Add support for setting headers in async relay requests

Extended `SendRelaysAsync` function to accept headers as a parameter. Added default headers and merged them with chain-specific headers across various handlers. Updated Dockerfile and included a utility function for merging maps.

@note: I was unable to get the test working following the README.md

Dockerfile

@@ -25,7 +25,7 @@ COPY --from=builder /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/
 COPY --from=builder /app/main .
 
 # Set default value for port exposed
-ENV HTTP_SERVER_PORT 8080
+ENV HTTP_SERVER_PORT=8080
 
 EXPOSE $HTTP_SERVER_PORT
 

cmd/gateway_server/internal/controllers/relay.go

@@ -35,11 +35,18 @@ func (c *RelayController) HandleRelay(ctx *fasthttp.RequestCtx) {
 		return
 	}
 
+	contentType := string(ctx.Request.Header.Peek("content-type"))
+	if contentType == "" {
+		contentType = "application/json"
+	}
+
 	relay, err := c.relayer.SendRelay(&models.SendRelayRequest{
 		Payload: &models.Payload{
-			Data:   string(ctx.PostBody()),
-			Method: string(ctx.Method()),
-			Path:   path,
+			// TODO: the best here will been able to get the chain configuration to use the configure headers.
+			Headers: map[string]string{"content-type": contentType},
+			Data:    string(ctx.PostBody()),
+			Method:  string(ctx.Method()),
+			Path:    path,
 		},
 		Chain: chainID,
 	})

internal/node_selector_service/checks/async_relay_handler.go

@@ -13,7 +13,7 @@ type nodeRelayResponse struct {
 	Error error
 }
 
-func SendRelaysAsync(relayer pokt_v0.PocketRelayer, nodes []*models.QosNode, payload string, method string, path string) chan *nodeRelayResponse {
+func SendRelaysAsync(relayer pokt_v0.PocketRelayer, nodes []*models.QosNode, payload string, method string, path string, headers map[string]string) chan *nodeRelayResponse {
 	// Define a channel to receive relay responses
 	relayResponses := make(chan *nodeRelayResponse, len(nodes))
 	var wg sync.WaitGroup
@@ -22,8 +22,13 @@ func SendRelaysAsync(relayer pokt_v0.PocketRelayer, nodes []*models.QosNode, pay
 	sendRelayAsync := func(node *models.QosNode) {
 		defer wg.Done()
 		relay, err := relayer.SendRelay(&relayer_models.SendRelayRequest{
-			Signer:             node.GetAppStakeSigner(),
-			Payload:            &relayer_models.Payload{Data: payload, Method: method, Path: path},
+			Signer: node.GetAppStakeSigner(),
+			Payload: &relayer_models.Payload{
+				Data:    payload,
+				Method:  method,
+				Path:    path,
+				Headers: headers,
+			},
 			Chain:              node.GetChain(),
 			SelectedNodePubKey: node.GetPublicKey(),
 			Session:            node.MorseSession,

internal/node_selector_service/checks/chain_config_handler.go

@@ -1,6 +1,9 @@
 package checks
 
-import "github.com/pokt-network/gateway-server/internal/chain_configurations_registry"
+import (
+	"github.com/pokt-network/gateway-server/internal/chain_configurations_registry"
+	"github.com/pokt-network/gateway-server/pkg/common"
+)
 
 // GetBlockHeightTolerance - helper function to retrieve block height tolerance across checks
 func GetBlockHeightTolerance(chainConfiguration chain_configurations_registry.ChainConfigurationsService, chainId string, defaultValue int) int {
@@ -19,3 +22,28 @@ func GetDataIntegrityHeightLookback(chainConfiguration chain_configurations_regi
 	}
 	return int(*chainConfig.DataIntegrityCheckLookbackHeight)
 }
+
+// GetFixedHeaders returns the fixed headers for a specific chain configuration.
+// It takes a ChainConfigurationsService to retrieve the chain configuration,
+// the chainId string to identify the specific chain,
+// and a defaultValue map[string]string to return in case the chain configuration is not found.
+// The function first retrieves the chain configuration using the chainConfiguration.GetChainConfiguration method.
+// If the chain configuration is not found, it returns the defaultValue.
+// If the chain configuration is found, it retrieves the fixed headers as a map[string]string from the chain configuration.
+// If the fixed headers cannot be cast into a map[string]string, it returns the defaultValue.
+// Otherwise, it returns the retrieved fixed headers.
+func GetFixedHeaders(chainConfiguration chain_configurations_registry.ChainConfigurationsService, chainId string, defaultValue map[string]string) map[string]string {
+	chainConfig, ok := chainConfiguration.GetChainConfiguration(chainId)
+	value := defaultValue
+
+	if ok && chainConfig.FixedHeaders != nil {
+		if headers, castOk := chainConfig.FixedHeaders.Get().(map[string]string); castOk {
+			// apply the specific headers override coming from chain configuration over the defaults one.
+			// in this way, the chain configuration on db only needs to hold the overrides or additions that are may
+			// not add to base code.
+			value = common.MergeStringMaps(value, headers)
+		}
+	}
+
+	return value
+}

internal/node_selector_service/checks/data_integrity_handler.go

@@ -20,6 +20,10 @@ const (
 	dataIntegrityHeightLookbackDefault = 25
 )
 
+var (
+	dataIntegrityHeadersDefault = map[string]string{"content-type": "application/json"}
+)
+
 type nodeHashRspPair struct {
 	node            *models.QosNode
 	blockIdentifier string
@@ -47,10 +51,12 @@ func PerformDataIntegrityCheck(check *Check, calculatePayload GetBlockByNumberPa
 
 	var nodeResponsePairs []*nodeHashRspPair
 
-	// find a random block to search that nodes should have access too
-	blockNumberToSearch := sourceOfTruth.GetLastKnownHeight() - uint64(GetDataIntegrityHeightLookback(check.ChainConfiguration, sourceOfTruth.GetChain(), dataIntegrityHeightLookbackDefault))
+	chainId := sourceOfTruth.GetChain()
+	checkHeaders := GetFixedHeaders(check.ChainConfiguration, chainId, dataIntegrityHeadersDefault)
 
-	attestationResponses := SendRelaysAsync(check.PocketRelayer, getEligibleDataIntegrityCheckNodes(check.NodeList), calculatePayload(blockNumberToSearch), "POST", path)
+	// find a random block to search that nodes should have access too
+	blockNumberToSearch := sourceOfTruth.GetLastKnownHeight() - uint64(GetDataIntegrityHeightLookback(check.ChainConfiguration, chainId, dataIntegrityHeightLookbackDefault))
+	attestationResponses := SendRelaysAsync(check.PocketRelayer, getEligibleDataIntegrityCheckNodes(check.NodeList), calculatePayload(blockNumberToSearch), "POST", path, checkHeaders)
 	for rsp := range attestationResponses {
 
 		if rsp.Error != nil {

internal/node_selector_service/checks/height_check_handler.go

@@ -17,6 +17,10 @@ const (
 	defaultCheckPenalty                = time.Minute * 5
 )
 
+var (
+	defaultHeaders = map[string]string{"content-type": "application/json"}
+)
+
 type HeightJsonParser func(response string) (uint64, error)
 
 // PerformDefaultHeightCheck is the default implementation of a height check by:
@@ -26,12 +30,13 @@ type HeightJsonParser func(response string) (uint64, error)
 // 3. Filtering out nodes that are returning a height out of the zScore threshold
 // 4. Punishing the nodes with defaultCheckPenalty that exceed the height tolerance.
 func PerformDefaultHeightCheck(check *Check, payload string, path string, parseHeight HeightJsonParser, logger *zap.Logger) {
-
-	logger.Sugar().Infow("running default height check", "chain", check.NodeList[0].GetChain())
+	chainId := check.NodeList[0].GetChain()
+	logger.Sugar().Infow("running default height check", "chain", chainId)
+	checkHeaders := GetFixedHeaders(check.ChainConfiguration, chainId, defaultHeaders)
 
 	var nodesResponded []*models.QosNode
 	// Send request to all nodes
-	relayResponses := SendRelaysAsync(check.PocketRelayer, getEligibleHeightCheckNodes(check.NodeList), payload, "POST", path)
+	relayResponses := SendRelaysAsync(check.PocketRelayer, getEligibleHeightCheckNodes(check.NodeList), payload, "POST", path, checkHeaders)
 
 	// Process relay responses
 	for resp := range relayResponses {

internal/relayer/relayer.go

@@ -216,6 +216,11 @@ func (r *Relayer) altruistRelay(req *models.SendRelayRequest) (*models.SendRelay
 		fasthttp.ReleaseResponse(response)
 	}()
 
+	checkHeaders := checks.GetFixedHeaders(r.chainConfigurationRegistry, req.Chain, map[string]string{"content-type": "application/json"})
+	for key, value := range checkHeaders {
+		request.Header.Set(key, value)
+	}
+
 	requestTimeout := r.getAltruistRequestTimeout(req.Chain)
 	request.Header.SetUserAgent(r.userAgent)
 	request.SetRequestURI(chainConfig.AltruistUrl.String)

pkg/common/maps.go

@@ -0,0 +1,18 @@
+package common
+
+func MergeStringMaps(map1, map2 map[string]string) map[string]string {
+	// Create a new map to store the merged result
+	mergedMap := make(map[string]string)
+
+	// Add all entries from map1 to mergedMap
+	for k, v := range map1 {
+		mergedMap[k] = v
+	}
+
+	// Add all entries from map2 to mergedMap
+	for k, v := range map2 {
+		mergedMap[k] = v
+	}
+
+	return mergedMap
+}

pkg/pokt/pokt_v0/basic_client.go

@@ -167,6 +167,7 @@ func (r BasicClient) makeRequest(endpoint string, method string, requestData any
 	}()
 
 	request.Header.SetUserAgent(r.userAgent)
+	request.Header.SetContentType("application/json")
 
 	if hostOverride != nil {
 		request.SetRequestURI(*hostOverride + endpoint)