type_unix.go

     1  // Copyright 2010 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  //go:build aix || darwin || dragonfly || freebsd || (js && wasm) || linux || netbsd || openbsd || solaris
     6  
     7  package mime
     8  
     9  import (
    10  	"bufio"
    11  	"os"
    12  	"strings"
    13  )
    14  
    15  func init() {
    16  	osInitMime = initMimeUnix
    17  }
    18  
    19  // See https://specifications.freedesktop.org/shared-mime-info-spec/shared-mime-info-spec-0.21.html
    20  // for the FreeDesktop Shared MIME-info Database specification.
    21  var mimeGlobs = []string{
    22  	"/usr/local/share/mime/globs2",
    23  	"/usr/share/mime/globs2",
    24  }
    25  
    26  // Common locations for mime.types files on unix.
    27  var typeFiles = []string{
    28  	"/etc/mime.types",
    29  	"/etc/apache2/mime.types",
    30  	"/etc/apache/mime.types",
    31  	"/etc/httpd/conf/mime.types",
    32  }
    33  
    34  func loadMimeGlobsFile(filename string) error {
    35  	f, err := os.Open(filename)
    36  	if err != nil {
    37  		return err
    38  	}
    39  	defer f.Close()
    40  
    41  	scanner := bufio.NewScanner(f)
    42  	for scanner.Scan() {
    43  		// Each line should be of format: weight:mimetype:*.ext
    44  		fields := strings.Split(scanner.Text(), ":")
    45  		if len(fields) < 3 || len(fields[0]) < 1 || len(fields[2]) < 2 {
    46  			continue
    47  		} else if fields[0][0] == '#' || fields[2][0] != '*' {
    48  			continue
    49  		}
    50  
    51  		extension := fields[2][1:]
    52  		if _, ok := mimeTypes.Load(extension); ok {
    53  			// We've already seen this extension.
    54  			// The file is in weight order, so we keep
    55  			// the first entry that we see.
    56  			continue
    57  		}
    58  
    59  		setExtensionType(extension, fields[1])
    60  	}
    61  	if err := scanner.Err(); err != nil {
    62  		panic(err)
    63  	}
    64  	return nil
    65  }
    66  
    67  func loadMimeFile(filename string) {
    68  	f, err := os.Open(filename)
    69  	if err != nil {
    70  		return
    71  	}
    72  	defer f.Close()
    73  
    74  	scanner := bufio.NewScanner(f)
    75  	for scanner.Scan() {
    76  		fields := strings.Fields(scanner.Text())
    77  		if len(fields) <= 1 || fields[0][0] == '#' {
    78  			continue
    79  		}
    80  		mimeType := fields[0]
    81  		for _, ext := range fields[1:] {
    82  			if ext[0] == '#' {
    83  				break
    84  			}
    85  			setExtensionType("."+ext, mimeType)
    86  		}
    87  	}
    88  	if err := scanner.Err(); err != nil {
    89  		panic(err)
    90  	}
    91  }
    92  
    93  func initMimeUnix() {
    94  	for _, filename := range mimeGlobs {
    95  		if err := loadMimeGlobsFile(filename); err == nil {
    96  			return // Stop checking more files if mimetype database is found.
    97  		}
    98  	}
    99  
   100  	// Fallback if no system-generated mimetype database exists.
   101  	for _, filename := range typeFiles {
   102  		loadMimeFile(filename)
   103  	}
   104  }
   105  
   106  func initMimeForTests() map[string]string {
   107  	mimeGlobs = []string{""}
   108  	typeFiles = []string{"testdata/test.types"}
   109  	return map[string]string{
   110  		".T1":  "application/test",
   111  		".t2":  "text/test; charset=utf-8",
   112  		".png": "image/png",
   113  	}
   114  }
   115
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