[mapserver-users] Mapcache with mapfile as layer

[Pablo Cecconi]

The problem is not the invalidation of the tiles (which is a very simple
step that can even be done with a simple bash script) but the need to list
every single layer with status ON on the mapfile. To do that automatically
we need to use mapscript (as TileCache does) but we also need to deal with
generating a valid mapcache config file (which we cannot do with
mapscript). With TileCache instead we just mapped a given layer name with a
mapfile and we only had to care about invalidating and reseeding of tiles
and not with modifying TileCache config file. It's not so bad though. I
just thought that being part of Mapserver maybe MapCache could have some
kind of "special integration" with it.
Anyway, I'll continue digging to see if I find some easier way to deal with
this particular problem and if I do I promise to let you know.
Thanks again.

Pablo


On Thu, Sep 19, 2013 at 11:00 PM, Pablo Cecconi <pcecconi at gmail.com> wrote:

> The problem is not the invalidation of the tiles (which is a very simple
> step that can even be done with a simple bash script) but the need to list
> every single layer with status ON on the mapfile. To do that automatically
> we need to use mapscript (as TileCache does) but we also need to deal with
> generating a valid mapcache config file (which we cannot do with
> mapscript). With TileCache instead we just mapped a given layer name with a
> mapfile and we only had to care about invalidating and reseeding of tiles
> and not with modifying TileCache config file. It's not so bad though. I
> just thought that being part of Mapserver maybe MapCache could have some
> kind of "special integration" with it.
> Anyway, I'll continue digging to see if I find some easier way to deal
> with this particular problem and if I do I promise to let you know.
> Thanks again.
>
> Pablo
>
>
>
> On Thu, Sep 19, 2013 at 10:18 PM, Stephen Woodbridge <
> woodbri at swoodbridge.com> wrote:
>
>> Try it, it might work, I don't remember, but you still have the problem
>> of invalidating the tiles when you changes the mapfile. But seriously, your
>> approach seems a little haphazard. Also how often to you make mapfile
>> changes? how did you deal with the invalidating cache problem before?
>>
>> The big difference here is that mapcache is using mapserver as a WMS
>> source and therefore it has to conform to the WMS rules.
>>
>> Anyway, Thomas is the one that you would need to convince or fund if you
>> want changes to the existing behavior. Meanwhile it would be worthwhile
>> your time to figure out how it curently works before asking for features
>> that might already exist. It has been a few months since I setup a mapcache
>> instance and I know there have been changes that I'm not on top of in the
>> newest  release.
>>
>> -Steve
>>
>>
>> On 9/19/2013 3:46 PM, Pablo Cecconi wrote:
>>
>>> The problem with that approach is that is the mapfile changes (a layer
>>> is added or the default status of a layer changes) then I also have to
>>> update mapcache config file. What i wonder is if there is a way to just
>>> modify the map and have Mapcache reflecting that change.
>>>
>>> Pablo
>>>
>>>
>>> On Thu, Sep 19, 2013 at 4:40 PM, Stephen Woodbridge
>>> <woodbri at swoodbridge.com <mailto:woodbri at swoodbridge.**com<woodbri at swoodbridge.com>>>
>>> wrote:
>>>
>>>     On 9/19/2013 3:02 PM, Pablo Cecconi wrote:
>>>
>>>         Hello,
>>>
>>>         I've been a Mapserver user for many years now but I'm new to
>>>         Mapcache
>>>         and I'm not sure whether it's possible to replicate a particular
>>>         TileCache setup using Mapcache.
>>>         What we have today is a number of mapfiles (with Mapserver 5.4)
>>>         set up
>>>         as WMS-C layers served with TileCache. We're migrating to
>>> Mapserver
>>>         6.2.1 and as it's incompatible with TileCache we expect to be
>>>         able to
>>>         replace it using Mapcache.
>>>         In our current setup if I have a mapfile where a particular
>>>         layer has
>>>         STATUS OFF then TileCache will honor that status and not render
>>>         the layer.
>>>         I'd like to know whether it's possible to have MapCache work
>>>         that way,
>>>         that is, passing the map name as the LAYERS parameter of the WMS
>>>         service
>>>         and make it honor whatever STATUS a particular layer would have
>>>         in the
>>>         mapfile.
>>>
>>>
>>>     I think the mapcache paradigm for this in mapcache works like this:
>>>
>>>     tileset
>>>        name=foo
>>>        source=foo-source
>>>
>>>     source
>>>        name=foo-source
>>>        map=/path/to/mapfile
>>>        layers=layer1,layer2,layers3,.**__..
>>>
>>>
>>>     So you can configure which layers a tileset returns. I'm not sure
>>>     how it deals with the status off, but it will work if you define the
>>>     list explicitly. This also allow you to do this in the same
>>> mapcache.xml
>>>
>>>     tileset
>>>        name=foo2
>>>        source=foo-source2
>>>
>>>     source
>>>        name=foo-source2
>>>        map=/path/to/mapfile
>>>        layers=streets,...
>>>        transparent=true
>>>
>>>     I do this a lot when I have a subset of data like streets that I
>>>     want to render as an overly on a raster image
>>>
>>>     -Steve W
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>>>
>>>
>>>
>>
>
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