WFS POST requests: "No template provided" error

Thu Nov 8 06:39:59 PST 2007

Hello List,

While developing a WFS client, I've encountered a problem with MapServer. I don't have a local setup of MapServer running, but use a few public available services at the web. Those are:
*	http://map.ns.ec.gc.ca/MapServer/mapserv.exe?map=/mapserver/services/envdat/config.map (MapServer 4.8.3)
*	http://www.bsc-eoc.org/cgi-bin/bsc_ows.asp (MapServer 4.8.1)

Our WFS client supports both GET and POST requests. It checks the Capabilities document which HTTP method to use. The document of the first service can be found here: http://map.ns.ec.gc.ca/MapServer/mapserv.exe?map=/mapserver/services/envdat/config.map&SERVICE=WFS&VERSION=1.0.0&REQUEST=GetCapabilities&. GetCapabilities is always done with GET, but other requests can vary. For testing purposes I made POST the default HTTP method for the requests. When I try to do a DescribeFeatureType or a GetFeature to these services with POST, I'm getting the following message:

<HTML>
<HEAD><TITLE>MapServer Message</TITLE></HEAD>

<BODY BGCOLOR="#FFFFFF">
mapserv(): Web application error. No template provided. <br>
</BODY></HTML>

The Capabilites document lists the online resource URL's for DescribeFeatureType and GetFeature, so POST should be allowed for these WFS requests. I'm sure that the WFS request is correct, since it works with other WFS servers, like Geoserver, and Oracle Spatial Web Services, and I can not find anything that might be wrong on my side. Here is the raw request (headers + post data):

POST /envdat/map.aspx HTTP/1.1
Content-Type: text/xml
Host: map.ns.ec.gc.ca
Content-Length: 579
Expect: 100-continue
Proxy-Connection: Close

<?xml version="1.0" encoding="iso-8859-1"?>
<DescribeFeatureType version="1.0.0" service="WFS" xsi:schemaLocation="http://www.opengis.net/wfs http://schemas.opengis.net/wfs/1.0.0/WFS-basic.xsd" xmlns="http://www.opengis.net/wfs" xmlns:b="http://www.bentley.com/schemas/x-Bentley.XMLTemplate.0.1" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:ows="http://www.opengis.net/ows" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:ogc="http://www.opengis.net/ogc" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <TypeName>wfs:envirodat</TypeName>
</DescribeFeatureType>

While searching the mailing list, I found replies of people suggesting that WFS might not be enabled (MapServer not compiled with WFS support), but since WFS requests with GET work fine, this is obviously not the case. I also found another suggestion here: http://lists.umn.edu/cgi-bin/wa?S2=MAPSERVER-USERS&q=wfs+post+template&s=&f=&a=&b=. It is suggested to add the parameters "service=WFS" and "version=1.0.0" to the URL for POST, but this doesn't work either. Maybe I would need to test with a more recent build, but I couldn't find one at the web. But this would mean that I have to change the online resource URL, but the correct URL cannot be predicted. The correct URL to post to should be mentioned in the Capabilities document. The second service (www.bsc-eoc.org) returned the same reply with the parameters, but the first service (at map.ns.ec.gc.ca) returned this:

<ServiceExceptionReport
xmlns="http://www.opengis.net/ogc" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.opengis.net/ogc http://schemas.opengis.net/wms/1.1.1/OGC-exception.xsd">
  <ServiceException>
msWFSDispatch(): WFS server error. Incomplete WFS request: REQUEST parameter missing
  </ServiceException>
</ServiceExceptionReport>

If I would add the Request parameter, then it would be WFS / GET again, and that's not what I want. (Well, I normally do, but this is for testing purposes.)
I was getting similar responses with GetFeature, but since I changed my code, the WFS client doesn't come that far (because DescribeFeatureType doesn't work) anymore. 

Since there are no problems with GET requests, our client can successfully query data. But since POST is also available, I would expect it to work as well. I hope that someone can look into this. If POST really causes problems, it would be better to remove the associated online resource URL's from the Capabilities document.

Regards,

Frank Steggink

Bentley Systems, Inc.
Software Developer Geospatial

3645, boul. Ste-Anne
Québec, Qc. G1E 3L1
Canada

Tel: +1 418 666 7691 ext. 289
E-mail: frank.steggink at bentley.com
WWW: http://www.bentley.com