Archive Module

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This XQuery Module contains functions to handle archives (including ePub, Open Office, JAR, and many other formats). New ZIP and GZIP archives can be created, existing archives can be updated, and the archive entries can be listed and extracted. The archive:extract-binary function includes an example for writing the contents of an archive to disk.

Conventions[edit]

All functions and errors in this module are assigned to the http://basex.org/modules/archive namespace, which is statically bound to the archive prefix.

Content Handling[edit]

archive:entries[edit]

Signature
archive:entries(
  $archive  as xs:base64Binary
) as element(archive:entry)*
Summary Returns the entry descriptors of the specified $archive. A descriptor contains the following attributes, provided that they are available in the archive format:
  • size: original file size
  • last-modified: timestamp, formatted as xs:dateTime
  • compressed-size: compressed file size

An example:

<archive:entry size="1840" last-modified="2009-03-20T03:30:32" compressed-size="672">
  doc/index.html
</archive:entry>
Errors error: archive creation failed.
Examples Sums up the file sizes of all entries of a JAR file:
sum(archive:entries(file:read-binary('zip.zip'))/@size)

archive:options[edit]

Signature
archive:options(
  $archive  as xs:base64Binary
) as map(*)
Summary Returns the options of the specified $archive in the format specified by archive:create.
Errors format: The archive format is not supported.
error: archive creation failed.
Examples A standard ZIP archive will return the following options:
map {
  "format": "zip",
  "algorithm": "deflate"
}

archive:extract-text[edit]

Signature
archive:extract-text(
  $archive   as xs:base64Binary,
  $entries   as item()*          := (),
  $encoding  as xs:string        := ()
) as xs:string*
Summary Extracts entries of the specified $archive and returns them as texts.
The returned entries can be limited via $entries. The format of the argument is the same as for archive:create (attributes will be ignored).
The encoding of the input files can be specified via $encoding.
Errors encode: the specified encoding is invalid or not supported, or the string conversion failed. Invalid XML characters will be ignored if CHECKSTRINGS is turned off.
error: archive creation failed.
Examples The following expression extracts all .txt files from an archive:
let $archive := file:read-binary("documents.zip")
for $entry in archive:entries($archive)[ends-with(., '.txt')]
return archive:extract-text($archive, $entry)

archive:extract-binary[edit]

Signature
archive:extract-binary(
  $archive  as xs:base64Binary,
  $entries  as item()*          := ()
) as xs:base64Binary*
Summary Extracts entries of the specified $archive and returns them as binaries.
The returned entries can be limited via $entries. The format of the argument is the same as for archive:create (attributes will be ignored).
Errors error: archive creation failed.
Examples This example unzips all files of an archive to the current directory:
let $archive  := file:read-binary('archive.zip')
let $entries  := archive:entries($archive)
let $contents := archive:extract-binary($archive)
return for-each-pair($entries, $contents, function($entry, $content) {
  file:create-dir(replace($entry, "[^/]+$", "")),
  file:write-binary($entry, $content)
})

Updates[edit]

archive:create[edit]

Signature
archive:create(
  $entries   as item(),
  $contents  as item()*,
  $options   as map(*)?  := map { }
) as xs:base64Binary
Summary Creates a new archive from the specified entries and contents.
The $entries argument contains meta information required to create new entries. All items may either be of type xs:string, representing the entry name, or element(archive:entry), containing the name as text node and additional, optional attributes:
  • last-modified: timestamp, specified as xs:dateTime (default: current time)
  • compression-level: 0-9, 0 = uncompressed (default: 8)
  • encoding: for textual entries (default: UTF-8)

An example:

<archive:entry last-modified='2011-11-11T11:11:11'
               compression-level='8'
               encoding='US-ASCII'>hello.txt</archive:entry>

The actual $contents must be xs:string or xs:base64Binary items.
The $options parameter contains archiving options:

  • format: allowed values are zip and gzip. zip is the default.
  • algorithm: allowed values are deflate and stored (for the zip format). deflate is the default.
Errors number: the number of entries and contents differs.
format: the specified option or its value is invalid or not supported.
descriptor: entry descriptors contain invalid entry names, timestamps or compression levels.
encode: the specified encoding is invalid or not supported, or the string conversion failed. Invalid XML characters will be ignored if CHECKSTRINGS is turned off.
single: the chosen archive format only allows single entries.
error: archive creation failed.
Examples The following one-liner creates an archive archive.zip with one file file.txt:
archive:create(<archive:entry>file.txt</archive:entry>, 'Hello World')

The following function creates an archive mp3.zip, which contains all MP3 files of a local directory:

let $path  := 'audio/'
let $files := file:list($path, true(), '*.mp3')
let $zip   := archive:create($files,
  for $file in $files
  return file:read-binary($path || $file)
)
return file:write-binary('mp3.zip', $zip)

archive:update[edit]

Signature
archive:update(
  $archive   as xs:base64Binary,
  $entries   as item()*,
  $contents  as item()*
) as xs:base64Binary
Summary Creates an updated version of the specified $archive with new or replaced entries.
The format of $entries and $contents is the same as for archive:create.
Errors number: the number of entries and contents differs.
descriptor: entry descriptors contain invalid entry names, timestamps, compression levels or encodings.
encode: the specified encoding is invalid or not supported, or the string conversion failed. Invalid XML characters will be ignored if CHECKSTRINGS is turned off.
modify: the entries of the given archive cannot be modified.
error: archive creation failed.
Examples This example replaces texts in a Word document:
declare variable $input  := "HelloWorld.docx";
declare variable $output := "HelloUniverse.docx";
declare variable $doc    := "word/document.xml";
 
let $archive := file:read-binary($input)
let $entry   :=
  copy $c := fn:parse-xml(archive:extract-text($archive, $doc))
  modify replace value of node $c//*[text() = "HELLO WORLD!"] with "HELLO UNIVERSE!"
  return fn:serialize($c)
let $updated := archive:update($archive, $doc, $entry)
return file:write-binary($output, $updated)

archive:delete[edit]

Signature
archive:delete(
  $archive  as xs:base64Binary,
  $entries  as item()*
) as xs:base64Binary
Summary Deletes entries from an $archive.
The format of $entries is the same as for archive:create.
Errors modify: the entries of the given archive cannot be modified.
error: archive creation failed.
Examples This example deletes all HTML files in an archive and creates a new file:
let $zip := file:read-binary('old.zip')
let $entries := archive:entries($zip)[matches(., '\.x?html?$', 'i')]
return file:write-binary('new.zip', archive:delete($zip, $entries))

Convenience[edit]

archive:create-from[edit]

Signature
archive:create-from(
  $path     as xs:string,
  $options  as map(*)?    := map { },
  $entries  as item()*    := ()
) as xs:base64Binary
Summary This convenience function creates an archive from all files in the specified directory $path.
The $options parameter contains archiving options, and the files to be archived can be limited via $entries. The format of the two last arguments is identical to archive:create, with two additional options:
  • recursive: parse all files recursively (default: true; ignored if entries are specified via the last argument).
  • root-dir: use name of supplied directory as archive root directory (default: false).
Errors file:no-dir: the specified path does not point to a directory.
file:is-dir: one of the specified entries points to a directory.
file:not-found: a specified entry does not exist.
error: archive creation failed.
Examples This example writes the files of a user’s home directory to archive.zip:
let $zip := archive:create-from('/home/user/')
return file:write-binary('archive.zip', $zip)

archive:extract-to[edit]

Signature
archive:extract-to(
  $path     as xs:string,
  $archive  as xs:base64Binary,
  $entries  as item()*          := ()
) as empty-sequence()
Summary This convenience function writes files of an $archive directly to the specified directory $path.
The archive entries to be written can be restricted via $entries. The format of the argument is the same as for archive:create (attributes will be ignored).
Errors error: archive creation failed.
Examples The following expression unzips all files of an archive to the current directory:
archive:extract-to('.', file:read-binary('archive.zip'))

archive:write[edit]

Signature
archive:write(
  $path      as xs:string,
  $entries   as item(),
  $contents  as item()*,
  $options   as map(*)?  := map { }
) as xs:base64Binary
Summary This convenience function creates a new archive from the specified $entries and $contents and writes it disk.
See archive:create for more details.
Errors number: the number of entries and contents differs.
format: the specified option or its value is invalid or not supported.
descriptor: entry descriptors contain invalid entry names, timestamps or compression levels.
encode: the specified encoding is invalid or not supported, or the string conversion failed. Invalid XML characters will be ignored if CHECKSTRINGS is turned off.
single: the chosen archive format only allows single entries.
error: archive creation failed.
Examples All mp3 files from a directory are zipped and written to a file, along with an info file:
let $files := file:children('music')[ends-with(., 'mp3')]
return archive:write(
  'music.zip',
  ('info.txt', $files ! file:name(.)),
  ('Archive with MP3 files', $files ! file:read-binary(.))
)

Errors[edit]

Code Description
descriptor Entry descriptors contain invalid entry names, timestamps or compression levels.
encode The specified encoding is invalid or not supported, or the string conversion failed. Invalid XML characters will be ignored if CHECKSTRINGS is turned off.
error processing failed.
format The archive format or the specified option is invalid or not supported.
modify The entries of the given archive cannot be modified.
number The number of specified entries and contents differs.
single The chosen archive format only allows single entries.

Changelog[edit]

Version 9.6
Version 9.0
  • Updated: archive:create-from: options added
  • Updated: error codes updated; errors now use the module namespace
Version 8.5
Version 8.3

The module was introduced with Version 7.3.