[MapServer-users] mapserver 8 - CGI map_object substitutions broken?

[Tim Kempisty]

Well that's... not shocking.  I'm imagining the regex that might sanitize a URL with all that syntax in it... uuuuughh...   *crumplecrumplecrumple* ~toss~ 

As for my own work... I realized yesterday late that I was going to have to find an alternative anyway.  All these maps need to go into Mapcache.  Turning that map_object notation into an intuitive mapcache dimension is a big ol Nope.  I can likely pass in a parameter on the URL (&fontsize=10)  and then use multiple classes in the vein of  CLASS: EXPRESSION (%fontsize% = 10).  Voila.  Easy mapcache dimension, easy sanitizing, supports a reasonable number of font sizes.

So I guess the item for the maintainers to fix is actually the documentation ( https://mapserver.org/cgi/controls.html )  which still makes it look like you can use map_object notation on the URL in MS8. 

Thanks for the info!

-Tim

> On Oct 6, 2022, at 3:49 PM, Steve Lime <sdlime at gmail.com> wrote:
> 
> Hi Tim: I was wondering if I'd see any messages on that topic. Short story is that the functionality was removed in MS8. I never liked the all-or-nothing aspect of it and was working on a method to control which objects would be allowed to be updated. The solutions I came up with were convoluted and were going to add a lot of complexity to the codebase for little value. That functionality is poorly documented and by itself overly complicates the code. So after a note to mapserver-users trying to judge how much it was used - with limited replies - it was decided to remove it. I'm dealing with my own upgrade issues as a result, but it's worth it in the end IMHO.
> 
> If necessary, it's better to revisit with another method - ideally something along the lines of runsubs. The challenge is specifying when to apply them and how to validate values. Strings are easy, but numeric/color values aren't so we'd need to do something like add runtime bindings (similar to attribute bindings) so you'd write SIZE %mysize% instead. One advantage being you could reuse the variable across layers.
> 
> So, what are the options right now? It sort of depends on your needs. Do you need to only support a couple of sizes for a class or do you truly need *any* size? Options include:
> multiple mapfiles - probably using includes to limit redundancy
> class groups
> if you're using a db backend I think attribute bindings could work paired with runsubs
> DATA "shape FROM (select *, %textsize% AS textsize FROM ...)
> VALIDATION
>     "textsize_default" "13"
>     "textsize" "^8|10|12|14$"
> END
> CLASS
>   LABEL
>     SIZE [textsize] # I think attribute binding works here
>   END
> END
> MapScript - load the mapfile, do the changes you need, render the map
> Happy to discuss further and perhaps other folks have ideas.
> 
> --Steve
> 
> On Thu, Oct 6, 2022 at 12:47 PM Tim Kempisty via MapServer-users <mapserver-users at lists.osgeo.org <mailto:mapserver-users at lists.osgeo.org>> wrote:
> Good afternoon, all.
> 
> I am migrating a project from MS7 to the new Mapserver 8.0.0, and I've stumbled upon evidence that map_object notation support for CGI variable substitution may be broken.
> 
> Here's the relevant doc for CGI Controls:
> 
> https://mapserver.org/cgi/controls.html <https://mapserver.org/cgi/controls.html> 
> 
> Scoll down to the heading:  "Changing map file parameters via a form or a URL" 
> We have been using the map_object notation method to set custom image sizes and font sizes.
> 
> Excuse the messy query string.  The important parts are  "&map_size" and "&map.layer[...]"
> 
> /var/www/cgi-bin/mapserv.cgi -nh "QUERY_STRING=mode=map&map=/usr/local/mapfiles/kempisty/nbm_view/foo.map&layer=genNoDec&model=blend&ver=v4.0&sector=conus&element=maxt&issuancetime=2022-10-06T14:00&validtime=2022-10-08T06:00&mapext=-3270279.3477121103%20-163255.0404466032%202666810.2533767014%203144901.0582670807&map_size=1215+677&map.layer[genNoDec].class[0].label[0]=SIZE+8" > /var/www/html/kempisty/foo7.png
> 
> MS7 gives a map size 1215x677 with labels rendered in 8 point font, as expected.  The same command, using mapserver 8 instead of 7, gives an image size 2345x1597 (map size as defined in the mapfile) with labels rendered in 13 point font (also as defined in the mapfile).
> 
> Using MS8... if I send &mapsize=1215+677 instead of &map_size=1215+677 ... I will get the image at the correct size.  So the predefined CGI control variables still work.  It suggests to me, it is only the map_object notation method that is broken.  Has that been disabled in MS8, or is it now subject to a new configuration requirement that I'm not aware of?
> 
> Relevant string isolated for reference:
> &map_size=1215+677&map.layer[genNoDec].class[0].label[0]=SIZE+8"
> 
> I'm open to other methods of changing font size on the fly.  We did it this way because %var% runtime substitutions aren't supported for CLASS: LABEL: SIZE.
> 
> -Tim Kempisty
> 
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