Add support for modifying relations based on object metadata

changegen/__main__.py

@@ -147,6 +147,27 @@ def _get_db_tables(suffix, dbname, dbport, dbuser, dbpass, dbhost):
     ),
     default="2000",
 )
+@click.option(
+    "--modify_relations",
+    is_flag=True,
+    help=(
+        "Add new objects to parent relations specified by a special tag.  "
+        'The default tag prefix for tags containing Relation IDs is "_member_of". '
+        "Pass the --relation_tag flag to change "
+        "this prefix, e.g. --relation_tag __a_different_prefix_. "
+        "See changegen.relations.py for more information. "
+    ),
+)
+@click.option(
+    "--relation_tag",
+    is_flag=False,
+    help=(
+        "Only used with --modify_relations. Specify the tag prefix "
+        "used to search for IDs to to add new OSM objects to."
+    ),
+    default="_member_of",
+    show_default=True,
+)
 @click.option("--osmsrc", help="Source OSM PBF File path", required=True)
 @click.argument("dbname", default=os.environ.get("PGDATABASE", "conflate"))
 @click.argument("dbport", default=os.environ.get("PGPORT", "15432"))
@@ -233,6 +254,8 @@ def main(*args: tuple, **kwargs: dict):
             self_intersections=kwargs["self"],
             max_nodes_per_way=int(max_nodes_per_way),
             modify_only=kwargs["modify_meta"],
+            modify_relations=kwargs["modify_relations"],
+            relation_tag=kwargs["relation_tag"],
         )
 
     for table in kwargs["deletions"]:

changegen/changewriter.py

@@ -107,14 +107,18 @@ class OSMChangeWriter(object):
     )
     _root_element_close = "</osmChange>"
 
-    def __init__(self, filename=None, compress=False):
+    def __init__(self, filename=None, compress=False, keepcopy=False):
         super(OSMChangeWriter, self).__init__()
 
         self.compress = compress
         self.filename = filename
         self.fileobj = None
         self.closed = False
         self._data_written = False
+        self.keepcopy = keepcopy
+        self.created = []
+        self.modified = []
+        self.deleted = []
 
         # set fileobj based on compression
         if self.filename and self.compress:
@@ -163,6 +167,8 @@ def add_modify(self, elementlist):
                     write_osm_object(e, writer)
             writer.flush()
         self._data_written = True
+        if self.keepcopy:
+            self.modified.extend(elementlist)
 
     def add_create(self, elementlist):
         """Creates <create> element containing
@@ -178,6 +184,8 @@ def add_create(self, elementlist):
                     write_osm_object(e, writer)
             writer.flush()
         self._data_written = True
+        if self.keepcopy:
+            self.created.extend(elementlist)
 
     def add_delete(self, elementlist):
         """Creates a <delete> element containing
@@ -189,3 +197,5 @@ def add_delete(self, elementlist):
                     write_osm_object(e, writer)
                 writer.flush()
         self._data_written = True
+        if self.keepcopy:
+            self.deleted.extend(elementlist)

changegen/generator.py

@@ -24,6 +24,7 @@
 from .changewriter import Tag
 from .changewriter import Way
 from .db import OGRDBReader
+from .relations import RelationUpdater
 
 WGS84 = pyproj.CRS("EPSG:4326")
 WEBMERC = pyproj.CRS("EPSG:3857")
@@ -483,6 +484,9 @@ def generate_changes(
     self_intersections=False,
     max_nodes_per_way=2000,
     modify_only=False,
+    modify_relations=False,
+    relation_tag="_member_of",
+    relation_insertion_tag="parent_osm_id",
 ):
     """
     Generate an osm changefile (outfile) based on features in <table>
@@ -514,7 +518,11 @@ def generate_changes(
     others = [others] if isinstance(others, str) else others
 
     db_reader = OGRDBReader(dbname, dbport, dbuser, dbpass, dbhost)
-    change_writer = OSMChangeWriter(outfile, compress=compress)
+    # keep a copy of elements if we modify_relations
+    # becasue we need them later
+    change_writer = OSMChangeWriter(
+        outfile, compress=compress, keepcopy=modify_relations
+    )
 
     new_feature_iter = db_reader.get_layer_iter(table)
     layer_fields = db_reader.get_layer_fields(table)
@@ -573,17 +581,32 @@ def generate_changes(
         ):
             raise NotImplementedError("Multi geometries not supported.")
         if isinstance(wgs84_geom, sg.LineString):
-            ways, nodes = _generate_ways_and_nodes(
-                wgs84_geom,
-                ids,
-                feat_tags,
-                intersection_db,
-                max_nodes_per_way=max_nodes_per_way,
-            )
-            new_nodes.extend(nodes)
-            new_ways.extend(ways)
-            _global_node_id_all_ways.extend(chain.from_iterable([w.nds for w in ways]))
-        if isinstance(wgs84_geom, sg.Polygon):
+            ## NOTE that modify_only does not support modifying geometries.
+            if modify_only:
+                existing_id = feature.GetFieldAsString(feature.GetFieldIndex("osm_id"))
+
+                new_ways.append(
+                    Way(
+                        id=existing_id,
+                        version=2,
+                        nds=existing_nodes_for_ways[existing_id],
+                        tags=[tag for tag in feat_tags if tag.key != "osm_id"],
+                    )
+                )
+            else:  # not modifying, just creating
+                ways, nodes = _generate_ways_and_nodes(
+                    wgs84_geom,
+                    ids,
+                    feat_tags,
+                    intersection_db,
+                    max_nodes_per_way=max_nodes_per_way,
+                )
+                new_nodes.extend(nodes)
+                new_ways.extend(ways)
+                _global_node_id_all_ways.extend(
+                    chain.from_iterable([w.nds for w in ways])
+                )
+        elif isinstance(wgs84_geom, sg.Polygon):
             ## If we're taking all features to be newly-created (~modify_only)
             ## we need to create ways and nodes for that feature.
             ## IF we're only modifying existing features with features
@@ -685,6 +708,53 @@ def generate_changes(
         if len(new_relations) > 0:
             change_writer.add_create(new_relations)
 
+    ## Relation Updates: If modify_relations is true,
+    ## we'll search through all newly-added objects
+    ## for Tags with prefix specified by `relation_tag`
+    ## and add them to the relations specified by the
+    ## values of those tags.
+    modified_relations = []
+    if modify_relations:
+        updater = RelationUpdater()
+        relations_mentioned = set()
+        for obj in change_writer.created:
+            relations_mentioned.update(
+                chain.from_iterable(
+                    [
+                        _t.value.split(",")
+                        for _t in obj.tags
+                        if _t.key.startswith(relation_tag)
+                    ]
+                )
+            )
+        # create relations DB
+        updater.get_relations(relations_mentioned, osmsrc)
+        # update db for each new object
+        for obj in tqdm(
+            change_writer.created,
+            desc="Checking objects for relations...",
+        ):
+            # check to see if a tag that matches `relation_insertion_tag`
+            # is present, and if so, provide the value as`
+            # at_id to insert the new object at the location of that
+            # ID in the relation.
+            at_id = None
+            try:
+                at_id = [
+                    t.value
+                    for t in obj.tags
+                    if t.key.startswith(relation_insertion_tag)
+                ][0]
+            except IndexError:
+                # did not find insertion tag. at_id is none.
+                at_id = None
+            updater.modify_relations_with_object(obj, relation_tag, at_id)
+        # get modified relations
+        modified_relations = updater.get_modified_relations()
+        ## Write modified relations too.
+        if len(modified_relations) > 0:
+            change_writer.add_modify(modified_relations)
+
     # Write all modified ways with intersections
     # Because we have to re-generate nodes for all points
     # within the intersecting linestrings, we write
@@ -796,7 +866,7 @@ def generate_deletions(
     osmsrc,
     outfile,
     compress=True,
-    skip_nodes=False,
+    skip_nodes=True,
 ):
     """
     Produce a changefile with <delete> nodes for all IDs in table.