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Add support for ZIP decompression using @tokenizer/deflate
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Changes:
- Extract mime-type from zipped `[Content_Types].xml` in Open Office XML (OOXML) documents
- Add dependency `@tokenizer/inflate`, used to decompress from the tokenizer stream
- Replace `fixture.zip` as the fixture seem to have invalid entries
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@Borewit
Borewit committed Dec 1, 2024
1 parent 2bc2eb7 commit 578c97f
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Showing 3 changed files with 98 additions and 125 deletions.
219 changes: 96 additions & 123 deletions core.js
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Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,8 @@ Primary entry point, Node.js specific entry point is index.js

import * as Token from 'token-types';
import * as strtok3 from 'strtok3/core';
import {includes, indexOf, getUintBE} from 'uint8array-extras';
import {ZipHandler} from '@tokenizer/inflate';
import {includes, getUintBE} from 'uint8array-extras';
import {
stringToBytes,
tarHeaderChecksumMatches,
Expand All @@ -26,6 +27,57 @@ export async function fileTypeFromBlob(blob) {
return new FileTypeParser().fromBlob(blob);
}

function getFileTypeFromMimeType(mimeType) {
switch (mimeType) {
case 'application/epub+zip':
return {
ext: 'epub',
mime: 'application/epub+zip',
};
case 'application/vnd.oasis.opendocument.text':
return {
ext: 'odt',
mime: 'application/vnd.oasis.opendocument.text',
};
case 'application/vnd.oasis.opendocument.spreadsheet':
return {
ext: 'ods',
mime: 'application/vnd.oasis.opendocument.spreadsheet',
};
case 'application/vnd.oasis.opendocument.presentation':
return {
ext: 'odp',
mime: 'application/vnd.oasis.opendocument.presentation',
};
case 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet':
return {
ext: 'xlsx',
mime: 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
};
case 'application/vnd.openxmlformats-officedocument.wordprocessingml.document':
return {
ext: 'docx',
mime: 'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
};
case 'application/vnd.openxmlformats-officedocument.presentationml.presentation':
return {
ext: 'pptx',
mime: 'application/vnd.openxmlformats-officedocument.presentationml.presentation',
};
case 'application/vnd.ms-visio.drawing':
return {
ext: 'vsdx',
mime: 'application/vnd.visio',
};
case 'application/vnd.ms-package.3dmanufacturing-3dmodel+xml':
return {
ext: '3mf',
mime: 'model/3mf',
};
default:
}
}

function _check(buffer, headers, options) {
options = {
offset: 0,
Expand Down Expand Up @@ -387,140 +439,61 @@ export class FileTypeParser {
// Zip-based file formats
// Need to be before the `zip` check
if (this.check([0x50, 0x4B, 0x3, 0x4])) { // Local file header signature
try {
while (tokenizer.position + 30 < tokenizer.fileInfo.size) {
await tokenizer.readBuffer(this.buffer, {length: 30});

const view = new DataView(this.buffer.buffer);

// https://en.wikipedia.org/wiki/Zip_(file_format)#File_headers
const zipHeader = {
compressedSize: view.getUint32(18, true),
uncompressedSize: view.getUint32(22, true),
filenameLength: view.getUint16(26, true),
extraFieldLength: view.getUint16(28, true),
};

zipHeader.filename = await tokenizer.readToken(new Token.StringType(zipHeader.filenameLength, 'utf-8'));
await tokenizer.ignore(zipHeader.extraFieldLength);

if (/classes\d*\.dex/.test(zipHeader.filename)) {
return {
ext: 'apk',
mime: 'application/vnd.android.package-archive',
};
}

// Assumes signed `.xpi` from addons.mozilla.org
if (zipHeader.filename === 'META-INF/mozilla.rsa') {
return {
let fileType;
await new ZipHandler(tokenizer).unzip(zipHeader => {
switch (zipHeader.filename) {
case 'META-INF/mozilla.rsa':
fileType = {
ext: 'xpi',
mime: 'application/x-xpinstall',
};
}

if (zipHeader.filename.endsWith('.rels') || zipHeader.filename.endsWith('.xml')) {
const type = zipHeader.filename.split('/')[0];
switch (type) {
case '_rels':
break;
case 'word':
return {
ext: 'docx',
mime: 'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
};
case 'ppt':
return {
ext: 'pptx',
mime: 'application/vnd.openxmlformats-officedocument.presentationml.presentation',
};
case 'xl':
return {
ext: 'xlsx',
mime: 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
};
case 'visio':
return {
ext: 'vsdx',
mime: 'application/vnd.visio',
};
default:
break;
}
}

if (zipHeader.filename.startsWith('xl/')) {
return {
ext: 'xlsx',
mime: 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
stop: true,
};
}

if (zipHeader.filename.startsWith('3D/') && zipHeader.filename.endsWith('.model')) {
case 'mimetype':
return {
ext: '3mf',
mime: 'model/3mf',
async handler(fileData) {
// Use TextDecoder to decode the UTF-8 encoded data
const mimeType = new TextDecoder('utf-8').decode(fileData).trim();
fileType = getFileTypeFromMimeType(mimeType);
},
stop: true,
};
}

// The docx, xlsx and pptx file types extend the Office Open XML file format:
// https://en.wikipedia.org/wiki/Office_Open_XML_file_formats
// We look for:
// - one entry named '[Content_Types].xml' or '_rels/.rels',
// - one entry indicating specific type of file.
// MS Office, OpenOffice and LibreOffice may put the parts in different order, so the check should not rely on it.
if (zipHeader.filename === 'mimetype' && zipHeader.compressedSize === zipHeader.uncompressedSize) {
let mimeType = await tokenizer.readToken(new Token.StringType(zipHeader.compressedSize, 'utf-8'));
mimeType = mimeType.trim();

switch (mimeType) {
case 'application/epub+zip':
return {
ext: 'epub',
mime: 'application/epub+zip',
};
case 'application/vnd.oasis.opendocument.text':
return {
ext: 'odt',
mime: 'application/vnd.oasis.opendocument.text',
};
case 'application/vnd.oasis.opendocument.spreadsheet':
return {
ext: 'ods',
mime: 'application/vnd.oasis.opendocument.spreadsheet',
};
case 'application/vnd.oasis.opendocument.presentation':
return {
ext: 'odp',
mime: 'application/vnd.oasis.opendocument.presentation',
};
default:
case '[Content_Types].xml':
return {
async handler(fileData) {
// Use TextDecoder to decode the UTF-8 encoded data
let xmlContent = new TextDecoder('utf-8').decode(fileData);
const endPos = xmlContent.indexOf('.main+xml"');
if (endPos >= 0) {
xmlContent = xmlContent.slice(0, Math.max(0, endPos));
const firstPos = xmlContent.lastIndexOf('"');
const mimeType = xmlContent.slice(Math.max(0, firstPos + 1));
fileType = getFileTypeFromMimeType(mimeType);
} else {
const mimeType = 'application/vnd.ms-package.3dmanufacturing-3dmodel+xml';
if (xmlContent.includes(`ContentType="${mimeType}"`)) {
fileType = getFileTypeFromMimeType(mimeType);
}
}
},
stop: true,
};
default:
if (/classes\d*\.dex/.test(zipHeader.filename)) {
fileType = {
ext: 'apk',
mime: 'application/vnd.android.package-archive',
};
return {stop: true};
}
}

// Try to find next header manually when current one is corrupted
if (zipHeader.compressedSize === 0) {
let nextHeaderIndex = -1;

while (nextHeaderIndex < 0 && (tokenizer.position < tokenizer.fileInfo.size)) {
await tokenizer.peekBuffer(this.buffer, {mayBeLess: true});

nextHeaderIndex = indexOf(this.buffer, new Uint8Array([0x50, 0x4B, 0x03, 0x04]));

// Move position to the next header if found, skip the whole buffer otherwise
await tokenizer.ignore(nextHeaderIndex >= 0 ? nextHeaderIndex : this.buffer.length);
}
} else {
await tokenizer.ignore(zipHeader.compressedSize);
}
return {};
}
} catch (error) {
if (!(error instanceof strtok3.EndOfStreamError)) {
throw error;
}
}
});

return {
return fileType ?? {
ext: 'zip',
mime: 'application/zip',
};
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4 changes: 2 additions & 2 deletions package.json
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Original file line number Diff line number Diff line change
Expand Up @@ -220,8 +220,8 @@
"apk"
],
"dependencies": {
"get-stream": "^9.0.1",
"strtok3": "^10.0.0",
"@tokenizer/inflate": "^0.2.3",
"strtok3": "^10.0.1",
"token-types": "^6.0.0",
"uint8array-extras": "^1.3.0"
},
Expand Down

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