43 lines
1.4 KiB
Go
43 lines
1.4 KiB
Go
package util
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import (
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"net/http"
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"strings"
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)
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// ContentTypeWriter is an implementation of http.ResponseWriter that will detect the content type and set the
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// Content-Type and (optionally) Content-Disposition headers accordingly.
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//
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// It will always set a Content-Type based on http.DetectContentType, but will never send the "text/html"
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// content type.
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type ContentTypeWriter struct {
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w http.ResponseWriter
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filename string
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sniffed bool
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}
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// NewContentTypeWriter creates a new ContentTypeWriter
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func NewContentTypeWriter(w http.ResponseWriter, filename string) *ContentTypeWriter {
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return &ContentTypeWriter{w, filename, false}
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}
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func (w *ContentTypeWriter) Write(p []byte) (n int, err error) {
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if w.sniffed {
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return w.w.Write(p)
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}
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// Detect and set Content-Type header
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// Fix content types that we don't want to inline-render in the browser. In particular,
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// we don't want to render HTML in the browser for security reasons.
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contentType, _ := DetectContentType(p, w.filename)
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if strings.HasPrefix(contentType, "text/html") {
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contentType = strings.ReplaceAll(contentType, "text/html", "text/plain")
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} else if contentType == "application/octet-stream" {
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contentType = "" // Reset to let downstream http.ResponseWriter take care of it
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}
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if contentType != "" {
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w.w.Header().Set("Content-Type", contentType)
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}
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w.sniffed = true
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return w.w.Write(p)
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}
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