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