reorganize code around result formatting

Code is now organized by api version. So formatting has moved to
the api.v1 module. Instead of holding a separate ResultFormatter
object per result format, simply move the functions to the
formater collector and hand in the requested format as a parameter.
Thus reorganized, the api.v1 module can export three simple functions
for result formatting which in turn makes the code that uses
the formatters much simpler.

nominatim/server/falcon/server.py

@@ -14,7 +14,7 @@ import falcon
 import falcon.asgi
 
 from nominatim.api import NominatimAPIAsync, StatusResult
-import nominatim.result_formatter.v1 as formatting
+import nominatim.api.v1 as api_impl
 
 CONTENT_TYPE = {
   'text': falcon.MEDIA_TEXT,
@@ -27,10 +27,6 @@ class NominatimV1:
 
     def __init__(self, project_dir: Path, environ: Optional[Mapping[str, str]]) -> None:
         self.api = NominatimAPIAsync(project_dir, environ)
-        self.formatters = {}
-
-        for rtype in (StatusResult, ):
-            self.formatters[rtype] = formatting.create(rtype)
 
 
     def parse_format(self, req: falcon.asgi.Request, rtype: Type[Any], default: str) -> None:
@@ -39,12 +35,11 @@ class NominatimV1:
             format value to assume when no parameter is present.
         """
         req.context.format = req.get_param('format', default=default)
-        req.context.formatter = self.formatters[rtype]
 
-        if not req.context.formatter.supports_format(req.context.format):
+        if not api_impl.supports_format(rtype, req.context.format):
             raise falcon.HTTPBadRequest(
                 description="Parameter 'format' must be one of: " +
-                            ', '.join(req.context.formatter.list_formats()))
+                            ', '.join(api_impl.list_formats(rtype)))
 
 
     def format_response(self, req: falcon.asgi.Request, resp: falcon.asgi.Response,
@@ -52,7 +47,7 @@ class NominatimV1:
         """ Render response into a string according to the formatter
             set in `parse_format()`.
         """
-        resp.text = req.context.formatter.format(result, req.context.format)
+        resp.text = api_impl.format_result(result, req.context.format)
         resp.content_type = CONTENT_TYPE.get(req.context.format, falcon.MEDIA_JSON)
 
 

nominatim/server/sanic/server.py

@@ -13,7 +13,7 @@ from pathlib import Path
 import sanic
 
 from nominatim.api import NominatimAPIAsync, StatusResult
-import nominatim.result_formatter.v1 as formatting
+import nominatim.api.v1 as api_impl
 
 api = sanic.Blueprint('NominatimAPI')
 
@@ -32,7 +32,7 @@ def api_response(request: sanic.Request, result: Any) -> sanic.HTTPResponse:
     """ Render a response from the query results using the configured
         formatter.
     """
-    body = request.ctx.formatter.format(result, request.ctx.format)
+    body = api_impl.format_result(result, request.ctx.format)
     return sanic.response.text(body,
                                content_type=CONTENT_TYPE.get(request.ctx.format,
                                                              'application/json'))
@@ -46,12 +46,11 @@ async def extract_format(request: sanic.Request) -> Optional[sanic.HTTPResponse]
         is present.
     """
     assert request.route is not None
-    request.ctx.formatter = request.app.ctx.formatters[request.route.ctx.result_type]
 
     request.ctx.format = request.args.get('format', request.route.ctx.default_format)
-    if not request.ctx.formatter.supports_format(request.ctx.format):
+    if not api_impl.supports_format(request.route.ctx.result_type, request.ctx.format):
         return usage_error("Parameter 'format' must be one of: " +
-                           ', '.join(request.ctx.formatter.list_formats()))
+                           ', '.join(api_impl.list_formats(request.route.ctx.result_type)))
 
     return None
 
@@ -76,9 +75,6 @@ def get_application(project_dir: Path,
     app = sanic.Sanic("NominatimInstance")
 
     app.ctx.api = NominatimAPIAsync(project_dir, environ)
-    app.ctx.formatters = {}
-    for rtype in (StatusResult, ):
-        app.ctx.formatters[rtype] = formatting.create(rtype)
 
     app.blueprint(api)
 

nominatim/server/starlette/server.py

@@ -17,40 +17,32 @@ from starlette.responses import Response
 from starlette.requests import Request
 
 from nominatim.api import NominatimAPIAsync, StatusResult
-import nominatim.result_formatter.v1 as formatting
+import nominatim.api.v1 as api_impl
 
 CONTENT_TYPE = {
   'text': 'text/plain; charset=utf-8',
   'xml': 'text/xml; charset=utf-8'
 }
 
-FORMATTERS = {
-    StatusResult: formatting.create(StatusResult)
-}
-
-
 def parse_format(request: Request, rtype: Type[Any], default: str) -> None:
     """ Get and check the 'format' parameter and prepare the formatter.
         `rtype` describes the expected return type and `default` the
         format value to assume when no parameter is present.
     """
     fmt = request.query_params.get('format', default=default)
-    fmtter = FORMATTERS[rtype]
 
-    if not fmtter.supports_format(fmt):
+    if not api_impl.supports_format(rtype, fmt):
         raise HTTPException(400, detail="Parameter 'format' must be one of: " +
-                                        ', '.join(fmtter.list_formats()))
+                                        ', '.join(api_impl.list_formats(rtype)))
 
     request.state.format = fmt
-    request.state.formatter = fmtter
 
 
 def format_response(request: Request, result: Any) -> Response:
-    """ Render response into a string according to the formatter
-        set in `parse_format()`.
+    """ Render response into a string according.
     """
     fmt = request.state.format
-    return Response(request.state.formatter.format(result, fmt),
+    return Response(api_impl.format_result(result, fmt),
                     media_type=CONTENT_TYPE.get(fmt, 'application/json'))