CompressionUtils

Utility class for compressing and decompressing data, plus reading ZIP archives. All methods are static.

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At a Glance

// Compress data before sending
const data = StringUtils.toBytes("Large payload...");
const compressed = CompressionUtils.compress('gzip', data);

// Decompress received data
const decompressed = CompressionUtils.decompress('gzip', compressed);

// Read ZIP archive contents
const files = CompressionUtils.zipList(zipData);
const content = CompressionUtils.zipRead(zipData, 'data.csv');

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Compression

compress(algorithm, data)

Compresses a byte array using the specified algorithm.

Parameter	Type	Description
algorithm	string	Compression algorithm
data	Uint8Array	Byte array to compress

Returns: Uint8Array

const data = StringUtils.toBytes("Hello, World!");
const compressed = CompressionUtils.compress('gzip', data);

decompress(algorithm, data)

Decompresses a byte array.

Parameter	Type	Description
algorithm	string	Compression algorithm (or 'auto' to detect)
data	Uint8Array	Compressed byte array

Returns: Uint8Array

const decompressed = CompressionUtils.decompress('gzip', compressed);
const text = StringUtils.fromBytes(decompressed);

Supported Algorithms

Algorithm	Description
gzip / gz	Gzip (most common)
deflate	Deflate
bzip2 / bz	Bzip2
lz4framed	LZ4 framed
lz4block	LZ4 block
lzma	LZMA
snappy	Snappy (fast)
xz	XZ
zstd	Zstandard
auto	Auto-detect (decompress only)

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ZIP Archives

zipList(data, password?)

Lists all file names in a ZIP archive.

Parameter	Type	Description
data	Uint8Array	ZIP archive bytes
password	string (optional)	Password if encrypted

Returns: string[]

const files = CompressionUtils.zipList(zipData);
stream.logInfo(`Files in archive: ${files.join(', ')}`);

zipRead(data, file, password?)

Reads a specific file from a ZIP archive.

Parameter	Type	Description
data	Uint8Array	ZIP archive bytes
file	string	File name to extract
password	string (optional)	Password if encrypted

Returns: string[]

// Read a file
const lines = CompressionUtils.zipRead(zipData, 'data.csv');
for (const line of lines) {
    stream.logInfo(line);
}

// Read with password
const lines = CompressionUtils.zipRead(zipData, 'sensitive.csv', 'password123');

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Complete Example

export function onMessage() {
    const fileContent = message.getByteString(dataDictionary.type.File.RAW_CONTENT);
    const bytes = StringUtils.toBytes(fileContent);

    // Compress for storage
    const compressed = CompressionUtils.compress('zstd', bytes);
    message.setByteString(dataDictionary.type.File.COMPRESSED, compressed);

    stream.emit(message, OUTPUT_PORT);
}

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See Also

• StringUtils — Convert between strings and bytes