one groupby per build thread + new resolver class

lektor_groupby/resolver.py

@@ -0,0 +1,50 @@
+from lektor.db import Record
+from lektor.environment import Environment
+from lektor.sourceobj import SourceObject
+from lektor.utils import build_url
+
+from typing import Dict, List, Tuple, Optional
+from .config import Config  # typing
+from .vobj import GroupBySource, VPATH
+
+
+class Resolver:
+    '''
+    Resolve virtual paths and urls ending in /.
+    Init will subscribe to @urlresolver and @virtualpathresolver.
+    '''
+
+    def __init__(self, env: Environment) -> None:
+        self._data = {}  # type: Dict[str, Tuple[str, Config]]
+
+        # Local server only: resolve /tag/rss/ -> /tag/rss/index.html
+        @env.urlresolver
+        def dev_server_path(node: SourceObject, pieces: List[str]) \
+                -> Optional[GroupBySource]:
+            if isinstance(node, Record):
+                rv = self._data.get(build_url([node.url_path] + pieces))
+                if rv:
+                    return GroupBySource(node, group=rv[0], config=rv[1])
+            return None
+
+        # Admin UI only: Prevent server error and null-redirect.
+        @env.virtualpathresolver(VPATH.lstrip('@'))
+        def virtual_path(node: SourceObject, pieces: List[str]) \
+                -> Optional[GroupBySource]:
+            if isinstance(node, Record) and len(pieces) >= 2:
+                path = node['_path']  # type: str
+                key, grp, *_ = pieces
+                for group, conf in self._data.values():
+                    if key == conf.key and path == conf.root:
+                        if conf.slugify(group) == grp:
+                            return GroupBySource(node, group, conf)
+            return None
+
+    def reset(self) -> None:
+        ''' Clear previously recorded virtual objects. '''
+        self._data.clear()
+
+    def add(self, vobj: GroupBySource) -> None:
+        ''' Track new virtual object (only if slug is set). '''
+        if vobj.slug:
+            self._data[vobj.url_path] = (vobj.group, vobj.config)