import Mime from "@effect/platform-node/Mime"; export const IMAGE_EXTENSION_BY_MIME_TYPE: Record<string, string> = { "image/avif": ".avif", "image/bmp": ".bmp", "image/gif": ".gif", "image/heic": ".heic", "image/heif": ".heif", "image/jpeg": ".jpg", "image/jpg": ".jpg", "image/png": ".png", "image/svg+xml": ".svg", "image/tiff": ".tiff", "image/webp": ".webp",}; export const SAFE_IMAGE_FILE_EXTENSIONS = new Set([ ".avif", ".bmp", ".gif", ".heic", ".heif", ".ico", ".jpeg", ".jpg", ".png", ".svg", ".tiff", ".webp",]); // Whether `code` is a character the base64 payload may contain, aside from// the whitespace handled separately below.function isBase64Char(code: number): boolean { return ( (code >= 0x61 && code <= 0x7a) || // a-z (code >= 0x41 && code <= 0x5a) || // A-Z (code >= 0x30 && code <= 0x39) || // 0-9 code === 0x2b || // + code === 0x2f || // / code === 0x3d // = );} function isBase64Whitespace(code: number): boolean { return code === 0x0d || code === 0x0a || code === 0x20; // \r \n space} // Data URLs carry the full image payload, so this parser must never run a// regex across the payload: V8's regex engine borrows the JS call stack, and// matching a multi-megabyte string from a deep call stack (e.g. inside fiber// execution) throws "Maximum call stack size exceeded".export function parseBase64DataUrl( dataUrl: string,): { readonly mimeType: string; readonly base64: string } | null { const trimmed = dataUrl.trim(); if (trimmed.slice(0, 5).toLowerCase() !== "data:") return null; const commaIndex = trimmed.indexOf(","); if (commaIndex === -1) return null; const header = trimmed.slice(5, commaIndex); if (header.length === 0) return null; const headerParts: Array<string> = []; for (const part of header.split(";")) { const partTrimmed = part.trim(); if (partTrimmed.length > 0) { headerParts.push(partTrimmed); } } if (headerParts.length < 2) { return null; } const trailingToken = headerParts.at(-1)?.toLowerCase(); if (trailingToken !== "base64") { return null; } const mimeType = headerParts[0]?.toLowerCase(); if (!mimeType) return null; const payload = trimmed.slice(commaIndex + 1); const runs: Array<string> = []; let runStart = -1; for (let index = 0; index < payload.length; index += 1) { const code = payload.charCodeAt(index); if (isBase64Char(code)) { if (runStart === -1) runStart = index; continue; } if (!isBase64Whitespace(code)) return null; if (runStart !== -1) { runs.push(payload.slice(runStart, index)); runStart = -1; } } if (runStart !== -1) { runs.push(payload.slice(runStart)); } const base64 = runs.length === 1 ? runs[0]! : runs.join(""); if (base64.length === 0 || base64.length % 4 !== 0) return null; const firstPad = base64.indexOf("="); if (firstPad !== -1) { // '=' is only valid as one or two trailing padding characters; Node's // decoder would otherwise silently truncate at the first '='. if (base64.length - firstPad > 2) return null; for (let index = firstPad; index < base64.length; index += 1) { if (base64.charCodeAt(index) !== 0x3d) return null; } } return { mimeType, base64 };} export function inferImageExtension(input: { mimeType: string; fileName?: string }): string { const key = input.mimeType.toLowerCase(); const fromMime = Object.hasOwn(IMAGE_EXTENSION_BY_MIME_TYPE, key) ? IMAGE_EXTENSION_BY_MIME_TYPE[key] : undefined; if (fromMime) { return fromMime; } const fromMimeExtension = Mime.getExtension(input.mimeType); if (fromMimeExtension && SAFE_IMAGE_FILE_EXTENSIONS.has(fromMimeExtension)) { return fromMimeExtension; } const fileName = input.fileName?.trim() ?? ""; const extensionMatch = /\.([a-z0-9]{1,8})$/i.exec(fileName); const fileNameExtension = extensionMatch ? `.${extensionMatch[1]!.toLowerCase()}` : ""; if (SAFE_IMAGE_FILE_EXTENSIONS.has(fileNameExtension)) { return fileNameExtension; } return ".bin";}
import Mime from "@effect/platform-node/Mime";
export const IMAGE_EXTENSION_BY_MIME_TYPE: Record<string, string> = {
"image/avif": ".avif",
"image/bmp": ".bmp",
"image/gif": ".gif",
"image/heic": ".heic",
"image/heif": ".heif",
"image/jpeg": ".jpg",
"image/jpg": ".jpg",
"image/png": ".png",
"image/svg+xml": ".svg",
"image/tiff": ".tiff",
"image/webp": ".webp",
};
export const SAFE_IMAGE_FILE_EXTENSIONS = new Set([
".avif",
".bmp",
".gif",
".heic",
".heif",
".ico",
".jpeg",
".jpg",
".png",
".svg",
".tiff",
".webp",
]);
// Whether `code` is a character the base64 payload may contain, aside from
// the whitespace handled separately below.
function isBase64Char(code: number): boolean {
return (
(code >= 0x61 && code <= 0x7a) || // a-z
(code >= 0x41 && code <= 0x5a) || // A-Z
(code >= 0x30 && code <= 0x39) || // 0-9
code === 0x2b || // +
code === 0x2f || // /
code === 0x3d // =
);
}
function isBase64Whitespace(code: number): boolean {
return code === 0x0d || code === 0x0a || code === 0x20; // \r \n space
}
// Data URLs carry the full image payload, so this parser must never run a
// regex across the payload: V8's regex engine borrows the JS call stack, and
// matching a multi-megabyte string from a deep call stack (e.g. inside fiber
// execution) throws "Maximum call stack size exceeded".
export function parseBase64DataUrl(
dataUrl: string,
): { readonly mimeType: string; readonly base64: string } | null {
const trimmed = dataUrl.trim();
if (trimmed.slice(0, 5).toLowerCase() !== "data:") return null;
const commaIndex = trimmed.indexOf(",");
if (commaIndex === -1) return null;
const header = trimmed.slice(5, commaIndex);
if (header.length === 0) return null;
const headerParts: Array<string> = [];
for (const part of header.split(";")) {
const partTrimmed = part.trim();
if (partTrimmed.length > 0) {
headerParts.push(partTrimmed);
}
}
if (headerParts.length < 2) {
return null;
}
const trailingToken = headerParts.at(-1)?.toLowerCase();
if (trailingToken !== "base64") {
return null;
}
const mimeType = headerParts[0]?.toLowerCase();
if (!mimeType) return null;
const payload = trimmed.slice(commaIndex + 1);
const runs: Array<string> = [];
let runStart = -1;
for (let index = 0; index < payload.length; index += 1) {
const code = payload.charCodeAt(index);
if (isBase64Char(code)) {
if (runStart === -1) runStart = index;
continue;
}
if (!isBase64Whitespace(code)) return null;
if (runStart !== -1) {
runs.push(payload.slice(runStart, index));
runStart = -1;
}
}
if (runStart !== -1) {
runs.push(payload.slice(runStart));
}
const base64 = runs.length === 1 ? runs[0]! : runs.join("");
if (base64.length === 0 || base64.length % 4 !== 0) return null;
const firstPad = base64.indexOf("=");
if (firstPad !== -1) {
// '=' is only valid as one or two trailing padding characters; Node's
// decoder would otherwise silently truncate at the first '='.
if (base64.length - firstPad > 2) return null;
for (let index = firstPad; index < base64.length; index += 1) {
if (base64.charCodeAt(index) !== 0x3d) return null;
}
}
return { mimeType, base64 };
}
export function inferImageExtension(input: { mimeType: string; fileName?: string }): string {
const key = input.mimeType.toLowerCase();
const fromMime = Object.hasOwn(IMAGE_EXTENSION_BY_MIME_TYPE, key)
? IMAGE_EXTENSION_BY_MIME_TYPE[key]
: undefined;
if (fromMime) {
return fromMime;
}
const fromMimeExtension = Mime.getExtension(input.mimeType);
if (fromMimeExtension && SAFE_IMAGE_FILE_EXTENSIONS.has(fromMimeExtension)) {
return fromMimeExtension;
}
const fileName = input.fileName?.trim() ?? "";
const extensionMatch = /\.([a-z0-9]{1,8})$/i.exec(fileName);
const fileNameExtension = extensionMatch ? `.${extensionMatch[1]!.toLowerCase()}` : "";
if (SAFE_IMAGE_FILE_EXTENSIONS.has(fileNameExtension)) {
return fileNameExtension;
}
return ".bin";
}