Files
lektor-groupby-plugin/lektor_groupby.py
2022-04-01 13:34:35 +02:00

499 lines
18 KiB
Python

# -*- coding: utf-8 -*-
from lektor.db import Database, Record # typing
from lektor.build_programs import BuildProgram
from lektor.builder import Artifact, Builder # typing
from lektor.pluginsystem import Plugin
from lektor.reporter import reporter
from lektor.sourceobj import SourceObject, VirtualSourceObject
from lektor.types.flow import Flow, FlowType
from lektor.utils import bool_from_string, build_url, prune_file_and_folder
# for quick config
from lektor.utils import slugify
from typing import Tuple, Dict, Set, List, NamedTuple
from typing import NewType, Optional, Iterator, Callable, Iterable
VPATH = '@groupby' # potentially unsafe. All matching entries are pruned.
# -----------------------------------
# Typing
# -----------------------------------
AttributeKey = NewType('AttributeKey', str) # attribute of lektor model
GroupKey = NewType('GroupKey', str) # key of group-by
class ResolverConf(NamedTuple):
attrib: AttributeKey
group: GroupKey
slug: str
class FieldKeyPath(NamedTuple):
fieldKey: str
flowIndex: Optional[int] = None
flowKey: Optional[str] = None
class GroupByCallbackArgs(NamedTuple):
record: Record
key: FieldKeyPath
field: object # lektor model data-field value
GroupingCallback = Callable[[GroupByCallbackArgs],
Iterator[Tuple[GroupKey, object]]]
# -----------------------------------
# VirtualSource & BuildProgram
# -----------------------------------
class GroupBySource(VirtualSourceObject):
'''
Holds information for a single group/cluster.
This object is accessible in your template file.
Attributes: record, attrib, group, slug, template, children
:DEFAULTS:
slug: "{attrib}/{group}/index.html"
template: "groupby-attribute.html"
'''
def __init__(
self,
record: Record,
attrib: AttributeKey,
group: GroupKey, *,
slug: Optional[str] = None, # default: "{attrib}/{group}/index.html"
template: Optional[str] = None # default: "groupby-attrib.html"
) -> None:
super().__init__(record)
self.attrib = attrib
self.group = group
self.template = template or 'groupby-{}.html'.format(self.attrib)
# custom user path
slug = slug or '{attrib}/{group}/index.html'
slug = slug.replace('{attrib}', self.attrib)
slug = slug.replace('{group}', self.group)
if slug.endswith('/index.html'):
slug = slug[:-10]
self.slug = slug
# user adjustable after init
self.children = {} # type: Dict[Record, List[object]]
self.dependencies = set() # type: Set[str]
@property
def path(self) -> str:
# Used in VirtualSourceInfo, used to prune VirtualObjects
return f'{self.record.path}{VPATH}/{self.attrib}/{self.group}'
@property
def url_path(self) -> str:
# Actual path to resource as seen by the browser
return build_url([self.record.path, self.slug])
def iter_source_filenames(self) -> Iterator[str]:
''' Enumerate all dependencies '''
if self.dependencies:
yield from self.dependencies
for record in self.children:
yield from record.iter_source_filenames()
def __str__(self) -> str:
txt = '<GroupBySource'
for x in ['attrib', 'group', 'slug', 'template']:
txt += ' {}="{}"'.format(x, getattr(self, x))
return txt + ' children={}>'.format(len(self.children))
class GroupByBuildProgram(BuildProgram):
''' Generate Build-Artifacts and write files. '''
def produce_artifacts(self) -> None:
url = self.source.url_path
if url.endswith('/'):
url += 'index.html'
self.declare_artifact(url, sources=list(
self.source.iter_source_filenames()))
GroupByPruner.track(url)
def build_artifact(self, artifact: Artifact) -> None:
self.source.pad.db.track_record_dependency(self.source)
artifact.render_template_into(self.source.template, this=self.source)
# -----------------------------------
# Helper
# -----------------------------------
class GroupByPruner:
'''
Static collector for build-artifact urls.
All non-tracked VPATH-urls will be pruned after build.
'''
_cache: Set[str] = set()
# Note: this var is static or otherwise two instances of
# GroupByCreator would prune each others artifacts.
@classmethod
def track(cls, url: str) -> None:
''' Add url to build cache to prevent pruning. '''
cls._cache.add(url.lstrip('/'))
@classmethod
def prune(cls, builder: Builder) -> None:
''' Remove previously generated, unreferenced Artifacts. '''
dest_path = builder.destination_path
con = builder.connect_to_database()
try:
with builder.new_build_state() as build_state:
for url, file in build_state.iter_artifacts():
if url.lstrip('/') in cls._cache:
continue # generated in this build-run
infos = build_state.get_artifact_dependency_infos(url, [])
for v_path, _ in infos:
if VPATH not in v_path:
continue # we only care about groupby Virtuals
reporter.report_pruned_artifact(url)
prune_file_and_folder(file.filename, dest_path)
build_state.remove_artifact(url)
break # there is only one VPATH-entry per source
finally:
con.close()
cls._cache.clear()
class GroupByModelReader:
''' Find models and flow-models which contain attrib '''
def __init__(self, db: Database, attrib: AttributeKey) -> None:
self._flows = {} # type: Dict[str, Set[str]]
self._models = {} # type: Dict[str, Dict[str, str]]
# find flow blocks with attrib
for key, flow in db.flowblocks.items():
tmp1 = set(f.name for f in flow.fields
if bool_from_string(f.options.get(attrib, False)))
if tmp1:
self._flows[key] = tmp1
# find models with attrib or flow-blocks containing attrib
for key, model in db.datamodels.items():
tmp2 = {} # Dict[str, str]
for field in model.fields:
if bool_from_string(field.options.get(attrib, False)):
tmp2[field.name] = '*' # include all children
elif isinstance(field.type, FlowType) and self._flows:
# only processed if at least one flow has attrib
fbs = field.type.flow_blocks
# if fbs == None, all flow-blocks are allowed
if fbs is None or any(x in self._flows for x in fbs):
tmp2[field.name] = '?' # only some flow blocks
if tmp2:
self._models[key] = tmp2
def read(
self,
record: Record,
flatten: bool = False
) -> Iterator[Tuple[FieldKeyPath, object]]:
'''
Enumerate all fields of a Record with attrib = True.
Flows are either returned directly (flatten=False) or
expanded so that each flow-block is yielded (flatten=True)
'''
assert isinstance(record, Record)
for r_key, subs in self._models.get(record.datamodel.id, {}).items():
if subs == '*': # either normal field or flow type (all blocks)
field = record[r_key]
if flatten and isinstance(field, Flow):
for i, flow in enumerate(field.blocks):
flowtype = flow['_flowblock']
for f_key, block in flow._data.items():
if f_key.startswith('_'): # e.g., _flowblock
continue
yield FieldKeyPath(r_key, i, f_key), block
else:
yield FieldKeyPath(r_key), field
else: # always flow type (only some blocks)
for i, flow in enumerate(record[r_key].blocks):
flowtype = flow['_flowblock']
for f_key in self._flows.get(flowtype, []):
yield FieldKeyPath(r_key, i, f_key), flow[f_key]
class GroupByState:
''' Holds and updates a groupby build state. '''
def __init__(self) -> None:
self.state = {} # type: Dict[GroupKey, Dict[Record, List]]
self._processed = set() # type: Set[Record]
def __contains__(self, record: Record) -> bool:
''' Returns True if record was already processed. '''
return record.path in self._processed
def items(self) -> Iterable[Tuple[GroupKey, Dict]]:
''' Iterable with (GroupKey, {record: extras}) tuples. '''
return self.state.items()
def add(self, record: Record, group: Dict[GroupKey, List]) -> None:
''' Append groups if not processed already. '''
if record.path not in self._processed:
self._processed.add(record.path)
for group_key, extras in group.items():
if group_key in self.state:
self.state[group_key][record] = extras
else:
self.state[group_key] = {record: extras}
class GroupByWatcher:
'''
Callback is called with (Record, FieldKeyPath, field-value).
Callback may yield one or more (group-key, extra-info) tuples.
'''
def __init__(
self,
root: str,
attrib: AttributeKey,
callback: GroupingCallback, *,
slug: Optional[str] = None, # default: "{attrib}/{group}/index.html"
template: Optional[str] = None # default: "groupby-attrib.html"
) -> None:
self.root = root
self.attrib = attrib
self.callback = callback
self.slug = slug
self.template = template
# user editable attributes
self.flatten = True # if False, dont explode FlowType
self.dependencies = set() # type: Set[str]
def initialize(self, db: Database) -> None:
''' Reset internal state. You must initialize before each build! '''
self._state = GroupByState()
self._model_reader = GroupByModelReader(db, self.attrib)
def should_process(self, node: SourceObject) -> bool:
''' Check if record path is being watched. '''
if isinstance(node, Record):
p = node['_path'] # type: str
return p.startswith(self.root) or p + '/' == self.root
return False
def process(self, record: Record) -> None:
'''
Will iterate over all record fields and call the callback method.
Each record is guaranteed to be processed only once.
'''
if record in self._state:
return
tmp = {}
for key, field in self._model_reader.read(record, self.flatten):
for ret in self.callback(GroupByCallbackArgs(record, key, field)):
assert isinstance(ret, (tuple, list)), \
'Must return tuple (group-key, extra-info)'
group_key, extra = ret
if group_key not in tmp:
tmp[group_key] = [extra]
else:
tmp[group_key].append(extra)
self._state.add(record, tmp)
def iter_sources(self, root: Record) -> Iterator[GroupBySource]:
''' Prepare and yield GroupBySource elements. '''
for group_key, children in self._state.items():
src = GroupBySource(root, self.attrib, group_key,
slug=self.slug, template=self.template)
src.dependencies = self.dependencies
src.children = children
yield src
def __str__(self) -> str:
txt = '<GroupByWatcher'
for x in [
'root', 'attrib', 'slug', 'template', 'flatten', 'dependencies'
]:
txt += ' {}="{}"'.format(x, getattr(self, x))
return txt + '>'
# -----------------------------------
# Main Component
# -----------------------------------
class GroupByCreator:
'''
Process all children with matching conditions under specified page.
Creates a grouping of pages with similar (self-defined) attributes.
The grouping is performed only once per build.
'''
def __init__(self) -> None:
self._watcher = [] # type: List[GroupByWatcher]
self._results = {} # type: Dict[str, GroupBySource]
self._resolve_map = {} # type: Dict[str, ResolverConf]
# ----------------
# Add Observer
# ----------------
def depends_on(self, *args: str) \
-> Callable[[GroupByWatcher], GroupByWatcher]:
''' Set GroupBySource dependency, e.g., a plugin config file. '''
def _decorator(r: GroupByWatcher) -> GroupByWatcher:
r.dependencies.update(list(args))
return r
return _decorator
def watch(
self,
root: str,
attrib: AttributeKey, *,
slug: Optional[str] = None, # default: "{attrib}/{group}/index.html"
template: Optional[str] = None, # default: "groupby-attrib.html"
flatten: bool = True, # if False, dont explode FlowType
) -> Callable[[GroupingCallback], GroupByWatcher]:
'''
Decorator to subscribe to attrib-elements.
(record, field-key, field) -> (group-key, extra-info)
:DEFAULTS:
slug: "{attrib}/{group}/index.html"
template: "groupby-attrib.html"
'''
root = root.rstrip('/') + '/'
def _decorator(fn: GroupingCallback) -> GroupByWatcher:
w = GroupByWatcher(root, attrib, fn, slug=slug, template=template)
w.flatten = flatten
self._watcher.append(w)
return w
return _decorator
# -----------
# Builder
# -----------
def clear_previous_results(self) -> None:
''' Reset prvious results. Must be called before each build. '''
self._watcher.clear()
self._results.clear()
self._resolve_map.clear()
def make_cluster(self, builder: Builder) -> None:
''' Perform groupby, iterate over all children. '''
if not self._watcher:
return
for w in self._watcher:
w.initialize(builder.pad.db)
queue = builder.pad.get_all_roots() # type: List[SourceObject]
while queue:
record = queue.pop()
self.queue_now(record)
if hasattr(record, 'attachments'):
queue.extend(record.attachments) # type: ignore[attr-defined]
if hasattr(record, 'children'):
queue.extend(record.children) # type: ignore[attr-defined]
# build artifacts
for w in self._watcher:
root = builder.pad.get(w.root)
for vobj in w.iter_sources(root):
self._results[vobj.url_path] = vobj
self._watcher.clear()
def queue_now(self, node: SourceObject) -> None:
''' Process record immediatelly (No-Op if already processed). '''
for w in self._watcher:
if w.should_process(node): # ensures type Record
w.process(node) # type: ignore[arg-type]
def build_all(self, builder: Builder) -> None:
''' Create virtual objects and build sources. '''
for url, x in sorted(self._results.items()):
builder.build(x)
self._resolve_map[url] = ResolverConf(x.attrib, x.group, x.slug)
self._results.clear()
# -----------------
# Path resolver
# -----------------
def resolve_dev_server_path(
self, node: SourceObject, pieces: List[str]
) -> Optional[GroupBySource]:
''' Dev server only: Resolves path/ -> path/index.html '''
if not isinstance(node, Record):
return None
conf = self._resolve_map.get(build_url([node.url_path] + pieces))
if not conf:
return None
return GroupBySource(node, conf.attrib, conf.group, slug=conf.slug)
# -----------------------------------
# Plugin Entry
# -----------------------------------
class GroupByPlugin(Plugin):
name = 'GroupBy Plugin'
description = 'Cluster arbitrary records with field attribute keyword.'
def on_setup_env(self, **extra: object) -> None:
self.creator = GroupByCreator()
self.env.add_build_program(GroupBySource, GroupByBuildProgram)
# resolve /tag/rss/ -> /tag/rss/index.html (local server only)
@self.env.urlresolver
def _(node: SourceObject, parts: List[str]) -> Optional[GroupBySource]:
return self.creator.resolve_dev_server_path(node, parts)
def _load_quick_config(self) -> None:
''' Load config file quick listeners. '''
config = self.get_config()
for attrib in config.sections():
sect = config.section_as_dict(attrib)
root = sect.get('root', '/')
slug = sect.get('slug')
temp = sect.get('template')
split = sect.get('split')
@self.creator.depends_on(self.config_filename)
@self.creator.watch(root, attrib, slug=slug, template=temp)
def _fn(args: GroupByCallbackArgs) \
-> Iterator[Tuple[GroupKey, object]]:
val = args.field
if isinstance(val, str):
val = val.split(split) if split else [val] # make list
if isinstance(val, list):
for tag in val:
yield slugify(tag), tag
def on_before_build_all(self, builder: Builder, **extra: object) -> None:
self.creator.clear_previous_results()
# let other plugins register their @groupby.watch functions
self.emit('before-build-all', groupby=self.creator, builder=builder)
self.creator.make_cluster(builder)
def on_before_build(self, source: SourceObject, **extra: object) -> None:
# before-build may be called before before-build-all (issue #1017)
# make sure it is evaluated immediatelly
self.creator.queue_now(source)
def on_after_build_all(self, builder: Builder, **extra: object) -> None:
self.emit('after-build-all', groupby=self.creator, builder=builder)
self._load_quick_config()
self.creator.make_cluster(builder)
self.creator.build_all(builder)
def on_after_prune(self, builder: Builder, **extra: object) -> None:
# TODO: find a better way to prune unreferenced elements
GroupByPruner.prune(builder)