【Gin-v1.9.0源码阅读】auth.go

// 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.
// AuthUserKey是基本身份验证中用户凭据的cookie名称。
const AuthUserKey = "user"

// Accounts defines a key/value for user/pass list of authorized logins.
// 帐户为授权登录的用户/通行证列表定义密钥/值。
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(bytesconv.StringToBytes(pair.value), bytesconv.StringToBytes(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.
// BasicAuthForRealm返回一个基本HTTP授权中间件。它采用map[string]字符串作为参数，其中键是用户名，值是密码，以及Realm的名称。
// If the realm is empty, "Authorization Required" will be used by default.
// 如果领域为空，则默认情况下将使用“需要授权”。
// (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
        // 在允许的凭据片段中搜索用户
        user, found := pairs.searchCredential(c.requestHeader("Authorization"))
        if !found {
            // Credentials doesn't match, we return 401 and abort handlers chain.
            // 凭据不匹配，我们返回401并中止处理程序链。
            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
        // 已找到用户凭据，请在此上下文中将用户的id设置为密钥AuthUserKey，稍后可以使用读取用户的id
        // 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.
// BasicAuth返回一个基本HTTP授权中间件。它采用map[string]字符串作为参数，其中键是用户名，值是密码。
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))
}