[mapserver-users] Fwd: World Wind and Map Server

Mon Nov 9 09:32:04 PST 2009

Hi,

it's a matter of properly setting up your service, since MAP is a 
vendor-specific parameter in this case. For instance using the 
MS_MAPFILE environment variable, so that clients don't need to use the 
MAP file parameter at all. Or you can do standard url rewrites with Apache.

Best regards,
Bart

Roger André wrote:
> Does anyone in the MapServer Dev. community want to respond to this?  
> I *think* the implication here is that a vanilla MapServer 
> "GetCapabilities" request is not conforming to spec.
>
> Roger
> --
>
> ---------- Forwarded message ----------
> From: *Tom Gaskins* <tom at tomgaskins.com <mailto:tom at tomgaskins.com>>
> Date: Sun, Nov 8, 2009 at 9:21 PM
> Subject: Re: World Wind and Map Server
> To: Roger André <randre at gmail.com <mailto:randre at gmail.com>>
> Cc: David Collins <paul.collins at nasa.gov <mailto:paul.collins at nasa.gov>>
>
>
> Roger, Thanks for clarifying, but I think I may still be confused. WMS 
> defines two primary requests, GetCapabilities and GetMap. The first 
> one requests the metadata associated with the server and each of the 
> layers it serves. The second requests a map, always in the form of a 
> raster. Reading your most recent mail, it seems you're expecting 
> the GetCapabilities request to return a particular map. Is this 
> correct? I'm also confused because the request you show that you'd 
> like to specify to the demo's layer manager doesn't meet the 
> definition of a valid WMS end point, which should be simply a host 
> address and not contain a query string (elements after the question 
> mark). The query string is exclusively for WMS parameters, which the 
> WWJ demo fills in when sending the request. I've included the relevant 
> text from the WMS spec below.
>
> I can understand that mapserver may have its own request protocol, but 
> the demo you're using is meant to work with only conforming WMS 
> servers. It's certainly possible for WWJ to visualize data from 
> servers using other protocols, and many applications do that. We'd be 
> more than happy to help you determine the best way to interact with 
> mapserver. The demo you're trying to use, though, isn't intended to to 
> that.
>
> Thanks,
> Tom
>
> *6.3.3 HTTP GET*
> A Web Map Service shall support the "GET" method of the HTTP protocol 
> (IETF RFC 2616).
> An Online Resource URL intended for HTTP GET requests is in fact only 
> a URL prefix to which additional parameters are appended in order to 
> construct a valid Operation request. A URL prefix is defined in 
> accordance with IETF RFC 2396 as a string including, in order, the 
> scheme ("http" or "https"), Internet Protocol hostname or numeric 
> address, optional port number, path, mandatory question mark '?', and 
> optional string comprising one or more server-specific parameters 
> ending in an ampersand '&'. The prefix defines the network address to 
> which request messages are to be sent for a particular operation on a 
> particular server. Each operation may have a different prefix. Each 
> prefix is entirely at the discretion of the service provider.
> This International Standard defines how to construct a query part that 
> is appended to the URL prefix in order to form a complete request 
> message. Every WMS operation has several mandatory or optional request 
> parameters. Each parameter has a defined name. Each parameter may have 
> one or more legal values, which are either defined by this 
> International Standard or are selected by the client based on service 
> metadata. To formulate the query part of the URL, a client shall 
> append the mandatory request parameters, and any desired optional 
> parameters, as name/value pairs in the form "name=value&" (parameter 
> name, equals sign, parameter value, ampersand). The '&' is a separator 
> between name/value pairs, and is therefore optional after the last 
> pair in the request string.
> When the HTTP GET method is used, the client-constructed query part is 
> appended to the URL prefix defined by the server, and the resulting 
> complete URL is invoked as defined by HTTP (IETF RFC 2616).
> Table 2 summarizes the components of an operation request URL when 
> HTTP GET is used.
> *Table 2 — Structure of WMS request using HTTP GET*
> *6.3.4 HTTP POST*
> A Web Map Service may support the "POST" method of the HTTP protocol 
> (IETF RFC 2616).
> An Online Resource URL intended for HTTP POST requests is a complete 
> URL (not merely a prefix as in the HTTP GET case) that is valid 
> according to IETF RFC 2396 to which clients transmit request 
> parameters in the body of the POST message. A WMS shall not require 
> additional parameters to be appended to the URL in order to construct 
> a valid target for the operation request. When POST is used, the 
> request message is formulated as an XML document.
> *URL Component*
> *Description*
> http://host[:port]/path[?{name[=value]&}] 
> <http://host%5B%3Aport%5D/path%5B?%7Bname%5B=value%5D&%7D%5D>
> URL prefix of service operation. [ ] denotes 0 or 1 occurrence of an 
> optional part; {} denotes 0 or more occurrences.
> name=value&
> One or more standard request parameter name/value pairs as defined for 
> each operation by this International Standard.
> On Nov 8, 2009, at 12:29 PM, Roger André wrote:
>
>> Hi Tom,
>>
>> Problem is pretty simple to describe actually.  One of the executives 
>> at my company found this page, 
>> http://worldwind.arc.nasa.gov/java/demos/ 
>> <http://worldwind.arc.nasa.gov/java/demos/>, and decided to try out 
>> the WMS Layer manager example, WMSLayerManager.jnlp 
>> <http://worldwind.arc.nasa.gov/java/demos/WMSLayerManager.jnlp>.  He 
>> liked the various layers that were available, and asked me if it 
>> would be possible to view some of our MapServer WMS layers that I 
>> publish internally.  We spent a couple hours trying to figure out 
>> what URL WWJ needed, and finally determined that it needed a full 
>> GetCapabilities URL.  This URL for MapServer look like this:
>>  "http://10.10.10.143/cgi-bin/mapserv?map=/var/www/mapfiles/precip/precip.map&REQUEST=GetCapabilities&SERVICE=WMS& 
>> <http://10.10.10.143/cgi-bin/mapserv?map=/var/www/mapfiles/precip/precip.map&REQUEST=GetCapabilities&SERVICE=WMS&>".
>>
>> However, this URL does not work in WWJ.  When I checked the server 
>> logs to see whether WWJ was actually trying to connect to my WMS, I 
>> found that the request it sends is truncated, and looks like this:
>> 10.10.10.143 - - [05/Nov/2009:09:51:37 -0800] "GET 
>> /cgi-bin/mapserv?EXCEPTIONS=application/vnd.ogc.se_xml&REQUEST=GetCapabilities&SERVICE=WMS& 
>> HTTP/1.1" 200 539 "-" "Java/1.6.0_07".
>>
>> As you can see, the "map" parameter, which is crucial for MapServer, 
>> has been completely stripped out of the request.  Without this, 
>> "map=/var/www/mapfiles/precip/precip.map" paremeter, there is no way 
>> for MapServer to determine which map to serve.
>>
>> Hope that helps,
>>
>> Roger
>> --
>>
>> On Sat, Nov 7, 2009 at 10:17 AM, Tom Gaskins <tom at tomgaskins.com 
>> <mailto:tom at tomgaskins.com>> wrote:
>>
>>     Roger, I was sent a copy of your mapserver-list message
>>     describing a problem you're having connecting to map server from
>>     WWJ. But the message seems to be saying that you're entering a
>>     GetCapabilities URL and expecting that to generate a GetMap
>>     request to the server. Would you please tell me what the
>>     situation is and what you're trying to do. We almost never have
>>     problems connecting to conforming WMS servers.
>>     Thanks
>>     Tom
>>
>>
>
>
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-- 
Bart van den Eijnden
OSGIS, Open Source GIS
bartvde at osgis.nl
http://www.osgis.nl