Initial commit

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

middleware/cors/cors.go

@@ -0,0 +1,133 @@
+package cors
+
+import (
+	"net/http"
+	"strconv"
+	"strings"
+
+	"github.com/gin-gonic/gin"
+)
+
+type Options struct {
+	Origin               *[]string //传入空指针，表示允许"*",  传入空数组表示禁止跨域
+	Methods              []string  //Methods
+	AllowedHeaders       []string  //AllowHeaders
+	ExposedHeaders       []string  //exposeHeader
+	Credentials          bool      //cookie
+	MaxAge               int64     //缓存MaxAge
+	PreflightContinue    bool      //在遇到Options的时候，继续，而不是返回请求
+	OptionsSuccessStatus int       //Options时，返回的状态码，默认204
+}
+
+func configureOrigin(o *Options, c *gin.Context) map[string]string {
+	reqOrigin := c.GetHeader("Origin")
+	if o.Origin == nil {
+		return map[string]string{"Access-Control-Allow-Origin": "*"}
+	}
+	headers := make(map[string]string)
+	isAllowed := false
+	for _, allowed := range *o.Origin {
+		if allowed == reqOrigin {
+			isAllowed = true
+			break
+		}
+	}
+	if isAllowed {
+		headers["Access-Control-Allow-Origin"] = reqOrigin
+	} else {
+		headers["Access-Control-Allow-Origin"] = strconv.FormatBool(false)
+	}
+	headers["Vary"] = "Origin"
+	return headers
+}
+
+func configureMethods(o *Options) map[string]string {
+	headers := make(map[string]string)
+	if len(o.Methods) > 0 {
+		headers["Access-Control-Allow-Methods"] = strings.ToUpper(strings.Join(o.Methods, ","))
+	}
+	return headers
+}
+
+func configureCredentials(o *Options) map[string]string {
+	headers := make(map[string]string)
+	if o.Credentials {
+		headers["Access-Control-Allow-Credentials"] = strconv.FormatBool(true)
+	}
+	return headers
+}
+
+func configureAllowedHeaders(o *Options, c *gin.Context) map[string]string {
+	headers := make(map[string]string)
+	if len(o.AllowedHeaders) > 0 {
+		headers["Access-Control-Allow-Headers"] = strings.Join(o.AllowedHeaders, ",")
+	}
+	return headers
+}
+
+func configureExposedHeaders(o *Options) map[string]string {
+	var headers = make(map[string]string)
+	if len(o.ExposedHeaders) > 0 {
+		headers["Access-Control-Expose-Headers"] = strings.Join(o.ExposedHeaders, ",")
+	}
+	return headers
+}
+
+func configureMaxAge(o *Options) map[string]string {
+	var headers = make(map[string]string)
+	if o.MaxAge >= 0 {
+		headers["Access-Control-Max-Age"] = strconv.FormatInt(o.MaxAge, 10)
+	}
+	return headers
+}
+
+func mergeMap(m ...map[string]string) map[string]string {
+	r := make(map[string]string)
+	for _, t := range m {
+		for k, v := range t {
+			r[k] = v
+		}
+	}
+	return r
+}
+
+func applyHeader(c *gin.Context, h map[string]string) {
+	for k, v := range h {
+		c.Header(k, v)
+	}
+}
+
+// Cors 跨域处理
+func Cors(o *Options) gin.HandlerFunc {
+	if o.OptionsSuccessStatus == 0 {
+		o.OptionsSuccessStatus = http.StatusNoContent
+	}
+	return func(c *gin.Context) {
+		method := c.Request.Method
+		//c.Header("Access-Control-Allow-Origin", "*")
+		//c.Header("Access-Control-Allow-Headers", "Content-Type,AccessToken,X-CSRF-Token,Authorization,Token,Content-Length,Etag,Content-Range,Accept-Ranges,User-Agent,Range,Bucket,Content-Disposition,Signature,X-Forwarded-For,X-Real-Ip")
+		if method == "OPTIONS" {
+			h := mergeMap(
+				configureOrigin(o, c),
+				configureCredentials(o),
+				configureMethods(o),
+				configureAllowedHeaders(o, c),
+				configureMaxAge(o),
+				configureExposedHeaders(o),
+			)
+			applyHeader(c, h)
+			if o.PreflightContinue {
+				return
+			}
+			c.Header("Content-Length", "0")
+			c.AbortWithStatus(o.OptionsSuccessStatus)
+			return
+		}
+		h := mergeMap(
+			configureOrigin(o, c),
+			configureCredentials(o),
+			configureExposedHeaders(o),
+		)
+		applyHeader(c, h)
+	}
+}