# -*- coding: ISO-8859-15 -*-
# =============================================================================
# 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
# =============================================================================
"""
API for Web Map Service (WMS) methods and metadata.
Currently supports only version 1.1.1 of the WMS protocol.
"""
import cgi
import urllib2
from urllib import urlencode
import warnings
from etree import etree
from .util import openURL, testXMLValue, extract_xml_list, xmltag_split
from fgdc import Metadata
from iso import MD_Metadata
class ServiceException(Exception):
"""WMS 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 WebMapService(object):
"""Abstraction for OGC Web Map Service (WMS).
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='1.1.1', 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 = WMSCapabilitiesReader(
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
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 = WMSCapabilitiesReader(
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
serviceelem=self._capabilities.find('Service')
self.identification=ServiceIdentification(serviceelem, self.version)
#serviceProvider metadata
self.provider=ServiceProvider(serviceelem)
#serviceOperations metadata
self.operations=[]
for elem in self._capabilities.find('Capability/Request')[:]:
self.operations.append(OperationMetadata(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('Capability')
#recursively gather content metadata for all layer elements.
#To the WebMapService.contents store only metadata of named layers.
def gather_layers(parent_elem, parent_metadata):
for index, elem in enumerate(parent_elem.findall('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:
warnings.warn('Content metadata for layer "%s" already exists. Using child layer' % cm.id)
self.contents[cm.id] = cm
gather_layers(elem, cm)
gather_layers(caps, None)
#exceptions
self.exceptions = [f.text for f \
in self._capabilities.findall('Capability/Exception/Format')]
def items(self):
'''supports dict-like items() access'''
items=[]
for item in self.contents:
items.append((item,self.contents[item]))
return items
def getcapabilities(self):
"""Request and return capabilities document from the WMS as a
file-like object.
NOTE: this is effectively redundant now"""
reader = WMSCapabilitiesReader(
self.version, url=self.url, un=self.username, pw=self.password
)
u = self._open(reader.capabilities_url(self.url))
# check for service exceptions, and return
if u.info().gettype() == 'application/vnd.ogc.se_xml':
se_xml = u.read()
se_tree = etree.fromstring(se_xml)
err_message = str(se_tree.find('ServiceException').text).strip()
raise ServiceException(err_message, se_xml)
return u
def getmap(self, layers=None, styles=None, srs=None, bbox=None,
format=None, size=None, time=None, transparent=False,
bgcolor='#FFFFFF',
exceptions='application/vnd.ogc.se_xml',
method='Get',
**kwargs
):
"""Request and return an image from the WMS as a file-like object.
Parameters
----------
layers : list
List of content layer names.
styles : list
Optional list of named styles, must be the same length as the
layers list.
srs : string
A spatial reference system identifier.
bbox : tuple
(left, bottom, right, top) in srs units.
format : string
Output image format such as 'image/jpeg'.
size : tuple
(width, height) in pixels.
transparent : bool
Optional. Transparent background if True.
bgcolor : string
Optional. Image background color.
method : string
Optional. HTTP DCP method name: Get or Post.
**kwargs : extra arguments
anything else e.g. vendor specific parameters
Example
-------
>>> wms = WebMapService('http://giswebservices.massgis.state.ma.us/geoserver/wms', version='1.1.1')
>>> img = wms.getmap(layers=['massgis:GISDATA.SHORELINES_ARC'],\
styles=[''],\
srs='EPSG:4326',\
bbox=(-70.8, 42, -70, 42.8),\
size=(300, 300),\
format='image/jpeg',\
transparent=True)
>>> out = open('example.jpg.jpg', 'wb')
>>> out.write(img.read())
>>> out.close()
"""
try:
base_url = next((m.get('url') for m in self.getOperationByName('GetMap').methods if m.get('type').lower() == method.lower()))
except StopIteration:
base_url = self.url
request = {'version': self.version, 'request': 'GetMap'}
# check layers and styles
assert len(layers) > 0
request['layers'] = ','.join(layers)
if styles:
assert len(styles) == len(layers)
request['styles'] = ','.join(styles)
else:
request['styles'] = ''
# size
request['width'] = str(size[0])
request['height'] = str(size[1])
request['srs'] = str(srs)
request['bbox'] = ','.join([repr(x) for x in bbox])
request['format'] = str(format)
request['transparent'] = str(transparent).upper()
request['bgcolor'] = '0x' + bgcolor[1:7]
request['exceptions'] = str(exceptions)
if time is not None:
request['time'] = str(time)
if kwargs:
for kw in kwargs:
request[kw]=kwargs[kw]
data = urlencode(request)
u = openURL(base_url, data, method, 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 ServiceIdentification(object):
''' Implements IServiceIdentificationMetadata '''
def __init__(self, infoset, version):
self._root=infoset
self.type = testXMLValue(self._root.find('Name'))
self.version = version
self.title = testXMLValue(self._root.find('Title'))
self.abstract = testXMLValue(self._root.find('Abstract'))
self.keywords = extract_xml_list(self._root.findall('KeywordList/Keyword'))
self.accessconstraints = testXMLValue(self._root.find('AccessConstraints'))
self.fees = testXMLValue(self._root.find('Fees'))
class ServiceProvider(object):
''' Implements IServiceProviderMetatdata '''
def __init__(self, infoset):
self._root=infoset
name=self._root.find('ContactInformation/ContactPersonPrimary/ContactOrganization')
if name is not None:
self.name=name.text
else:
self.name=None
self.url=self._root.find('OnlineResource').attrib.get('{http://www.w3.org/1999/xlink}href', '')
#contact metadata
contact = self._root.find('ContactInformation')
## sometimes there is a contact block that is empty, so make
## sure there are children to parse
if contact is not None and contact[:] != []:
self.contact = ContactMetadata(contact)
else:
self.contact = None
def getContentByName(self, name):
"""Return a named content item."""
for item in self.contents:
if item.name == name:
return item
raise KeyError, "No content named %s" % name
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 ContentMetadata:
"""
Abstraction for WMS layer metadata.
Implements IContentMetadata.
"""
def __init__(self, elem, parent=None, index=0, parse_remote_metadata=False, timeout=30):
if elem.tag != '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('Name'))
# layer attributes
self.queryable = int(elem.attrib.get('queryable', 0))
self.cascaded = int(elem.attrib.get('cascaded', 0))
self.opaque = int(elem.attrib.get('opaque', 0))
self.noSubsets = int(elem.attrib.get('noSubsets', 0))
self.fixedWidth = int(elem.attrib.get('fixedWidth', 0))
self.fixedHeight = int(elem.attrib.get('fixedHeight', 0))
# title is mandatory property
self.title = None
title = testXMLValue(elem.find('Title'))
if title is not None:
self.title = title.strip()
self.abstract = testXMLValue(elem.find('Abstract'))
# bboxes
b = elem.find('BoundingBox')
self.boundingBox = None
if b is not None:
try: #sometimes the SRS attribute is (wrongly) not provided
srs=b.attrib['SRS']
except KeyError:
srs=None
self.boundingBox = (
float(b.attrib['minx']),
float(b.attrib['miny']),
float(b.attrib['maxx']),
float(b.attrib['maxy']),
srs,
)
elif self.parent:
if hasattr(self.parent, 'boundingBox'):
self.boundingBox = self.parent.boundingBox
# ScaleHint
sh = elem.find('ScaleHint')
self.scaleHint = None
if sh is not None:
self.scaleHint = {'min': sh.attrib['min'], 'max': sh.attrib['max']}
attribution = elem.find('Attribution')
if attribution is not None:
self.attribution = dict()
title = attribution.find('Title')
url = attribution.find('OnlineResource')
logo = attribution.find('LogoURL')
if title is not None:
self.attribution['title'] = title.text
if url is not None:
self.attribution['url'] = url.attrib['{http://www.w3.org/1999/xlink}href']
if logo is not None:
self.attribution['logo_size'] = (int(logo.attrib['width']), int(logo.attrib['height']))
self.attribution['logo_url'] = logo.find('OnlineResource').attrib['{http://www.w3.org/1999/xlink}href']
b = elem.find('LatLonBoundingBox')
if b is not None:
self.boundingBoxWGS84 = (
float(b.attrib['minx']),
float(b.attrib['miny']),
float(b.attrib['maxx']),
float(b.attrib['maxy']),
)
elif self.parent:
self.boundingBoxWGS84 = self.parent.boundingBoxWGS84
else:
self.boundingBoxWGS84 = None
#SRS options
self.crsOptions = []
#Copy any parent SRS options (they are inheritable properties)
if self.parent:
self.crsOptions = list(self.parent.crsOptions)
#Look for SRS option attached to this layer
if elem.find('SRS') is not None:
## some servers found in the wild use a single SRS
## tag containing a whitespace separated list of SRIDs
## instead of several SRS tags. hence the inner loop
for srslist in map(lambda x: x.text, elem.findall('SRS')):
if srslist:
for srs in srslist.split():
self.crsOptions.append(srs)
#Get rid of duplicate entries
self.crsOptions = list(set(self.crsOptions))
#Set self.crsOptions to None if the layer (and parents) had no SRS options
if len(self.crsOptions) == 0:
#raise ValueError('%s no SRS available!?' % (elem,))
#Comment by D Lowe.
#Do not raise ValueError as it is possible that a layer is purely a parent layer and does not have SRS specified. Instead set crsOptions to None
# Comment by Jachym:
# Do not set it to None, but to [], which will make the code
# work further. Fixed by anthonybaxter
self.crsOptions=[]
#Styles
self.styles = {}
#Copy any parent styles (they are inheritable properties)
if self.parent:
self.styles = self.parent.styles.copy()
#Get the styles for this layer (items with the same name are replaced)
for s in elem.findall('Style'):
name = s.find('Name')
title = s.find('Title')
if name is None or title is None:
raise ValueError('%s missing name or title' % (s,))
style = { 'title' : title.text }
# legend url
legend = s.find('LegendURL/OnlineResource')
if legend is not None:
style['legend'] = legend.attrib['{http://www.w3.org/1999/xlink}href']
self.styles[name.text] = style
# keywords
self.keywords = [f.text for f in elem.findall('KeywordList/Keyword')]
# timepositions - times for which data is available.
self.timepositions=None
self.defaulttimeposition = None
for extent in elem.findall('Extent'):
if extent.attrib.get("name").lower() =='time':
if extent.text:
self.timepositions=extent.text.split(',')
self.defaulttimeposition = extent.attrib.get("default")
break
# Elevations - available vertical levels
self.elevations=None
for extent in elem.findall('Extent'):
if extent.attrib.get("name").lower() =='elevation':
if extent.text:
self.elevations=extent.text.split(',')
break
# MetadataURLs
self.metadataUrls = []
for m in elem.findall('MetadataURL'):
metadataUrl = {
'type': testXMLValue(m.attrib['type'], attrib=True),
'format': testXMLValue(m.find('Format')),
'url': testXMLValue(m.find('OnlineResource').attrib['{http://www.w3.org/1999/xlink}href'], attrib=True)
}
if metadataUrl['url'] is not None and parse_remote_metadata: # download URL
try:
content = urllib2.urlopen(metadataUrl['url'], timeout=timeout)
doc = etree.parse(content)
if metadataUrl['type'] is not None:
if metadataUrl['type'] == 'FGDC':
metadataUrl['metadata'] = Metadata(doc)
if metadataUrl['type'] == 'TC211':
metadataUrl['metadata'] = MD_Metadata(doc)
except Exception, err:
metadataUrl['metadata'] = None
self.metadataUrls.append(metadataUrl)
# DataURLs
self.dataUrls = []
for m in elem.findall('DataURL'):
dataUrl = {
'format': m.find('Format').text.strip(),
'url': m.find('OnlineResource').attrib['{http://www.w3.org/1999/xlink}href']
}
self.dataUrls.append(dataUrl)
self.layers = []
for child in elem.findall('Layer'):
self.layers.append(ContentMetadata(child, self))
def __str__(self):
return 'Layer Name: %s Title: %s' % (self.name, self.title)
class OperationMetadata:
"""Abstraction for WMS OperationMetadata.
Implements IOperationMetadata.
"""
def __init__(self, elem):
"""."""
self.name = xmltag_split(elem.tag)
# formatOptions
self.formatOptions = [f.text for f in elem.findall('Format')]
self.methods = []
for verb in elem.findall('DCPType/HTTP/*'):
url = verb.find('OnlineResource').attrib['{http://www.w3.org/1999/xlink}href']
self.methods.append({'type' : xmltag_split(verb.tag), 'url': url})
class ContactMetadata:
"""Abstraction for contact details advertised in GetCapabilities.
"""
def __init__(self, elem):
name = elem.find('ContactPersonPrimary/ContactPerson')
if name is not None:
self.name=name.text
else:
self.name=None
email = elem.find('ContactElectronicMailAddress')
if email is not None:
self.email=email.text
else:
self.email=None
self.address = self.city = self.region = None
self.postcode = self.country = None
address = elem.find('ContactAddress')
if address is not None:
street = address.find('Address')
if street is not None: self.address = street.text
city = address.find('City')
if city is not None: self.city = city.text
region = address.find('StateOrProvince')
if region is not None: self.region = region.text
postcode = address.find('PostCode')
if postcode is not None: self.postcode = postcode.text
country = address.find('Country')
if country is not None: self.country = country.text
organization = elem.find('ContactPersonPrimary/ContactOrganization')
if organization is not None: self.organization = organization.text
else:self.organization = None
position = elem.find('ContactPosition')
if position is not None: self.position = position.text
else: self.position = None
class WMSCapabilitiesReader:
"""Read and parse capabilities document into a lxml.etree infoset
"""
def __init__(self, version='1.1.1', url=None, un=None, pw=None):
"""Initialize"""
self.version = version
self._infoset = None
self.url = url
self.username = un
self.password = pw
#if self.username and self.password:
## Provide login information in order to use the WMS server
## Create an OpenerDirector with support for Basic HTTP
## Authentication...
#passman = HTTPPasswordMgrWithDefaultRealm()
#passman.add_password(None, self.url, self.username, self.password)
#auth_handler = HTTPBasicAuthHandler(passman)
#opener = build_opener(auth_handler)
#self._open = opener.open
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', 'WMS'))
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 WMS 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 WMS 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)