cors middleware for api

cmd/api.go

@@ -52,6 +52,7 @@ func RunApi(cmd *cobra.Command, args []string) {
 	root := r.Group("/:chainId")
 	{
 		root.Use(middleware.Authorization)
+		root.Use(middleware.Cors)
 		// wildcard queries
 		root.GET("/transactions", handlers.GetTransactions)
 		root.GET("/events", handlers.GetLogs)

internal/middleware/cors.go

@@ -0,0 +1,18 @@
+package middleware
+
+import (
+	"github.com/gin-gonic/gin"
+)
+
+func Cors(c *gin.Context) {
+	c.Writer.Header().Set("Access-Control-Allow-Origin", "*")
+	c.Writer.Header().Set("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, OPTIONS")
+	c.Writer.Header().Set("Access-Control-Allow-Headers", "Origin, Content-Type, Content-Length, Accept-Encoding, X-CSRF-Token, Authorization, accept, origin, Cache-Control, X-Requested-With")
+	c.Writer.Header().Set("Access-Control-Allow-Credentials", "true")
+
+	if c.Request.Method == "OPTIONS" {
+		c.AbortWithStatus(200)
+		return
+	}
+	c.Next()
+}