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WIP-feat(searchUtxosByAsset): changes to add support for searchUtxosByAsset #510

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138 changes: 138 additions & 0 deletions internal/api/localstatequery.go
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Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,7 @@

"github.com/blinklabs-io/cardano-node-api/internal/node"
"github.com/blinklabs-io/gouroboros/ledger"
"github.com/blinklabs-io/gouroboros/protocol/localstatequery"
"github.com/gin-gonic/gin"
)

Expand All @@ -30,6 +31,7 @@
group.GET("/tip", handleLocalStateQueryTip)
group.GET("/era-history", handleLocalStateQueryEraHistory)
group.GET("/protocol-params", handleLocalStateQueryProtocolParams)
group.GET("/utxos/search-by-asset", handleLocalStateQuerySearchUTxOsByAsset)
// TODO: uncomment after this is fixed:
// - https://github.com/blinklabs-io/gouroboros/issues/584
// group.GET("/genesis-config", handleLocalStateQueryGenesisConfig)
Expand Down Expand Up @@ -374,3 +376,139 @@
//}
c.JSON(200, genesisConfig)
}

type responseLocalStateQuerySearchUTxOsByAsset struct {
UTxOs []utxoItem `json:"utxos"`
Count int `json:"count"`
}

type utxoItem struct {
TxHash string `json:"tx_hash"`
Index uint32 `json:"index"`
Address string `json:"address"`
Amount uint64 `json:"amount"`
Assets interface{} `json:"assets,omitempty"`
}

Comment on lines +380 to +392
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⚠️ Potential issue | 🟠 Major

🧩 Analysis chain

🏁 Script executed:

# First, let's examine the file mentioned in the review
cat -n internal/api/localstatequery.go | head -100

Repository: blinklabs-io/cardano-node-api

Length of output: 3653

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sed -n '370,400p' internal/api/localstatequery.go

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rg "utxoItem\{|utxoItem(" internal/api/ -A 5 -B 2

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head -30 internal/api/localstatequery.go

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Convert Assets interface{} to an explicit, concrete type with a defined JSON structure. Since Assets comes from a third-party library type without a guaranteed JSON format, assign it to a concrete struct (e.g., map[string]map[string]uint64 for {policy_id: {asset_name: quantity}}) or define a custom struct that explicitly represents the asset structure. Update the OpenAPI definition to document the response schema. This ensures API stability and allows clients to depend on a predictable contract.

// handleLocalStateQuerySearchUTxOsByAsset godoc
//
// @Summary Search UTxOs by Asset
// @Tags localstatequery
// @Produce json
// @Param policy_id query string true "Policy ID (hex)"
// @Param asset_name query string true "Asset name (hex)"
// @Param address query string false "Optional: Filter by address"
// @Success 200 {object} responseLocalStateQuerySearchUTxOsByAsset
// @Failure 400 {object} responseApiError
// @Failure 500 {object} responseApiError
// @Router /localstatequery/utxos/search-by-asset [get]
func handleLocalStateQuerySearchUTxOsByAsset(c *gin.Context) {
// Get query parameters
policyIdHex := c.Query("policy_id")
assetNameHex := c.Query("asset_name")
addressStr := c.Query("address")

// Validate required parameters
if policyIdHex == "" {
c.JSON(400, apiError("policy_id parameter is required"))
return
}
if assetNameHex == "" {
c.JSON(400, apiError("asset_name parameter is required"))
return
}

// Parse policy ID (28 bytes)
policyIdBytes, err := hex.DecodeString(policyIdHex)
if err != nil {
c.JSON(400, apiError("invalid policy_id hex: "+err.Error()))
return
}
if len(policyIdBytes) != 28 {
c.JSON(400, apiError("policy_id must be 28 bytes"))
return
}
var policyId ledger.Blake2b224
copy(policyId[:], policyIdBytes)

// Parse asset name
assetName, err := hex.DecodeString(assetNameHex)
if err != nil {
c.JSON(400, apiError("invalid asset_name hex: "+err.Error()))
return
}

// Parse optional address
var addrs []ledger.Address
if addressStr != "" {
addr, err := ledger.NewAddress(addressStr)
if err != nil {
c.JSON(400, apiError("invalid address: "+err.Error()))
return
}
addrs = append(addrs, addr)
}
Comment on lines +405 to +450
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⚠️ Potential issue | 🟠 Major

Validate asset_name length (and consider upper-bounding query sizes).
Cardano asset names are bounded (commonly max 32 bytes). Without a length check, a large hex string can force large allocations during decode and later filtering.
Proposed patch:

  // Parse asset name
  assetName, err := hex.DecodeString(assetNameHex)
  if err != nil {
    c.JSON(400, apiError("invalid asset_name hex: "+err.Error()))
    return
  }
+ if len(assetName) > 32 {
+   c.JSON(400, apiError("asset_name must be <= 32 bytes"))
+   return
+ }
📝 Committable suggestion

‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.

Suggested change
func handleLocalStateQuerySearchUTxOsByAsset(c *gin.Context) {
// Get query parameters
policyIdHex := c.Query("policy_id")
assetNameHex := c.Query("asset_name")
addressStr := c.Query("address")
// Validate required parameters
if policyIdHex == "" {
c.JSON(400, apiError("policy_id parameter is required"))
return
}
if assetNameHex == "" {
c.JSON(400, apiError("asset_name parameter is required"))
return
}
// Parse policy ID (28 bytes)
policyIdBytes, err := hex.DecodeString(policyIdHex)
if err != nil {
c.JSON(400, apiError("invalid policy_id hex: "+err.Error()))
return
}
if len(policyIdBytes) != 28 {
c.JSON(400, apiError("policy_id must be 28 bytes"))
return
}
var policyId ledger.Blake2b224
copy(policyId[:], policyIdBytes)
// Parse asset name
assetName, err := hex.DecodeString(assetNameHex)
if err != nil {
c.JSON(400, apiError("invalid asset_name hex: "+err.Error()))
return
}
// Parse optional address
var addrs []ledger.Address
if addressStr != "" {
addr, err := ledger.NewAddress(addressStr)
if err != nil {
c.JSON(400, apiError("invalid address: "+err.Error()))
return
}
addrs = append(addrs, addr)
}
func handleLocalStateQuerySearchUTxOsByAsset(c *gin.Context) {
// Get query parameters
policyIdHex := c.Query("policy_id")
assetNameHex := c.Query("asset_name")
addressStr := c.Query("address")
// Validate required parameters
if policyIdHex == "" {
c.JSON(400, apiError("policy_id parameter is required"))
return
}
if assetNameHex == "" {
c.JSON(400, apiError("asset_name parameter is required"))
return
}
// Parse policy ID (28 bytes)
policyIdBytes, err := hex.DecodeString(policyIdHex)
if err != nil {
c.JSON(400, apiError("invalid policy_id hex: "+err.Error()))
return
}
if len(policyIdBytes) != 28 {
c.JSON(400, apiError("policy_id must be 28 bytes"))
return
}
var policyId ledger.Blake2b224
copy(policyId[:], policyIdBytes)
// Parse asset name
assetName, err := hex.DecodeString(assetNameHex)
if err != nil {
c.JSON(400, apiError("invalid asset_name hex: "+err.Error()))
return
}
if len(assetName) > 32 {
c.JSON(400, apiError("asset_name must be <= 32 bytes"))
return
}
// Parse optional address
var addrs []ledger.Address
if addressStr != "" {
addr, err := ledger.NewAddress(addressStr)
if err != nil {
c.JSON(400, apiError("invalid address: "+err.Error()))
return
}
addrs = append(addrs, addr)
}
🤖 Prompt for AI Agents 
In internal/api/localstatequery.go around lines 405 to 450, the handler
currently decodes asset_name hex without checking length which can lead to large
allocations and unexpected inputs; before decoding, validate the hex string
length and resulting byte length (e.g. ensure the hex string is even-length and
the decoded asset name is <= 32 bytes, or a configured MAX_ASSET_NAME_BYTES) and
return a 400 error if it exceeds the limit; additionally, enforce a reasonable
upper bound on query parameter sizes (reject overly long
policy_id/asset_name/address strings) to prevent abuse and resource exhaustion.


// Connect to node
oConn, err := node.GetConnection(nil)
if err != nil {
c.JSON(500, apiError(err.Error()))
return
}
// Async error handler
go func() {
err, ok := <-oConn.ErrorChan()
if !ok {
return
}
c.JSON(500, apiError(err.Error()))
}()
defer func() {
// Close Ouroboros connection
oConn.Close()
}()
// Start client
oConn.LocalStateQuery().Client.Start()

// Get UTxOs (either by address or whole set)
var utxos *localstatequery.UTxOsResult
if len(addrs) > 0 {
utxos, err = oConn.LocalStateQuery().Client.GetUTxOByAddress(addrs)
} else {
utxos, err = oConn.LocalStateQuery().Client.GetUTxOWhole()
}
if err != nil {
c.JSON(500, apiError(err.Error()))
return
}
Comment on lines +452 to +483
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⚠️ Potential issue | 🔴 Critical

🧩 Analysis chain

🏁 Script executed:

# Get the full function context
cd internal/api && head -n 500 localstatequery.go | tail -n +420 | cat -n

Repository: blinklabs-io/cardano-node-api

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rg "ErrorChan()" -A 5 -B 2

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rg -A 50 "func.*addrs.*\(" internal/api/localstatequery.go | head -100

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🌐 Web query:

gin-gonic gin.Context thread safety concurrent writes JSON

💡 Result:

Short answer: gin.Context is not safe for concurrent writes. Don’t call c.JSON / c.Writer methods from multiple goroutines simultaneously — use c.Copy() when starting goroutines and avoid writing to the ResponseWriter after the handler returns. Instead marshal/prepare the response (or synchronize with a mutex) and write once from the handler, or extract needed data and pass plain values/context.Context to background goroutines.

Key references:

  • Gin docs: “When starting new Goroutines ... you SHOULD NOT use the original context inside it, you have to use a read-only copy” (use c.Copy()). [1]
  • pkg.go.dev: Context.Copy() documentation: “Copy returns a copy of the current context that can be safely used outside the request's scope.” [2]
  • Guidance & examples + community issues showing races/overwrites and cancellation pitfalls (don’t rely on *gin.Context for long-running background work; clone request context if you need no cancellation). [3]

🏁 Script executed:

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sed -n '445,490p' internal/api/localstatequery.go | cat -n

Repository: blinklabs-io/cardano-node-api

Length of output: 1410

Don't write to gin.Context from the async ErrorChan() goroutine—this causes race conditions and duplicate response writes.

When the handler returns (e.g., after calling c.JSON() at line 481) and the goroutine later attempts c.JSON(), you get "headers already written" errors or data races on the response. This pattern is repeated across multiple handlers (chainsync.go, localtxmonitor.go, etc.).

Use c.Copy() if passing context to goroutines, or better yet, avoid writing responses from background goroutines. Instead, log the error and close the connection, or signal the error through a channel to let the main handler decide the response.


// Filter UTxOs by asset
results := make([]utxoItem, 0)
for utxoId, output := range utxos.Results {
// Check if output has assets
assets := output.Assets()
if assets == nil {
continue
}

// Check if the asset exists in this UTxO
amount := assets.Asset(policyId, assetName)
if amount > 0 {
item := utxoItem{
TxHash: hex.EncodeToString(utxoId.Hash[:]),
Index: uint32(utxoId.Idx),

Check failure on line 499 in internal/api/localstatequery.go

View workflow job for this annotation

GitHub Actions / lint 

G115: integer overflow conversion int -> uint32 (gosec)
Address: output.Address().String(),
Amount: output.Amount(),
Assets: assets,
}
results = append(results, item)
}
}

// Create response
resp := responseLocalStateQuerySearchUTxOsByAsset{
UTxOs: results,
Count: len(results),
}
c.JSON(200, resp)
}
Comment on lines +473 to +514
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⚠️ Potential issue | 🔴 Critical

Blocker: fix gosec G115 overflow on uint32(utxoId.Idx) (CI failing).
Add a bounds check before converting:

      if amount > 0 {
+       if utxoId.Idx < 0 || utxoId.Idx > math.MaxUint32 {
+         c.JSON(500, apiError("utxo index out of range"))
+         return
+       }
        item := utxoItem{
          TxHash:  hex.EncodeToString(utxoId.Hash[:]),
-         Index:   uint32(utxoId.Idx),
+         Index:   uint32(utxoId.Idx),
          Address: output.Address().String(),
          Amount:  output.Amount(),
          Assets:  assets,
        }

Also: fetching GetUTxOWhole() when address is omitted is a likely DoS footgun (latency/memory). At minimum, consider adding server-side guardrails (require address, or add pagination/limit + timeouts).

🧰 Tools
🪛 GitHub Actions: golangci-lint

[error] 499-499: G115: integer overflow conversion int -> uint32 (gosec)

🪛 GitHub Check: lint

[failure] 499-499:
G115: integer overflow conversion int -> uint32 (gosec)

🤖 Prompt for AI Agents 
In internal/api/localstatequery.go around lines 473-514, add a bounds check
before converting utxoId.Idx to uint32 to fix the gosec G115 overflow: if
utxoId.Idx > math.MaxUint32 either skip that UTxO or return a 400/500 error as
appropriate instead of blindly casting. Additionally, remove or guard the
expensive GetUTxOWhole() path when len(addrs)==0: require an address parameter
(return 400 if missing) or implement server-side guardrails such as a max
limit/pagination (enforce a capped limit on results and support offset/page
token) and wrap the LocalStateQuery client calls with a context timeout to avoid
DoS/latency issues. Ensure any new imports (math, context) are added and
behavior is well-documented in the handler comment.

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