From a0b1ff8635751d277a7a1612ac37aec1c92c887e Mon Sep 17 00:00:00 2001
From: Guilhem Moulin <guilhem@fripost.org>
Date: Sat, 19 Oct 2024 19:47:21 +0200
Subject: webmap-publish: Pass a serialized configuration string.

Cf. https://gdal.org/en/latest/drivers/vector/mvt.html .  This enables
customizing min/maxzoom and target layer name.
---
 webmap-publish | 42 +++++++++++++++++++++++-------------------
 1 file changed, 23 insertions(+), 19 deletions(-)

diff --git a/webmap-publish b/webmap-publish
index a33d56e..c4103ef 100755
--- a/webmap-publish
+++ b/webmap-publish
@@ -482,6 +482,7 @@ if __name__ == '__main__':
         raise Exception('Configuration does not specify source dataset')
 
     export_layers = {}
+    mvtconf = {}
     for layername, layerdef in common.config.get('layers', {}).items():
         exportdef = layerdef.get('publish', None)
         if exportdef is None:
@@ -491,11 +492,14 @@ if __name__ == '__main__':
         elif isinstance(exportdef, list):
             exportdef = { l:{} for l in exportdef }
         for export_layername, export_layerdef in exportdef.items():
-            if 'target_name' in export_layerdef:
-                export_layername = export_layerdef.pop('target_name')
-            if export_layername not in export_layers:
-                export_layers[export_layername] = []
-            export_layers[export_layername].append(export_layerdef)
+            if export_layername in export_layers:
+                raise Exception(f'Duplicate definition for {export_layername}')
+            x = {}
+            for k in ['target_name', 'minzoom', 'maxzoom']:
+                if k in export_layerdef:
+                    x[k] = export_layerdef[k]
+            mvtconf[export_layername] = x
+            export_layers[export_layername] = export_layerdef
             export_layerdef['__layername-src__'] = layername
 
     if args.destdir != os.curdir:
@@ -546,6 +550,7 @@ if __name__ == '__main__':
                 'BUFFER': 32,
                 'TILE_EXTENSION': tile_extension.removeprefix('.'),
                 'TEMPORARY_DB': Path(tempdir).joinpath('tmp-mvt.db'),
+                'CONF': json.dumps(mvtconf, ensure_ascii=False, separators=(',',':')),
         })
 
         # use a temporary directory for the metadata to avoid messing
@@ -558,25 +563,24 @@ if __name__ == '__main__':
             os.chmod(metadata['tempdir'], 0o0755, dir_fd=metadata.get('dirfd', None),
                      follow_symlinks=False)
             nextfid = 0
-            for layername, layerdefs in export_layers.items():
+            for layername, layerdef in export_layers.items():
                 # create destination layer
                 lyr_dst = ds_dst.CreateLayer(layername, srs=srs, geom_type=ogr.wkbUnknown)
                 if lyr_dst is None:
                     raise Exception(f'Could not create destination layer "{layername}"')
 
-                for layerdef in layerdefs:
-                    lyr_src = getSourceLayer(ds, layerdef, extent=extent)
-                    try:
-                        # use the non-dense geometry (a rectangle) for clipping as it's faster
-                        # and there is no need to reproject (the SRSs match)
-                        nextfid, count0 = exportLayer(lyr_dst, lyr_src,
-                            layername=layerdef['__layername-src__'],
-                            srs=srs, clip=extent_simple,
-                            coordinate_precision=coordinate_precision,
-                            nextfid=nextfid, metadata=metadata)
-                        nFeatures += count0
-                    finally:
-                        ds.ReleaseResultSet(lyr_src)
+                lyr_src = getSourceLayer(ds, layerdef, extent=extent)
+                try:
+                    # use the non-dense geometry (a rectangle) for clipping as it's faster
+                    # and there is no need to reproject (the SRSs match)
+                    nextfid, count0 = exportLayer(lyr_dst, lyr_src,
+                        layername=layerdef['__layername-src__'],
+                        srs=srs, clip=extent_simple,
+                        coordinate_precision=coordinate_precision,
+                        nextfid=nextfid, metadata=metadata)
+                    nFeatures += count0
+                finally:
+                    ds.ReleaseResultSet(lyr_src)
                 lyr_dst = None
 
             # close datasets
-- 
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