Merge bitcoin/bitcoin#34074: A few followups after introducing /rest/blockpart/ endpoint

59b93f11e8 rest: print also HTTP response reason in case of an error (Roman Zeyde)
7fe94a0493 rest: add a test for unsuported `/blockpart/` request type (Roman Zeyde)
55d0d19b5c rest: deduplicate `interface_rest.py` negative tests (Roman Zeyde)
89eb531024 rest: update release notes for `/blockpart/` endpoint (Roman Zeyde)
41118e17f8 blockstorage: simplify partial block read validation (Roman Zeyde)
599effdeab rest: reformat `uri_prefixes` initializer list (Roman Zeyde)

Pull request description:

  The commits below should resolve a few leftovers from #33657.

ACKs for top commit:
  l0rinc:
    ACK 59b93f11e8
  hodlinator:
    re-ACK 59b93f11e8

Tree-SHA512: ae45e08edd315018e11283b354fb32f9658f5829c956554dc662a81c2e16397def7c3700e6354e0a91ff03c850def35638a69ec2668b7c015d25d6fed42b92bb

doc/release-notes-33657.md

@@ -1,5 +1,5 @@
 New REST API
 ------------
 
-- A new REST API endpoint (`/rest/blockpart/BLOCKHASH.bin?offset=X&size=Y`) has been introduced
+- A new REST API endpoint (`/rest/blockpart/<BLOCK-HASH>.<bin|hex>?offset=<OFFSET>&size=<SIZE>`) has been introduced
-  for efficiently fetching a range of bytes from block `BLOCKHASH`.
+  for efficiently fetching a range of bytes from block `<BLOCK-HASH>`.

src/node/blockstorage.cpp

@@ -1091,7 +1091,7 @@ BlockManager::ReadRawBlockResult BlockManager::ReadRawBlock(const FlatFilePos& p
 
         if (block_part) {
             const auto [offset, size]{*block_part};
-            if (size == 0 || offset >= blk_size || size > blk_size - offset) {
+            if (size == 0 || SaturatingAdd(offset, size) > blk_size) {
                 return util::Unexpected{ReadRawError::BadPartRange}; // Avoid logging - offset/size come from untrusted REST input
             }
             filein.seek(offset, SEEK_CUR);

test/functional/interface_rest.py

@@ -84,7 +84,7 @@ class RESTTest (BitcoinTestFramework):
             conn.request('POST', rest_uri, body)
         resp = conn.getresponse()
 
-        assert resp.status == status, f"Expected: {status}, Got: {resp.status} - Response: {str(resp.read())}"
+        assert resp.status == status, f"Expected: {status}, Got: {resp.status} ({resp.reason}) - Response: {str(resp.read())}"
 
         if ret_type == RetType.OBJ:
             return resp
@@ -485,12 +485,15 @@ class RESTTest (BitcoinTestFramework):
 
             get_block_part(status=400, query_params={"offset": 0, "size": 0})
             get_block_part(status=400, query_params={"offset": len(block_bin), "size": 0})
-            get_block_part(status=400, query_params={"offset": len(block_bin) + 1, "size": 1})
             get_block_part(status=400, query_params={"offset": len(block_bin), "size": 1})
             get_block_part(status=400, query_params={"offset": len(block_bin) + 1, "size": 1})
             get_block_part(status=400, query_params={"offset": 0, "size": len(block_bin) + 1})
 
-        self.test_rest_request(f"/blockpart/{blockhash}", status=400, req_type=ReqType.JSON, ret_type=RetType.OBJ)
+        res = self.test_rest_request(f"/blockpart/{blockhash}", status=400, req_type=ReqType.BIN, ret_type=RetType.OBJ)
+        assert res.read().decode().startswith("Block part offset missing or invalid")
+
+        res = self.test_rest_request(f"/blockpart/{blockhash}", query_params={"offset":0, "size":1}, status=400, req_type=ReqType.JSON, ret_type=RetType.OBJ)
+        assert res.read().decode().startswith("JSON output is not supported for this request type")
 
         self.log.info("Missing block data should cause REST API to fail")