plugins: basic auth & cors

plugins/cors/cors.go

@@ -0,0 +1,229 @@
+// Copyright 2014 beego Author. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package cors provides handlers to enable CORS support.
+// Usage
+//
+// import (
+//  "github.com/astaxie/beego"
+//  "github.com/astaxie/beego/plugins/cors"
+// )
+
+//func main() {
+//  // CORS for https://foo.* origins, allowing:
+//  // - PUT and PATCH methods
+//  // - Origin header
+//  // - Credentials share
+//  beego.InsertFilter("*", beego.BeforeRouter,cors.Allow(&cors.Options{
+//    AllowOrigins:     []string{"https://*.foo.com"},
+//    AllowMethods:     []string{"PUT", "PATCH"},
+//    AllowHeaders:     []string{"Origin"},
+//    ExposeHeaders:    []string{"Content-Length"},
+//    AllowCredentials: true,
+//  }))
+//  beego.Run()
+//}
+package cors
+
+import (
+	"net/http"
+	"regexp"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/astaxie/beego"
+	"github.com/astaxie/beego/context"
+)
+
+const (
+	headerAllowOrigin      = "Access-Control-Allow-Origin"
+	headerAllowCredentials = "Access-Control-Allow-Credentials"
+	headerAllowHeaders     = "Access-Control-Allow-Headers"
+	headerAllowMethods     = "Access-Control-Allow-Methods"
+	headerExposeHeaders    = "Access-Control-Expose-Headers"
+	headerMaxAge           = "Access-Control-Max-Age"
+
+	headerOrigin         = "Origin"
+	headerRequestMethod  = "Access-Control-Request-Method"
+	headerRequestHeaders = "Access-Control-Request-Headers"
+)
+
+var (
+	defaultAllowHeaders = []string{"Origin", "Accept", "Content-Type", "Authorization"}
+	// Regex patterns are generated from AllowOrigins. These are used and generated internally.
+	allowOriginPatterns = []string{}
+)
+
+// Options represents Access Control options.
+type Options struct {
+	// If set, all origins are allowed.
+	AllowAllOrigins bool
+	// A list of allowed origins. Wild cards and FQDNs are supported.
+	AllowOrigins []string
+	// If set, allows to share auth credentials such as cookies.
+	AllowCredentials bool
+	// A list of allowed HTTP methods.
+	AllowMethods []string
+	// A list of allowed HTTP headers.
+	AllowHeaders []string
+	// A list of exposed HTTP headers.
+	ExposeHeaders []string
+	// Max age of the CORS headers.
+	MaxAge time.Duration
+}
+
+// Header converts options into CORS headers.
+func (o *Options) Header(origin string) (headers map[string]string) {
+	headers = make(map[string]string)
+	// if origin is not allowed, don't extend the headers
+	// with CORS headers.
+	if !o.AllowAllOrigins && !o.IsOriginAllowed(origin) {
+		return
+	}
+
+	// add allow origin
+	if o.AllowAllOrigins {
+		headers[headerAllowOrigin] = "*"
+	} else {
+		headers[headerAllowOrigin] = origin
+	}
+
+	// add allow credentials
+	headers[headerAllowCredentials] = strconv.FormatBool(o.AllowCredentials)
+
+	// add allow methods
+	if len(o.AllowMethods) > 0 {
+		headers[headerAllowMethods] = strings.Join(o.AllowMethods, ",")
+	}
+
+	// add allow headers
+	if len(o.AllowHeaders) > 0 {
+		headers[headerAllowHeaders] = strings.Join(o.AllowHeaders, ",")
+	}
+
+	// add exposed header
+	if len(o.ExposeHeaders) > 0 {
+		headers[headerExposeHeaders] = strings.Join(o.ExposeHeaders, ",")
+	}
+	// add a max age header
+	if o.MaxAge > time.Duration(0) {
+		headers[headerMaxAge] = strconv.FormatInt(int64(o.MaxAge/time.Second), 10)
+	}
+	return
+}
+
+// PreflightHeader converts options into CORS headers for a preflight response.
+func (o *Options) PreflightHeader(origin, rMethod, rHeaders string) (headers map[string]string) {
+	headers = make(map[string]string)
+	if !o.AllowAllOrigins && !o.IsOriginAllowed(origin) {
+		return
+	}
+	// verify if requested method is allowed
+	for _, method := range o.AllowMethods {
+		if method == rMethod {
+			headers[headerAllowMethods] = strings.Join(o.AllowMethods, ",")
+			break
+		}
+	}
+
+	// verify if requested headers are allowed
+	var allowed []string
+	for _, rHeader := range strings.Split(rHeaders, ",") {
+		rHeader = strings.TrimSpace(rHeader)
+	lookupLoop:
+		for _, allowedHeader := range o.AllowHeaders {
+			if strings.ToLower(rHeader) == strings.ToLower(allowedHeader) {
+				allowed = append(allowed, rHeader)
+				break lookupLoop
+			}
+		}
+	}
+
+	headers[headerAllowCredentials] = strconv.FormatBool(o.AllowCredentials)
+	// add allow origin
+	if o.AllowAllOrigins {
+		headers[headerAllowOrigin] = "*"
+	} else {
+		headers[headerAllowOrigin] = origin
+	}
+
+	// add allowed headers
+	if len(allowed) > 0 {
+		headers[headerAllowHeaders] = strings.Join(allowed, ",")
+	}
+
+	// add exposed headers
+	if len(o.ExposeHeaders) > 0 {
+		headers[headerExposeHeaders] = strings.Join(o.ExposeHeaders, ",")
+	}
+	// add a max age header
+	if o.MaxAge > time.Duration(0) {
+		headers[headerMaxAge] = strconv.FormatInt(int64(o.MaxAge/time.Second), 10)
+	}
+	return
+}
+
+// IsOriginAllowed looks up if the origin matches one of the patterns
+// generated from Options.AllowOrigins patterns.
+func (o *Options) IsOriginAllowed(origin string) (allowed bool) {
+	for _, pattern := range allowOriginPatterns {
+		allowed, _ = regexp.MatchString(pattern, origin)
+		if allowed {
+			return
+		}
+	}
+	return
+}
+
+// Allow enables CORS for requests those match the provided options.
+func Allow(opts *Options) beego.FilterFunc {
+	// Allow default headers if nothing is specified.
+	if len(opts.AllowHeaders) == 0 {
+		opts.AllowHeaders = defaultAllowHeaders
+	}
+
+	for _, origin := range opts.AllowOrigins {
+		pattern := regexp.QuoteMeta(origin)
+		pattern = strings.Replace(pattern, "\\*", ".*", -1)
+		pattern = strings.Replace(pattern, "\\?", ".", -1)
+		allowOriginPatterns = append(allowOriginPatterns, "^"+pattern+"$")
+	}
+
+	return func(ctx *context.Context) {
+		var (
+			origin           = ctx.Input.Header(headerOrigin)
+			requestedMethod  = ctx.Input.Header(headerRequestMethod)
+			requestedHeaders = ctx.Input.Header(headerRequestHeaders)
+			// additional headers to be added
+			// to the response.
+			headers map[string]string
+		)
+
+		if ctx.Input.Method() == "OPTIONS" &&
+			(requestedMethod != "" || requestedHeaders != "") {
+			headers = opts.PreflightHeader(origin, requestedMethod, requestedHeaders)
+			for key, value := range headers {
+				ctx.Output.Header(key, value)
+			}
+			ctx.Output.SetStatus(http.StatusOK)
+			return
+		}
+		headers = opts.Header(origin)
+
+		for key, value := range headers {
+			ctx.Output.Header(key, value)
+		}
+	}
+}