content_encoding.go

Documentation: github.com/go-chi/chi/middleware

     1  package middleware
     2  
     3  import (
     4  	"net/http"
     5  	"strings"
     6  )
     7  
     8  // AllowContentEncoding enforces a whitelist of request Content-Encoding otherwise responds
     9  // with a 415 Unsupported Media Type status.
    10  func AllowContentEncoding(contentEncoding ...string) func(next http.Handler) http.Handler {
    11  	allowedEncodings := make(map[string]struct{}, len(contentEncoding))
    12  	for _, encoding := range contentEncoding {
    13  		allowedEncodings[strings.TrimSpace(strings.ToLower(encoding))] = struct{}{}
    14  	}
    15  	return func(next http.Handler) http.Handler {
    16  		fn := func(w http.ResponseWriter, r *http.Request) {
    17  			requestEncodings := r.Header["Content-Encoding"]
    18  			// skip check for empty content body or no Content-Encoding
    19  			if r.ContentLength == 0 {
    20  				next.ServeHTTP(w, r)
    21  				return
    22  			}
    23  			// All encodings in the request must be allowed
    24  			for _, encoding := range requestEncodings {
    25  				if _, ok := allowedEncodings[strings.TrimSpace(strings.ToLower(encoding))]; !ok {
    26  					w.WriteHeader(http.StatusUnsupportedMediaType)
    27  					return
    28  				}
    29  			}
    30  			next.ServeHTTP(w, r)
    31  		}
    32  		return http.HandlerFunc(fn)
    33  	}
    34  }
    35
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