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 http://bitcoin-rest.bitcoin.ninja/rest//blockfilter/basic/header/000000005b7a58a939b2636f61fa4ddd62258c5fed57667a35d23f2334c4f86d.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),
             )