.log

sudo cp pywps/default.cfg /var/www/html/pywps/pywps.cfg

sudo pico /var/www/html/pywps/pywps.cfg

In the configuration file only the Server environment needs to be tweaked, in order to match the asset locations created before. The set up of the GRASS and MapServer environments are left for a later date.

  [server]
  maxoperations=30
  maxinputparamlength=1024
  maxfilesize=500mb
  tempPath=/tmp
  processesPath=/var/www/html/pywps/processes
  outputUrl=http://localhost/wpsoutputs
  outputPath=/var/www/html/wpsoutputs
  debug=true # deprecated since 3.2, use logLevel instead
  logFile=/var/www/pywps/pywps.log

Pass ownership to the www-data user (again, in a server setup you might want to be more conservative):

sudo chown -R www-data:www-data /var/www/html/pywps /var/www/html/wpsoutputs

Configure the web service

Copy the PyWPS CGI to /usr/lib/cgi-bin:

sudo cp webservices/cgi/pywps.cgi /usr/lib/cgi-bin

whereis wps.py

Copy the path of wps.py to the clipboard.

sudo pico /usr/lib/cgi-bin/pywps.cgi

Modify pywps.cgi to match the present setup:

export PYWPS_CFG=/var/www/html/pywps/pywps.cfg
export PYWPS_PROCESSES=/var/www/html/pywps/processes/

/usr/local/bin/wps.py $1

Give it a try:

cd /usr/lib/cgi-bin

sudo sh pywps.cgi "request=GetCapabilities&service=WPS"

Make sure Apache is configured to run CGI scripts; the CGI module might need to be explicitly enabled:

sudo a2enmod cgid

Edit the default site configuration

sudo pico /etc/apache2/sites-available/000-default.conf

Add the following to the file:

ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/
<Directory "/usr/lib/cgi-bin">
    AllowOverride None
    Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch
    Order allow,deny
    Allow from all
</Directory>

Restart Apache:

sudo service apache2 restart

Various URL strings for accessing the WPS service

Get capabilities

http://52.17.144.192/cgi-bin/pywps.cgi?service=WPS&version=1.0.0&request=getcapabilities

Execute a function

http://52.17.144.192/cgi-bin/pywps.cgi?request=execute&service=WPS&version=1.0.0&identifier=flooding&datainputs=[rasterin%3Dhttp%3A%2F%2F52.16.38.28%2FNEWTIF.tif%3Bvectorin%3Dhttp%3A%2F%2F52.16.38.28%2Ftest.geojson]

Describe process

http://52.17.144.192/cgi-bin/pywps.cgi?service=WPS&version=1.0.0&request=DescribeProcess&Identifier=flooding

Installations

Installation structure of PyWPS

To give a better overview of where the files on the server have been installed, a file-tree of the location of all important files is provided below:

/
├── /var/
|   └── /www/
|       └── /html/
|           └──/pywps/
|               ├── pywps.cfg
|               ├── pywps.log
|               ├── /wpsoutputs/
|               └── /processes/
|                     └── __init__.py
|                     └── process1.py
├── /lib/
|    └── /cgi-bin/
|        └── pywps.cgi
|
└── /etc/
    └── /apache2/
        └── /sites-available/
            └── 000-default.conf

GRASS installation on server

~
├── .grass6
|     └── rc
└── grassdata
      └── <LOCATION>
            └── <MAPSET>

File structure of the webserver

/
└── /var/
    └── /www/
        └── /html/
            └── /FlaskApp/
            	├── flaskapp.wsgi
            	└── /FlaskApp/
            	    ├── /templates/
            	    ├── /static/
            	    ├── /images
            	    └── __init__.py

Debugging

When wanting to debug there are two important file locations, the first one is the pywps.log that we created above, the second one is the general server (apache) error log. These are found in these locations

/
└── /var/
    ├── /www/
    |   └── /html/
    |       └── /pywps/
    |           └── pywps.log
    |
    └── /log/
        └── /apache2/
            └── error.log

CGI-BIN

CGI wrapper

#!/bin/sh

# Author: Jachym Cepicky
# Purpose: CGI script for wrapping PyWPS script
# Licence: GNU/GPL
# Usage: Put this script to your web server cgi-bin directory, e.g.
# /usr/lib/cgi-bin/ and make it executable (chmod 755 pywps.cgi)

# NOTE: tested on linux/apache

export PYWPS_CFG=/var/www/html/pywps/pywps.cfg
export PYWPS_PROCESSES=/var/www/html/pywps/processes/

/usr/local/bin/wps.py $1

Creating functions

It is not the name of the python script, but the name of the "Class" defined within that determines the name of the service.

Setting up Flask with Apache

http://alex.nisnevich.com/blog/2014/10/01/setting_up_flask_on_ec2.html