zip

MODULE

zip

MODULE SUMMARY

Utility for reading and creating 'zip' arhcives.

DESCRIPTION

The zip module archives and extract files to and from a zip archive. The zip format is specified by the "ZIP Appnote.txt" file available on PKWare's website www.pkware.com.

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

By convention, the name of a zip file should end in ".zip". To abide to the convention, you'll need to add ".zip" yourself to the name.

Zip archives are created with the zip/2 or the zip/3 function. (They are also available as create, to resemble the erl_tar module.)

To extract files from a zip archive, use the unzip/1 or the unzip/2 function. (They are also available as extract.)

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

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

In some cases, it is desirable to open a zip archive, and to unzip files from it file by file, without having to reopen the archive. The functions zip_open, zip_get, zip_list_dir and zip_close do this.

LIMITATIONS

Zip64 archives are not currently supported.

Password-protected and encrypted archives are not currently supported

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

The size of the archive is limited to 2 G-byte (32 bits).

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

There is currently no support for altering an existing zip archive. To add or remove a file from an archive, the whole archive must be recreated.

EXPORTS

zip(Name, FileList)
zip(Name, FileList, Options)
create(Name, FileList)
create(Name, FileList, Options)

Types:

Name = filename()
FileList = [FileSpec]
FileSpec = filename() | {filename(), binary()
Options = [Option]
Option = memory | cooked | verbose | {comment, Comment}
Comment = string()
RetValue = ok | {Name, binary} | {error, {Name, Reason}}
Reason = term()

The zip/2 function creates a zip archive containing the files specified in FileList. The zip/3 function provides options.

As synonyms, the functions create/2 and create/3 are provided, to make it resemble the erl_tar module.

The file-list is a list of files, with paths relative to the current directory, they will be stored with this path in the archive. Files may also be specified with data in binaries, to create an archive directly from data.

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

The following options are available:

cooked: By default, the open/2 function will open 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 will override the default and open the zip file without the raw option. The same goes for the files added.
verbose: Print an informational message about each file being added.
memory: The output will not be to a file, but instead as a tuple {FileName, binary()}. The binary will be a full zip archive with header, and can be extracted with for instance unzip/2.
{comment, Comment}: Add a comment to the zip-archive.

unzip(Archive) -> RetValue
unzip(Archive, Options) -> RetValue
extract(Archive) -> RetValue
extract(Archive, Options) -> RetValue

Types:

Name = filename() | binary()
Options = [Option]
Option = {files, FileList} | keep_old_files | verbose | memory | {file_filter, FileFilter}
FileList = [filename()]
FileFilter = fun(ZipFile) -> true | false
ZipFile = #zip_file
RetValue = ok | {error, Reason} | {error, {Name, Reason}}
Reason = term()

The unzip/1 function extracts all files from a zip archive. The unzip/2 function provides options to extract some files, and more.

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

The following options are available:

{files, FileList}: By default, all files will be extracted from the zip archive. With the {files,Files} option, the unzip/2 function will only extract the files whose names are included in FileList.
cooked: By default, the open/2 function will open 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 will override the default and open zip file without the raw option. The same goes for the files extracted.
keep_old_files: By default, all existing files with the same name as file in the zip archive will be overwritten. With the keep_old_files option, the unzip/2 function will not overwrite any existing files. Not that even with the memory option given, which means that no files will be overwritten, files existing will be excluded from the result.
verbose: Print an informational message as each file is being extracted.

list_dir(Archive) -> RetValue
list_dir(Archive, Options)
table(Archive) -> RetValue
table(Archive, Options)

Types:

Name = filename() | binary()
RetValue = {ok, [Comment, Files]} | {error, Reason}
Options = [Option]
Option = cooked
Reason = term()

The list_dir/1 function retrieves the names of all files in the zip archive Archive. The list_dir/2 function provides options.

As synonyms, the functions table/2 and table/3 are provided, to make it resemble the erl_tar module.

The result value is the tuple {ok, List}, where List contains the zip archive comment as the first element. The rest is tuples: {filename(), fileinfo(), CompSize, Comment}, where CompSize is the compressed size of the file in the archive and Comment is the files comment.

The following options are available:

cooked: By default, the open/2 function will open 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 will override the default and open zip file without the raw option.

t(Archive)

Types:

Archive = filename() | binary() | ZipHandle
ZipHandle = pid()

The t/1 function prints the names of all files in the zip archive Archive to the Erlang shell. (Similar to "tar t".)

tt(Archive)

Types:

Name = filename() | binary()

The tt/1 function prints names and information about all files in the zip archive Archive to the Erlang shell. (Similar to "tar tv".)

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

Types:

Name = filename() | binary()
Options = [Option]
Options = cooked | memory
ZipHandle = pid()

The zip_open function opens a zip archive, and reads and saves its directory. This means that subsequently reading files from the archive will be faster than unzipping files one at a time with unzip.

The archive must be closed with zip_close/1.

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

Types:

Result = [ZipComment, ZipFile...]
ZipComment = #zip_comment{}
ZipFile = #zip_file{}
ZipHandle = pid()

The zip_list_dir/1 function returns the file list of an open zip archive.

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

Types:

Name = filename() | binary() | ZipHandle
ZipHandle = pid()

The zip_get function extracts one or all files from an open archive.

The files will be unzipped to memory or to file, depending on the options given to the zip_open function when the archive was opened.

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

Types:

ZipHandle = pid()

The zip_close/1 function closes a zip archive, previously opened with zip_open. All resources are closed, and the handle should not be used after closing.

AUTHORS

Jakob Cederlund - support@erlang.ericsson.se