Send payload api (#501)

*  Add sendPayload API

*  WIP

* 

 Fix webapi linter warnings

* Fix after cherry-pick

* Fix linter

Co-authored-by: capossele <angelocapossele@gmail.com>

client/message.go

@@ -7,7 +7,8 @@ import (
 )
 
 const (
-	routeFindByID = "message/findById"
+	routeFindByID    = "message/findById"
+	routeSendPayload = "message/sendPayload"
 )
 
 // FindMessageByID finds messages by the given base58 encoded IDs. The messages are returned in the same order as
@@ -26,3 +27,14 @@ func (api *GoShimmerAPI) FindMessageByID(base58EncodedIDs []string) (*webapi_mes
 
 	return res, nil
 }
+
+// SendPayload send a message with the given payload.
+func (api *GoShimmerAPI) SendPayload(payload []byte) (string, error) {
+	res := &webapi_message.MsgResponse{}
+	if err := api.do(http.MethodPost, routeSendPayload,
+		&webapi_message.MsgRequest{Payload: payload}, res); err != nil {
+		return "", err
+	}
+
+	return res.ID, nil
+}

plugins/webapi/message/plugin.go

@@ -23,6 +23,7 @@ var (
 func configure(plugin *node.Plugin) {
 	log = logger.NewLogger(PluginName)
 	webapi.Server.POST("message/findById", findMessageByID)
+	webapi.Server.POST("message/sendPayload", sendPayload)
 }
 
 // findMessageByID returns the array of messages for the

plugins/webapi/message/sendPayload.go

+package message
+
+import (
+	"net/http"
+
+	"github.com/iotaledger/goshimmer/packages/binary/messagelayer/payload"
+	"github.com/iotaledger/goshimmer/plugins/issuer"
+	"github.com/labstack/echo"
+)
+
+// sendPayload creates a message of the given payload and
+// broadcasts it to the node's neighbors. It returns the message ID if successful.
+func sendPayload(c echo.Context) error {
+	var request MsgRequest
+	if err := c.Bind(&request); err != nil {
+		log.Info(err.Error())
+		return c.JSON(http.StatusBadRequest, MsgResponse{Error: err.Error()})
+	}
+
+	//TODO: to check max payload size allowed, if exceeding return an error
+
+	parsedPayload, _, err := payload.FromBytes(request.Payload)
+	if err != nil {
+		return c.JSON(http.StatusBadRequest, MsgResponse{Error: "not a valid payload"})
+	}
+
+	msg, err := issuer.IssuePayload(parsedPayload)
+	if err != nil {
+		return c.JSON(http.StatusBadRequest, MsgResponse{Error: err.Error()})
+	}
+
+	return c.JSON(http.StatusOK, MsgResponse{ID: msg.Id().String()})
+}
+
+// MsgResponse contains the ID of the message sent.
+type MsgResponse struct {
+	ID    string `json:"id,omitempty"`
+	Error string `json:"error,omitempty"`
+}
+
+// MsgRequest contains the message to send.
+type MsgRequest struct {
+	Payload []byte `json:"payload"`
+}