52 lines
1.3 KiB
Go
52 lines
1.3 KiB
Go
package middleware
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import (
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"net/http"
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"strings"
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)
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// ContentCharset generates a handler that writes a 415 Unsupported Media Type response if none of the charsets match.
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// An empty charset will allow requests with no Content-Type header or no specified charset.
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func ContentCharset(charsets ...string) func(next http.Handler) http.Handler {
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for i, c := range charsets {
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charsets[i] = strings.ToLower(c)
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}
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return func(next http.Handler) http.Handler {
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return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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if !contentEncoding(r.Header.Get("Content-Type"), charsets...) {
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w.WriteHeader(http.StatusUnsupportedMediaType)
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return
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}
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next.ServeHTTP(w, r)
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})
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}
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}
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// Check the content encoding against a list of acceptable values.
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func contentEncoding(ce string, charsets ...string) bool {
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_, ce = split(strings.ToLower(ce), ";")
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_, ce = split(ce, "charset=")
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ce, _ = split(ce, ";")
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for _, c := range charsets {
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if ce == c {
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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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// Split a string in two parts, cleaning any whitespace.
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func split(str, sep string) (string, string) {
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var a, b string
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var parts = strings.SplitN(str, sep, 2)
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a = strings.TrimSpace(parts[0])
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if len(parts) == 2 {
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b = strings.TrimSpace(parts[1])
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}
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return a, b
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}
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