[OpenLayers-Users] WFS layer visible in IE6 and IE7,
but not in Firefox. Tried to set up proxy. No succes yet.
sendeman
martijnsendenspam at gmail.com
Thu Jun 18 10:38:44 EDT 2009
Hi all,
I'm trying to serve a WFS layer from mapserver using openlayers. I have it
working in IE7, but Firefox doesn't show the WFS layer. Now, as I understand
it from other threads on this mailing list, the issue might be that I need
to set up a Proxy to allow Firefox to show the WFS features. (I'm not
entirely sure though, since all the layers are served/requested from the
same localhost server.....?). I am no expert at server configuration, but I
followed some advice from
http://trac.openlayers.org/wiki/FrequentlyAskedQuestions#ProxyHost the FAQ .
When I visit http://localhost/cgi-bin/proxy.cgi
http://localhost/cgi-bin/proxy.cgi , I get the openlayers site, like I'm
supposed to. The WFS layer still doesn't show up in Firefox though, so maybe
something is wrong with my javascript. I added the openlayers init script
below.
I used Firebug to log to the console. The GET request seems to work, (line
193 in openlayers.js), but I get an error: "parentnode is undefined" in line
199 of openalyers.js. It's a line with the following code:
OpenLayers.Ajax.Responders.dispatch('onException',this,exception);}});OpenLayers.Ajax.Request.Events=['Uninitialized','Loading','Loaded','Interactive','Complete'];OpenLayers.Ajax.getElementsByTagNameNS=function(parentnode,nsuri,nsprefix,tagname){var
elem=null;if(parentnode.getElementsByTagNameNS){elem=parentnode.getElementsByTagNameNS(nsuri,tagname);}else{elem=parentnode.getElementsByTagName(nsprefix+':'+tagname);}
I don't understand the error or know a solution for it.
I also tried the suggestions on
http://www.imladris.com/Scripts/PythonForWindows.html this site about Python
on windows . This didn't result in anything useful though. When I rename the
proxy.cgi to proxy.py and add the required text to httpd.conf, I get even
more errors than before. (See below for the additions I made to the
httpd.conf file and the Proxy.cgi.
What to do? Should the proxy be the solution to my problem? Or don't I need
one and is the problem coming from elsewhere? The error I het in Firebug is
the same with or without the proxy, so I think something else might be going
on (or I'm not calling the proxy script correctly in the javascript.)
I hope someone may be able to help me out. Please let me know if more
information about my setup and code is needed. Any help will be appreciated!
Best regards,
Martijn Senden.
The javascript of my init() function
__________________________________________
function init(){
OpenLayers.ProxyHost="/cgi-bin/proxy.cgi/?url=";
//Create a new OpenLayers mapwindow with associated controls
var map = new OpenLayers.Map('map', {
projection: "EPSG:28992",
maxResolution: 1328.125,
numZoomLevels: 14,
maxExtent : new OpenLayers.Bounds(-23500,289000,316500,629000),
restrictedExtent: new OpenLayers.Bounds(80000,442000,88000,452000),
units : "meters",
controls: [
new OpenLayers.Control.ZoomToMaxExtent(),
new OpenLayers.Control.PanZoomBar({zoomWorldIcon: true}),
new OpenLayers.Control.LayerSwitcher({'ascending':false}),
//new OpenLayers.Control.MousePosition(),
new OpenLayers.Control.MouseDefaults(),
new OpenLayers.Control.KeyboardDefaults()
]
});
// Add Spoortunnel Delft Mapserver .map-files
layer = new OpenLayers.Layer.MapServer( "Topografie",
"/geoviewerbin/mapserv.exe", {map:
"c:/OSGeo4W/apps/geoviewer/maps/spoortunnel.map", layers: "Topografie"} );
map.addLayer(layer);
// layer = new OpenLayers.Layer.MapServer( "Spoortunnel",
// "/geoviewerbin/mapserv.exe", {map:
"c:/OSGeo4W/apps/geoviewer/maps/spoortunnel.map", layers: "Spoortunnel"},
// {isBaseLayer: false, opacity: 0.6} );
// map.addLayer(layer);
wfs = new OpenLayers.Layer.WFS(
"Contour spoortunnel",
"http://localhost/geoviewerbin/mapserv.exe?map=c:/OSGeo4W/apps/geoviewer/maps/spoortunnel.map",
{typename: 'SpoortunnelWFS'},
{
typename: "SpoortunnelWFS",
featureNS: "http://localhost/geoviewer",
extractAttributes: true
}
);
//wfs.styleMap = new OpenLayers.StyleMap({strokeColor: "#00ffff"});
map.addLayer(wfs);
//Add a scalebar to the map
scalebar = new OpenLayers.Control.ScaleBar();
map.addControl(scalebar);
//Set extents of initial mapview
var geoviewerExtent=new Array();
geoviewerExtent[0] = 83600; // x-min
geoviewerExtent[1] = 446000; // y-min
geoviewerExtent[2] = 84600; // x-max
geoviewerExtent[3] = 448200; // y-max
ZoomToSetExtent(geoviewerExtent[0],geoviewerExtent[1],geoviewerExtent[2],geoviewerExtent[3],map);
// Add a permanent link to the current view
//map.addControl(new OpenLayers.Control.Permalink() );
}
function ZoomToSetExtent(Xmin,Ymin,Xmax,Ymax,geoviewermap){
// Set mapview extents to input parameters
var extentRatio = (Xmax-Xmin)/(Ymax-Ymin);
var geoviewerSize = geoviewermap.getSize();
var sizeRatio = geoviewerSize.w/geoviewerSize.h;
if (sizeRatio >= extentRatio) {
var geoviewerResolution = (Ymax-Ymin)/geoviewerSize.h;
var minX = ((Xmin+Xmax)/2)-(geoviewerResolution*geoviewerSize.w/2);
var minY = Ymin;
var maxX = ((Xmin+Xmax)/2)+(geoviewerResolution*geoviewerSize.w/2);
var maxY = Ymax;
} else {
var geoviewerResolution = (Xmax-Xmin)/geoviewerSize.w;
var minX = Xmin;
var minY = ((Ymin+Ymax)/2)-(geoviewerResolution*geoviewerSize.h/2);
var maxX = Xmax;
var maxY = ((Ymin+Ymax)/2)+(geoviewerResolution*geoviewerSize.h/2);
};
// Zoom to set extent
geoviewermap.zoomToExtent(new OpenLayers.Bounds(minX,minY,maxX,maxY));
}
__________________________________________
The changes/additions I made in the httpd.conf file:
__________________________________________
# Added by Martijn Senden - to handle python scripts as cgi scripts
AddHandler cgi-script .py
# Added by Martijn Senden - to ignore the 'shebang lines' of cgi-scripts
# (see http://www.imladris.com/Scripts/PythonForWindows.html)
ScriptInterpreterSource registry
# Added by Martijn Senden - when 'shebang lines' of cgi-scripts are ignored,
# the -u switch is ignored as well. It is used to run python in the
'unbuffered'
# mode. Trying to run python cgi scripts in the (default) buffered mode will
# either result in a complete lack of return value from your cgi script
# (manifesting as a blank html page) or a "premature end of script headers"
# error. The lines below put python into the unbuffered mode.
PassEnv PYTHONPATH
SetEnv PYTHONUNBUFFERED 1
# Settings for access to the geoviewer folder
<Directory "C:\OSGeo4W/apps/geoviewer/htdocs">
AllowOverride None
Options Indexes FollowSymLinks Multiviews ExecCGI
Order allow,deny
Allow from all
</Directory>
The Proxy.cgi I currently have:
__________________________________________
#!C:/OSGeo4W/bin/python.exe -u
"""This is a blind proxy that we use to get around browser
restrictions that prevent the Javascript from loading pages not on the
same server as the Javascript. This has several problems: it's less
efficient, it might break some sites, and it's a security risk because
people can use this proxy to browse the web and possibly do bad stuff
with it. It only loads pages via http and https, but it can load any
content type. It supports GET and POST requests."""
import urllib2
import cgi
import sys, os
# Designed to prevent Open Proxy type stuff.
allowedHosts = ['www.openlayers.org', 'openlayers.org',
'labs.metacarta.com', 'world.freemap.in',
'prototype.openmnnd.org', 'geo.openplans.org',
'sigma.openplans.org', 'demo.opengeo.org',
'www.openstreetmap.org', 'sample.avencia.com', 'localhost']
method = os.environ["REQUEST_METHOD"]
if method == "POST":
qs = os.environ["QUERY_STRING"]
d = cgi.parse_qs(qs)
if d.has_key("url"):
url = d["url"][0]
else:
url = "http://www.openlayers.org"
else:
fs = cgi.FieldStorage()
url = fs.getvalue('url', "http://www.openlayers.org")
try:
host = url.split("/")[2]
if allowedHosts and not host in allowedHosts:
print "Status: 502 Bad Gateway"
print "Content-Type: text/plain"
print
print "This proxy does not allow you to access that location (%s)."
% (host,)
print
print os.environ
elif url.startswith("http://") or url.startswith("https://"):
if method == "POST":
length = int(os.environ["CONTENT_LENGTH"])
headers = {"Content-Type": os.environ["CONTENT_TYPE"]}
body = sys.stdin.read(length)
r = urllib2.Request(url, body, headers)
y = urllib2.urlopen(r)
else:
y = urllib2.urlopen(url)
# print content type header
i = y.info()
if i.has_key("Content-Type"):
print "Content-Type: %s" % (i["Content-Type"])
else:
print "Content-Type: text/plain"
print
print y.read()
y.close()
else:
print "Content-Type: text/plain"
print
print "Illegal request."
except Exception, E:
print "Status: 500 Unexpected Error"
print "Content-Type: text/plain"
print
print "Some unexpected error occurred. Error text was:", E
--
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