path: root/lib/stdlib/doc/src/zip.xml

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<!DOCTYPE erlref SYSTEM "erlref.dtd">

<erlref>
  <header>
    <copyright>
      <year>2006</year><year>2011</year>
      <holder>Ericsson AB. All Rights Reserved.</holder>
    </copyright>
    <legalnotice>
      The contents of this file are subject to the Erlang Public License,
      Version 1.1, (the "License"); you may not use this file except in
      compliance with the License. You should have received a copy of the
      Erlang Public License along with this software. If not, it can be
      retrieved online at http://www.erlang.org/.

      Software distributed under the License is distributed on an "AS IS"
      basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
      the License for the specific language governing rights and limitations
      under the License.

    </legalnotice>

    <title>zip</title>
    <prepared>Jakob Cederlund</prepared>
    <responsible>Jakob Cederlund</responsible>
    <docno>1</docno>
    <approved></approved>
    <checked></checked>
    <date>05-11-02</date>
    <rev>PA1</rev>
    <file>zip.sgml</file>
  </header>
  <module>zip</module>
  <modulesummary>Utility for reading and creating 'zip' archives.</modulesummary>
  <description>
    <p>The <c>zip</c> module archives and extracts 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.</p>
    <p>The zip module supports zip archive versions up to 6.1. However,
      password-protection and Zip64 are not supported.</p>
    <p>By convention, the name of a zip file should end in "<c>.zip</c>".
      To abide to the convention, you'll need to add "<c>.zip</c>" yourself
      to the name.</p>
    <p>Zip archives are created with the
      <seealso marker="#zip_2">zip/2</seealso> or the
      <seealso marker="#zip_2">zip/3</seealso> function. (They are
      also available as <c>create</c>, to resemble the <c>erl_tar</c>
      module.)</p>
    <p>To extract files from a zip archive, use the
      <seealso marker="#unzip_1">unzip/1</seealso> or the
      <seealso marker="#unzip_2">unzip/2</seealso> function. (They are
      also available as <c>extract</c>.)</p>
    <p>To fold a function over all files in a zip archive, use the
      <seealso marker="#foldl_3">foldl_3</seealso> function.</p>
    <p>To return a list of the files in a zip archive, use the
      <seealso marker="#list_dir_1">list_dir/1</seealso> or the
      <seealso marker="#list_dir_2">list_dir/2</seealso> function. (They
      are also available as <c>table</c>.)</p>
    <p>To print a list of files to the Erlang shell,
      use either the <seealso marker="#t_1">t/1</seealso> or
      <seealso marker="#tt_1">tt/1</seealso> function.</p>
    <p>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
      <seealso marker="#zip_open">zip_open</seealso>,
      <seealso marker="#zip_get">zip_get</seealso>,
      <seealso marker="#zip_list_dir">zip_list_dir</seealso> and
      <seealso marker="#zip_close">zip_close</seealso> do this.</p>
  </description>

  <section>
    <title>LIMITATIONS</title>
    <p>Zip64 archives are not currently supported.</p>
    <p>Password-protected and encrypted archives are not currently
      supported</p>
    <p>Only the DEFLATE (zlib-compression) and the STORE (uncompressed
      data) zip methods are supported.</p>
    <p>The size of the archive is limited to 2 G-byte (32 bits).</p>
    <p>Comments for individual files is not supported when creating zip
      archives. The zip archive comment for the whole zip archive is
      supported.</p>
    <p>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.</p>
  </section>

  <datatypes>
    <datatype>
      <name name="zip_comment"/>
      <desc>
        <p>The record <c>zip_comment</c> just contains the archive comment for
          a zip archive</p>
      </desc>
    </datatype>
    <datatype>
      <name name="zip_file"/>
      <desc>
        <p>The record <c>zip_file</c> contains the following fields.</p>
        <taglist>
          <tag><c>name</c></tag>
          <item>
            <p>the name of the file</p>
          </item>
          <tag><c>info</c></tag>
          <item>
            <p>file info as in
              <seealso marker="kernel:file#read_file_info/1">file:read_file_info/1</seealso></p>
          </item>
          <tag><c>comment</c></tag>
          <item>
            <p>the comment for the file in the zip archive</p>
          </item>
          <tag><c>offset</c></tag>
          <item>
            <p>the offset of the file in the zip archive (used internally)</p>
          </item>
          <tag><c>comp_size</c></tag>
          <item>
            <p>the compressed size of the file (the uncompressed size is found
              in <c>info</c>)</p>
          </item>
        </taglist>
      </desc>
    </datatype>
  </datatypes>
  <funcs>
    <func>
      <name name="zip" arity="2"/>
      <name name="zip" arity="3"/>
      <name name="create" arity="2"/>
      <name name="create" arity="3"/>
      <fsummary>Create a zip archive with options</fsummary>
      <desc>
        <p>The <marker id="zip_2"></marker><c>zip</c> function creates a
          zip archive containing the files specified in <c><anno>FileList</anno></c>.</p>
        <p>As synonyms, the functions <c>create/2</c> and <c>create/3</c>
          are provided, to make it resemble the <c>erl_tar</c> module.</p>
        <p>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.</p>
        <p>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 <c>zip/2</c> and <c>zip/3</c> functions check the file extension
          to see whether the file should be stored without compression.
          Files with the following extensions are not compressed:
          <c>.Z</c>, <c>.zip</c>, <c>.zoo</c>, <c>.arc</c>, <c>.lzh</c>,
          <c>.arj</c>.</p>
        <p>It is possible to override the default behavior and
        explicitly control what types of files that should be
        compressed by using the <c>{compress, <anno>What</anno>}</c> and
        <c>{uncompress, <anno>What</anno>}</c> options. It is possible to have
        several <c>compress</c> and <c>uncompress</c> options. In
        order to trigger compression of a file, its extension must
        match with the
        <c>compress</c> condition and must not match the
        <c>uncompress</c> condition. For example if <c>compress</c> is
        set to <c>["gif", "jpg"]</c> and <c>uncompress</c> is set to
        <c>["jpg"]</c>, only files with <c>"gif"</c> as extension will
        be compressed. No other files will be compressed.</p>
        <p>The following options are available:</p>
        <taglist>
          <tag><c>cooked</c></tag>
          <item>
            <p>By default, the <c>open/2</c> function will open the
              zip file in <c>raw</c> mode, which is faster but does not allow
              a remote (erlang) file server to be used. Adding <c>cooked</c>
              to the mode list will override the default and open the zip file
              without the <c>raw</c> option. The same goes for the files
              added.</p>
          </item>
          <tag><c>verbose</c></tag>
          <item>
            <p>Print an informational message about each file
              being added.</p>
          </item>
          <tag><c>memory</c></tag>
          <item>
            <p>The output will not be to a file, but instead as a tuple
              <c>{<anno>FileName</anno>, binary()}</c>. The binary will be a full zip
              archive with header, and can be extracted with for instance
              <c>unzip/2</c>.</p>
          </item>
          <tag><c>{comment, <anno>Comment</anno>}</c></tag>
          <item>
            <p>Add a comment to the zip-archive.</p>
          </item>
          <tag><c>{cwd, <anno>CWD</anno>}</c></tag>
          <item>
            <p>Use the given directory as current directory, it will be
              prepended to file names when adding them, although it will not
              be in the zip-archive. (Acting like a file:set_cwd/1, but
              without changing the global cwd property.)</p>
          </item>
          <tag><c>{compress, <anno>What</anno>}</c></tag>
          <item>
            <p>Controls what types of files will be
            compressed. It is by default set to <c>all</c>. The
            following values of <c>What</c> are allowed:</p>
	      <taglist>
	            <tag><c>all</c></tag>
		    <item><p> means that all files will be compressed (as long
		       as they pass the <c>uncompress</c> condition).</p></item>
		    <tag><c>[<anno>Extension</anno>]</c></tag>
		    <item><p>means that only files with exactly these extensions
		     will be compressed.</p></item>
	            <tag><c>{add,[<anno>Extension</anno>]}</c></tag>
		    <item><p>adds these extensions to the list of compress
		     extensions.</p></item>
	            <tag><c>{del,[<anno>Extension</anno>]}</c></tag>
		    <item><p>deletes these extensions from the list of compress
		     extensions.</p></item>
	      </taglist>
	  </item>
          <tag><c>{uncompress, <anno>What</anno>}</c></tag>
          <item>
            <p>Controls what types of files will be uncompressed. It is by
            default set to <c>[".Z", ".zip", ".zoo", ".arc", ".lzh", ".arj"]</c>.
	    The following values of <c>What</c> are allowed:</p>
	      <taglist>
	            <tag><c>all</c></tag>
		    <item><p> means that no files will be compressed.</p></item>
		    <tag><c>[<anno>Extension</anno>]</c></tag>
		    <item><p>means that files with these extensions will be
		    uncompressed.</p></item>
	            <tag><c>{add,[<anno>Extension</anno>]}</c></tag>
		    <item><p>adds these extensions to the list of uncompress
		     extensions.</p></item>
	            <tag><c>{del,[<anno>Extension</anno>]}</c></tag>
		    <item><p>deletes these extensions from the list of uncompress
		     extensions.</p></item>
	      </taglist>
	  </item>
        </taglist>
      </desc>
    </func>
    <func>
      <name name="unzip" arity="1"/>
      <name name="unzip" arity="2"/>
      <name name="extract" arity="1"/>
      <name name="extract" arity="2"/>
      <fsummary>Extract files from a zip archive</fsummary>
      <desc>
        <p>The <marker id="unzip_1"></marker><c>unzip/1</c> function extracts
          all files from a zip archive.
          The <marker id="unzip_2"></marker><c>unzip/2</c> function provides
           options to extract some files, and more.</p>
        <p>If the <c><anno>Archive</anno></c> argument is given as a binary,
          the contents of the binary is assumed to be a zip archive,
          otherwise it should be a filename.</p>
        <p>The following options are available:</p>
        <taglist>
          <tag><c>{file_list, <anno>FileList</anno>}</c></tag>
          <item>
            <p>By default, all files will be extracted from the zip
              archive. With the <c>{file_list, <anno>FileList</anno>}</c> option,
              the <c>unzip/2</c> function will only extract the files
              whose names are included in <c><anno>FileList</anno></c>. The full
              paths, including the names of all sub directories within
              the zip archive, must be specified.</p>
          </item>
          <tag><c>cooked</c></tag>
          <item>
            <p>By default, the <c>open/2</c> function will open the
              zip file in <c>raw</c> mode, which is faster but does not allow
              a remote (erlang) file server to be used. Adding <c>cooked</c>
              to the mode list will override the default and open the zip file
              without the <c>raw</c> option. The same goes for the files
              extracted.</p>
          </item>
          <tag><c>keep_old_files</c></tag>
          <item>
            <p>By default, all existing files with the same name as file in
              the zip archive will be overwritten. With the <c>keep_old_files</c>
              option, the <c>unzip/2</c> function will not overwrite any existing
              files. Note that even with the <c>memory</c> option given, which
              means that no files will be overwritten, files existing will be
              excluded from the result.</p>
          </item>
          <tag><c>verbose</c></tag>
          <item>
            <p>Print an informational message as each file is being
              extracted.</p>
          </item>
          <tag><c>memory</c></tag>
          <item>
            <p>Instead of extracting to the current directory, the
              <c>memory</c> option will give the result as a list of tuples
              <c>{Filename, Binary}</c>, where <c>Binary</c> is a binary
              containing the extracted data of the file named <c>Filename</c>
              in the zip archive.</p>
          </item>
          <tag><c>{cwd, CWD}</c></tag>
          <item>
            <p>Use the given directory as current directory, it will be
              prepended to file names when extracting them from the
              zip-archive. (Acting like a file:set_cwd/1, but without
              changing the global cwd property.)</p>
          </item>
        </taglist>
      </desc>
    </func>
    <func>
      <name name="foldl" arity="3"/>
      <fsummary>Fold a function over all files in a zip archive</fsummary>
      <desc>
        <p>The <marker id="foldl_3"></marker> <c>foldl/3</c> function
        calls <c><anno>Fun</anno>(<anno>FileInArchive</anno>, <anno>GetInfo
        </anno>, <anno>GetBin</anno>, <anno>AccIn</anno>)</c> on
        successive files in the <c>Archive</c>, starting with
        <c><anno>AccIn</anno>
        == <anno>Acc0</anno></c>. <c><anno>FileInArchive</anno></c> is
        the name that the file
        has in the archive. <c><anno>GetInfo</anno></c> is a fun that
        returns info
        about the the file. <c><anno>GetBin</anno></c> returns the contents
        of the
        file. Both <c><anno>GetInfo</anno></c> and <c><anno>GetBin</anno></c>
        must be called
        within the <c><anno>Fun</anno></c>. Their behavior is undefined if
        they are
        called outside the context of the <c><anno>Fun</anno></c>.
        The <c><anno>Fun</anno></c>
        must return a new accumulator which is passed to the next
        call. <c>foldl/3</c> returns the final value of the
        accumulator. <c><anno>Acc0</anno></c> is returned if the archive is
        empty. It is not necessary to iterate over all files in the
        archive. The iteration may be ended prematurely in a
        controlled manner by throwing an exception.</p>

	<p>For example:</p>
        <pre>
&gt; <input>Name = "dummy.zip".</input>
"dummy.zip"
&gt; <input>{ok, {Name, Bin}} = zip:create(Name, [{"foo", &lt;&lt;"FOO"&gt;&gt;}, {"bar", &lt;&lt;"BAR"&gt;&gt;}], [memory]).</input>
{ok,{"dummy.zip",
     &lt;&lt;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,...&gt;&gt;}}
&gt; <input>{ok, FileSpec} = zip:foldl(fun(N, I, B, Acc) -> [{N, B(), I()} | Acc] end, [], {Name, Bin}).</input>
{ok,[{"bar",&lt;&lt;"BAR"&gt;&gt;,
      {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",&lt;&lt;"FOO"&gt;&gt;,
      {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}}]}
&gt; <input>{ok, {Name, Bin}} = zip:create(Name, lists:reverse(FileSpec), [memory]).</input>
{ok,{"dummy.zip",
     &lt;&lt;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,...&gt;&gt;}}
&gt; <input>catch zip:foldl(fun("foo", _, B, _) -> throw(B()); (_,_,_,Acc) -> Acc end, [], {Name, Bin}). </input>
&lt;&lt;"FOO"&gt;&gt;
</pre>
      </desc>
    </func>
    <func>
      <name name="list_dir" arity="1"/>
      <name name="list_dir" arity="2"/>
      <name name="table" arity="1" />
      <name name="table" arity="2"/>
      <fsummary>Retrieve the name of all files in a zip archive</fsummary>
      <desc>
        <p>The <marker id="list_dir_1"></marker><c>list_dir/1</c>
          function retrieves the names of all files in the zip archive
          <c><anno>Archive</anno></c>. The <marker id="list_dir_2"></marker>
          <c>list_dir/2</c> function provides options.</p>
        <p>As synonyms, the functions <c>table/2</c> and <c>table/3</c>
          are provided, to make it resemble the <c>erl_tar</c> module.</p>
        <p>The result value is the tuple <c>{ok, List}</c>, where <c>List</c>
          contains the zip archive comment as the first element.</p>
        <p>The following options are available:</p>
        <taglist>
          <tag><c>cooked</c></tag>
          <item>
            <p>By default, the <c>open/2</c> function will open the
              zip file in <c>raw</c> mode, which is faster but does not allow
              a remote (erlang) file server to be used. Adding <c>cooked</c>
              to the mode list will override the default and open the zip file
              without the <c>raw</c> option.</p>
          </item>
        </taglist>
      </desc>
    </func>
    <func>
      <name name="t" arity="1"/>
      <fsummary>Print the name of each file in a zip archive</fsummary>
      <desc>
        <p>The <marker id="t_1"></marker><c>t/1</c> function prints the names
          of all files in the zip archive <c><anno>Archive</anno></c> to the Erlang shell.
          (Similar to "<c>tar&nbsp;t</c>".)</p>
      </desc>
    </func>
    <func>
      <name name="tt" arity="1"/>
      <fsummary>Print name and information for each file in a zip archive</fsummary>
      <desc>
        <p>The <marker id="tt_1"></marker><c>tt/1</c> function prints names and
          information about all files in the zip archive <c><anno>Archive</anno></c> to
          the Erlang shell. (Similar to "<c>tar tv</c>".)</p>
      </desc>
    </func>
    <func>
      <name name="zip_open" arity="1"/>
      <name name="zip_open" arity="2"/>
      <fsummary>Open an archive and return a handle to it</fsummary>
      <desc>
        <p>The <marker id="zip_open"></marker><c>zip_open</c> 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 <c>unzip</c>.</p>
        <p>The archive must be closed with <c>zip_close/1</c>.</p>
      </desc>
    </func>
    <func>
      <name name="zip_list_dir" arity="1"/>
      <fsummary>Return a table of files in open zip archive</fsummary>
      <desc>
        <p>The <marker id="zip_list_dir"></marker>
          <c>zip_list_dir/1</c> function
          returns the file list of an open zip archive. The first returned
          element is the zip archive comment.</p>
      </desc>
    </func>
    <func>
      <name name="zip_get" arity="1"/>
      <name name="zip_get" arity="2"/>
      <fsummary>Extract files from an open archive</fsummary>
      <desc>
        <p>The <marker id="zip_get"></marker><c>zip_get</c> function extracts
          one or all files from an open archive.</p>
        <p>The files will be unzipped to memory or to file, depending on
          the options given to the <c>zip_open</c> function when the
          archive was opened.</p>
      </desc>
    </func>
    <func>
      <name name="zip_close" arity="1"/>
      <fsummary>Close an open archive</fsummary>
      <desc>
        <p>The <marker id="zip_close"></marker><c>zip_close/1</c> function
          closes a zip archive, previously opened with <c>zip_open</c>. All
          resources are closed, and the handle should not be used after
          closing.</p>
      </desc>
    </func>
  </funcs>
</erlref>