Merge bitcoin/bitcoin#17631: Expose block filters over REST

2b64fa3251 Update REST docs with new accessors (Matt Corallo)
ef7c8228fd Expose block filters over REST. (Matt Corallo)

Pull request description:

  This adds a new rest endpoint:
  /rest/blockfilter/filtertype/requesttype/blockhash (eg
  /rest/blockfilter/basic/header/000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f.hex)
  which exposes either the filter "header" or the filter data itself.
  Most of the code is cribbed from the equivalent RPC.

  You can test it at 000000005b.hex

ACKs for top commit:
  dergoegge:
    ACK 2b64fa3251 - Adding blockfilters to the REST interface is analogous to serving other public data such as transactions or blocks.

Tree-SHA512: d487bc694266375c94d6fcf2e9d788a8a42a3b94e8d3290e46335a64cbcde55084ce5ea6119b79a4065888d94d7c3ae25a59a901fa46e3711f0eb296add12696

test/functional/interface_rest.py

@@ -41,7 +41,7 @@ class RESTTest (BitcoinTestFramework):
     def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 2
-        self.extra_args = [["-rest"], []]
+        self.extra_args = [["-rest", "-blockfilterindex=1"], []]
         self.supports_cli = False
 
     def skip_test_if_missing_module(self):
@@ -272,11 +272,14 @@ class RESTTest (BitcoinTestFramework):
         self.generate(self.nodes[1], 5)
         json_obj = self.test_rest_request(f"/headers/5/{bb_hash}")
         assert_equal(len(json_obj), 5)  # now we should have 5 header objects
+        json_obj = self.test_rest_request(f"/blockfilterheaders/basic/5/{bb_hash}")
+        assert_equal(len(json_obj), 5)  # now we should have 5 filter header objects
+        self.test_rest_request(f"/blockfilter/basic/{bb_hash}", req_type=ReqType.BIN, ret_type=RetType.OBJ)
 
         # Test number parsing
         for num in ['5a', '-5', '0', '2001', '99999999999999999999999999999999999']:
             assert_equal(
-                bytes(f'Header count out of range: {num}\r\n', 'ascii'),
+                bytes(f'Header count out of acceptable range (1-2000): {num}\r\n', 'ascii'),
                 self.test_rest_request(f"/headers/{num}/{bb_hash}", ret_type=RetType.BYTES, status=400),
             )