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--- doc:appunti:linux:sa:debian_11_12_mapserver_upgrade [2023/11/23 17:31] – niccolo
+++ doc:appunti:linux:sa:debian_11_12_mapserver_upgrade [2023/11/23 18:11] (current) – [MAP:TRANSPARENT not longer valid] niccolo
@@ Line 3: / Line 3: @@
 Finally I decided to upgrade my home server from **Debian 11 Bullseye** to **Debian 12 Bookworm**; here you can read some notes about the upgrade: **[[debian_upgrade_11_12]]**.
-One change that deserves a dedicated page is the upgrade from **MapServer 7.6.2** shipped with Debian 11 to **MapServer 8.0.1** shipped with Debian 12; in fact it happened that almost all MapServer based applications stopped working.
+One change that deserves a dedicated page is the upgrade from **MapServer 7.6.2** shipped with Debian 11 to **MapServer 8.0.1** shipped with Debian 12; in fact it happened that almost all the MapServer based applications stopped working.
+===== Mandatory /etc/mapserver.conf =====
+In version 8 it became mandatory to have a configuration file, the default location of which is **/etc/mapserver.conf**. See the syntax here: [[https://mapserver.org/mapfile/config.html]]. You must declare at least the ''MS_MAP_PATTERN'' path.
+==== CONFIG:MAPS aliases ====
+In the past I used to have some CGI-Mapserver services (as native MapServer or as WMS service) where the service URL contained **the full path of the mapfile**, something like this:
+<code>
+http://www.rigacci.org/cgi-bin/mapserv?map=/usr/local/lib/mapserver/mie-strade-wms.map&
+</code>
+It is not a good practice to accept from the internet a parameter that is the full path to a local file. MapServer 8 requires that you declare at least a pattern that the received mapfile must obey to (''MS_MAP_PATTERN''). Better than that, you can define several aliases (short names pointing to the mapfiles wherever they resied) and **accept from the client only that aliases**, disallowing the requests for a full path mapfile (''MS_MAP_NO_PATH''). I opted for the latter mode:
+<file>
+# MapServer 8.0 Config File
+# https://mapserver.org/mapfile/config.html
+CONFIG
+  MAPS
+    # Define the aliases for mapfile paths.
+    MIE_STRADE_WMS "/usr/local/lib/mapserver/mie-strade-wms.map"
+  END
+  ENV
+    # Disallow using full path for mapfiles (use aliases defined in CONFIG:MAPS instead).
+    MS_MAP_NO_PATH "true"
+    # Limit mapfile access when using full paths, this setting is never used
+    # if CONFIG:ENV:MS_MAP_NO_PATH is set.
+    MS_MAP_PATTERN "^/usr/local/lib/mapserver"
+  END
+END
+</file>
+In this way the above URL will be changed into:
+<code>
+http://www.rigacci.org/cgi-bin/mapserv?map=MIE_STRADE_WMS&
+</code>
+===== MAP:TRANSPARENT not longer valid =====
+In MapServer 8 mapfiles the **TRANSPARENT** identifier is not longer accepted inside the MAP object, you have to move it into the **OUTPUTFORMAT** object; something like this:
+<file>
+  OUTPUTFORMAT
+    NAME agg_png
+    DRIVER "AGG/PNG"
+    MIMETYPE "image/png"
+    IMAGEMODE RGBA
+    EXTENSION "png"
+    TRANSPARENT ON
+  END
+</file>
+===== Name change of CGI parameters =====
+One of the biggest problem of the upgrade is the change of the name of some CGI parameters; notably the **map_size** option is not longer supported.
+I had web application based on OpenLayers 2.11, which included a MapServer bitmap layer. The JavaScript code automatically generates the request URL, something like this (parameters are split on different lines for readability):
+<code>
+/cgi-bin/mapserv?map=/usr/local/lib/mapserver/mie_strade.map
+    &format=image%2Fpng
+    &mode=map
+    &map_imagetype=png
+    &mapext=1235758.1079621+5432310.5814201+1242666.1043925+5443174.1940635
+    &imgext=1235758.1079621+5432310.5814201+1242666.1043925+5443174.1940635
+    &map_size=1446+2274
+    &imgx=723
+    &imgy=1137
+    &imgxy=1446+2274
+</code>
+Unfortunately the **map_size** option is not longer accepted and the resulting PNG image has the default size declared into the MAP:SIZE object of the mapfile, instead of the requested 1446x2274 pixels. This causes a **totally distorted map** image into the web application!
+This problem cannot be easily fixed, because the URL options are hard-coded into the OpenLayers code. So I had to replace all the OpenLayers 2.x code with the current **OpenLayers 8.x**, which required a total refactory of the code.