support legacy Web Merc Google EPSG:900913 for proj

Author: justb4

.github/workflows/main.yml

@@ -25,6 +25,6 @@ jobs:
         username: ${{ secrets.DOCKER_USERNAME }}
         password: ${{ secrets.DOCKER_PASSWORD }}
         repository: justb4/mapproxy
-        tags: latest,1.12.0-1
+        tags: latest,1.12.0-2
         tag_with_ref: false
         tag_with_sha: false

Dockerfile

@@ -16,11 +16,14 @@ FROM debian:buster-slim
 # Upgrade notes: in bullseye: use libproj19 uwsgi-plugin-python3 (i.s.o. pip3 uwsgi)
 # --plugin /usr/lib/uwsgi/plugins/python3_plugin.so in uwsgi command and remove --wsgi-disable-file-wrapper
 #
+# Nasty fix: added Google Web Merc projection EPSG:900913 for legacy MP configs (clients use /EPSG:900913/ in URLs!)
+# Upgrade notes: Debian bullseye-slim and proj.6: will need SQLite for proj.db i.s.o. /usr/share/proj/epsg!!
+
 LABEL original_developer="Arne Schubert <atd.schubert@gmail.com>"
 LABEL contributor="Just van den Broecke <justb4@gmail.com>"
 
 # Build ARGS
-ARG TIMEZONE="Europe/Amsterdam"
+ARG TZ="Europe/Amsterdam"
 ARG LOCALE="en_US.UTF-8"
 # Only adds 1MB and handy tools
 ARG ADD_DEB_PACKAGES="curl xsltproc libxml2-utils"
@@ -33,11 +36,13 @@ ENV MAPPROXY_PROCESSES="4" \
 	DEBIAN_FRONTEND="noninteractive" \
 	DEB_BUILD_DEPS="python3-pip build-essential python3-dev python3-setuptools python3-wheel" \
 	DEB_PACKAGES="python3-pil python3-yaml python3-gdal libproj13 python3-lxml python3-shapely libgeos-dev uwsgi-plugin-python3 ${ADD_DEB_PACKAGES}" \
-	PIP_PACKAGES="uwsgi requests geojson MapProxy==${MAPPROXY_VERSION} ${ADD_PIP_PACKAGES}"
+	PIP_PACKAGES="uwsgi requests geojson MapProxy==${MAPPROXY_VERSION} ${ADD_PIP_PACKAGES}" \
+	GOOGLE_WEB_MERC_EPSG="<900913> +proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null +wktext +no_defs <>"
 
 RUN set -x \
   && apt-get update \
   && apt-get install --no-install-recommends -y ${DEB_BUILD_DEPS} ${DEB_PACKAGES} ${ADD_DEB_PACKAGES} \
+  && echo ${GOOGLE_WEB_MERC_EPSG} >> /usr/share/proj/epsg \
   && useradd -ms /bin/bash mapproxy \
   && mkdir -p /mapproxy \
   && chown mapproxy /mapproxy \