README.md
1# zipextra
2
3[](http://godoc.org/github.com/saracen/zipextra)
4
5`zipextra` is a library for encoding and decoding ZIP archive format's
6"Extra Fields".
7
8The intention is to eventually support and provide a low-level API for the
9majority of PKWARE's and Info-ZIP's extra fields.
10
11Contributions are welcome.
12
13## Supported Fields
14
15| Identifier | Name |
16| ---------- | -------------------------- |
17| `0x000a` | NTFS |
18| `0x6375` | Info-ZIP's Unicode Comment |
19| `0x7875` | Info-ZIP's New Unix |
20
21### Example
22
23```
24func ExampleZipExtra() {
25 // create temporary file
26 w, err := ioutil.TempFile("", "zipextra-example")
27 if err != nil {
28 panic(err)
29 }
30
31 // create new zip writer
32 zw := zip.NewWriter(w)
33
34 // create a new zip file header
35 fh := &zip.FileHeader{Name: "test_file.txt"}
36
37 // add some extra fields
38 fh.Extra = append(fh.Extra, zipextra.NewInfoZIPNewUnix(big.NewInt(1000), big.NewInt(1000)).Encode()...)
39 fh.Extra = append(fh.Extra, zipextra.NewInfoZIPUnicodeComment("Hello, 世界").Encode()...)
40
41 // create the file
42 fw, err := zw.CreateHeader(fh)
43 if err != nil {
44 panic(err)
45 }
46 fw.Write([]byte("foobar"))
47 zw.Close()
48
49 // open the newly created zip
50 zr, err := zip.OpenReader(w.Name())
51 if err != nil {
52 panic(err)
53 }
54 defer zr.Close()
55
56 // parse extra fields
57 fields, err := zipextra.Parse(zr.File[0].Extra)
58 if err != nil {
59 panic(err)
60 }
61
62 // print extra field information
63 for id, field := range fields {
64 switch id {
65 case zipextra.ExtraFieldUnixN:
66 unix, _ := field.InfoZIPNewUnix()
67 fmt.Printf("UID: %d, GID: %d\n", unix.Uid, unix.Gid)
68
69 case zipextra.ExtraFieldUCom:
70 ucom, _ := field.InfoZIPUnicodeComment()
71 fmt.Printf("Comment: %s\n", ucom.Comment)
72 }
73 }
74 // Output:
75 // UID: 1000, GID: 1000
76 // Comment: Hello, 世界
77}
78```
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