Tar Lua Reference Documentation
chilkat.Tar
Current Version: 11.7.0
Markdown version of this page for AI tools (v 11.7.0) · all AI docs
Chilkat.Tar
Add files or directory trees and write standard TAR output, with control
over archive paths, directory handling, and write format.
Work with common compressed archive forms such as
Inspect archive entries, verify archive structure, and produce XML
listings for display, logging, or programmatic processing.
Extract entire archives or selected entries, including workflows that
extract matching files directly to memory or
Include or exclude files using filters, control relative paths in the
archive, and manage how entries are restored during extraction.
Preserve or override UNIX-style permissions and create Debian
For an extended overview, see
Tar Class Overview.
Create, list, verify, filter, and extract TAR archives and compressed TAR formats.
Chilkat.Tar creates, verifies, lists, and extracts TAR archives,
including compressed TAR formats such as .tar.gz,
.tgz, .tar.bz2, and .tar.Z. It
supports adding individual files and directory trees, controlling archive
paths, preserving or overriding file permissions, filtering included or
extracted files, extracting from memory, extracting selected entries to
memory or BinData, producing XML listings, and creating Debian
.deb package archives from control and data tarballs.
Create TAR archives
Compressed TAR formats
.tar.gz,
.tgz, .tar.bz2, and .tar.Z.
List and verify contents
Selective extraction
BinData.
Filters and paths
Permissions and packages
.deb package archives from control and data tarballs.
Tar when the data is a TAR archive or a compressed TAR
archive. Configure the archive paths, filters, permissions, and compression
format, then create, list, verify, or extract the archive as needed. Use
Chilkat.Zip for ZIP archives, Chilkat.Gzip for a
single GZIP stream, and Chilkat.Compression for raw compression
operations.
Object Creation
local chilkat = require("chilkat")
local tar = chilkat.Tar.new()Creates the object (chilkat.Tar() does the same). Lua's garbage collector frees it when it is no longer referenced; tar:dispose() frees it at once, and in Lua 5.4 and later local tar <close> = chilkat.Tar.new() frees it when the block ends. Calling a method of a disposed object raises an error.
Errors
A method that fails returns nil followed by the error text, as io.open does: local body, err = tar:method(...), where err is the object's last_error_text. Wrap the call in assert() to raise an error with that text instead. Methods that answer a question return true or false, numbers are returned as they are (check last_method_success where the description says a value means failure), and property reads and writes never fail for Chilkat reasons.
Misuse raises a Lua error: a wrong argument type or a missing argument (bad argument #1 to ...), an unknown property name, a write to a read-only property, an out-of-range integer, or an object of the wrong class.
Names are Chilkat's in snake_case: QuickGetStr is quick_get_str, LastErrorText is last_error_text. Properties are fields (tar.verbose_logging = true) and methods use the colon (tar:method(...)). Strings are UTF-8; binary data is a Lua string of bytes. Indexes are 0-based, as in every Chilkat API. Unlocking: call chilkat.unlock_bundle("...") once at startup.
Properties
CaptureXmlListing
local boolVal = tar.capture_xml_listing
tar.capture_xml_listing = boolVal
Controls whether extraction methods also capture an XML inventory of the archive. When set to true, methods such as Untar, UntarGz, UntarBz2, and UntarZ store the listing in XmlListing. The XML has the same structure as the string returned by ListXml. The default is false.
CaptureXmlListing and SuppressOutput to true before an untar operation to scan the archive and obtain its XML listing without writing archive entries to disk.Charset
local strVal = tar.charset
tar.charset = strVal
Specifies the character encoding used to decode filenames stored in a TAR archive during extraction. The default is utf-8, which is normally appropriate for modern archives.
This property affects archive entry names only. It does not convert or otherwise alter the contents of extracted files. TAR archives written by the WriteTar* methods store filenames as UTF-8.
DebugLogFilePath
local strVal = tar.debug_log_file_path
tar.debug_log_file_path = strVal
If set to a file path, this property logs the LastErrorText of each Chilkat method or property call to the specified file. This logging helps identify the context and history of Chilkat calls leading up to any crash or hang, aiding in debugging.
Enabling the VerboseLogging property provides more detailed information. This property is mainly used for debugging rare instances where a Chilkat method call causes a hang or crash, which should generally not happen.
Possible causes of hangs include:
- A timeout property set to 0, indicating an infinite timeout.
- A hang occurring within an event callback in the application code.
- An internal bug in the Chilkat code causing the hang.
DirMode
local intVal = tar.dir_mode
tar.dir_mode = intVal
Specifies the UNIX permission bits written to the TAR header for directory entries created by the WriteTar* methods. The default is octal 0755, which represents rwxr-xr-x.
DirPrefix
local strVal = tar.dir_prefix
tar.dir_prefix = strVal
Specifies a path prefix to prepend to entries when a TAR archive is created. For example, setting this property to subdir1 causes an entry such as report.txt to be stored as subdir1/report.txt.
The prefix changes only the path stored in the archive; it does not rename or move the source file on disk.
AddFile2 explicitly supplies the complete path within the archive, so DirPrefix is not applied to files added by that method.FileMode
local intVal = tar.file_mode
tar.file_mode = intVal
Specifies the UNIX permission bits written to the TAR header for ordinary file entries created by the WriteTar* methods. The default is octal 0644, which represents rw-r--r--.
ScriptFileMode instead, allowing executable permissions to be recorded separately.GroupId
local intVal = tar.group_id
tar.group_id = intVal
Specifies the numeric group identifier (GID) written to TAR headers when an archive is created. The default value is 1000.
GroupName
local strVal = tar.group_name
tar.group_name = strVal
Specifies the group name written to TAR headers when an archive is created. By default, Chilkat uses the username of the account running the application.
GroupId. Extraction tools and operating systems may give different precedence to these fields.HeartbeatMs
local intVal = tar.heartbeat_ms
tar.heartbeat_ms = intVal
Specifies the approximate interval, in milliseconds, between AbortCheck event callbacks during supported long-running operations. The default is 0, which disables periodic AbortCheck callbacks.
LastErrorHtml
local strVal = tar.last_error_html
Provides HTML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.
topLastErrorText
local strVal = tar.last_error_text
Provides plain text information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.
LastErrorXml
local strVal = tar.last_error_xml
Provides XML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.
topLastMethodSuccess
local boolVal = tar.last_method_success
tar.last_method_success = boolVal
Indicates the success or failure of the most recent method call: true means success, false means failure. This property remains unchanged by property setters or getters. This method is present to address challenges in checking for null or Nothing returns in certain programming languages. Note: This property does not apply to methods that return integer values or to boolean-returning methods where the boolean does not indicate success or failure.
MatchCaseSensitive
local boolVal = tar.match_case_sensitive
tar.match_case_sensitive = boolVal
Controls whether the patterns in MustMatch and MustNotMatch are matched case-sensitively. The default is false.
MustMatch
local strVal = tar.must_match
tar.must_match = strVal
Specifies an inclusion pattern applied when creating or extracting TAR archives, including compressed TAR formats. A candidate path is included or extracted only when it matches this pattern. The default is an empty string, which permits all paths.
The pattern may contain zero or more asterisks (*), where each asterisk matches zero or more characters. For example, *.txt selects paths ending in .txt. Case handling is controlled by MatchCaseSensitive.
MustMatch and MustNotMatch are set, a path must satisfy the inclusion pattern and must not satisfy the exclusion pattern.MustNotMatch
local strVal = tar.must_not_match
tar.must_not_match = strVal
Specifies an exclusion pattern applied when creating or extracting TAR archives, including compressed TAR formats. A candidate path that matches this pattern is skipped. The default is an empty string, which excludes nothing.
The pattern may contain zero or more asterisks (*), where each asterisk matches zero or more characters. For example, *.obj skips paths ending in .obj. Case handling is controlled by MatchCaseSensitive.
MustMatch does not override a match in MustNotMatch.NoAbsolutePaths
local boolVal = tar.no_absolute_paths
tar.no_absolute_paths = boolVal
Controls whether absolute archive paths are converted to relative paths during extraction. When true, a leading / or \ is removed before the entry is written. The default is true.
NumDirRoots
local intVal = tar.num_dir_roots
Returns the number of directory roots currently registered for archive creation by calls to AddDirRoot and AddDirRoot2. Individual files added with AddFile or AddFile2 are not included in this count.
Use zero-based indexes from 0 through NumDirRoots - 1 with GetDirRoot.
PercentDoneScale
local intVal = tar.percent_done_scale
tar.percent_done_scale = intVal
Specifies the value reported by PercentDone when an eligible operation is 100% complete. The default is 100. Increasing the scale allows finer-grained integer progress values; for example, a scale of 1000 allows 453 to represent 45.3%.
The value is clamped to the range 10 through 100000. This property is available only in environments that support event callbacks, and only methods for which measurable progress is available emit percentage updates.
ScriptFileMode
local intVal = tar.script_file_mode
tar.script_file_mode = intVal
Specifies the UNIX permission bits written to TAR headers for shell-script files recognized by extensions such as .sh, .csh, .bash, and .bsh. The default is octal 0755, which records executable permissions.
SuppressOutput
local boolVal = tar.suppress_output
tar.suppress_output = boolVal
Controls whether untar operations write extracted files and directories to the filesystem. When true, methods such as Untar, UntarGz, UntarBz2, and UntarZ scan the archive without producing extracted output. The default is false.
CaptureXmlListing to obtain an XML listing without extracting the archive.UntarCaseSensitive
local boolVal = tar.untar_case_sensitive
tar.untar_case_sensitive = boolVal
Deprecated. Use MatchCaseSensitive instead.
Until this property is removed, reading or setting it has the same effect as reading or setting MatchCaseSensitive.
UntarDebugLog
local boolVal = tar.untar_debug_log
tar.untar_debug_log = boolVal
Controls whether untar methods add per-entry extraction details to LastErrorText, LastErrorXml, and LastErrorHtml. The default is false.
UntarDiscardPaths
local boolVal = tar.untar_discard_paths
tar.untar_discard_paths = boolVal
Controls whether directory components from archive entry names are discarded during extraction. When true, each file is written directly into UntarFromDir rather than recreating the archived directory tree. The default is false.
UntarFromDir
local strVal = tar.untar_from_dir
tar.untar_from_dir = strVal
Specifies the destination directory for extraction. The default is ., meaning the current working directory of the calling process.
When UntarDiscardPaths is false, archived subdirectories are recreated beneath this directory. When it is true, extracted files are placed directly in this directory.
UntarMaxCount
local intVal = tar.untar_max_count
tar.untar_max_count = intVal
Limits the number of matching entries extracted by an untar operation. The default is 0, which means no maximum.
For example, set MustMatch to select a particular path and set UntarMaxCount to 1 to stop after the first matching entry is extracted.
UserId
local intVal = tar.user_id
tar.user_id = intVal
Specifies the numeric user identifier (UID) written to TAR headers when an archive is created. The default value is 1000.
UserName
local strVal = tar.user_name
tar.user_name = strVal
Specifies the user name written to TAR headers when an archive is created. By default, Chilkat uses the username of the account running the application.
UserId. Their interpretation depends on the extracting tool and destination system.VerboseLogging
local boolVal = tar.verbose_logging
tar.verbose_logging = boolVal
If set to true, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is false. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.
Version
local strVal = tar.version
WriteFormat
local strVal = tar.write_format
tar.write_format = strVal
Specifies the TAR header format used by the WriteTar* methods. The default is gnu. Supported values are:
| Value | Use |
|---|---|
gnu | GNU TAR format and extensions. This is the Chilkat default and supports archive metadata beyond classic ustar limits. |
pax | POSIX pax extended format. It is designed to represent long names and additional metadata through extensible records. |
ustar | POSIX ustar format. It is broadly interoperable but has stricter limits on path lengths and metadata fields. |
ustar when compatibility with simple TAR readers is the priority and the archive fits its limits. Use pax for portable extended metadata, or retain gnu when GNU TAR compatibility is expected.XmlListing
local strVal = tar.xml_listing
tar.xml_listing = strVal
Contains the XML listing captured by the most recent untar operation for which CaptureXmlListing was true. The XML structure is the same as the output from ListXml.
Methods
AddDirRoot
-- ok is true, or nil and err on failure
local ok, err = tar:add_dir_root(dir_path)
Adds the directory tree at dir_path to the set of sources used by the next WriteTar* operation. Call this method multiple times to include multiple directory trees in one archive.
Use AddDirRoot2 when the tree should appear beneath an explicit prefix inside the archive.
ClearDirRootsAndFiles is called.Returns true on success, nil, err on failure. The second return value, err, is the object's last_error_text; wrap the call in assert() to raise an error instead.
AddDirRoot2
-- root_path is a string
-- ok is true, or nil and err on failure
local ok, err = tar:add_dir_root2(root_prefix, root_path)
Adds the directory tree at root_path to the archive-creation source list and stores its entries beneath the archive prefix supplied in root_prefix. Call this method multiple times, or combine it with AddDirRoot, before calling a WriteTar* method.
root_prefix should be a relative archive path such as abc/123 and should not end with /. If DirPrefix is also set, DirPrefix is applied first.
DirPrefix = "package" and rootPrefix = "assets", files from this root are stored beneath package/assets/.Returns true on success, nil, err on failure. The second return value, err, is the object's last_error_text; wrap the call in assert() to raise an error instead.
AddFile
-- ok is true, or nil and err on failure
local ok, err = tar:add_file(path)
Adds the local file at path to the set of sources used by the next WriteTar* operation. Call AddFile, AddFile2, and the directory-root methods as needed before writing a single archive.
Use AddFile2 when the path stored inside the TAR must be specified independently of the source file path.
ClearDirRootsAndFiles is called.Returns true on success, nil, err on failure. The second return value, err, is the object's last_error_text; wrap the call in assert() to raise an error instead.
AddFile2
-- path_within_tar is a string
-- ok is true, or nil and err on failure
local ok, err = tar:add_file2(file_path, path_within_tar)
Adds the local file at file_path to the archive-creation source list and stores it using the exact archive path supplied in path_within_tar. This allows the source path and the path visible inside the TAR to differ.
Call this method as many times as needed, optionally together with the other file and directory-root methods, before calling a single WriteTar* method.
path_within_tar already specifies the path within the TAR, DirPrefix does not modify entries added by this method. Use forward slashes and a relative path for portable archive names.Returns true on success, nil, err on failure. The second return value, err, is the object's last_error_text; wrap the call in assert() to raise an error instead.
ClearDirRootsAndFiles
local ok, err = tar:clear_dir_roots_and_files()
Removes all files and directory roots previously registered by AddDirRoot, AddDirRoot2, AddFile, and AddFile2.
Call this method before building a different archive with the same Tar object when the earlier source list should not be reused.
Returns true on success, nil, err on failure. The second return value, err, is the object's last_error_text; wrap the call in assert() to raise an error instead.
CreateDeb
-- data_path is a string
-- deb_path is a string
-- ok is true, or nil and err on failure
local ok, err = tar:create_deb(control_path, data_path, deb_path)
Creates a Debian binary package at deb_path from the prepared control archive at control_path and data archive at data_path. The inputs are typically named control.tar.gz and data.tar.gz, or use another compression form accepted by the target Debian tooling.
.deb file is an ar archive containing a debian-binary format marker, a control.tar.* member for package metadata and maintainer scripts, and a data.tar.* member for the installed filesystem payload.Returns true on success, nil, err on failure. The second return value, err, is the object's last_error_text; wrap the call in assert() to raise an error instead.
GetDirRoot
-- str is a string, or nil and err on failure
local str, err = tar:get_dir_root(index)
Returns a directory root previously added with AddDirRoot or AddDirRoot2. index is a zero-based index.
Valid indexes range from 0 through NumDirRoots - 1. For example, after two roots are added, GetDirRoot(0) returns the first and GetDirRoot(1) returns the second.
Returns the string, or nil, err on failure (or when nothing is found). The second return value, err, is the object's last_error_text; wrap the call in assert() to raise an error instead.
ListXml
-- str is a string, or nil and err on failure
local str, err = tar:list_xml(tar_path)
Scans the uncompressed TAR archive at tar_path and returns an XML description of its files, directories, and archive metadata. The archive is not extracted.
CaptureXmlListing. Set SuppressOutput as well when no files should be written.Returns the string, or nil, err on failure (or when nothing is found). The second return value, err, is the object's last_error_text; wrap the call in assert() to raise an error instead.
Untar
-- n is an integer
local n = tar:untar(tar_path)
Extracts the uncompressed TAR archive at tar_path into the directory specified by UntarFromDir. Archived directory trees are recreated unless UntarDiscardPaths is true.
Returns the number of files and directories extracted, or -1 if the operation fails. Extraction is also affected by the matching, path-safety, count-limit, listing, and output-suppression properties of this object.
.tar archive is not compressed. Use UntarGz, UntarBz2, or UntarZ for the corresponding compressed tarball formats.UntarBz2
-- ok is true, or nil and err on failure
local ok, err = tar:untar_bz2(tar_path)
Decompresses and extracts the .tar.bz2 archive at tar_path into UntarFromDir. This format is also commonly named .tbz, .tbz2, or .tb2.
Returns true on success and false on failure. The same extraction filters, path controls, listing options, and output settings used by Untar also apply.
Returns true on success, nil, err on failure. The second return value, err, is the object's last_error_text; wrap the call in assert() to raise an error instead.
UntarFirstMatchingToBd
-- match_pattern is a string
-- bd is a chilkat.BinData
-- ok is true, or nil and err on failure
local ok, err = tar:untar_first_matching_to_bd(tar_path, match_pattern, bd)
Scans the uncompressed TAR archive at tar_path and copies the contents of the first file whose archive path matches match_pattern into the BinData object supplied in bd. Matching is evaluated in archive order.
No archive entry is written to the local filesystem. Returns true when a matching file is successfully extracted to bd and false otherwise.
Returns true on success, nil, err on failure. The second return value, err, is the object's last_error_text; wrap the call in assert() to raise an error instead.
UntarGz
-- ok is true, or nil and err on failure
local ok, err = tar:untar_gz(tar_path)
Decompresses and extracts the .tar.gz archive at tar_path into UntarFromDir. The .tgz extension is a common short form for the same gzip-compressed TAR structure.
Returns true on success and false on failure. The same extraction filters, path controls, listing options, and output settings used by Untar also apply.
Returns true on success, nil, err on failure. The second return value, err, is the object's last_error_text; wrap the call in assert() to raise an error instead.
UntarZ
-- ok is true, or nil and err on failure
local ok, err = tar:untar_z(tar_path)
Decompresses and extracts the .tar.Z archive at tar_path into UntarFromDir. The .Z suffix denotes the historical UNIX compress format; .taz is a common alternate extension.
Returns true on success and false on failure. The same extraction filters, path controls, listing options, and output settings used by Untar also apply.
Returns true on success, nil, err on failure. The second return value, err, is the object's last_error_text; wrap the call in assert() to raise an error instead.
VerifyTar
-- flag is true or false
local flag = tar:verify_tar(tar_path)
Opens the uncompressed TAR archive at tar_path and scans its headers through the end of the archive. Returns true when the archive structure is accepted and no TAR-format errors are found; otherwise returns false.
Returns true or false: an answer, not a success flag.
WriteTar
-- ok is true, or nil and err on failure
local ok, err = tar:write_tar(tar_path)
Creates an uncompressed TAR archive at tar_path from the files and directory trees previously added with AddFile, AddFile2, AddDirRoot, and AddDirRoot2. Archive paths, permissions, ownership metadata, filters, and header format are controlled by the corresponding properties.
Returns true on success and false on failure.
Returns true on success, nil, err on failure. The second return value, err, is the object's last_error_text; wrap the call in assert() to raise an error instead.
WriteTarBz2
-- ok is true, or nil and err on failure
local ok, err = tar:write_tar_bz2(bz2_path)
Creates a bzip2-compressed TAR archive at bz2_path from the files and directory trees previously added to this object. Common filename extensions include .tar.bz2, .tbz, .tbz2, and .tb2.
Returns true on success and false on failure.
Returns true on success, nil, err on failure. The second return value, err, is the object's last_error_text; wrap the call in assert() to raise an error instead.
WriteTarGz
-- ok is true, or nil and err on failure
local ok, err = tar:write_tar_gz(gz_path)
Creates a gzip-compressed TAR archive at gz_path from the files and directory trees previously added to this object. The usual extensions are .tar.gz and .tgz.
Returns true on success and false on failure.
Returns true on success, nil, err on failure. The second return value, err, is the object's last_error_text; wrap the call in assert() to raise an error instead.
Events
All Chilkat methods are synchronous: the call returns when the work is done. During a long-running call, chilkat.Tar reports progress to the functions given to set_event_handler, in a table keyed by event name (plain functions, not methods: closures carry whatever state they need):
tar:set_event_handler({
percent_done = function(pct) print(pct .. "%") end, -- return true to abort
progress_info = function(name, value) print(name, value) end,
})
tar.heartbeat_ms = 250 -- abort_check is called 4 times per secondInstalls the handlers, replacing any installed before; tar:set_event_handler(nil) removes them. The event names are checked when the table is installed: a misspelled one raises an error.
The abort_check handler is called at the interval set by the heartbeat_ms property (0, the default, disables it); percent_done is called when an operation's completion percentage is known; progress_info delivers named progress values. A true return from abort_check or percent_done aborts the running method, which then fails in the usual way (nil, err). An error raised in a handler aborts the method and is raised again from the method call; the object remains usable.
AbortCheck
tar:set_event_handler({ abort_check = function() ... end })
Enables a method call to be aborted by triggering the AbortCheck event at intervals defined by the HeartbeatMs property. If HeartbeatMs is set to its default value of 0, no events will occur. For instance, set HeartbeatMs to 200 to trigger 5 AbortCheck events per second.
Example
local deadline = os.time() + 30 -- give up after 30 seconds
tar.heartbeat_ms = 250 -- call the handler 4 times per second
tar:set_event_handler({ abort_check = function() return os.time() > deadline end })PercentDone
tar:set_event_handler({ percent_done = function(pct_done) ... end })
This provides the percentage completion for any method involving network communications or time-consuming processing, assuming the progress can be measured as a percentage. This event is triggered only when it's possible and logical to express the operation's progress as a percentage. The pctDone argument will range from 1 to 100. For methods that finish quickly, the number of PercentDone callbacks may vary, but the final callback will have pctDone equal to 100. For longer operations, callbacks will not exceed one per percentage point (e.g., 1, 2, 3, ..., 98, 99, 100).
The PercentDone callback also acts as an AbortCheck event. For fast methods where PercentDone fires, an AbortCheck event may not trigger since the PercentDone callback already provides an opportunity to abort. For longer operations, where time between PercentDone callbacks is extended, AbortCheck callbacks enable more responsive operation termination.
To abort the operation, set the abort output argument to true. This will cause the method to terminate and return a failure status or corresponding failure value.
Example
tar:set_event_handler({
percent_done = function(pct_done) -- 0 to 100
print("Percent done: " .. pct_done)
return false -- return true to abort the method in progress
end,
})ProgressInfo
tar:set_event_handler({ progress_info = function(name, value) ... end })
This event callback provides tag name/value pairs that detail what occurs during a method call. To discover existing tag names, create code to handle the event, emit the pairs, and review them. Most tag names are self-explanatory.
Note: Some Chilkat methods don't fire any ProgressInfo events.
Example
tar:set_event_handler({
progress_info = function(name, value) print(name .. ": " .. value) end,
})