github.com/hellobchain/third_party@v0.0.0-20230331131523-deb0478a2e52/go-chi/chi/middleware/content_charset.go (about)

     1  package middleware
     2  
     3  import (
     4  	"strings"
     5  
     6  	"github.com/hellobchain/newcryptosm/http"
     7  )
     8  
     9  // ContentCharset generates a handler that writes a 415 Unsupported Media Type response if none of the charsets match.
    10  // An empty charset will allow requests with no Content-Type header or no specified charset.
    11  func ContentCharset(charsets ...string) func(next http.Handler) http.Handler {
    12  	for i, c := range charsets {
    13  		charsets[i] = strings.ToLower(c)
    14  	}
    15  
    16  	return func(next http.Handler) http.Handler {
    17  		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
    18  			if !contentEncoding(r.Header.Get("Content-Type"), charsets...) {
    19  				w.WriteHeader(http.StatusUnsupportedMediaType)
    20  				return
    21  			}
    22  
    23  			next.ServeHTTP(w, r)
    24  		})
    25  	}
    26  }
    27  
    28  // Check the content encoding against a list of acceptable values.
    29  func contentEncoding(ce string, charsets ...string) bool {
    30  	_, ce = split(strings.ToLower(ce), ";")
    31  	_, ce = split(ce, "charset=")
    32  	ce, _ = split(ce, ";")
    33  	for _, c := range charsets {
    34  		if ce == c {
    35  			return true
    36  		}
    37  	}
    38  
    39  	return false
    40  }
    41  
    42  // Split a string in two parts, cleaning any whitespace.
    43  func split(str, sep string) (string, string) {
    44  	var a, b string
    45  	var parts = strings.SplitN(str, sep, 2)
    46  	a = strings.TrimSpace(parts[0])
    47  	if len(parts) == 2 {
    48  		b = strings.TrimSpace(parts[1])
    49  	}
    50  
    51  	return a, b
    52  }