zip

Utility for reading and creating 'zip' archives.

This module archives and extracts files to and from a zip archive. The zip format is specified by the "ZIP Appnote.txt" file, available on the PKWARE web site www.pkware.com.

The zip module supports zip archive versions up to 6.1. However, password-protection and Zip64 are not supported.

By convention, the name of a zip file is to end with .zip. To abide to the convention, add .zip to the filename.

To create zip archives, use function zip/2 or zip/3. They are also available as create/2,3, to resemble the erl_tar module.

To extract files from a zip archive, use function unzip/1 or unzip/2. They are also available as extract/1,2, to resemble the erl_tar module.

To fold a function over all files in a zip archive, use function foldl/3.

To return a list of the files in a zip archive, use function list_dir/1 or list_dir/2. They are also available as table/1,2, to resemble the erl_tar module.

To print a list of files to the Erlang shell, use function t/1 or tt/1.

Sometimes it is desirable to open a zip archive, and to unzip files from it file by file, without having to reopen the archive. This can be done by functions zip_open/1,2, zip_get/1,2, zip_list_dir/1, and zip_close/1.

Limitations

Zip64 archives are not supported.

Password-protected and encrypted archives are not supported.

Only the DEFLATE (zlib-compression) and the STORE (uncompressed data) zip methods are supported.

The archive size is limited to 2 GB (32 bits).

Comments for individual files are not supported when creating zip archives. The zip archive comment for the whole zip archive is supported.

Changing a zip archive is not supported. To add or remove a file from an archive, the whole archive must be recreated.

Types

zip_comment() = #zip_comment{comment = string()}

The record zip_comment only contains the archive comment for a zip archive.

zip_file() =
            #zip_file{name = string(),
                      info = file:file_info(),
                      comment = string(),
                      offset = integer() >= 0,
                      comp_size = integer() >= 0}

The record zip_file contains the following fields:

name

The filename
info

File information as in file:read_file_info/1 in Kernel
comment

The comment for the file in the zip archive
offset

The file offset in the zip archive (used internally)
comp_size

The size of the compressed file (the size of the uncompressed file is found in info)

filename() = file:filename()

The name of a zip file.

extension() = string()

extension_spec() =
            all |
            [extension()] |
            {add, [extension()]} |
            {del, [extension()]}

create_option() =
            memory | cooked | verbose |
            {comment, string()} |
            {cwd, file:filename()} |
            {compress, extension_spec()} |
            {uncompress, extension_spec()}

These options are described in create/3.

handle()

As returned by zip_open/2.

Functions

foldl(Fun, Acc0, Archive) -> {ok, Acc1} | {error, Reason}

  • Fun = fun((FileInArchive, GetInfo, GetBin, AccIn) -> AccOut)
  • FileInArchive = file:name()
  • GetInfo = fun(() -> file:file_info())
  • GetBin = fun(() -> binary())
  • Acc0 = Acc1 = AccIn = AccOut = term()
  • Archive = file:name() | {file:name(), binary()}
  • Reason = term()

Calls Fun(FileInArchive, GetInfo , GetBin, AccIn) on successive files in the Archive, starting with AccIn == Acc0.

FileInArchive is the name that the file has in the archive.

GetInfo is a fun that returns information about the file.

GetBin returns the file contents.

Both GetInfo and GetBin must be called within the Fun. Their behavior is undefined if they are called outside the context of Fun.

The Fun must return a new accumulator, which is passed to the next call. foldl/3 returns the final accumulator value. Acc0 is returned if the archive is empty. It is not necessary to iterate over all files in the archive. The iteration can be ended prematurely in a controlled manner by throwing an exception.

Example:

> Name = "dummy.zip".
"dummy.zip"
> {ok, {Name, Bin}} = zip:create(Name, [{"foo", <<"FOO">>}, {"bar", <<"BAR">>}], [memory]).
{ok,{"dummy.zip",
     <<80,75,3,4,20,0,0,0,0,0,74,152,97,60,171,39,212,26,3,0,
       0,0,3,0,0,...>>}}
> {ok, FileSpec} = zip:foldl(fun(N, I, B, Acc) -> [{N, B(), I()} | Acc] end, [], {Name, Bin}).
{ok,[{"bar",<<"BAR">>,
      {file_info,3,regular,read_write,
                 {{2010,3,1},{19,2,10}},
                 {{2010,3,1},{19,2,10}},
                 {{2010,3,1},{19,2,10}},
                 54,1,0,0,0,0,0}},
     {"foo",<<"FOO">>,
      {file_info,3,regular,read_write,
                 {{2010,3,1},{19,2,10}},
                 {{2010,3,1},{19,2,10}},
                 {{2010,3,1},{19,2,10}},
                 54,1,0,0,0,0,0}}]}
> {ok, {Name, Bin}} = zip:create(Name, lists:reverse(FileSpec), [memory]).
{ok,{"dummy.zip",
     <<80,75,3,4,20,0,0,0,0,0,74,152,97,60,171,39,212,26,3,0,
       0,0,3,0,0,...>>}}
> catch zip:foldl(fun("foo", _, B, _) -> throw(B()); (_,_,_,Acc) -> Acc end, [], {Name, Bin}). 
<<"FOO">>

list_dir(Archive) -> RetValue

list_dir(Archive, Options) -> RetValue

  • Archive = file:name() | binary()
  • RetValue = {ok, CommentAndFiles} | {error, Reason :: term()}
  • CommentAndFiles = [zip_comment() | zip_file()]
  • Options = [Option]
  • Option = cooked

table(Archive) -> RetValue

table(Archive, Options) -> RetValue

  • Archive = file:name() | binary()
  • RetValue = {ok, CommentAndFiles} | {error, Reason :: term()}
  • CommentAndFiles = [zip_comment() | zip_file()]
  • Options = [Option]
  • Option = cooked

list_dir/1 retrieves all filenames in the zip archive Archive.

list_dir/2 provides options.

table/1 and table/2 are provided as synonyms to resemble the erl_tar module.

The result value is the tuple {ok, List}, where List contains the zip archive comment as the first element.

One option is available:

cooked

By default, this function opens the zip file in raw mode, which is faster but does not allow a remote (Erlang) file server to be used. Adding cooked to the mode list overrides the default and opens the zip file without option raw.

t(Archive) -> ok

Prints all filenames in the zip archive Archive to the Erlang shell. (Similar to tar t.)

tt(Archive) -> ok

Prints filenames and information about all files in the zip archive Archive to the Erlang shell. (Similar to tar tv.)

unzip(Archive) -> RetValue

  • Archive = file:name() | binary()
  • RetValue =
        {ok, FileList} |
        {ok, FileBinList} |
        {error, Reason :: term()} |
        {error, {Name :: file:name(), Reason :: term()}}
  • FileList = [file:name()]
  • FileBinList = [{file:name(), binary()}]

unzip(Archive, Options) -> RetValue

  • Archive = file:name() | binary()
  • Options = [Option]
  • Option =
        {file_list, FileList} |
        cooked | keep_old_files | verbose | memory |
        {file_filter, FileFilter} |
        {cwd, CWD}
  • FileList = [file:name()]
  • FileBinList = [{file:name(), binary()}]
  • FileFilter = fun((ZipFile) -> boolean())
  • CWD = file:filename()
  • ZipFile = zip_file()
  • RetValue =
        {ok, FileList} |
        {ok, FileBinList} |
        {error, Reason :: term()} |
        {error, {Name :: file:name(), Reason :: term()}}

extract(Archive) -> RetValue

  • Archive = file:name() | binary()
  • RetValue =
        {ok, FileList} |
        {ok, FileBinList} |
        {error, Reason :: term()} |
        {error, {Name :: file:name(), Reason :: term()}}
  • FileList = [file:name()]
  • FileBinList = [{file:name(), binary()}]

extract(Archive, Options) -> RetValue

  • Archive = file:name() | binary()
  • Options = [Option]
  • Option =
        {file_list, FileList} |
        keep_old_files | verbose | memory |
        {file_filter, FileFilter} |
        {cwd, CWD}
  • FileList = [file:name()]
  • FileBinList = [{file:name(), binary()}]
  • FileFilter = fun((ZipFile) -> boolean())
  • CWD = file:filename()
  • ZipFile = zip_file()
  • RetValue =
        {ok, FileList} |
        {ok, FileBinList} |
        {error, Reason :: term()} |
        {error, {Name :: file:name(), Reason :: term()}}

unzip/1 extracts all files from a zip archive.

unzip/2 provides options to extract some files, and more.

extract/1 and extract/2 are provided as synonyms to resemble module erl_tar.

If argument Archive is specified as a binary, the contents of the binary is assumed to be a zip archive, otherwise a filename.

Options:

{file_list, FileList}

By default, all files are extracted from the zip archive. With option {file_list, FileList}, function unzip/2 only extracts the files whose names are included in FileList. The full paths, including the names of all subdirectories within the zip archive, must be specified.
cooked

By default, this function opens the zip file in raw mode, which is faster but does not allow a remote (Erlang) file server to be used. Adding cooked to the mode list overrides the default and opens the zip file without option raw. The same applies for the files extracted.
keep_old_files

By default, all files with the same name as files in the zip archive are overwritten. With option keep_old_files set, function unzip/2 does not overwrite existing files. Notice that even with option memory specified, which means that no files are overwritten, existing files are excluded from the result.
verbose

Prints an informational message for each extracted file.
memory

Instead of extracting to the current directory, the result is given as a list of tuples {Filename, Binary}, where Binary is a binary containing the extracted data of file Filename in the zip archive.
{cwd, CWD}

Uses the specified directory as current directory. It is prepended to filenames when extracting them from the zip archive. (Acting like file:set_cwd/1 in Kernel, but without changing the global cwd property.)

zip(Name, FileList) -> RetValue

zip(Name, FileList, Options) -> RetValue

  • Name = file:name()
  • FileList = [FileSpec]
  • FileSpec =
        file:name() |
        {file:name(), binary()} |
        {file:name(), binary(), file:file_info()}
  • Options = [Option]
  • Option =
        memory | cooked | verbose |
        {comment, Comment} |
        {cwd, CWD} |
        {compress, What} |
        {uncompress, What}
  • What =
        all | [Extension] | {add, [Extension]} | {del, [Extension]}
  • Extension = Comment = string()
  • CWD = file:filename()
  • RetValue =
        {ok, FileName :: file:name()} |
        {ok, {FileName :: file:name(), binary()}} |
        {error, Reason :: term()}

create(Name, FileList) -> RetValue

create(Name, FileList, Options) -> RetValue

Creates a zip archive containing the files specified in FileList.

create/2 and create/3 are provided as synonyms to resemble module erl_tar.

FileList is a list of files, with paths relative to the current directory, which are stored with this path in the archive. Files can also be specified with data in binaries to create an archive directly from data.

Files are compressed using the DEFLATE compression, as described in the "Appnote.txt" file. However, files are stored without compression if they are already compressed. zip/2 and zip/3 check the file extension to determine if the file is to be stored without compression. Files with the following extensions are not compressed: .Z, .zip, .zoo, .arc, .lzh, .arj.

It is possible to override the default behavior and control what types of files that are to be compressed by using options {compress, What} and {uncompress, What}. It is also possible to use many compress and uncompress options.

To trigger file compression, its extension must match with the compress condition and must not match the uncompress condition. For example, if compress is set to ["gif", "jpg"] and uncompress is set to ["jpg"], only files with extension "gif" are compressed.

Options:

cooked

By default, this function opens the zip file in mode raw, which is faster but does not allow a remote (Erlang) file server to be used. Adding cooked to the mode list overrides the default and opens the zip file without the raw option. The same applies for the files added.
verbose

Prints an informational message about each added file.
memory

The output is not to a file, but instead as a tuple {FileName, binary()}. The binary is a full zip archive with header and can be extracted with, for example, unzip/2.
{comment, Comment}

Adds a comment to the zip archive.
{cwd, CWD}

Uses the specified directory as current work directory (cwd). This is prepended to filenames when adding them, although not in the zip archive (acting like file:set_cwd/1 in Kernel, but without changing the global cwd property.).
{compress, What}

Controls what types of files to be compressed. Defaults to all. The following values of What are allowed:

all

All files are compressed (as long as they pass the uncompress condition).
[Extension]

Only files with exactly these extensions are compressed.
{add,[Extension]}

Adds these extensions to the list of compress extensions.
{del,[Extension]}

Deletes these extensions from the list of compress extensions.
{uncompress, What}

Controls what types of files to be uncompressed. Defaults to [".Z", ".zip", ".zoo", ".arc", ".lzh", ".arj"]. The following values of What are allowed:

all

No files are compressed.
[Extension]

Files with these extensions are uncompressed.
{add,[Extension]}

Adds these extensions to the list of uncompress extensions.
{del,[Extension]}

Deletes these extensions from the list of uncompress extensions.

zip_close(ZipHandle) -> ok | {error, einval}

Closes a zip archive, previously opened with zip_open/1,2. All resources are closed, and the handle is not to be used after closing.

zip_get(ZipHandle) -> {ok, [Result]} | {error, Reason}

zip_get(FileName, ZipHandle) -> {ok, Result} | {error, Reason}

Extracts one or all files from an open archive.

The files are unzipped to memory or to file, depending on the options specified to function zip_open/1,2 when opening the archive.

zip_list_dir(ZipHandle) -> {ok, Result} | {error, Reason}

Returns the file list of an open zip archive. The first returned element is the zip archive comment.

zip_open(Archive) -> {ok, ZipHandle} | {error, Reason}

zip_open(Archive, Options) -> {ok, ZipHandle} | {error, Reason}

Opens a zip archive, and reads and saves its directory. This means that later reading files from the archive is faster than unzipping files one at a time with unzip/1,2.

The archive must be closed with zip_close/1.

The ZipHandle is closed if the process that originally opened the archive dies.