[WMS/WFS] Ability to specify a proxy for remote connections

[dmorissette]

We need the ability to specify a proxy when connecting to remote WMS/WFS servers.

This could possibly be added as layer metadata wms_proxy_*, but I wonder if we should instead create global configuration parameters inside the WEB object?

I never really worked in environments with proxies, so I wonder if it is safe to assume that when someone uses a proxy, then they use it for *all* their http connections and not only to get to specific hosts? i.e. is it a good idea to have a single global proxy setting in the web object in the mapfile or should this be local at the layer level?

[fwarmerdam]

I agree that this should be map wide, rather than layer specific.  

I am not sure it belongs in the WEB section though, since it relates to 
how remote requests are made, now how the local configuraton works.  

There are also a number of other global configuration options I would like
to add in the not-to-distant-future, including .map file driven overrides for
GDAL_DATA, and PROJ_LIB.   I'm not sure that these are related though. 

[bartvde@…]

The production environments I have been in would only need to have a global 
proxy setting in the MAP file, not a per layer proxy setting.

[franck.villoin@…]

Attention, we can imagine use Services WMS without proxy for certain layers in 
the Intranet, and others services WMS/WFS out of intranet use the proxy.
But I use only one the proxy in my production environment. 

[dmorissette]

Franck, what would happen in your case if you tried to access a WMS server from
the intranet via the proxy?  Would things still work?

[franck.villoin@…]

No, it does not function. 
If I pass by my proxy, the addresses of my Intranet are not solved.
By fixing the proxy in a permanent way in my navigator,
I do not see any more the sites of my Intranet.

Is it possible to define a global proxy parameter, and to make it active by 
layer if necessary?

Franck

[dmorissette]

Pushing to 4.4 release

[tjmitchell@…]

I also need this functionality due to some relocation of our servers.  Our 
proxy requires our username/password too!  Ugh.

Curl docs say:

"NOTE2: libcurl respects the environment variables http_proxy, ftp_proxy, 
all_proxy etc, if any of those is set."

Can this be used somehow as a quick workaround?

Tyler

[dmorissette]

The libcurl tutorial talks about those environment variables as well. They must
be lowercase, and the value is in the format
"[protocol://][user:password@]machine[:port]". They also note that the
"protocol://" part is simply ignored if present. (Proxies are always http).

Tyler, I think the best way to go is for you to try this and let us know if that
works.

[dmorissette]

Not in 4.4. Setting FUTURE target milsetone.

[bartvde@…]

I checked this by using SetEnv http_proxy in the Apache conf and all works fine!
There is also an option in curl to exclude certain domains if needed.

For my use this would be enough. I can't think of any situation in which you
want per layer proxy url's.

[elromero@…]

Hello,

I'm a new MapServer user and I have a problem. I want to call a layer from a 
remote WMS but I can't because I have a problem whith the proxy.
I have inserted the next line in httpd.conf file:
SetEnv http_proxy "http://isas.vivienda.local:8080"

And I have inserted in my map file:
LAYER # MODIS WMS map from JPL
    NAME         modis_jpl
    TYPE         RASTER
    OFFSITE      0 0 0
    STATUS       OFF
    CONNECTIONTYPE WMS
    DEBUG        ON
    CONNECTION "http://wms.jpl.nasa.gov/wms.cgi?"
    
    METADATA
      "wms_srs" "EPSG:4326"
      "wms_name" "modis"
      "wms_server_version" "1.1.1"
      "wms_format" "image/jpeg"      
      "wms_proxy_*" "isas.vivienda.local:8080"
    END

    PROJECTION
      "init=epsg:4326"
    END
  END # Modis WMS image ends here

But I only get a temporary file with an autentification proxy problem.

What am I doing bad? What more do I need?

Thak you,

Emilio

[dmorissette]

Emilio, this is a bug report, it is not the place to ask for support, I would
suggest that you send your question to the mapserver-users list. If it turns out
that better proxy support would solve your problem then the conclusions of the
list discussion can be added in support to this bug later on.
(Hint: also include a copy of the proxy error messages in your post to the list.)

[project10]

Initial implementation