fix signature handling (#169)

### TL;DR
Improved signature handling for logs and transactions by moving ABI construction into the main handler functions.

### What changed?
- Consolidated log and transaction handler logic by moving signature processing into the main handler functions
- Updated signature hash calculation to use ABI-generated IDs instead of manual Keccak256 hashing
- Simplified function signatures by removing unnecessary parameter passing
- Improved error handling for ABI construction

### How to test?
1. Query event logs with a valid event signature
   - `GET /{chainId}/events/{contract}/{signature}`
2. Query transactions with a valid function signature
   - `GET /{chainId}/transactions/{to}/{signature}`
3. Verify that signature hashes are correctly generated from ABIs
4. Confirm that error handling works for invalid signatures

### Why make this change?
The previous implementation had redundant signature processing and used a less reliable method for generating signature hashes. This change makes the code more maintainable and uses the more accurate ABI-generated IDs for signature matching, reducing potential edge cases and improving reliability.

Author: iuwqyir

internal/common/abi.go

@@ -48,7 +48,7 @@ func GetABIForContract(chainId string, contract string) (*abi.ABI, error) {
 
 func ConstructEventABI(signature string) (*abi.Event, error) {
 	// Regex to extract the event name and parameters
-	regex := regexp.MustCompile(`^(\w+)\((.*)\)$`)
+	regex := regexp.MustCompile(`^(\w+)\s*\((.*)\)$`)
 	matches := regex.FindStringSubmatch(strings.TrimSpace(signature))
 	if len(matches) != 3 {
 		return nil, fmt.Errorf("invalid event signature format")
@@ -68,7 +68,7 @@ func ConstructEventABI(signature string) (*abi.Event, error) {
 }
 
 func ConstructFunctionABI(signature string) (*abi.Method, error) {
-	regex := regexp.MustCompile(`^(\w+)\((.*)\)$`)
+	regex := regexp.MustCompile(`^(\w+)\s*\((.*)\)$`)
 	matches := regex.FindStringSubmatch(strings.TrimSpace(signature))
 	if len(matches) != 3 {
 		return nil, fmt.Errorf("invalid function signature format")

internal/handlers/logs_handlers.go

@@ -5,7 +5,6 @@ import (
 	"sync"
 
 	"github.com/ethereum/go-ethereum/accounts/abi"
-	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/gin-gonic/gin"
 	"github.com/rs/zerolog/log"
 	"github.com/thirdweb-dev/indexer/api"
@@ -42,7 +41,7 @@ var (
 // @Failure 500 {object} api.Error
 // @Router /{chainId}/events [get]
 func GetLogs(c *gin.Context) {
-	handleLogsRequest(c, "", "", nil)
+	handleLogsRequest(c)
 }
 
 // @Summary Get logs by contract
@@ -67,8 +66,7 @@ func GetLogs(c *gin.Context) {
 // @Failure 500 {object} api.Error
 // @Router /{chainId}/events/{contract} [get]
 func GetLogsByContract(c *gin.Context) {
-	contractAddress := c.Param("contract")
-	handleLogsRequest(c, contractAddress, "", nil)
+	handleLogsRequest(c)
 }
 
 // @Summary Get logs by contract and event signature
@@ -94,32 +92,33 @@ func GetLogsByContract(c *gin.Context) {
 // @Failure 500 {object} api.Error
 // @Router /{chainId}/events/{contract}/{signature} [get]
 func GetLogsByContractAndSignature(c *gin.Context) {
-	contractAddress := c.Param("contract")
-	eventSignature := c.Param("signature")
-	strippedSignature := common.StripPayload(eventSignature)
-	eventABI, err := common.ConstructEventABI(eventSignature)
-	if err != nil {
-		log.Debug().Err(err).Msgf("Unable to construct event ABI for %s", eventSignature)
-	}
-	handleLogsRequest(c, contractAddress, strippedSignature, eventABI)
+	handleLogsRequest(c)
 }
 
-func handleLogsRequest(c *gin.Context, contractAddress, signature string, eventABI *abi.Event) {
+func handleLogsRequest(c *gin.Context) {
 	chainId, err := api.GetChainId(c)
 	if err != nil {
 		api.BadRequestErrorHandler(c, err)
 		return
 	}
 
+	contractAddress := c.Param("contract")
+	signature := c.Param("signature")
+
 	queryParams, err := api.ParseQueryParams(c.Request)
 	if err != nil {
 		api.BadRequestErrorHandler(c, err)
 		return
 	}
 
+	var eventABI *abi.Event
 	signatureHash := ""
 	if signature != "" {
-		signatureHash = crypto.Keccak256Hash([]byte(signature)).Hex()
+		eventABI, err = common.ConstructEventABI(signature)
+		if err != nil {
+			log.Debug().Err(err).Msgf("Unable to construct event ABI for %s", signature)
+		}
+		signatureHash = eventABI.ID.Hex()
 	}
 
 	mainStorage, err := getMainStorage()

internal/handlers/transactions_handlers.go

@@ -4,13 +4,12 @@ import (
 	"net/http"
 
 	"github.com/ethereum/go-ethereum/accounts/abi"
-	"github.com/ethereum/go-ethereum/crypto"
+	gethCommon "github.com/ethereum/go-ethereum/common"
 	"github.com/gin-gonic/gin"
 	"github.com/rs/zerolog/log"
 	"github.com/thirdweb-dev/indexer/api"
 	config "github.com/thirdweb-dev/indexer/configs"
 	"github.com/thirdweb-dev/indexer/internal/common"
-	"github.com/thirdweb-dev/indexer/internal/rpc"
 	"github.com/thirdweb-dev/indexer/internal/storage"
 )
 
@@ -35,7 +34,7 @@ import (
 // @Failure 500 {object} api.Error
 // @Router /{chainId}/transactions [get]
 func GetTransactions(c *gin.Context) {
-	handleTransactionsRequest(c, "", "", nil)
+	handleTransactionsRequest(c)
 }
 
 // @Summary Get transactions by contract
@@ -60,8 +59,7 @@ func GetTransactions(c *gin.Context) {
 // @Failure 500 {object} api.Error
 // @Router /{chainId}/transactions/{to} [get]
 func GetTransactionsByContract(c *gin.Context) {
-	to := c.Param("to")
-	handleTransactionsRequest(c, to, "", nil)
+	handleTransactionsRequest(c)
 }
 
 // @Summary Get transactions by contract and signature
@@ -87,32 +85,33 @@ func GetTransactionsByContract(c *gin.Context) {
 // @Failure 500 {object} api.Error
 // @Router /{chainId}/transactions/{to}/{signature} [get]
 func GetTransactionsByContractAndSignature(c *gin.Context) {
-	to := c.Param("to")
-	signature := c.Param("signature")
-	strippedSignature := common.StripPayload(signature)
-	functionABI, err := common.ConstructFunctionABI(signature)
-	if err != nil {
-		log.Debug().Err(err).Msgf("Unable to construct function ABI for %s", signature)
-	}
-	handleTransactionsRequest(c, to, strippedSignature, functionABI)
+	handleTransactionsRequest(c)
 }
 
-func handleTransactionsRequest(c *gin.Context, contractAddress, signature string, functionABI *abi.Method) {
+func handleTransactionsRequest(c *gin.Context) {
 	chainId, err := api.GetChainId(c)
 	if err != nil {
 		api.BadRequestErrorHandler(c, err)
 		return
 	}
 
+	contractAddress := c.Param("to")
+	signature := c.Param("signature")
+
 	queryParams, err := api.ParseQueryParams(c.Request)
 	if err != nil {
 		api.BadRequestErrorHandler(c, err)
 		return
 	}
 
+	var functionABI *abi.Method
 	signatureHash := ""
 	if signature != "" {
-		signatureHash = rpc.ExtractFunctionSelector(crypto.Keccak256Hash([]byte(signature)).Hex())
+		functionABI, err = common.ConstructFunctionABI(signature)
+		if err != nil {
+			log.Debug().Err(err).Msgf("Unable to construct function ABI for %s", signature)
+		}
+		signatureHash = "0x" + gethCommon.Bytes2Hex(functionABI.ID)
 	}
 
 	mainStorage, err := getMainStorage()