Add function to extract anchor data from certificate

Author: palas

cardano-api/internal/Cardano/Api/Certificate.hs

@@ -56,6 +56,9 @@ module Cardano.Api.Certificate
   , Ledger.MIRPot (..)
   , selectStakeCredentialWitness
 
+    -- * Anchor data
+  , getAnchorDataFromCertificate
+
     -- * Internal conversion functions
   , toShelleyCertificate
   , fromShelleyCertificate
@@ -90,6 +93,7 @@ import           Cardano.Api.StakePoolMetadata
 import           Cardano.Api.Utils (noInlineMaybeToStrictMaybe)
 import           Cardano.Api.Value
 
+import           Cardano.Ledger.BaseTypes (strictMaybe)
 import qualified Cardano.Ledger.Coin as L
 import qualified Cardano.Ledger.Keys as Ledger
 
@@ -724,3 +728,46 @@ fromShelleyPoolParams
     fromShelleyDnsName =
       Text.encodeUtf8
         . Ledger.dnsToText
+
+-- | Get anchor data hash from a certificate
+getAnchorDataFromCertificate :: Certificate era -> Maybe (Ledger.Anchor StandardCrypto)
+getAnchorDataFromCertificate =
+  \case
+    ShelleyRelatedCertificate _ shelleyCert ->
+      case shelleyCert of
+        Ledger.ShelleyTxCertDelegCert shelleyDelegCert ->
+          case shelleyDelegCert of
+            Ledger.ShelleyRegCert _ -> Nothing
+            Ledger.ShelleyUnRegCert _ -> Nothing
+            Ledger.ShelleyDelegCert _ _ -> Nothing
+        Ledger.ShelleyTxCertPool shelleyPoolCert ->
+          case shelleyPoolCert of
+            Ledger.RegPool poolParams -> strictMaybe Nothing anchorDataFromPoolMetadata $ Ledger.ppMetadata poolParams
+            Ledger.RetirePool _ _ -> Nothing
+        Ledger.ShelleyTxCertGenesisDeleg _ -> Nothing
+        Ledger.ShelleyTxCertMir _ -> Nothing
+    ConwayCertificate ceo conwayCert ->
+      conwayEraOnwardsConstraints ceo $
+        case conwayCert of
+          Ledger.ConwayTxCertDeleg _ -> Nothing
+          Ledger.ConwayTxCertPool conwayPoolCert ->
+            case conwayPoolCert of
+              Ledger.RegPool poolParams -> strictMaybe Nothing anchorDataFromPoolMetadata $ Ledger.ppMetadata poolParams
+              Ledger.RetirePool _ _ -> Nothing
+          Ledger.ConwayTxCertGov govCert ->
+            case govCert of
+              Ledger.ConwayRegDRep _ _ mAnchor -> Ledger.strictMaybeToMaybe mAnchor
+              Ledger.ConwayUnRegDRep _ _ -> Nothing
+              Ledger.ConwayUpdateDRep _ mAnchor -> Ledger.strictMaybeToMaybe mAnchor
+              Ledger.ConwayAuthCommitteeHotKey _ _ -> Nothing
+              Ledger.ConwayResignCommitteeColdKey _ mAnchor -> Ledger.strictMaybeToMaybe mAnchor
+ where
+  anchorDataFromPoolMetadata :: Ledger.PoolMetadata -> Maybe (Ledger.Anchor StandardCrypto)
+  anchorDataFromPoolMetadata (Ledger.PoolMetadata{Ledger.pmUrl = url, Ledger.pmHash = hashBytes}) = do
+    hash <- Ledger.hashFromBytes hashBytes
+    return
+      ( Ledger.Anchor
+          { Ledger.anchorUrl = url
+          , Ledger.anchorDataHash = Ledger.unsafeMakeSafeHash hash
+          }
+      )

cardano-api/src/Cardano/Api.hs

@@ -483,6 +483,9 @@ module Cardano.Api
   , StakePoolRelay
   , StakePoolMetadataReference
 
+    -- ** Anchor data
+  , getAnchorDataFromCertificate
+
     -- * Rewards
   , DelegationsAndRewards (..)
   , mergeDelegsAndRewards