got/dist/source/core/utils/decompress-response.js

Human-friendly and powerful HTTP request library for Node.js

import zlib from 'node:zlib';
import decompressResponse from 'decompress-response';
const supportedEncodings = new Set(['gzip', 'deflate', 'br', ...(typeof zlib.createZstdDecompress === 'function' ? ['zstd'] : [])]);
export default function decompressResponseBody(response) {
    const encodings = (response.headers['content-encoding'] ?? '')
        .toLowerCase()
        .split(',')
        .map(encoding => encoding.trim())
        // Empty list members are ignored (RFC 9110, section 5.6.1.1).
        .filter(encoding => encoding.length > 0)
        // `identity` means the content was not transformed, so it adds no decoding step.
        .filter(encoding => encoding !== 'identity')
        .map(encoding => encoding === 'x-gzip' ? 'gzip' : encoding);
    if (encodings.some(encoding => !supportedEncodings.has(encoding))) {
        return decompressResponse(response);
    }
    const nativeResponse = response;
    // Content-Encoding lists codings in application order (RFC 9110, section 8.4).
    for (const encoding of encodings.toReversed()) {
        const source = response;
        const originalHeaders = source.headers;
        try {
            // The dependency accepts one coding. Retain the native headers for wire-byte validation.
            source.headers = { ...originalHeaders, 'content-encoding': encoding };
            response = decompressResponse(source);
        }
        finally {
            source.headers = originalHeaders;
        }
        if (source === nativeResponse) {
            continue;
        }
        const decoded = response;
        source.once('error', error => {
            decoded.destroy(error);
        });
    }
    return response;
}