455 lines
18 KiB
Python

# -*- coding: UTF-8 -*-
# =============================================================================
# Copyright (C) 2012 Brad Hards <bradh@frogmouth.net>
#
# Based on wms.py, which has the following copyright statement:
# Copyright (c) 2004, 2006 Sean C. Gillies
# Copyright (c) 2005 Nuxeo SARL <http://nuxeo.com>
#
# Authors : Sean Gillies <sgillies@frii.com>
# Julien Anguenot <ja@nuxeo.com>
#
# Contact email: sgillies@frii.com
# =============================================================================
"""
Abstract
--------
The wmts module of the OWSlib package provides client-side functionality for fetching tiles from an OGC Web Map Tile Service (WMTS)
Disclaimer
----------
PLEASE NOTE: the owslib wmts module should be considered in early-beta state: it has been tested against only one WMTS server (NASA EODSIS).
More extensive testing is needed and feedback (to bradh@frogmouth.net) would be appreciated.
"""
import cgi
import urllib2
from urllib import urlencode
from etree import etree
from .util import openURL, testXMLValue
from fgdc import Metadata
from iso import MD_Metadata
from ows import ServiceProvider, ServiceIdentification, OperationsMetadata
class ServiceException(Exception):
"""WMTS ServiceException
Attributes:
message -- short error message
xml -- full xml error message from server
"""
def __init__(self, message, xml):
self.message = message
self.xml = xml
def __str__(self):
return repr(self.message)
class CapabilitiesError(Exception):
pass
class WebMapTileService(object):
"""Abstraction for OGC Web Map Tile Service (WMTS).
Implements IWebMapService.
"""
def __getitem__(self,name):
''' check contents dictionary to allow dict like access to service layers'''
if name in self.__getattribute__('contents').keys():
return self.__getattribute__('contents')[name]
else:
raise KeyError, "No content named %s" % name
def __init__(self, url, version='1.0.0', xml=None,
username=None, password=None, parse_remote_metadata=False
):
"""Initialize."""
self.url = url
self.username = username
self.password = password
self.version = version
self._capabilities = None
# Authentication handled by Reader
reader = WMTSCapabilitiesReader(
self.version, url=self.url, un=self.username, pw=self.password
)
if xml: # read from stored xml
self._capabilities = reader.readString(xml)
else: # read from server
self._capabilities = reader.read(self.url)
# avoid building capabilities metadata if the response is a ServiceExceptionReport
# TODO: check if this needs a namespace
se = self._capabilities.find('ServiceException')
if se is not None:
err_message = str(se.text).strip()
raise ServiceException(err_message, xml)
# build metadata objects
self._buildMetadata(parse_remote_metadata)
def _getcapproperty(self):
if not self._capabilities:
reader = WMTSCapabilitiesReader(
self.version, url=self.url, un=self.username, pw=self.password
)
self._capabilities = ServiceMetadata(reader.read(self.url))
return self._capabilities
def _buildMetadata(self, parse_remote_metadata=False):
''' set up capabilities metadata objects '''
#serviceIdentification metadata
serviceident=self._capabilities.find('{http://www.opengis.net/ows/1.1}ServiceIdentification')
self.identification=ServiceIdentification(serviceident)
#serviceProvider metadata
serviceprov=self._capabilities.find('{http://www.opengis.net/ows/1.1}ServiceProvider')
self.provider=ServiceProvider(serviceprov)
#serviceOperations metadata
self.operations=[]
for elem in self._capabilities.find('{http://www.opengis.net/ows/1.1}OperationsMetadata')[:]:
self.operations.append(OperationsMetadata(elem))
#serviceContents metadata: our assumption is that services use a top-level
#layer as a metadata organizer, nothing more.
self.contents={}
caps = self._capabilities.find('{http://www.opengis.net/wmts/1.0}Contents')
def gather_layers(parent_elem, parent_metadata):
for index, elem in enumerate(parent_elem.findall('{http://www.opengis.net/wmts/1.0}Layer')):
cm = ContentMetadata(elem, parent=parent_metadata, index=index+1, parse_remote_metadata=parse_remote_metadata)
if cm.id:
if cm.id in self.contents:
raise KeyError('Content metadata for layer "%s" already exists' % cm.id)
self.contents[cm.id] = cm
gather_layers(elem, cm)
gather_layers(caps, None)
self.tilematrixsets = {}
for elem in caps.findall('{http://www.opengis.net/wmts/1.0}TileMatrixSet'):
tms = TileMatrixSet(elem)
if tms.identifier:
if tms.identifier in self.tilematrixsets:
raise KeyError('TileMatrixSet with identifier "%s" already exists' % tms.identifier)
self.tilematrixsets[tms.identifier] = tms
self.themes = {}
for elem in self._capabilities.findall('{http://www.opengis.net/wmts/1.0}Themes/{http://www.opengis.net/wmts/1.0}Theme'):
theme = Theme(elem)
if theme.identifier:
if theme.identifier in self.themes:
raise KeyError('Theme with identifier "%s" already exists' % theme.identifier)
self.themes[theme.identifier] = theme
serviceMetadataURL = self._capabilities.find('{http://www.opengis.net/wmts/1.0}ServiceMetadataURL')
if serviceMetadataURL is not None:
self.serviceMetadataURL = serviceMetadataURL.attrib['{http://www.w3.org/1999/xlink}href']
else:
self.serviceMetadataURL = None
def items(self):
'''supports dict-like items() access'''
items=[]
for item in self.contents:
items.append((item,self.contents[item]))
return items
def buildTileRequest(self, layer=None, style=None, format=None, tilematrixset=None, tilematrix=None, row=None, column=None):
request = {'version': self.version, 'request': 'GetTile'}
if (layer is None):
raise ValueError("layer is mandatory (cannot be None)")
if style is None:
style = self[layer].styles.keys()[0]
if format is None:
format = self[layer].formats[0]
if tilematrixset is None:
tilematrixset = self[layer].tilematrixsets[0]
if tilematrix is None:
raise ValueError("tilematrix (zoom level) is mandatory (cannot be None)")
if row is None:
raise ValueError("row is mandatory (cannot be None)")
if column is None:
raise ValueError("column is mandatory (cannot be None)")
request = list()
request.append(('SERVICE', 'WMTS'))
request.append(('REQUEST', 'GetTile'))
request.append(('VERSION', '1.0.0'))
request.append(('LAYER', layer))
request.append(('STYLE', style))
request.append(('TILEMATRIXSET', tilematrixset))
request.append(('TILEMATRIX', tilematrix))
request.append(('TILEROW', str(row)))
request.append(('TILECOL', str(column)))
request.append(('FORMAT', format))
data = urlencode(request, True)
return data
def gettile(self, base_url=None, layer=None, style=None, format=None, tilematrixset=None, tilematrix=None, row=None, column=None):
"""Request a tile from a WMTS server
"""
data = self.buildTileRequest(layer, style, format, tilematrixset, tilematrix, row, column)
if base_url is None:
base_url = self.getOperationByName('GetTile').methods['Get']['url']
u = openURL(base_url, data, username = self.username, password = self.password)
# check for service exceptions, and return
if u.info()['Content-Type'] == 'application/vnd.ogc.se_xml':
se_xml = u.read()
se_tree = etree.fromstring(se_xml)
err_message = unicode(se_tree.find('ServiceException').text).strip()
raise ServiceException(err_message, se_xml)
return u
def getServiceXML(self):
xml = None
if self._capabilities is not None:
xml = etree.tostring(self._capabilities)
return xml
def getfeatureinfo(self):
raise NotImplementedError
def getOperationByName(self, name):
"""Return a named content item."""
for item in self.operations:
if item.name == name:
return item
raise KeyError, "No operation named %s" % name
class TileMatrixSet(object):
'''Holds one TileMatrixSet'''
def __init__(self, elem):
if elem.tag != '{http://www.opengis.net/wmts/1.0}TileMatrixSet':
raise ValueError('%s should be a TileMatrixSet' % (elem,))
self.identifier = testXMLValue(elem.find('{http://www.opengis.net/ows/1.1}Identifier')).strip()
self.crs = testXMLValue(elem.find('{http://www.opengis.net/ows/1.1}SupportedCRS')).strip()
if (self.crs == None) or (self.identifier == None):
raise ValueError('%s incomplete TileMatrixSet' % (elem,))
self.tilematrix = {}
for tilematrix in elem.findall('{http://www.opengis.net/wmts/1.0}TileMatrix'):
tm = TileMatrix(tilematrix)
if tm.identifier:
if tm.identifier in self.tilematrix:
raise KeyError('TileMatrix with identifier "%s" already exists' % tm.identifier)
self.tilematrix[tm.identifier] = tm
class TileMatrix(object):
'''Holds one TileMatrix'''
def __init__(self, elem):
if elem.tag != '{http://www.opengis.net/wmts/1.0}TileMatrix':
raise ValueError('%s should be a TileMatrix' % (elem,))
self.identifier = testXMLValue(elem.find('{http://www.opengis.net/ows/1.1}Identifier')).strip()
sd = testXMLValue(elem.find('{http://www.opengis.net/wmts/1.0}ScaleDenominator'))
if sd is None:
raise ValueError('%s is missing ScaleDenominator' % (elem,))
self.scaledenominator = float(sd)
tl = testXMLValue(elem.find('{http://www.opengis.net/wmts/1.0}TopLeftCorner'))
if tl is None:
raise ValueError('%s is missing TopLeftCorner' % (elem,))
(lon, lat) = tl.split(" ")
self.topleftcorner = (float(lon), float(lat))
width = testXMLValue(elem.find('{http://www.opengis.net/wmts/1.0}TileWidth'))
height = testXMLValue(elem.find('{http://www.opengis.net/wmts/1.0}TileHeight'))
if (width is None) or (height is None):
raise ValueError('%s is missing TileWidth and/or TileHeight' % (elem,))
self.tilewidth = int(width)
self.tileheight = int(height)
mw = testXMLValue(elem.find('{http://www.opengis.net/wmts/1.0}MatrixWidth'))
mh = testXMLValue(elem.find('{http://www.opengis.net/wmts/1.0}MatrixHeight'))
if (mw is None) or (mh is None):
raise ValueError('%s is missing MatrixWidth and/or MatrixHeight' % (elem,))
self.matrixwidth = int(mw)
self.matrixheight = int(mh)
class Theme:
"""
Abstraction for a WMTS theme
"""
def __init__(self, elem):
if elem.tag != '{http://www.opengis.net/wmts/1.0}Theme':
raise ValueError('%s should be a Theme' % (elem,))
self.identifier = testXMLValue(elem.find('{http://www.opengis.net/ows/1.1}Identifier')).strip()
title = testXMLValue(elem.find('{http://www.opengis.net/ows/1.1}Title'))
if title is not None:
self.title = title.strip()
else:
self.title = None
abstract = testXMLValue(elem.find('{http://www.opengis.net/ows/1.1}Abstract'))
if abstract is not None:
self.abstract = abstract.strip()
else:
self.abstract = None
self.layerRefs = []
layerRefs = elem.findall('{http://www.opengis.net/wmts/1.0}LayerRef')
for layerRef in layerRefs:
if layerRef.text is not None:
self.layerRefs.append(layerRef.text)
class ContentMetadata:
"""
Abstraction for WMTS layer metadata.
Implements IContentMetadata.
"""
def __init__(self, elem, parent=None, index=0, parse_remote_metadata=False):
if elem.tag != '{http://www.opengis.net/wmts/1.0}Layer':
raise ValueError('%s should be a Layer' % (elem,))
self.parent = parent
if parent:
self.index = "%s.%d" % (parent.index, index)
else:
self.index = str(index)
self.id = self.name = testXMLValue(elem.find('{http://www.opengis.net/ows/1.1}Identifier'))
# title is mandatory property
self.title = None
title = testXMLValue(elem.find('{http://www.opengis.net/ows/1.1}Title'))
if title is not None:
self.title = title.strip()
self.abstract = testXMLValue(elem.find('{http://www.opengis.net/ows/1.1}Abstract'))
# bboxes
b = elem.find('{http://www.opengis.net/ows/1.1}WGS84BoundingBox')
self.boundingBox = None
if b is not None:
lc = b.find("{http://www.opengis.net/ows/1.1}LowerCorner")
uc = b.find("{http://www.opengis.net/ows/1.1}UpperCorner")
ll = [float(s) for s in lc.text.split()]
ur = [float(s) for s in uc.text.split()]
self.boundingBoxWGS84 = (ll[0],ll[1],ur[0],ur[1])
# TODO: there is probably some more logic here, and it should probably be shared code
self.tilematrixsets = [f.text.strip() for f in elem.findall('{http://www.opengis.net/wmts/1.0}TileMatrixSetLink/{http://www.opengis.net/wmts/1.0}TileMatrixSet')]
self.resourceURLs = []
for resourceURL in elem.findall('{http://www.opengis.net/wmts/1.0}ResourceURL'):
resource = {}
for attrib in ['format', 'resourceType', 'template']:
resource[attrib] = resourceURL.attrib[attrib]
self.resourceURLs.append(resource)
#Styles
self.styles = {}
for s in elem.findall('{http://www.opengis.net/wmts/1.0}Style'):
style = {}
isdefaulttext = s.attrib.get('isDefault')
style['isDefault'] = (isdefaulttext == "true")
identifier = s.find('{http://www.opengis.net/ows/1.1}Identifier')
if identifier is None:
raise ValueError('%s missing identifier' % (s,))
title = s.find('{http://www.opengis.net/ows/1.1}Title')
if title is not None:
style['title'] = title.text
self.styles[identifier.text] = style
self.formats = [f.text for f in elem.findall('{http://www.opengis.net/wmts/1.0}Format')]
self.infoformats = [f.text for f in elem.findall('{http://www.opengis.net/wmts/1.0}InfoFormat')]
self.layers = []
for child in elem.findall('{http://www.opengis.net/wmts/1.0}Layer'):
self.layers.append(ContentMetadata(child, self))
def __str__(self):
return 'Layer Name: %s Title: %s' % (self.name, self.title)
class OperationsMetadata:
"""Abstraction for WMTS OperationsMetadata.
Implements IOperationMetadata.
"""
def __init__(self, elem):
"""."""
self.name = elem.attrib['name']
# formatOptions
self.formatOptions = [f.text for f in elem.findall('{http://www.opengis.net/ows/1.1}Format')]
methods = []
for verb in elem.findall('{http://www.opengis.net/ows/1.1}DCP/{http://www.opengis.net/ows/1.1}HTTP'):
url = verb.find('{http://www.opengis.net/ows/1.1}Get').attrib['{http://www.w3.org/1999/xlink}href']
encodings = []
constraints = verb.findall('{http://www.opengis.net/ows/1.1}Get/{http://www.opengis.net/ows/1.1}Constraint')
for constraint in constraints:
if constraint.attrib['name'] == "GetEncoding":
for encoding in constraint.findall('{http://www.opengis.net/ows/1.1}AllowedValues/{http://www.opengis.net/ows/1.1}Value'):
encodings.append(encoding.text)
if len(encodings) < 1: # KVP is only a SHOULD requirement, and SFS doesn't provide it.
encodings = ['KVP']
methods.append(('Get', {'url': url, 'encodings': encodings}))
self.methods = dict(methods)
class WMTSCapabilitiesReader:
"""Read and parse capabilities document into a lxml.etree infoset
"""
def __init__(self, version='1.0.0', url=None, un=None, pw=None):
"""Initialize"""
self.version = version
self._infoset = None
self.url = url
self.username = un
self.password = pw
def capabilities_url(self, service_url):
"""Return a capabilities url
"""
qs = []
if service_url.find('?') != -1:
qs = cgi.parse_qsl(service_url.split('?')[1])
params = [x[0] for x in qs]
if 'service' not in params:
qs.append(('service', 'WMTS'))
if 'request' not in params:
qs.append(('request', 'GetCapabilities'))
if 'version' not in params:
qs.append(('version', self.version))
urlqs = urlencode(tuple(qs))
return service_url.split('?')[0] + '?' + urlqs
def read(self, service_url):
"""Get and parse a WMTS capabilities document, returning an
elementtree instance
service_url is the base url, to which is appended the service,
version, and request parameters
"""
getcaprequest = self.capabilities_url(service_url)
#now split it up again to use the generic openURL function...
spliturl=getcaprequest.split('?')
u = openURL(spliturl[0], spliturl[1], method='Get', username = self.username, password = self.password)
return etree.fromstring(u.read())
def readString(self, st):
"""Parse a WMTS capabilities document, returning an elementtree instance
string should be an XML capabilities document
"""
if not isinstance(st, str):
raise ValueError("String must be of type string, not %s" % type(st))
return etree.fromstring(st)