Merge pull request #35 from go-slide/feature/core/addded-cors

Added cors

README.md

@@ -43,6 +43,11 @@ func main() {
 	// compression middleware
 	app.Use(middleware.Compress())
 
+	// this is with config
+	app.Use(middleware.CorsWithConfig(middleware.CorsConfig{
+		AllowOrigins: []string{"https://www.postgresqltutorial.com"},
+	}))
+
 	// you can multiple middlewares also
 	app.Use(func(ctx *slide.Ctx) error {
 		fmt.Println("this will run for all URL(s)")

example/main.go

@@ -25,6 +25,14 @@ func main() {
 
 	app := slide.InitServer(&config)
 
+	// this is with config
+	app.Use(middleware.CorsWithConfig(middleware.CorsConfig{
+		AllowOrigins: []string{"https://www.postgresqltutorial.com"},
+	}))
+
+	// without config, which uses default config
+	// app.Use(middleware.Cors())
+
 	app.HandleNotFound(func(ctx *slide.Ctx) error {
 		return ctx.JSON(http.StatusNotFound, "check url idiot")
 	})

middleware/cors.go

@@ -0,0 +1,95 @@
+package middleware
+
+import (
+	"net/http"
+	"strconv"
+	"strings"
+
+	"github.com/go-slide/slide"
+)
+
+// CorsConfig configuration for Corsfeat
+type CorsConfig struct {
+	AllowMethods     []string
+	AllowOrigins     []string
+	AllowHeaders     []string
+	AllowCredentials bool
+	ExposeHeaders    []string
+	MaxAge           int
+}
+
+var (
+	// DefaultCORSConfig defeault config for cors
+	DefaultCORSConfig = CorsConfig{
+		AllowOrigins: []string{"*"},
+		AllowMethods: []string{http.MethodGet, http.MethodHead, http.MethodPut, http.MethodPatch, http.MethodPost, http.MethodDelete},
+	}
+)
+
+// Cors Middleware with default config
+// Reference https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS
+func Cors() func(ctx *slide.Ctx) error {
+	return CorsWithConfig(DefaultCORSConfig)
+}
+
+// CorsWithConfig Cors with a config
+func CorsWithConfig(config CorsConfig) func(ctx *slide.Ctx) error {
+	return func(ctx *slide.Ctx) error {
+		if len(config.AllowOrigins) == 0 {
+			config.AllowOrigins = DefaultCORSConfig.AllowOrigins
+		}
+		if len(config.AllowMethods) == 0 {
+			config.AllowMethods = DefaultCORSConfig.AllowMethods
+		}
+		allowMethods := strings.Join(config.AllowMethods, ",")
+		allowHeaders := strings.Join(config.AllowHeaders, ",")
+		exposeHeaders := strings.Join(config.ExposeHeaders, ",")
+		maxAge := strconv.Itoa(config.MaxAge)
+		origin := string(ctx.RequestCtx.Request.Header.Peek(slide.HeaderOrigin))
+		allowOrigin := ""
+		for _, o := range config.AllowOrigins {
+			if o == "*" && config.AllowCredentials {
+				allowOrigin = origin
+				break
+			}
+			if o == "*" || o == origin {
+				allowOrigin = o
+				break
+			}
+		}
+		if string(ctx.RequestCtx.Method()) != http.MethodOptions {
+			ctx.RequestCtx.Response.Header.Set(slide.HeaderAccessControlAllowOrigin, allowOrigin)
+			ctx.RequestCtx.Response.Header.Set(slide.HeaderVary, slide.HeaderOrigin)
+			if config.AllowCredentials {
+				ctx.RequestCtx.Response.Header.Set(slide.HeaderAccessControlAllowCredentials, "true")
+			}
+			if exposeHeaders != "" {
+				ctx.RequestCtx.Response.Header.Set(slide.HeaderAccessControlExposeHeaders, exposeHeaders)
+			}
+			return ctx.Next()
+		}
+		// Options request
+		ctx.RequestCtx.Response.Header.Set(slide.HeaderVary, slide.HeaderOrigin)
+		ctx.RequestCtx.Response.Header.Set(slide.HeaderVary, slide.HeaderAccessControlRequestMethod)
+		ctx.RequestCtx.Response.Header.Set(slide.HeaderVary, slide.HeaderAccessControlRequestHeaders)
+		ctx.RequestCtx.Response.Header.Set(slide.HeaderAccessControlAllowOrigin, allowOrigin)
+		ctx.RequestCtx.Response.Header.Set(slide.HeaderAccessControlAllowMethods, allowMethods)
+
+		if config.AllowCredentials {
+			ctx.RequestCtx.Response.Header.Set(slide.HeaderAccessControlAllowCredentials, "true")
+		}
+		if allowHeaders != "" {
+			ctx.RequestCtx.Response.Header.Set(slide.HeaderAccessControlAllowHeaders, allowHeaders)
+		} else {
+			h := string(ctx.RequestCtx.Request.Header.Peek(slide.HeaderAccessControlRequestHeaders))
+			if h != "" {
+				ctx.RequestCtx.Response.Header.Set(slide.HeaderAccessControlAllowHeaders, h)
+			}
+		}
+		if config.MaxAge > 0 {
+			ctx.RequestCtx.Response.Header.Set(slide.HeaderAccessControlMaxAge, maxAge)
+		}
+		return ctx.SendStatusCode(http.StatusNoContent)
+	}
+
+}

utils.go

@@ -18,6 +18,18 @@ const (
 	ApplicationJSON   = "application/json"
 	Attachment        = "attachment"
 
+	// cors headers
+	HeaderOrigin                        = "Origin"
+	HeaderVary                          = "Vary"
+	HeaderAccessControlAllowOrigin      = "Access-Control-Allow-Origin"
+	HeaderAccessControlAllowMethods     = "Access-Control-Allow-Methods"
+	HeaderAccessControlAllowCredentials = "Access-Control-Allow-Credentials"
+	HeaderAccessControlExposeHeaders    = "Access-Control-Expose-Headers"
+	HeaderAccessControlRequestMethod    = "Access-Control-Request-Method"
+	HeaderAccessControlRequestHeaders   = "Access-Control-Request-Headers"
+	HeaderAccessControlAllowHeaders     = "Access-Control-Allow-Headers"
+	HeaderAccessControlMaxAge           = "Access-Control-Max-Age"
+
 	routerRegexReplace = "[a-zA-Z0-9_-]*"
 
 	// routing error messages