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|
package cors
import (
"net/http"
"strings"
"github.com/gin-gonic/gin"
)
type cors struct {
allowAllOrigins bool
allowCredentials bool
allowOriginFunc func(string) bool
allowOrigins []string
normalHeaders http.Header
preflightHeaders http.Header
wildcardOrigins [][]string
}
var (
DefaultSchemas = []string{
"http://",
"https://",
}
ExtensionSchemas = []string{
"chrome-extension://",
"safari-extension://",
"moz-extension://",
"ms-browser-extension://",
}
FileSchemas = []string{
"file://",
}
WebSocketSchemas = []string{
"ws://",
"wss://",
}
)
func newCors(config Config) *cors {
if err := config.Validate(); err != nil {
panic(err.Error())
}
for _, origin := range config.AllowOrigins {
if origin == "*" {
config.AllowAllOrigins = true
}
}
return &cors{
allowOriginFunc: config.AllowOriginFunc,
allowAllOrigins: config.AllowAllOrigins,
allowCredentials: config.AllowCredentials,
allowOrigins: normalize(config.AllowOrigins),
normalHeaders: generateNormalHeaders(config),
preflightHeaders: generatePreflightHeaders(config),
wildcardOrigins: config.parseWildcardRules(),
}
}
func (cors *cors) applyCors(c *gin.Context) {
origin := c.Request.Header.Get("Origin")
if len(origin) == 0 {
// request is not a CORS request
return
}
host := c.Request.Host
if origin == "http://"+host || origin == "https://"+host {
// request is not a CORS request but have origin header.
// for example, use fetch api
return
}
if !cors.validateOrigin(origin) {
c.AbortWithStatus(http.StatusForbidden)
return
}
if c.Request.Method == "OPTIONS" {
cors.handlePreflight(c)
defer c.AbortWithStatus(http.StatusNoContent) // Using 204 is better than 200 when the request status is OPTIONS
} else {
cors.handleNormal(c)
}
if !cors.allowAllOrigins {
c.Header("Access-Control-Allow-Origin", origin)
}
}
func (cors *cors) validateWildcardOrigin(origin string) bool {
for _, w := range cors.wildcardOrigins {
if w[0] == "*" && strings.HasSuffix(origin, w[1]) {
return true
}
if w[1] == "*" && strings.HasPrefix(origin, w[0]) {
return true
}
if strings.HasPrefix(origin, w[0]) && strings.HasSuffix(origin, w[1]) {
return true
}
}
return false
}
func (cors *cors) validateOrigin(origin string) bool {
if cors.allowAllOrigins {
return true
}
for _, value := range cors.allowOrigins {
if value == origin {
return true
}
}
if len(cors.wildcardOrigins) > 0 && cors.validateWildcardOrigin(origin) {
return true
}
if cors.allowOriginFunc != nil {
return cors.allowOriginFunc(origin)
}
return false
}
func (cors *cors) handlePreflight(c *gin.Context) {
header := c.Writer.Header()
for key, value := range cors.preflightHeaders {
header[key] = value
}
}
func (cors *cors) handleNormal(c *gin.Context) {
header := c.Writer.Header()
for key, value := range cors.normalHeaders {
header[key] = value
}
}
|
