Handle CORS requests (#6289)

vendor/github.com/go-macaron/cors/.gitignore

@@ -0,0 +1,12 @@
+# Binaries for programs and plugins
+*.exe
+*.exe~
+*.dll
+*.so
+*.dylib
+
+# Test binary, build with `go test -c`
+*.test
+
+# Output of the go coverage tool, specifically when used with LiteIDE
+*.out

vendor/github.com/go-macaron/cors/LICENSE

@@ -0,0 +1,201 @@
+                                 Apache License
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+
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vendor/github.com/go-macaron/cors/README.md

@@ -0,0 +1,2 @@
+# cors
+Package cors is a middleware that handles CORS requests & headers for Macaron.

vendor/github.com/go-macaron/cors/cors.go

@@ -0,0 +1,139 @@
+package cors
+
+import (
+	"fmt"
+	"log"
+	"net/http"
+	"net/url"
+	"strconv"
+	"strings"
+
+	macaron "gopkg.in/macaron.v1"
+)
+
+const _VERSION = "0.1.0"
+
+func Version() string {
+	return _VERSION
+}
+
+// Options represents a struct for specifying configuration options for the CORS middleware.
+type Options struct {
+	Section          string
+	Scheme           string
+	AllowDomain      string
+	AllowSubdomain   bool
+	Methods          []string
+	MaxAgeSeconds    int
+	AllowCredentials bool
+}
+
+func prepareOptions(options []Options) Options {
+	var opt Options
+	if len(options) > 0 {
+		opt = options[0]
+	}
+
+	if len(opt.Section) == 0 {
+		opt.Section = "cors"
+	}
+	sec := macaron.Config().Section(opt.Section)
+
+	if len(opt.Scheme) == 0 {
+		opt.Scheme = sec.Key("SCHEME").MustString("http")
+	}
+	if len(opt.AllowDomain) == 0 {
+		opt.AllowDomain = sec.Key("ALLOW_DOMAIN").MustString("*")
+	}
+	if !opt.AllowSubdomain {
+		opt.AllowSubdomain = sec.Key("ALLOW_SUBDOMAIN").MustBool(false)
+	}
+	if len(opt.Methods) == 0 {
+		opt.Methods = sec.Key("METHODS").Strings(",")
+		if len(opt.Methods) == 0 {
+			opt.Methods = []string{
+				http.MethodGet,
+				http.MethodHead,
+				http.MethodPost,
+				http.MethodPut,
+				http.MethodPatch,
+				http.MethodDelete,
+				http.MethodOptions,
+			}
+		}
+	}
+	if opt.MaxAgeSeconds <= 0 {
+		// cache options response for 600 secs
+		// ref: https://stackoverflow.com/questions/54300997/is-it-possible-to-cache-http-options-response?noredirect=1#comment95790277_54300997
+		// ref: https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Access-Control-Max-Age
+		opt.MaxAgeSeconds = sec.Key("MAX_AGE_SECONDS").MustInt(600)
+	}
+	if !opt.AllowCredentials {
+		opt.AllowCredentials = sec.Key("ALLOW_CREDENTIALS").MustBool(true)
+	}
+
+	return opt
+}
+
+// https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Access-Control-Allow-Origin
+// https://fetch.spec.whatwg.org/#cors-protocol-and-credentials
+// For requests without credentials, the server may specify "*" as a wildcard, thereby allowing any origin to access the resource.
+func CORS(options ...Options) macaron.Handler {
+	opt := prepareOptions(options)
+	return func(ctx *macaron.Context, log *log.Logger) {
+		reqOptions := ctx.Req.Method == http.MethodOptions
+
+		headers := map[string]string{
+			"access-control-allow-methods": strings.Join(opt.Methods, ","),
+			"access-control-allow-headers": ctx.Req.Header.Get("access-control-request-headers"),
+			"access-control-max-age":       strconv.Itoa(opt.MaxAgeSeconds),
+		}
+		if opt.AllowDomain == "*" {
+			headers["access-control-allow-origin"] = "*"
+		} else if opt.AllowDomain != "" {
+			origin := ctx.Req.Header.Get("Origin")
+			if reqOptions && origin == "" {
+				respErrorf(ctx, log, http.StatusBadRequest, "missing origin header in CORS request")
+				return
+			}
+
+			u, err := url.Parse(origin)
+			if err != nil {
+				respErrorf(ctx, log, http.StatusBadRequest, "Failed to parse CORS origin header. Reason: %v", err)
+				return
+			}
+
+			ok := u.Hostname() == opt.AllowDomain ||
+				(opt.AllowSubdomain && strings.HasSuffix(u.Hostname(), "."+opt.AllowDomain))
+			if ok {
+				u.Scheme = opt.Scheme
+				headers["access-control-allow-origin"] = u.String()
+				headers["access-control-allow-credentials"] = strconv.FormatBool(opt.AllowCredentials)
+				headers["vary"] = "Origin"
+			}
+			if reqOptions && !ok {
+				respErrorf(ctx, log, http.StatusBadRequest, "CORS request from prohibited domain %v", origin)
+				return
+			}
+		}
+		ctx.Resp.Before(func(w macaron.ResponseWriter) {
+			for k, v := range headers {
+				w.Header().Set(k, v)
+			}
+		})
+		if reqOptions {
+			ctx.Status(200) // return response
+		}
+	}
+}
+
+func respErrorf(ctx *macaron.Context, log *log.Logger, statusCode int, format string, a ...interface{}) {
+	msg := fmt.Sprintf(format, a...)
+	log.Println(msg)
+	ctx.WriteHeader(statusCode)
+	_, err := ctx.Write([]byte(msg))
+	if err != nil {
+		panic(err)
+	}
+	return
+}

vendor/github.com/go-macaron/cors/go.mod

@@ -0,0 +1,11 @@
+module github.com/go-macaron/cors
+
+go 1.12
+
+require (
+	github.com/Unknwon/com v0.0.0-20190321035513-0fed4efef755 // indirect
+	github.com/go-macaron/inject v0.0.0-20160627170012-d8a0b8677191 // indirect
+	golang.org/x/crypto v0.0.0-20190418165655-df01cb2cc480 // indirect
+	gopkg.in/ini.v1 v1.42.0 // indirect
+	gopkg.in/macaron.v1 v1.3.2
+)

vendor/github.com/go-macaron/cors/go.sum

@@ -0,0 +1,19 @@
+github.com/Unknwon/com v0.0.0-20190321035513-0fed4efef755 h1:1B7wb36fHLSwZfHg6ngZhhtIEHQjiC5H4p7qQGBEffg=
+github.com/Unknwon/com v0.0.0-20190321035513-0fed4efef755/go.mod h1:voKvFVpXBJxdIPeqjoJuLK+UVcRlo/JLjeToGxPYu68=
+github.com/go-macaron/inject v0.0.0-20160627170012-d8a0b8677191 h1:NjHlg70DuOkcAMqgt0+XA+NHwtu66MkTVVgR4fFWbcI=
+github.com/go-macaron/inject v0.0.0-20160627170012-d8a0b8677191/go.mod h1:VFI2o2q9kYsC4o7VP1HrEVosiZZTd+MVT3YZx4gqvJw=
+github.com/gopherjs/gopherjs v0.0.0-20181103185306-d547d1d9531e h1:JKmoR8x90Iww1ks85zJ1lfDGgIiMDuIptTOhJq+zKyg=
+github.com/gopherjs/gopherjs v0.0.0-20181103185306-d547d1d9531e/go.mod h1:wJfORRmW1u3UXTncJ5qlYoELFm8eSnnEO6hX4iZ3EWY=
+github.com/jtolds/gls v4.2.1+incompatible h1:fSuqC+Gmlu6l/ZYAoZzx2pyucC8Xza35fpRVWLVmUEE=
+github.com/jtolds/gls v4.2.1+incompatible/go.mod h1:QJZ7F/aHp+rZTRtaJ1ow/lLfFfVYBRgL+9YlvaHOwJU=
+github.com/smartystreets/assertions v0.0.0-20190116191733-b6c0e53d7304 h1:Jpy1PXuP99tXNrhbq2BaPz9B+jNAvH1JPQQpG/9GCXY=
+github.com/smartystreets/assertions v0.0.0-20190116191733-b6c0e53d7304/go.mod h1:OnSkiWE9lh6wB0YB77sQom3nweQdgAjqCqsofrRNTgc=
+github.com/smartystreets/goconvey v0.0.0-20181108003508-044398e4856c h1:Ho+uVpkel/udgjbwB5Lktg9BtvJSh2DT0Hi6LPSyI2w=
+github.com/smartystreets/goconvey v0.0.0-20181108003508-044398e4856c/go.mod h1:XDJAKZRPZ1CvBcN2aX5YOUTYGHki24fSF0Iv48Ibg0s=
+golang.org/x/crypto v0.0.0-20190418165655-df01cb2cc480 h1:O5YqonU5IWby+w98jVUG9h7zlCWCcH4RHyPVReBmhzk=
+golang.org/x/crypto v0.0.0-20190418165655-df01cb2cc480/go.mod h1:WFFai1msRO1wXaEeE5yQxYXgSfI8pQAWXbQop6sCtWE=
+golang.org/x/sys v0.0.0-20190403152447-81d4e9dc473e/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+gopkg.in/ini.v1 v1.42.0 h1:7N3gPTt50s8GuLortA00n8AqRTk75qOP98+mTPpgzRk=
+gopkg.in/ini.v1 v1.42.0/go.mod h1:pNLf8WUiyNEtQjuu5G5vTm06TEv9tsIgeAvK8hOrP4k=
+gopkg.in/macaron.v1 v1.3.2 h1:AvWIaPmwBUA87/OWzePkoxeaw6YJWDfBt1pDFPBnLf8=
+gopkg.in/macaron.v1 v1.3.2/go.mod h1:PrsiawTWAGZs6wFbT5hlr7SQ2Ns9h7cUVtcUu4lQOVo=