/
content_type.go
73 lines (62 loc) · 2.01 KB
/
content_type.go
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package httputil
import (
"fmt"
"mime"
"net/http"
"strings"
"github.com/authgear/authgear-server/pkg/util/httproute"
)
func CheckContentType(raws []string) httproute.MiddlewareFunc {
allowedMediaTypes := getAllowedMediaType(raws)
return httproute.MiddlewareFunc(func(next http.Handler) http.Handler {
return makeCheckContentTypeHandlerFunc(next, allowedMediaTypes)
})
}
func getAllowedMediaType(raws []string) []string {
var allowedMediaTypes []string
for _, raw := range raws {
mediaType, _, err := mime.ParseMediaType(raw)
if err != nil {
panic(fmt.Errorf("httputil: invalid content type: %w", err))
}
allowedMediaTypes = append(allowedMediaTypes, mediaType)
}
return allowedMediaTypes
}
func makeCheckContentTypeHandlerFunc(next http.Handler, allowedMediaTypes []string) http.HandlerFunc {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
// For some reason, body is not nil when the request is GET or HEAD.
if r.Method == "GET" || r.Method == "HEAD" || r.Body == nil {
// Content-Type is irrelevant without body.
next.ServeHTTP(w, r)
return
}
raw := r.Header.Get("Content-Type")
requestContentType, params, err := mime.ParseMediaType(raw)
if err != nil {
http.Error(w, fmt.Sprintf("invalid content type: %v", raw), http.StatusUnsupportedMediaType)
return
}
isAllowed := false
for _, allowedMediaType := range allowedMediaTypes {
if allowedMediaType == requestContentType {
isAllowed = true
break
}
}
if !isAllowed {
http.Error(w, fmt.Sprintf("invalid content type: %v", requestContentType), http.StatusUnsupportedMediaType)
return
}
// In case charset is specified, ensure it is utf-8.
if charset, ok := params["charset"]; ok {
charset = strings.ToLower(charset)
if charset != "utf-8" && charset != "utf8" {
http.Error(w, fmt.Sprintf("invalid content type: %v", requestContentType), http.StatusUnsupportedMediaType)
return
}
}
// Allow params to contain something we do not understand.
next.ServeHTTP(w, r)
})
}