rudeshark.net/src/misc/get-file-info.ts

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import * as fs from 'fs';
import * as crypto from 'crypto';
import * as fileType from 'file-type';
import isSvg from 'is-svg';
import * as probeImageSize from 'probe-image-size';
import * as sharp from 'sharp';
export type FileInfo = {
size: number;
md5: string;
type: {
mime: string;
ext: string | null;
};
width?: number;
height?: number;
avgColor?: number[];
warnings: string[];
};
const TYPE_OCTET_STREAM = {
mime: 'application/octet-stream',
ext: null
};
const TYPE_SVG = {
mime: 'image/svg+xml',
ext: 'svg'
};
/**
* Get file information
*/
export async function getFileInfo(path: string): Promise<FileInfo> {
const warnings = [] as string[];
const size = await getFileSize(path);
const md5 = await calcHash(path);
let type = await detectType(path);
// image dimensions
let width: number | undefined;
let height: number | undefined;
if (['image/jpeg', 'image/gif', 'image/png', 'image/apng', 'image/webp', 'image/bmp', 'image/tiff', 'image/svg+xml', 'image/vnd.adobe.photoshop'].includes(type.mime)) {
const imageSize = await detectImageSize(path).catch(e => {
warnings.push(`detectImageSize failed: ${e}`);
return undefined;
});
// うまく判定できない画像は octet-stream にする
if (!imageSize) {
warnings.push(`cannot detect image dimensions`);
type = TYPE_OCTET_STREAM;
} else if (imageSize.wUnits === 'px') {
width = imageSize.width;
height = imageSize.height;
// 制限を超えている画像は octet-stream にする
if (imageSize.width > 16383 || imageSize.height > 16383) {
warnings.push(`image dimensions exceeds limits`);
type = TYPE_OCTET_STREAM;
}
} else {
warnings.push(`unsupported unit type: ${imageSize.wUnits}`);
}
}
// average color
let avgColor: number[] | undefined;
if (['image/jpeg', 'image/gif', 'image/png', 'image/apng', 'image/webp', 'image/svg+xml'].includes(type.mime)) {
avgColor = await calcAvgColor(path).catch(e => {
warnings.push(`calcAvgColor failed: ${e}`);
return undefined;
});
}
return {
size,
md5,
type,
width,
height,
avgColor,
warnings,
};
}
/**
* Detect MIME Type and extension
*/
export async function detectType(path: string) {
// Check 0 byte
const fileSize = await getFileSize(path);
if (fileSize === 0) {
return TYPE_OCTET_STREAM;
}
const type = await fileType.fromFile(path);
if (type) {
// XMLはSVGかもしれない
if (type.mime === 'application/xml' && await checkSvg(path)) {
return TYPE_SVG;
}
return {
mime: type.mime,
ext: type.ext
};
}
// 種類が不明でもSVGかもしれない
if (await checkSvg(path)) {
return TYPE_SVG;
}
// それでも種類が不明なら application/octet-stream にする
return TYPE_OCTET_STREAM;
}
/**
* Check the file is SVG or not
*/
export async function checkSvg(path: string) {
try {
const size = await getFileSize(path);
if (size > 1 * 1024 * 1024) return false;
return isSvg(fs.readFileSync(path));
} catch {
return false;
}
}
/**
* Get file size
*/
export async function getFileSize(path: string): Promise<number> {
return new Promise<number>((res, rej) => {
fs.stat(path, (err, stats) => {
if (err) return rej(err);
res(stats.size);
});
});
}
/**
* Calculate MD5 hash
*/
async function calcHash(path: string): Promise<string> {
return new Promise<string>((res, rej) => {
const readable = fs.createReadStream(path);
const hash = crypto.createHash('md5');
const chunks: Buffer[] = [];
readable
.on('error', rej)
.pipe(hash)
.on('error', rej)
.on('data', chunk => chunks.push(chunk))
.on('end', () => {
const buffer = Buffer.concat(chunks);
res(buffer.toString('hex'));
});
});
}
/**
* Detect dimensions of image
*/
async function detectImageSize(path: string): Promise<{
width: number;
height: number;
wUnits: string;
hUnits: string;
}> {
const readable = fs.createReadStream(path);
const imageSize = await probeImageSize(readable);
readable.destroy();
return imageSize;
}
/**
* Calculate average color of image
*/
async function calcAvgColor(path: string): Promise<number[]> {
const img = sharp(path);
const info = await (img as any).stats();
if (info.isOpaque) {
const r = Math.round(info.channels[0].mean);
const g = Math.round(info.channels[1].mean);
const b = Math.round(info.channels[2].mean);
return [r, g, b];
} else {
return [255, 255, 255];
}
}