forked from kartverket/kivyMaps
/
WFSOverlayServer.py
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WFSOverlayServer.py
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from projections import *
from urllib2 import urlopen
from httplib import HTTPConnection
from threading import Thread
from kivy.logger import Logger
from kivy.loader import Loader
from os.path import join, dirname
import time, os
import hashlib
GMLNS = "http://www.opengis.net/gml"
try:
from pyproj import Proj
from lxml.etree import ElementTree as ET
except:
# try:
from xml.etree import ElementTree as ET
# except:
# pass
class WFSOverlayServer(object):
cache = {}
available_maptype = dict(roadmap = 'Roadmap') # default
type = "wfs" # TODO: replace handling in mapviewer with action handlers in the overlay class
def __init__(self, progress_callback=None):
self.progress_callback = progress_callback
def setProgressCallback(self, progress_callback):
self.progress_callback = progress_callback
def load(self, url):
# read from internet
blocksize = 4096
self.progress_callback(0)
fd = urlopen(url)
idata = fd.read(blocksize)
loaded = blocksize
while True:
bdata = fd.read(blocksize)
if not bdata: break
loaded += blocksize
if self.progress_callback:
self.progress_callback(loaded)
idata += bdata
fd.close()
self.progress_callback(-1)
return idata
def findGeometry(self, elem):
geoms = elem.find("{%s}Point" % GMLNS)
if geoms is not None:
return geoms
geoms = elem.find("{%s}LinearRing" % GMLNS)
if geoms is not None:
return geoms
for c in elem.getchildren():
geom = self.findGeometry(c)
if geom is not None:
return geom
def findGeometries(self, members):
geoms = []
for m in members:
geom = self.findGeometry(m)
if geom is not None:
geoms.append(geom)
return geoms
def get(self, parent, width, height):
self.bl = parent.bottom_left
self.tr = parent.top_right
self.zoom = parent.zoom
url = self.geturl(self.bl[0], self.bl[1], self.tr[0], self.tr[1])
if not url:
return None
key = hashlib.md5(url).hexdigest()
if key in self.cache:
return self.cache[key]
try:
xml = self.load('http://' + self.provider_host + url)
tree = ET.fromstring(xml)
members = tree.findall("{%s}featureMember" % GMLNS)
self.geometries = self.findGeometries(members)
self.cache[key] = self.geometries
return self.geometries
except Exception,e:
Logger.error('OverlayServer could not find (or read) WFS from %s [%s]' % (url, e))
image = None
def getInfoText(self, member):
fields = member.getchildren()[0].getchildren()
info = ""
for field in fields:
if field.text is not None and field.text.strip() != "":
info += "%s: %s\n" % (field.tag[field.tag.index("}")+1:], field.text)
return info
def getInfo(self, lat, lon, epsilon):
try:
url = self.geturl(lat-epsilon, lon-epsilon, lat+epsilon, lon+epsilon)
except:
return None
try:
xml = self.load('http://' + self.provider_host + url)
tree = ET.fromstring(xml)
member = tree.find("{%s}featureMember" % GMLNS)
if member is not None:
infotext = self.getInfoText(member)
return infotext
except Exception,e:
Logger.error('OverlayServer could not find (or read) WFS from %s [%s]' % (url, e))
return None
def xy_to_co(self, lat, lon):
if self.customBounds:
x, y = latlon_to_custom(lat, lon, self.bounds)
elif self.isPLatLon: # patch for android - does not require pyproj library
x, y = lon, lat
elif self.isPGoogle: # patch for android - does not require pyproj library
x, y = latlon_to_google (lat, lon)
else:
x, y = transform(pLatlon, self.projection, lon, lat)
return x,y
def co_to_ll(self,x,y):
if self.customBounds:
l, m = custom_to_latlon(x, y, self.bounds)
elif self.isPLatLon: # patch for android - does not require pyproj library
l, m = y, x
elif self.isPGoogle: # patch for android - does not require pyproj library
l, m = google_to_latlon (y, x)
else:
l, m = transform(self.projection, pLatlon, y, x)
return l, m
def geturl(self, lat1, lon1, lat2, lon2):
try:
x1, y1 = self.xy_to_co(lat1, lon1)
x2, y2 = self.xy_to_co(lat2, lon2)
return self.url + "&bbox=%f,%f,%f,%f" % (x1, y1, x2, y2)
except RuntimeError, e:
return None
def parseFeature(self, feature, data):
try:
name = feature.find("Name").text
title = feature.find("Title").text
except:
name = None
title = None
srss = feature.findall("DefaultSRS")
if name:# and srss:
data[name] = map(lambda x:x.text, srss)
if self.debug:
print "Provider %s provides feature %s in projections %s" % (self.provider_host, name, data[name])
def initFromGetCapabilities(self, host, baseurl, feature = None, index = 0, srs = None):
self.debug = (feature == None) and (index == 0)
# GetCapabilities (Features + SRS)
capabilities = urlopen(host + baseurl + "?SERVICE=WFS&Request=GetCapabilities").read().strip()
try:
tree = ET.fromstring(capabilities)
if self.debug:
ET.dump(tree)
features = tree.findall("FeatureType") #TODO: proper parsing of cascading layers and their SRS
data = {}
for f in features:
self.parseFeature(f, data)
# Choose Feature and SRS by (alphabetical) index
if feature is None:
feature = sorted(data.keys())[index]
if srs is None:
srs = sorted(data[feature])[0]
except:
pass
print "Displaying from %s/%s: feature %s in SRS %s." % (host, baseurl, feature, srs)
# generate tile URL and init projection by EPSG code
self.feature = feature
self.url = baseurl + "?typeName=namespace:%s&SERVICE=WFS&VERSION=1.1.0&REQUEST=GetFeature&maxFeatures=50" % (feature)
self.isPGoogle = False
self.isPLatLon = False
if srs=="EPSG:4326":
self.isPLatLon = True
elif srs=="EPSG:900913" or srs == "EPSG:3857":
self.isPGoogle = True
try:
self.projection = pGoogle
except:
pass
else:
try:
self.projection = Proj(init=srs)
except:
pass