fix: revert eTag cache feature for dashboard (#11203)

* revert #11137

* revert #10963

superset/utils/decorators.py

@@ -17,7 +17,7 @@
 import logging
 from datetime import datetime, timedelta
 from functools import wraps
-from typing import Any, Callable, Iterator, Optional
+from typing import Any, Callable, Iterator
 
 from contextlib2 import contextmanager
 from flask import request
@@ -46,13 +46,7 @@ def stats_timing(stats_key: str, stats_logger: BaseStatsLogger) -> Iterator[floa
         stats_logger.timing(stats_key, now_as_float() - start_ts)
 
 
-def etag_cache(
-    max_age: int,
-    check_perms: Callable[..., Any],
-    get_last_modified: Optional[Callable[..., Any]] = None,
-    skip: Optional[Callable[..., Any]] = None,
-    must_revalidate: Optional[bool] = False,
-) -> Callable[..., Any]:
+def etag_cache(max_age: int, check_perms: Callable[..., Any]) -> Callable[..., Any]:
     """
     A decorator for caching views and handling etag conditional requests.
 
@@ -75,12 +69,10 @@ def etag_cache(
             # for POST requests we can't set cache headers, use the response
             # cache nor use conditional requests; this will still use the
             # dataframe cache in `superset/viz.py`, though.
-            if request.method == "POST" or (skip and skip(*args, **kwargs)):
+            if request.method == "POST":
                 return f(*args, **kwargs)
 
             response = None
-            last_modified = get_last_modified and get_last_modified(*args, **kwargs)
-
             if cache:
                 try:
                     # build the cache key from the function arguments and any
@@ -97,37 +89,17 @@ def etag_cache(
                         raise
                     logger.exception("Exception possibly due to cache backend.")
 
-                # if cache is stale?
-                if (
-                    response
-                    and last_modified
-                    and response.last_modified
-                    and response.last_modified < last_modified
-                ):
-                    response = None
-
+            # if no response was cached, compute it using the wrapped function
             if response is None:
-                # if no response was cached, compute it using the wrapped function
                 response = f(*args, **kwargs)
 
-                # set expiration headers:
-                #   Last-Modified, Expires, Cache-Control, ETag
-                response.last_modified = last_modified or datetime.utcnow()
+                # add headers for caching: Last Modified, Expires and ETag
+                response.cache_control.public = True
+                response.last_modified = datetime.utcnow()
                 expiration = max_age if max_age != 0 else FAR_FUTURE
                 response.expires = response.last_modified + timedelta(
                     seconds=expiration
                 )
-
-                # when needed, instruct the browser to always revalidate cache
-                if must_revalidate:
-                    # `Cache-Control: no-cache` asks the browser to always store
-                    # the cache, but also must validate it with the server.
-                    response.cache_control.no_cache = True
-                else:
-                    # `Cache-Control: Public` asks the browser to always store
-                    # the cache.
-                    response.cache_control.public = True
-
                 response.add_etag()
 
                 # if we have a cache, store the response from the request