[mapguide-users] RE: WMS Data Source?

[Thomas M. Tuerke]

> I guess the only problem is that the server service has to know what the url for the "local" DTDs is.

 

Yeah, there’s a lot of open-endedness in terms of installation possibilities, but theoretically, these DTDs are static, so finding a single public location is probably adequate.  An installation double-tasked as both extranet and intranet server can always point to some place external server’s content for these files (I doubt you’d want two flavors of DTD.)  Would I be over-reaching in saying that this would satisfy a fair number of use cases?

 

> for instance serving WMS internally and externally from the same server but through different DNS entries / IP addresses

 

Hmmm… if two IPs or subdomains resolve to the same MapGuide HttpHandler, it’s not clear to me that the present implementation isn’t going to know the difference… for WMS for sure, (and for all of MapGuide as well, I’m not sure), as I think the configuration information is stored relative to the binaries on the server. Either way, you’re going to expose the same layers in the WMS either way, so there may not be much advantage to two paths to the same HttpHandler.

 

That said, it wouldn’t be hard for the web-tier HttpHandler to ask for a nuanced config file from the server (given that somebody wants to modify the OS code,) but that functionality doesn’t exist yet.  Certainly that’s the strength of OS over shrink-wrapped code: there’s no way for us developers to conceive – a priori – of every possible installation the site administrator will want, so we try to address the majority cases (make simple things simple and complex things possible, as the saying goes) but with the source, the creative site administrator has a great deal more flexibility.

 

Anyway, happy Friday, and have a great weekend.

 

- Thomas

 

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From: Jason Birch [mailto:Jason.Birch at nanaimo.ca] 
Sent: Friday, November 03, 2006 6:56 PM
To: users at mapguide.osgeo.org
Subject: RE: [mapguide-users] RE: WMS Data Source?

 

Nope, that’s Friday Night Bleary-eyed Syndrome on my part.

 

Heh.  Got that going on myself...

 

Ideally, though, you’re right: the truly robust installation will simply host the DTDs on its own webserver, updating the templates accordingly.  That’s not hard for the site admin to do, either.

 

I guess the only problem is that the server service has to know what the url for the "local" DTDs is. This will vary based on the installation, which isn't a big deal (set a value in serverconfig), but it will also vary based on the network used to access the web extensions, for instance serving WMS internally and externally from the same server but through different DNS entries / IP addresses.

 

I guess if the value was set in serverconfig to the default OGC server, and the admin had the option to change it, then this would put the responsibility in the hands of the site administrator to make sure they were pointing to a web-accessible DTD for all of their users.

 

Jason

 

 

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From: Jason Birch [mailto:Jason.Birch at nanaimo.ca] 
Sent: Friday, November 03, 2006 6:06 PM
To: users at mapguide.osgeo.org
Subject: RE: [mapguide-users] RE: WMS Data Source?

 

OK, weird choice from the specification pov then.  Counting on the persistence of a single external resource in a distributed system doesn't seem like a great idea.  One change brings the whole thing tumbling down.

 

What do you mean by ourselves?  Included in the MapGuide installation (local reference)?  Hosted somewhere at OSGeo?

 

Jason


 

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From: Thomas M. Tuerke
Sent: Fri 2006-11-03 5:49 PM
To: users at mapguide.osgeo.org
Subject: RE: [mapguide-users] RE: WMS Data Source?

Hi Jason,

 

Just a bit of historical perspective:

 

> … instead of digitalearth (weird choice):

 

Deprecated, perhaps, but not necessarily weird. It’s what the relevant specs call for, and until recently they seemed to work just fine.

 

Fortunately, it looks like we’ve decided to host the DTD files ourselves to eliminate that external dependency.

 

- Thomas

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From: Jason Birch [mailto:Jason.Birch at nanaimo.ca] 
Sent: Friday, November 03, 2006 5:34 PM
To: users at mapguide.osgeo.org
Subject: RE: [mapguide-users] RE: WMS Data Source?

 

This is a known issue:

 

https://mapguide.osgeo.org/servlets/Scarab?id=MG434 <https://mapguide.osgeo.org/servlets/Scarab?id=MG434> 

 

It looks like you may be able to fix it by grabbing the three fixed files from SVN:

 

https://mapguide.osgeo.org/source/browse/mapguide/branches/1.0.x/MgDev/Server/src/Wms/ <https://mapguide.osgeo.org/source/browse/mapguide/branches/1.0.x/MgDev/Server/src/Wms/> 

 

or just updating the AWD templates on your site to hit OGC instead of digitalearth (weird choice):

http://schemas.opengis.net/wms/1.0.0/capabilities_1_0_0.dtd <http://schemas.opengis.net/wms/1.0.0/capabilities_1_0_0.dtd> 
http://schemas.opengis.net/wms/1.1.0/capabilities_1_1_0.dtd <http://schemas.opengis.net/wms/1.1.0/capabilities_1_1_0.dtd> 
 
<http://schemas.opengis.net/wms/1.1.1/capabilities_1_1_1.dtd> http://schemas.opengis.net/wms/1.1.1/capabilities_1_1_1.dtd
 
respectively, for the three templates.
 
I recall something similar with LiteView in MapGuide 6.x, and I think I had to repoint to a local DTD.  Bit fuzzy on that though; I gave up on LiteView pretty quickly.

Jason


 

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From: Andy Morsell
Sent: Fri 2006-11-03 5:12 PM
To: users at mapguide.osgeo.org
Subject: RE: [mapguide-users] RE: WMS Data Source?

There is an OSGeo FDO WMS data provider for this purpose
(https://mapguide.osgeo.org/servlets/ProjectDocumentList?folderID=100&expand
Folder=100&folderID=0).  However, I just tried working with it and there
appears to be a problem today.  If you try to use it to define a data
connection, and then enter a WMS server name and press the Test Connection
button, you will get an error

"An exception occurred in FDO component.
XML Document parse error at line 8 column 3: An exception occurred!
Type:NetAccessorException, Message:The host/address 'www.digitalearth.gov'
could not be resolved "

It appears that the FDO provider is looking up a DTD at digitalearth.gov and
their web site is currently down (at least on my end). 

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