github.com/blend/go-sdk@v1.20220411.3/webutil/detect_content_type.go (about)

     1  /*
     2  
     3  Copyright (c) 2022 - Present. Blend Labs, Inc. All rights reserved
     4  Use of this source code is governed by a MIT license that can be found in the LICENSE file.
     5  
     6  */
     7  
     8  package webutil
     9  
    10  import (
    11  	"net/http"
    12  	"os"
    13  	"path/filepath"
    14  
    15  	"github.com/blend/go-sdk/ex"
    16  )
    17  
    18  // KnownExtenions are known extenions mapped to their content types.
    19  var (
    20  	KnownExtensions = map[string]string{
    21  		".html": "text/html; charset=utf-8",
    22  		".xml":  "text/xml; charset",
    23  		".json": "application/json; charset=utf-8",
    24  		".css":  "text/css; charset=utf-8",
    25  		".js":   "application/javascript",
    26  		".jpg":  "image/jpeg",
    27  		".jpeg": "image/jpeg",
    28  		".png":  "image/png",
    29  	}
    30  )
    31  
    32  // DetectContentType generates the content type of a given file by path.
    33  func DetectContentType(path string) (string, error) {
    34  	if contentType, ok := KnownExtensions[filepath.Ext(path)]; ok {
    35  		return contentType, nil
    36  	}
    37  
    38  	f, err := os.Open(path)
    39  	if err != nil {
    40  		return "", ex.New(err)
    41  	}
    42  	defer f.Close()
    43  	header := make([]byte, 512)
    44  	_, err = f.Read(header)
    45  	if err != nil {
    46  		return "", ex.New(err)
    47  	}
    48  	return http.DetectContentType(header), nil
    49  }