init

godl/godl.go

@@ -0,0 +1,90 @@
+// Package godl provides utilities for serving files over HTTP, with MIME type
+// inference and support for setting Content-Disposition headers to control
+// whether files are served inline or as attachments.
+package godl
+
+import (
+	"mime"
+	"net/http"
+	"net/url"
+	"path/filepath"
+
+	"github.com/gabriel-vasile/mimetype"
+)
+
+// Infer returns the MIME type of the file specified by the given path. It
+// first attempts to determine the MIME type using InferByMagic, and if
+// unsuccessful, it falls back to InferByExtension.
+func Infer(path string) string {
+	m := InferByMagic(path)
+	if m == "" {
+		return InferByExtension(path)
+	}
+	return m
+}
+
+// InferByExtension returns the MIME type of the file specified by the given
+// path using the file extension, or an empty string if no match is found.
+func InferByExtension(path string) string {
+	return mime.TypeByExtension(filepath.Ext(path))
+}
+
+// InferByMagic returns the MIME type of the file specified by the given
+// path using the mimetype module, or an empty string if no match is found.
+func InferByMagic(path string) string {
+	if m, err := mimetype.DetectFile(path); err == nil {
+		return m.String()
+	}
+	return ""
+}
+
+// SetContentType sets the Content-Type header for the file specified by the
+// given path, inferred using the provided infer function.
+func SetContentType(w http.ResponseWriter, path string, infer func(string) string) {
+	m := infer(path)
+	if m == "" {
+		m = "application/octet-stream"
+	}
+	w.Header().Set("Content-Type", m)
+}
+
+// SetAttachment sets the Content-Disposition header to inform the client
+// that the file is an attachment, specifying the name of the file.
+func SetAttachment(w http.ResponseWriter, name string) {
+	w.Header().Set(
+		"Content-Disposition",
+		"attachment; filename*=UTF-8''"+url.QueryEscape(name),
+	)
+}
+
+// ServeAttachment serves a file with the specified name and path, setting
+// the Content-Type header using the provided infer function and marking it as
+// an attachment by setting the Content-Disposition header.
+func ServeAttachment(w http.ResponseWriter, r *http.Request, path string, name string, infer func(string) string) {
+	SetContentType(w, path, infer)
+	SetAttachment(w, name)
+	http.ServeFile(w, r, path)
+}
+
+// ServeDownload serves a file with the specified name and path, setting the
+// Content-Type header using the provided infer function and determining
+// whether to show the file inline based on the list of inline types. If the
+// list is empty, all content types are treated as inline. Additionally, it
+// sets the Content-Disposition header accordingly.
+func ServeDownload(w http.ResponseWriter, r *http.Request, path string, name string, inlineTypes []string, infer func(string) string) {
+	SetContentType(w, path, infer)
+
+	inline := len(inlineTypes) == 0
+	for _, it := range inlineTypes {
+		if it == w.Header().Get("Content-Type") {
+			inline = true
+			break
+		}
+	}
+
+	if !inline {
+		SetAttachment(w, name)
+	}
+
+	http.ServeFile(w, r, path)
+}