adrianbonpin
cd72b7a948
- Move web app into apps/web/ - Create packages/shared/ with shared types - Create plugins/decky-vault/ scaffold - Root package.json manages workspaces only
98 lines
3.2 KiB
TypeScript
98 lines
3.2 KiB
TypeScript
import sharp from "sharp"
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const MAX_WIDTH = 1920
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const MAX_HEIGHT = 1080
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const QUALITY_HIGH = 80
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const QUALITY_FLOOR = 75
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const MAX_SIZE_BYTES = 400 * 1024 // 400 KB
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const FALLBACK_WIDTH = 1280
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const FALLBACK_HEIGHT = 720
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const ALLOWED_MIME_TYPES = ["image/jpeg", "image/png", "image/webp"]
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// Magic byte signatures for file type validation
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const MAGIC_BYTES: Record<string, number[]> = {
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"image/jpeg": [0xff, 0xd8, 0xff],
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"image/png": [0x89, 0x50, 0x4e, 0x47],
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"image/webp": [0x52, 0x49, 0x46, 0x46], // RIFF header (WEBP container)
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}
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export function validateMagicBytes(buffer: Buffer, declaredMime: string): boolean {
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const expected = MAGIC_BYTES[declaredMime]
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if (!expected) return false
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if (buffer.length < expected.length) return false
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return expected.every((byte, i) => buffer[i] === byte)
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}
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export function isAllowedMimeType(mimeType: string): boolean {
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return ALLOWED_MIME_TYPES.includes(mimeType)
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}
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export interface ProcessedImage {
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buffer: Buffer
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width: number
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height: number
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mimeType: string // Always "image/jpeg" after processing
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size: number
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}
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/**
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* Process a screenshot for storage:
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* 1. Validate format via magic bytes
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* 2. Resize to max 1920×1080, maintain aspect ratio
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* 3. Convert to progressive JPEG
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* 4. If size > 400KB, reduce quality to 75
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* 5. If still > 400KB at quality 75, resize to 1280×720 and try again
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* 6. Strip ALL EXIF data
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*/
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export async function processScreenshot(
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inputBuffer: Buffer,
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declaredMime: string,
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): Promise<ProcessedImage> {
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if (!isAllowedMimeType(declaredMime)) {
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throw new Error(`Invalid MIME type: ${declaredMime}`)
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}
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if (!validateMagicBytes(inputBuffer, declaredMime)) {
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throw new Error("File content does not match declared type")
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}
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let pipeline = sharp(inputBuffer, { animated: false })
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.rotate() // Auto-rotate based on EXIF orientation
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.resize(MAX_WIDTH, MAX_HEIGHT, { fit: "inside", withoutEnlargement: true })
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.jpeg({ quality: QUALITY_HIGH, progressive: true, mozjpeg: true })
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// Metadata is stripped by default (no .withMetadata() / .keepMetadata() call)
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let outputBuffer = await pipeline.toBuffer()
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let metadata = await sharp(outputBuffer).metadata()
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// If still over 400KB, reduce quality to floor
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if (outputBuffer.length > MAX_SIZE_BYTES) {
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pipeline = sharp(inputBuffer, { animated: false })
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.rotate()
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.resize(MAX_WIDTH, MAX_HEIGHT, { fit: "inside", withoutEnlargement: true })
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.jpeg({ quality: QUALITY_FLOOR, progressive: true, mozjpeg: true })
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outputBuffer = await pipeline.toBuffer()
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metadata = await sharp(outputBuffer).metadata()
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}
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// If STILL over 400KB, downscale to 1280×720
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if (outputBuffer.length > MAX_SIZE_BYTES) {
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pipeline = sharp(inputBuffer, { animated: false })
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.rotate()
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.resize(FALLBACK_WIDTH, FALLBACK_HEIGHT, { fit: "inside", withoutEnlargement: true })
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.jpeg({ quality: QUALITY_FLOOR, progressive: true, mozjpeg: true })
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outputBuffer = await pipeline.toBuffer()
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metadata = await sharp(outputBuffer).metadata()
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}
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return {
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buffer: outputBuffer,
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width: metadata.width ?? FALLBACK_WIDTH,
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height: metadata.height ?? FALLBACK_HEIGHT,
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mimeType: "image/jpeg",
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size: outputBuffer.length,
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}
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} |