add api endpoints for contracts

api/client.go

@@ -97,3 +97,15 @@ func (c *Client) AddressBalance(address types.Address) (resp AddressBalanceRespo
 	err = c.c.GET(fmt.Sprintf("/explorer/addresses/%s/balance", address), &resp)
 	return
 }
+
+// Contract returns the file contract with the specified ID.
+func (c *Client) Contract(id types.FileContractID) (resp explorer.FileContract, err error) {
+	err = c.c.GET(fmt.Sprintf("/explorer/contracts/%s", id), &resp)
+	return
+}
+
+// Contracts returns the transactions with the specified IDs.
+func (c *Client) Contracts(ids []types.FileContractID) (resp []explorer.FileContract, err error) {
+	err = c.c.POST("/explorer/contracts", ids, &resp)
+	return
+}

api/server.go

@@ -47,9 +47,18 @@ type (
 		Balance(address types.Address) (sc types.Currency, sf uint64, err error)
 		UnspentSiacoinOutputs(address types.Address, limit, offset uint64) ([]explorer.SiacoinOutput, error)
 		UnspentSiafundOutputs(address types.Address, limit, offset uint64) ([]explorer.SiafundOutput, error)
+		Contracts(ids []types.FileContractID) (result []explorer.FileContract, err error)
 	}
 )
 
+const (
+	maxIDs = 5000
+)
+
+var (
+	errTooManyIDs = fmt.Errorf("too many IDs provided (provide less than %d)", maxIDs)
+)
+
 type server struct {
 	cm ChainManager
 	e  Explorer
@@ -171,11 +180,6 @@ func (s *server) explorerTransactionsIDHandler(jc jape.Context) {
 }
 
 func (s *server) explorerTransactionsHandler(jc jape.Context) {
-	const (
-		maxIDs = 5000
-	)
-	errTooManyIDs := fmt.Errorf("too many IDs provided (provide less than %d)", maxIDs)
-
 	var ids []types.TransactionID
 	if jc.Decode(&ids) != nil {
 		return
@@ -235,6 +239,39 @@ func (s *server) explorerAddressessAddressBalanceHandler(jc jape.Context) {
 	})
 }
 
+func (s *server) explorerContractIDHandler(jc jape.Context) {
+	errNotFound := errors.New("no contract found")
+
+	var id types.FileContractID
+	if jc.DecodeParam("id", &id) != nil {
+		return
+	}
+	fcs, err := s.e.Contracts([]types.FileContractID{id})
+	if jc.Check("failed to get contract", err) != nil {
+		return
+	} else if len(fcs) == 0 {
+		jc.Error(errNotFound, http.StatusNotFound)
+		return
+	}
+	jc.Encode(fcs[0])
+}
+
+func (s *server) explorerContractsHandler(jc jape.Context) {
+	var ids []types.FileContractID
+	if jc.Decode(&ids) != nil {
+		return
+	} else if len(ids) > maxIDs {
+		jc.Error(errTooManyIDs, http.StatusBadRequest)
+		return
+	}
+
+	fcs, err := s.e.Contracts(ids)
+	if jc.Check("failed to get contracts", err) != nil {
+		return
+	}
+	jc.Encode(fcs)
+}
+
 // NewServer returns an HTTP handler that serves the explored API.
 func NewServer(e Explorer, cm ChainManager, s Syncer) http.Handler {
 	srv := server{
@@ -257,5 +294,7 @@ func NewServer(e Explorer, cm ChainManager, s Syncer) http.Handler {
 		"POST   /explorer/transactions":               srv.explorerTransactionsHandler,
 		"GET    /explorer/addresses/:address/utxos":   srv.explorerAddressessAddressUtxosHandler,
 		"GET    /explorer/addresses/:address/balance": srv.explorerAddressessAddressBalanceHandler,
+		"GET    /explorer/contracts/:id":              srv.explorerContractIDHandler,
+		"POST   /explorer/contracts":                  srv.explorerContractsHandler,
 	})
 }

explorer/explorer.go

@@ -17,6 +17,7 @@ type Store interface {
 	UnspentSiacoinOutputs(address types.Address, limit, offset uint64) ([]SiacoinOutput, error)
 	UnspentSiafundOutputs(address types.Address, limit, offset uint64) ([]SiafundOutput, error)
 	Balance(address types.Address) (sc types.Currency, sf uint64, err error)
+	Contracts(ids []types.FileContractID) (result []FileContract, err error)
 
 	MerkleProof(leafIndex uint64) ([]types.Hash256, error)
 }
@@ -72,3 +73,8 @@ func (e *Explorer) UnspentSiafundOutputs(address types.Address, limit, offset ui
 func (e *Explorer) Balance(address types.Address) (sc types.Currency, sf uint64, err error) {
 	return e.s.Balance(address)
 }
+
+// Contracts returns the contracts with the specified IDs.
+func (e *Explorer) Contracts(ids []types.FileContractID) (result []FileContract, err error) {
+	return e.s.Contracts(ids)
+}

persist/sqlite/contracts.go

@@ -0,0 +1,41 @@
+package sqlite
+
+import (
+	"fmt"
+
+	"go.sia.tech/core/types"
+	"go.sia.tech/explored/explorer"
+)
+
+// Contracts implements explorer.Store.
+func (s *Store) Contracts(ids []types.FileContractID) (result []explorer.FileContract, err error) {
+	encodedIDs := func(ids []types.FileContractID) []any {
+		result := make([]any, len(ids))
+		for i, id := range ids {
+			result[i] = dbEncode(id)
+		}
+		return result
+	}
+
+	err = s.transaction(func(tx txn) error {
+		query := `SELECT fc1.contract_id, fc1.leaf_index, fc1.merkle_proof, fc1.resolved, fc1.valid, fc1.filesize, fc1.file_merkle_root, fc1.window_start, fc1.window_end, fc1.payout, fc1.unlock_hash, fc1.revision_number
+		FROM file_contract_elements fc1
+		WHERE fc1.contract_id IN (` + queryPlaceHolders(len(ids)) + `)
+		AND fc1.revision_number = (SELECT max(revision_number) FROM file_contract_elements fc2 WHERE fc2.contract_id = fc1.contract_id)`
+		rows, err := tx.Query(query, encodedIDs(ids)...)
+		if err != nil {
+			return err
+		}
+		defer rows.Close()
+
+		for rows.Next() {
+			var fc explorer.FileContract
+			if err := rows.Scan(dbDecode(&fc.StateElement.ID), dbDecode(&fc.StateElement.LeafIndex), dbDecode(&fc.StateElement.MerkleProof), &fc.Resolved, &fc.Valid, &fc.Filesize, dbDecode(&fc.FileMerkleRoot), &fc.WindowStart, &fc.WindowEnd, dbDecode(&fc.Payout), dbDecode(&fc.UnlockHash), &fc.RevisionNumber); err != nil {
+				return fmt.Errorf("failed to scan transaction: %w", err)
+			}
+			result = append(result, fc)
+		}
+		return nil
+	})
+	return
+}

persist/sqlite/init.sql

@@ -75,6 +75,8 @@ CREATE TABLE file_contract_elements (
         UNIQUE(contract_id, revision_number)
 );
 
+CREATE INDEX file_contract_elements_contract_id_index ON file_contract_elements(contract_id);
+
 CREATE TABLE file_contract_valid_proof_outputs (
         contract_id INTEGER REFERENCES file_contract_elements(id) ON DELETE CASCADE NOT NULL,
         contract_order INTEGER NOT NULL,

persist/sqlite/transactions.go

@@ -169,7 +169,7 @@ ORDER BY ts.transaction_order DESC`
 func transactionFileContractRevisions(tx txn, txnIDs []int64) (map[int64][]explorer.FileContractRevision, error) {
 	query := `SELECT ts.transaction_id, ts.parent_id, ts.unlock_conditions, fc.contract_id, fc.leaf_index, fc.merkle_proof, fc.resolved, fc.valid, fc.filesize, fc.file_merkle_root, fc.window_start, fc.window_end, fc.payout, fc.unlock_hash, fc.revision_number
 FROM file_contract_elements fc
-INNER JOIN transaction_file_contracts ts ON (ts.contract_id = fc.id)
+INNER JOIN transaction_file_contract_revisions ts ON (ts.contract_id = fc.id)
 WHERE ts.transaction_id IN (` + queryPlaceHolders(len(txnIDs)) + `)
 ORDER BY ts.transaction_order DESC`
 	rows, err := tx.Query(query, queryArgs(txnIDs)...)