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package middleware
import (
"net/http"
"strings"
)
// SetHeader is a convenience handler to set a response header key/value
func SetHeader(key, value string) func(http.Handler) http.Handler {
return func(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
w.Header().Set(key, value)
next.ServeHTTP(w, r)
})
}
}
// AllowContentType enforces a whitelist of request Content-Types otherwise responds
// with a 415 Unsupported Media Type status.
func AllowContentType(contentTypes ...string) func(http.Handler) http.Handler {
allowedContentTypes := make(map[string]struct{}, len(contentTypes))
for _, ctype := range contentTypes {
allowedContentTypes[strings.TrimSpace(strings.ToLower(ctype))] = struct{}{}
}
return func(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
if r.ContentLength == 0 {
// Skip check for empty content body
next.ServeHTTP(w, r)
return
}
s := strings.ToLower(strings.TrimSpace(strings.Split(r.Header.Get("Content-Type"), ";")[0]))
if _, ok := allowedContentTypes[s]; ok {
next.ServeHTTP(w, r)
return
}
w.WriteHeader(http.StatusUnsupportedMediaType)
})
}
}
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