Initial commit

vendor/github.com/gin-gonic/gin/auth.go

@@ -0,0 +1,91 @@
+// Copyright 2014 Manu Martinez-Almeida.  All rights reserved.
+// Use of this source code is governed by a MIT style
+// license that can be found in the LICENSE file.
+
+package gin
+
+import (
+	"crypto/subtle"
+	"encoding/base64"
+	"net/http"
+	"strconv"
+
+	"github.com/gin-gonic/gin/internal/bytesconv"
+)
+
+// AuthUserKey is the cookie name for user credential in basic auth.
+const AuthUserKey = "user"
+
+// Accounts defines a key/value for user/pass list of authorized logins.
+type Accounts map[string]string
+
+type authPair struct {
+	value string
+	user  string
+}
+
+type authPairs []authPair
+
+func (a authPairs) searchCredential(authValue string) (string, bool) {
+	if authValue == "" {
+		return "", false
+	}
+	for _, pair := range a {
+		if subtle.ConstantTimeCompare([]byte(pair.value), []byte(authValue)) == 1 {
+			return pair.user, true
+		}
+	}
+	return "", false
+}
+
+// BasicAuthForRealm returns a Basic HTTP Authorization middleware. It takes as arguments a map[string]string where
+// the key is the user name and the value is the password, as well as the name of the Realm.
+// If the realm is empty, "Authorization Required" will be used by default.
+// (see http://tools.ietf.org/html/rfc2617#section-1.2)
+func BasicAuthForRealm(accounts Accounts, realm string) HandlerFunc {
+	if realm == "" {
+		realm = "Authorization Required"
+	}
+	realm = "Basic realm=" + strconv.Quote(realm)
+	pairs := processAccounts(accounts)
+	return func(c *Context) {
+		// Search user in the slice of allowed credentials
+		user, found := pairs.searchCredential(c.requestHeader("Authorization"))
+		if !found {
+			// Credentials doesn't match, we return 401 and abort handlers chain.
+			c.Header("WWW-Authenticate", realm)
+			c.AbortWithStatus(http.StatusUnauthorized)
+			return
+		}
+
+		// The user credentials was found, set user's id to key AuthUserKey in this context, the user's id can be read later using
+		// c.MustGet(gin.AuthUserKey).
+		c.Set(AuthUserKey, user)
+	}
+}
+
+// BasicAuth returns a Basic HTTP Authorization middleware. It takes as argument a map[string]string where
+// the key is the user name and the value is the password.
+func BasicAuth(accounts Accounts) HandlerFunc {
+	return BasicAuthForRealm(accounts, "")
+}
+
+func processAccounts(accounts Accounts) authPairs {
+	length := len(accounts)
+	assert1(length > 0, "Empty list of authorized credentials")
+	pairs := make(authPairs, 0, length)
+	for user, password := range accounts {
+		assert1(user != "", "User can not be empty")
+		value := authorizationHeader(user, password)
+		pairs = append(pairs, authPair{
+			value: value,
+			user:  user,
+		})
+	}
+	return pairs
+}
+
+func authorizationHeader(user, password string) string {
+	base := user + ":" + password
+	return "Basic " + base64.StdEncoding.EncodeToString(bytesconv.StringToBytes(base))
+}