feat: add GET /v0/blockInfo/{blockHash} endpoint

  Add a new endpoint that returns block information for a given block hash.
  The response uses the existing BlockInfo type which already has a ToJSON
  instance, so the full block metadata is returned directly.

  Returns 404 if no block with the given hash exists.
  Returns 400 if the provided hash is malformed.

Author: lysyi3m

ChangeLog.md

@@ -2,6 +2,8 @@
 
 ## [unreleased]
 
+- Add `GET` endpoint `/v0/blockInfo/{blockHash}` for getting block information for a given block hash.
+
 - Add `GET` endpoint `/v0/consensusInfo` for getting the current consensus status from the node, including last finalized block, best block, protocol version, and timing parameters.
 
 ## [0.45.0] - 2026-02-23

README.md

@@ -54,6 +54,7 @@ cooldowns and the available balance) and get the info if an account is on any al
 * `POST /v0/transakOnRamp`: create a URL to initiate purchasing CCDs through the Transak on-ramp.
 * `GET /v0/genesisHash`: get the genesis block hash for the connected network.
 * `GET /v0/consensusInfo`: get the current consensus status from the node.
+* `GET /v0/blockInfo/{blockHash}`: get block information for a given block hash.
 
 ### Errors
 
@@ -1545,6 +1546,60 @@ Example response (protocol version 6+):
 }
 ```
 
+## Block info
+
+A GET request to `/v0/blockInfo/{blockHash}` returns information about the block with the given hash.
+
+Returns `404 Not Found` if no block with the given hash exists.
+
+The response includes:
+
+| Field | Type | Description |
+|---|---|---|
+| `blockHash` | string (hex) | Hash of the block |
+| `blockParent` | string (hex) | Hash of the parent block |
+| `blockLastFinalized` | string (hex) | Hash of the last finalized block at the time this block was baked |
+| `blockHeight` | number | Absolute height of the block |
+| `genesisIndex` | number | Number of protocol updates preceding this block |
+| `eraBlockHeight` | number | Height of this block relative to the (re)genesis block of its era |
+| `blockReceiveTime` | string (ISO 8601) | Time the block was received |
+| `blockArriveTime` | string (ISO 8601) | Time the block was verified |
+| `blockSlotTime` | string (ISO 8601) | Nominal time of the slot in which the block was baked |
+| `blockBaker` | number or null | Identifier of the block baker, or `null` for a genesis block |
+| `finalized` | boolean | Whether the block is finalized |
+| `transactionCount` | number | Number of transactions in the block |
+| `transactionEnergyCost` | number | Total energy cost of transactions in the block |
+| `transactionsSize` | number | Total size of transactions in the block (bytes) |
+| `blockStateHash` | string (hex) | Hash of the block state |
+| `protocolVersion` | number | Protocol version of the block |
+
+Additionally, `blockSlot` (slot number) is included for protocol versions 1–5, and `round` and `epoch` are included for protocol version 6 and later.
+
+Example response:
+
+```json
+{
+  "blockHash": "63e2571547f8e9b7dbef849ab5fce5eae7fe96a1ab94b52e1adcb62adcab3e42",
+  "blockParent": "a5e75c2419f539dfbde1fcc41c2c2b8dd1b9f0a0d4a2fd3d5e52c75a1b00000",
+  "blockLastFinalized": "a5e75c2419f539dfbde1fcc41c2c2b8dd1b9f0a0d4a2fd3d5e52c75a1b00000",
+  "blockHeight": 12345678,
+  "genesisIndex": 5,
+  "eraBlockHeight": 100000,
+  "blockReceiveTime": "2024-01-15T12:00:01Z",
+  "blockArriveTime": "2024-01-15T12:00:01Z",
+  "blockSlotTime": "2024-01-15T12:00:00Z",
+  "blockBaker": 42,
+  "finalized": true,
+  "transactionCount": 3,
+  "transactionEnergyCost": 6000,
+  "transactionsSize": 512,
+  "blockStateHash": "9dd9aee09a3b6d9c3f48e4f3df4f8b2c1e4d7a9b2f6c8e1d3a5b7c9e2f4a6b8",
+  "protocolVersion": 6,
+  "round": 42,
+  "epoch": 100
+}
+```
+
 # Deployment
 
 The wallet proxy must have access to

src/Internationalization/Base.hs

@@ -26,6 +26,7 @@ data ErrorMessage
     | EMTransactionRejected
     | EMMalformedTransaction
     | EMMalformedAddress
+    | EMMalformedBlockHash
     | EMDatabaseError
     | EMAccountNotFinal
     | EMConfigurationError

src/Internationalization/En.hs

@@ -291,6 +291,7 @@ translation = I18n{..}
     i18nErrorMessage EMTransactionRejected = "Transaction rejected by the node"
     i18nErrorMessage EMMalformedTransaction = "Malformed transaction hash"
     i18nErrorMessage EMMalformedAddress = "Malformed account address"
+    i18nErrorMessage EMMalformedBlockHash = "Malformed block hash"
     i18nErrorMessage EMDatabaseError = "Database error"
     i18nErrorMessage EMAccountNotFinal = "Account creation is not finalized"
     i18nErrorMessage EMConfigurationError = "Server configuration error"

src/Proxy.hs

@@ -325,6 +325,7 @@ mkYesod
 /v0/transakOnRamp TransakOnRamp POST
 /v0/genesisHash GenesisHash GET
 /v0/consensusInfo ConsensusInfoR GET
+/v0/blockInfo/#Text BlockInfoR GET
 |]
 
 instance Yesod Proxy where
@@ -3014,6 +3015,20 @@ getConsensusInfoR =
               "triggerBlockTime" .= cbftsTriggerBlockTime bft
             ]
 
+-- | Returns block information for the block with the given hash.
+--  Returns 404 if no block with the given hash exists.
+getBlockInfoR :: Text -> Handler TypedContent
+getBlockInfoR hashText =
+    case readMaybe (Text.unpack hashText) of
+        Nothing -> respond400Error EMMalformedBlockHash RequestInvalid
+        Just blockHash ->
+            runGRPCWithCustomError
+                (Just (StatusNotOkError NOT_FOUND, Just notFound404, Nothing, Just $ EMErrorResponse NotFound))
+                (getBlockInfo (Given blockHash))
+                $ \blockInfo -> do
+                    $(logOther "Trace") "Successfully got block info."
+                    sendResponse $ toJSON blockInfo
+
 -- | Create a Transak on-ramp session. This requires an "address" parameter to be specified, which
 --  will be the address of the account to which the purchased funds will be sent.
 postTransakOnRamp :: Handler TypedContent