Tag: qgis server

Sorry, this entry is only available in French.

Recently I was invited by the colleagues from OpenGIS.ch to lend a hand in a training session about QGIS server.

This was a good opportunity to update my presentation for QGIS3, to fix a few bugs and to explore the powerful capabilities of QGIS server and Python.

As a result, I published the full recipe of a Vagrant VM on github: https://github.com/elpaso/qgis3-server-vagrant

The presentation is online here: http://www.itopen.it/bulk/qgis3-server/

What’s worth mentioning is the sample plugins (I’ll eventually package and upload them to the official plugin site):

• XYZ: add simple XYZ tile server, ready to use within QGIS XYZ connections: https://github.com/elpaso/qgis3-server-vagrant/tree/master/resources/web/plugins/xyz
• custom service, does nothing but shows how to create a Python custom service by exploiting the new service capabilities available in QGIS3: https://github.com/elpaso/qgis3-server-vagrant/tree/master/resources/web/plugins/customservice
• HTTP Basic auth (how to add your auth scheme to QGIS server): https://github.com/elpaso/qgis3-server-vagrant/tree/master/resources/web/plugins/httpbasic
• more …

 

The VM uses 4 different (although similar) deployment strategies:

• good old Apache + mod_fcgi and plain CGI
• Nginx + Fast CGI
• Nginx + standalone HTTP Python wrapped server
• Nginx + standalone WSGI Python wrapped server

Have fun with QGIS server: it was completely refactored in QGIS 3 and it’s now better than ever!

 

The post QGIS 3 Server deployment showcase with Python superpowers first appeared on Open Web Solutions, GIS & Python Development.

Here is a little first experiment for a wsgi wrapper to QGIS 3 Server, not much tested, but basically working:  

#!/usr/bin/env python

# Simple QGIS 3 Server wsgi test

import signal
import sys
from cgi import escape, parse_qs
from urllib.parse import quote
# Python's bundled WSGI server
from wsgiref.simple_server import make_server

from qgis.core import QgsApplication
from qgis.server import *

# Init QGIS
qgs_app = QgsApplication([], False)
# Init server
qgs_server = QgsServer()


def reconstruct_url(environ):
    """Standard algorithm to retrieve the full URL from wsgi request
    From: https://www.python.org/dev/peps/pep-0333/#url-reconstruction
    """
    url = environ['wsgi.url_scheme']+'://'

    if environ.get('HTTP_HOST'):
        url += environ['HTTP_HOST']
    else:
        url += environ['SERVER_NAME']

        if environ['wsgi.url_scheme'] == 'https':
            if environ['SERVER_PORT'] != '443':
                url += ':' + environ['SERVER_PORT']
        else:
            if environ['SERVER_PORT'] != '80':
                url += ':' + environ['SERVER_PORT']

    url += quote(environ.get('SCRIPT_NAME', ''))
    url += quote(environ.get('PATH_INFO', ''))
    if environ.get('QUERY_STRING'):
        url += '?' + environ['QUERY_STRING']
    return url

def application (environ, start_response):

    headers = {} # Parse headers from environ here if needed

    # the environment variable CONTENT_LENGTH may be empty or missing
    # When the method is POST the variable will be sent
    # in the HTTP request body which is passed by the WSGI server
    # in the file like wsgi.input environment variable.
    try:
        request_body_size = int(environ.get('CONTENT_LENGTH', 0))
        request_body = environ['wsgi.input'].read(request_body_size)
    except (ValueError):
        request_body_size = 0
        request_body = None

    request = QgsBufferServerRequest(reconstruct_url(environ), (QgsServerRequest.PostMethod 
        if environ['REQUEST_METHOD'] == 'POST' else QgsServerRequest.GetMethod), {}, request_body)
    response = QgsBufferServerResponse()
    qgs_server.handleRequest(request, response)
    headers_dict = response.headers()
    try:
        status = headers_dict['Status']
    except KeyError:
        status = '200 OK'
    start_response(status, [(k, v) for k, v in headers_dict.items()])
    return [bytes(response.body())]

# Instantiate the server
httpd = make_server (
    'localhost', # The host name
    8051, # A port number where to wait for the request
    application # The application object name, in this case a function
)

print("Listening to http://localhost:8051 press CTRL+C to quit")

def signal_handler(signal, frame):
    """Exit QGIS cleanly"""
    global qgs_app
    print("\nExiting QGIS...")
    qgs_app.exitQgis()
    sys.exit(0)

signal.signal(signal.SIGINT, signal_handler)

httpd.serve_forever()

 

The post A little QGIS3 Server wsgi experiment first appeared on Open Web Solutions, GIS & Python Development.

Another great QGIS hackfest is gone, and it’s time for a quick report. The location was the Linux Hotel, one of the best places where open source developers could meet, friendly, geek-oriented and when the weather is good, like this time, villa Vogelsang is a wonderful place to have a beer in the garden while talking about software development or life in general. This is a short list of what kept me busy during the hackfest:

• fixed some bugs and feature requests on the official QGIS plugin repo that I’m maintaining since the very beginning
• make the QGIS official plugin repository website mobile-friendly
• QGIS Server Python Plugin API refactoring, I’ve completed the work on the new API, thanks to the ongoing server refactoring it’s now much cleaner than it was in the first version
• attribute table bugs: I started to address some nasty bugs in the attribute table, some of those were fixed during the week right after the hackfest
• unified add layer button, we had a productive meeting where we decided the path forward to implement this feature, thanks to Boundless that is funding the development, this feature is what’s I’m currently working on these days

Thanks to all QGIS donors and funders that made yet another great hackfest possible and in particular to Boundless Spatial Inc. for funding my personal expenses.    

The post Essen 2017 QGIS Hackfest first appeared on Open Web Solutions, GIS & Python Development.

QGIS Developer Sprint in Lyon   QGIS Server 3.0 is going to be better than ever! Last week I attended to the mini code-sprint organized by the french QGIS developers in Lyon.   The code sprint was focused on QGIS Server refactoring to reach the following goals:

• increase maintainability through modularity and clean code responsibilities
• increase performances
• better multi-project handling and caching
• scalability
• multi threaded rendering

By working for different companies on such a big Open Source project like QGIS, coordination between developers is fundamentally achieved through those kind of events. We were a small group of engaged QGIS Server developers and I think that the alternance between brainstorming and coding has proven to be very productive: after two days we were able to set common milestones and commitments that will ensure a bright future to QGIS Server. A huge and warm thank to the french QGIS developers that organized this meeting!   Photo: courtesy of Règis Haubourg    

The post QGIS Developer Sprint in Lyon first appeared on Open Web Solutions, GIS & Python Development.