Gzip Node.js Reference Documentation

Gzip

Current Version: 9.5.0.75

GZip compression component.

Object Creation

var obj = new chilkat.Gzip();

Properties

AbortCurrent
AbortCurrent
· boolean
Introduced in version 9.5.0.58

When set to true, causes the currently running method to abort. Methods that always finish quickly (i.e.have no length file operations or network communications) are not affected. If no method is running, then this property is automatically reset to false when the next method is called. When the abort occurs, this property is reset to false. Both synchronous and asynchronous method calls can be aborted. (A synchronous method call could be aborted by setting this property from a separate thread.)

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Comment
Comment
· string

Specifies an optional comment string that can be embedded within the .gz when any Compress* method is called.

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CompressionLevel
CompressionLevel
· integer
Introduced in version 9.5.0.50

The compression level to be used when compressing. The default is 6, which is the typical value used for zip utility programs when compressing data. The compression level may range from 0 (no compression) to 9 (the most compression). The benefits of trying to increase compression may not be worth the added expense in compression time. In many cases (which is data dependent), the improvement in compression is minimal while the increase in computation time is significant.

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DebugLogFilePath
DebugLogFilePath
· string

If set to a file path, causes each Chilkat method or property call to automatically append it's LastErrorText to the specified log file. The information is appended such that if a hang or crash occurs, it is possible to see the context in which the problem occurred, as well as a history of all Chilkat calls up to the point of the problem. The VerboseLogging property can be set to provide more detailed information.

This property is typically used for debugging the rare cases where a Chilkat method call hangs or generates an exception that halts program execution (i.e. crashes). A hang or crash should generally never happen. The typical causes of a hang are:

  1. a timeout related property was set to 0 to explicitly indicate that an infinite timeout is desired,
  2. the hang is actually a hang within an event callback (i.e. it is a hang within the application code), or
  3. there is an internal problem (bug) in the Chilkat code that causes the hang.

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ExtraData
ExtraData
· Buffer

Optional extra-data that can be included within a .gz when a Compress* method is called.

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Filename
Filename
· string

The filename that is embedded within the .gz during any Compress* method call. When extracting from a .gz using applications such as WinZip, this will be the filename that is created.

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LastErrorHtml
LastErrorHtml
· string, read-only

Provides information in HTML format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

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LastErrorText
LastErrorText
· string, read-only

Provides information in plain-text format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

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LastErrorXml
LastErrorXml
· string, read-only

Provides information in XML format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

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LastMethodSuccess
LastMethodSuccess
· boolean
Introduced in version 9.5.0.52

Indicate whether the last method call succeeded or failed. A value of true indicates success, a value of false indicates failure. This property is automatically set for method calls. It is not modified by property accesses. The property is automatically set to indicate success for the following types of method calls:

  • Any method that returns a string.
  • Any method returning a Chilkat object, binary bytes, or a date/time.
  • Any method returning a standard boolean status value where success = true and failure = false.
  • Any method returning an integer where failure is defined by a return value less than zero.

Note: Methods that do not fit the above requirements will always set this property equal to true. For example, a method that returns no value (such as a "void" in C++) will technically always succeed.

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LastModStr
LastModStr
· string

The same as the LastMod property, but allows the date/time to be get/set in RFC822 string format.

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UseCurrentDate
UseCurrentDate
· boolean

If set to true, the file produced by an Uncompress* method will use the current date/time for the last-modification date instead of the date/time found within the Gzip format.

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VerboseLogging
VerboseLogging
· boolean

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.

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Version
Version
· string, read-only

Version of the component/library, such as "9.5.0.63"

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Methods

CompressBd
var status = CompressBd(binDat);
· Returns Boolean (true for success, false for failure).
· binDatbool
Introduced in version 9.5.0.67

In-place gzip the contents of binDat.

Returns true for success, false for failure.

More Information and Examples
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CompressBdAsync (1)
var ret_task = CompressBdAsync(binDat);
· Returns a Task
· binDatTask
Introduced in version 9.5.0.67

Creates an asynchronous task to call the CompressBd method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns null on failure

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CompressFile
var status = CompressFile(inFilename, destPath);
· Returns Boolean (true for success, false for failure).
· inFilename String
· destPath String

Compresses a file to create a GZip compressed file (.gz).

Returns true for success, false for failure.

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CompressFileAsync (1)
var ret_task = CompressFileAsync(inFilename, destPath);
· Returns a Task
· inFilename String
· destPath String

Creates an asynchronous task to call the CompressFile method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns null on failure

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CompressFile2
var status = CompressFile2(inFilename, embeddedFilename, destPath);
· Returns Boolean (true for success, false for failure).
· inFilename String
· embeddedFilename String
· destPath String

Compresses a file to create a GZip compressed file (.gz). inFilename is the actual filename on disk. embeddedFilename is the filename to be embedded in the .gz such that when it is un-gzipped, this is the name of the file that will be created.

Returns true for success, false for failure.

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CompressFile2Async (1)
var ret_task = CompressFile2Async(inFilename, embeddedFilename, destPath);
· Returns a Task
· inFilename String
· embeddedFilename String
· destPath String

Creates an asynchronous task to call the CompressFile2 method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns null on failure

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CompressFileToMem
var retBuf = CompressFileToMem(inFilename);
· Returns a Buffer.

Gzip compresses a file to an in-memory image of a .gz file.

Returns null on failure

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CompressFileToMemAsync (1)
var ret_task = CompressFileToMemAsync(inFilename);
· Returns a Task
· inFilename String

Creates an asynchronous task to call the CompressFileToMem method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns null on failure

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CompressMemory
var retBuf = CompressMemory(inData);
· Returns a Buffer.

Compresses in-memory data to an in-memory image of a .gz file.

Returns null on failure

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CompressMemoryAsync (1)
var ret_task = CompressMemoryAsync(inData);
· Returns a Task
· inData Buffer

Creates an asynchronous task to call the CompressMemory method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns null on failure

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CompressMemToFile
var status = CompressMemToFile(inData, destPath);
· Returns Boolean (true for success, false for failure).
· inData Buffer
· destPath String

Gzip compresses and creates a .gz file from in-memory data.

Returns true for success, false for failure.

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CompressMemToFileAsync (1)
var ret_task = CompressMemToFileAsync(inData, destPath);
· Returns a Task
· inData Buffer
· destPath String

Creates an asynchronous task to call the CompressMemToFile method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns null on failure

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CompressString
var retBuf = CompressString(inStr, destCharset);
· Returns a Buffer.

Gzip compresses a string and writes the output to a byte array. The string is first converted to the charset specified by destCharset. Typical charsets are "utf-8", "iso-8859-1", "shift_JIS", etc.

Returns null on failure

More Information and Examples
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CompressStringAsync (1)
var ret_task = CompressStringAsync(inStr, destCharset);
· Returns a Task
· inStr String
· destCharset String

Creates an asynchronous task to call the CompressString method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns null on failure

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CompressStringENC
var retStr = CompressStringENC(inStr, charset, encoding);
· Returns a String.
· inStr String
· charset String
· encoding String

The same as CompressString, except the binary output is returned in encoded string form according to the encoding. The encoding can be any of the following: "Base64", "modBase64", "Base32", "UU", "QP" (for quoted-printable), "URL" (for url-encoding), "Hex", "Q", "B", "url_oath", "url_rfc1738", "url_rfc2396", and "url_rfc3986".

Returns null on failure

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CompressStringToFile
var status = CompressStringToFile(inStr, destCharset, destPath);
· Returns Boolean (true for success, false for failure).
· inStr String
· destCharset String
· destPath String

Gzip compresses a string and writes the output to a .gz compressed file. The string is first converted to the charset specified by destCharset. Typical charsets are "utf-8", "iso-8859-1", "shift_JIS", etc.

Returns true for success, false for failure.

More Information and Examples
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CompressStringToFileAsync (1)
var ret_task = CompressStringToFileAsync(inStr, destCharset, destPath);
· Returns a Task
· inStr String
· destCharset String
· destPath String

Creates an asynchronous task to call the CompressStringToFile method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns null on failure

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Decode
var retBuf = Decode(encodedStr, encoding);
· Returns a Buffer.

Decodes an encoded string and returns the original data. The encoding mode is determined by encoding. It may be "base64", "hex", "quoted-printable", or "url".

Returns null on failure

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DeflateStringENC
var retStr = DeflateStringENC(inString, charsetName, outputEncoding);
· Returns a String.
· inString String
· charsetName String
· outputEncoding String

Provides the ability to use the zip/gzip's deflate algorithm directly to compress a string. Internal to this method, inString is first converted to the charset specified by charsetName. The data is then compressed using the deflate compression algorithm. The binary output is then encoded according to outputEncoding. Possible values for outputEncoding are "hex", "base64", "url", and "quoted-printable".

Note: The output of this method is compressed data with no Gzip file format. Use the Compress* methods to produce Gzip file format output.

Returns null on failure

More Information and Examples
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Encode
var retStr = Encode(byteData, encoding);
· Returns a String.
· byteData Buffer
· encoding String

Encodes binary data to a printable string. The encoding mode is determined by encoding. It may be "base64", "hex", "quoted-printable", or "url".

Returns null on failure

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ExamineFile
var retBool = ExamineFile(inGzFilename);
· Returns a Boolean.
· inGzFilename String

Determines if the inGzFilename is a Gzip formatted file. Returns true if it is a Gzip formatted file, otherwise returns false.

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ExamineMemory
var retBool = ExamineMemory(inGzData);
· Returns a Boolean.
· inGzData Buffer

Determines if the in-memory bytes (inGzData) contain a Gzip formatted file. Returns true if it is Gzip format, otherwise returns false.

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GetDt
var ret_ckDateTime = GetDt();
· Returns a CkDateTime

Gets the last-modification date/time to be embedded within the .gz.

Returns null on failure

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InflateStringENC
var retStr = InflateStringENC(inString, convertFromCharset, inputEncoding);
· Returns a String.
· inString String
· convertFromCharset String
· inputEncoding String

This the reverse of DeflateStringENC.

The input string is first decoded according to inputEncoding. (Possible values for inputEncoding are "hex", "base64", "url", and "quoted-printable".) The compressed data is then inflated, and the result is then converted from convertFromCharset (if necessary) to return a string.

Returns null on failure

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IsUnlocked
var retBool = IsUnlocked();
· Returns a Boolean.

Returns true if the component has been unlocked.

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ReadFile
var retBuf = ReadFile(path);
· Returns a Buffer.

Reads a binary file into memory and returns the byte array. Note: This method does not parse a Gzip, it is only a convenience method for reading a binary file into memory.

Returns null on failure

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SaveLastError
var status = SaveLastError(path);
· Returns Boolean (true for success, false for failure).
· path String

Saves the last-error information (the contents of LastErrorXml) to an XML formatted file.

Returns true for success, false for failure.

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SetDt
var status = SetDt(dt);
· Returns Boolean (true for success, false for failure).
· dtbool

Sets the last-modification date/time to be embedded within the .gz when a Compress* method is called. If not explicitly set, the current system date/time is used.

Returns true for success, false for failure.

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UncompressBd
var status = UncompressBd(binDat);
· Returns Boolean (true for success, false for failure).
· binDatbool
Introduced in version 9.5.0.67

In-place ungzip the contents of binDat.

Returns true for success, false for failure.

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UncompressBdAsync (1)
var ret_task = UncompressBdAsync(binDat);
· Returns a Task
· binDatTask
Introduced in version 9.5.0.67

Creates an asynchronous task to call the UncompressBd method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns null on failure

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UncompressFile
var status = UncompressFile(srcPath, destPath);
· Returns Boolean (true for success, false for failure).
· srcPath String
· destPath String

Un-Gzips a .gz file. The output filename is specified by the 2nd argument and not by the filename embedded within the .gz.

Returns true for success, false for failure.

More Information and Examples
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UncompressFileAsync (1)
var ret_task = UncompressFileAsync(srcPath, destPath);
· Returns a Task
· srcPath String
· destPath String

Creates an asynchronous task to call the UncompressFile method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns null on failure

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UncompressFileToMem
var retBuf = UncompressFileToMem(inFilename);
· Returns a Buffer.

Un-Gzips a .gz file directly to memory.

Returns null on failure

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UncompressFileToMemAsync (1)
var ret_task = UncompressFileToMemAsync(inFilename);
· Returns a Task
· inFilename String

Creates an asynchronous task to call the UncompressFileToMem method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns null on failure

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UncompressFileToString
var retStr = UncompressFileToString(gzFilename, charset);
· Returns a String.
· gzFilename String
· charset String

Uncompresses a .gz file that contains a text file. The contents of the text file are returned as a string. The character encoding of the text file is specified by charset. Typical charsets are "iso-8859-1", "utf-8", "windows-1252", "shift_JIS", "big5", etc.

Returns null on failure

More Information and Examples
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UncompressFileToStringAsync (1)
var ret_task = UncompressFileToStringAsync(gzFilename, charset);
· Returns a Task
· gzFilename String
· charset String

Creates an asynchronous task to call the UncompressFileToString method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns null on failure

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UncompressMemory
var retBuf = UncompressMemory(inData);
· Returns a Buffer.

Un-Gzips from an in-memory image of a .gz file directly into memory.

Returns null on failure

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UncompressMemoryAsync (1)
var ret_task = UncompressMemoryAsync(inData);
· Returns a Task
· inData Buffer

Creates an asynchronous task to call the UncompressMemory method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns null on failure

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UncompressMemToFile
var status = UncompressMemToFile(inData, destPath);
· Returns Boolean (true for success, false for failure).
· inData Buffer
· destPath String

Un-Gzips from an in-memory image of a .gz file to a file.

Returns true for success, false for failure.

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UncompressMemToFileAsync (1)
var ret_task = UncompressMemToFileAsync(inData, destPath);
· Returns a Task
· inData Buffer
· destPath String

Creates an asynchronous task to call the UncompressMemToFile method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns null on failure

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UncompressString
var retStr = UncompressString(inData, inCharset);
· Returns a String.
· inData Buffer
· inCharset String

The reverse of CompressString.

The bytes in inData are uncompressed, then converted from inCharset (if necessary) to return a string.

Returns null on failure

More Information and Examples
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UncompressStringAsync (1)
var ret_task = UncompressStringAsync(inData, inCharset);
· Returns a Task
· inData Buffer
· inCharset String

Creates an asynchronous task to call the UncompressString method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns null on failure

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UncompressStringENC
var retStr = UncompressStringENC(inStr, charset, encoding);
· Returns a String.
· inStr String
· charset String
· encoding String

The same as UncompressString, except the compressed data is provided in encoded string form based on the value of encoding. The encoding can be "Base64", "modBase64", "Base32", "UU", "QP" (for quoted-printable), "URL" (for url-encoding), "Hex", "Q", "B", "url_oath", "url_rfc1738", "url_rfc2396", and "url_rfc3986".

Returns null on failure

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UnlockComponent
var status = UnlockComponent(unlockCode);
· Returns Boolean (true for success, false for failure).
· unlockCode String

Unlocks the component allowing for the full functionality to be used.

Returns true for success, false for failure.

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UnTarGz
var status = UnTarGz(tgzFilename, destDir, bNoAbsolute);
· Returns Boolean (true for success, false for failure).
· tgzFilename String
· destDir String
· bNoAbsolute Boolean

Unpacks a .tar.gz file. The ungzip and untar occur in streaming mode. There are no temporary files and the memory footprint is constant (and small) while untarring. bNoAbsolute may be true or false. A value of true protects from untarring to absolute paths. (For example, imagine the trouble if the tar contains files with absolute paths beginning with /Windows/system32)

Returns true for success, false for failure.

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UnTarGzAsync (1)
var ret_task = UnTarGzAsync(tgzFilename, destDir, bNoAbsolute);
· Returns a Task
· tgzFilename String
· destDir String
· bNoAbsolute Boolean

Creates an asynchronous task to call the UnTarGz method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns null on failure

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WriteFile
var status = WriteFile(path, binaryData);
· Returns Boolean (true for success, false for failure).
· path String
· binaryData Buffer

A convenience method for writing a binary byte array to a file.

Returns true for success, false for failure.

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XfdlToXml
var retStr = XfdlToXml(xfldData);
· Returns a String.
· xfldData String

Converts base64-gzip .xfdl data to a decompressed XML string. The xfldData contains the base64 data. This method returns the decoded/decompressed XML string.

Returns null on failure

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