gisaf-backend/src/gisaf/geoapi.py

"""
Geographical json stores, served under /gj
Used for displaying features on maps
"""
from json import JSONDecodeError
import logging
from typing import Annotated
from asyncio import CancelledError

from fastapi import (FastAPI, HTTPException, Response, Header, WebSocket, WebSocketDisconnect,
                     status, responses)

from gisaf.redis_tools import store as redis_store
from gisaf.live import live_server
from gisaf.registry import registry


logger = logging.getLogger(__name__)

api = FastAPI(
    default_response_class=responses.ORJSONResponse,
)

class ConnectionManager:
    active_connections: list[WebSocket]
    def __init__(self):
        self.active_connections = []

    async def connect(self, websocket: WebSocket):
        await websocket.accept()
        self.active_connections.append(websocket)

    def disconnect(self, websocket: WebSocket):
        self.active_connections.remove(websocket)

    async def send_personal_message(self, message: str, websocket: WebSocket):
        await websocket.send_text(message)

    async def broadcast(self, message: str):
        for connection in self.active_connections:
            await connection.send_text(message)

manager = ConnectionManager()

@api.websocket('/live/{store}')
async def live_layer(store: str, websocket: WebSocket):
    """
    Websocket for live layer updates
    """
    await websocket.accept()
    try:
        while True:
            try:
                msg_data = await websocket.receive_json()
            except JSONDecodeError:
                msg_text = await websocket.receive_text()
                if msg_text == 'close':
                    await websocket.close()
                continue
            # else:
            if 'message' in msg_data:
                if msg_data['message'] == 'subscribeLiveLayer':
                    live_server.add_subscription(websocket, store)
                elif msg_data['message'] == 'unsubscribeLiveLayer':
                    live_server.remove_subscription(websocket, store)
            else:
                logger.warning(f'Got websocket message with no message field: {msg_data}')
    except WebSocketDisconnect:
        logger.debug('Websocket disconnected')

        # logger.debug('websocket connection closed')

@api.get('/{store_name}')
async def get_geojson(store_name,
                      If_None_Match: Annotated[str | None, Header()] = None,
                      simplify: Annotated[float | None, Header()] = 50.0,
                      ):
    """
    Some REST stores coded manually (route prefixed with "gj": geojson).
    :param store_name: name of the model
    :return: json
    """
    use_cache = False
    try:
        model = registry.stores.loc[store_name].model
    except KeyError:
        raise HTTPException(status.HTTP_404_NOT_FOUND)

    if hasattr(model, 'viewable_role') and model.viewable_role:
        await check_permission(request, model.viewable_role)

    if await redis_store.has_channel(store_name):
        ## Live layers
        data = await redis_store.get_layer_as_json(store_name)
        return Response(content=data.decode(),
                        media_type="application/json")

    # elif not model:
    #     raise HTTPException(status.HTTP_404_NOT_FOUND)

    if model.cache_enabled:
        ttag = await redis_store.get_ttag(store_name)
        if ttag and If_None_Match == ttag:
            return status.HTTP_304_NOT_MODIFIED

    if hasattr(model, 'get_geojson'):
        geojson = await model.get_geojson(simplify_tolerance=simplify, registry=registry)
        ## Store to redis for caching
        if use_cache:
            await redis_store.store_json(model, geojson)
        resp = geojson

    elif model.can_get_features_as_df:
        ## Get the GeoDataframe (gdf) with GeoPandas
        ## get_popup and get_propertites get the gdf as argument and can use vectorised operations
        try:
            gdf = await model.get_geo_df(cast=True, with_related=True, filter_columns=True)
        except CancelledError as err:
            logger.debug(f'Request for {store_name} cancelled while getting gdf')
            raise err
        except Exception as err:
            logger.exception(err)
            raise status.HTTP_500_INTERNAL_SERVER_ERROR
        ## The query of category defined models gets the status (not sure how and this could be skipped)
        ## Other models do not have: just add it manually from the model itself
        if 'status' not in gdf.columns:
            gdf['status'] = model.status
        if 'popup' not in gdf.columns:
            gdf['popup'] = await model.get_popup(gdf)
        properties = await model.get_properties(gdf)
        columns = ['geometry', 'status', 'popup']
        for property, values in properties.items():
            columns.append(property)
            gdf[property] = values
        geojson = gdf[columns].to_json(separators=(',', ':'), check_circular=False)
        ## Store to redis for caching
        if use_cache:
            await redis_store.store_json(model, geojson)
        resp = geojson

    else:
        logger.warn(f"{model} doesn't allow using dataframe for generating json!")
        attrs, features_kwargs = await model.get_features_attrs(simplify)
        ## Using gino: allows OO model (get_info, etc)
        try:
            attrs['features'] = await model.get_features_in_bulk_gino(**features_kwargs)
        except Exception as err:
            logger.exception(err)
            raise status.HTTP_500_INTERNAL_SERVER_ERROR
        resp = attrs

    headers = {}
    if model.cache_enabled and ttag:
        headers['ETag'] = ttag
    return Response(content=resp, media_type="application/json", headers=headers)


@api.get('/gj/{store_name}/popup/{id}')
async def gj_popup(store_name: str, id: int):
    model = registry.geom.get(store_name)
    if not hasattr(model, 'get_popup_dynamic'):
        return ''
    obj = await model.get(id)
    ## Escape characters for json
    popup_more = obj.get_popup_dynamic().replace('"', '\\"').replace('\n', '\\n')
    return {"text": popup_more}