@extenshi/mcp/dist/project-media.js

Extenshi MCP server — bring the extension catalog (search, security, market research) and pre-publish scanning into your AI tools

/**
 * Client-side half of `upload_project_media`: turn a tool call into the BFF's
 * `{ mime, dataBase64 }` payload.
 *
 * The BFF is the real gate (magic bytes, metadata stripping, dimension and
 * quota limits). What only the client can decide is WHICH local file may be
 * read at all. The stdio server runs with the developer's filesystem, so a
 * `filePath` is confined to the workspace (the server's working directory):
 * a prompt-injected "upload ~/Pictures/passport.jpg" must not be able to
 * publish an arbitrary personal image to a public bucket. Files elsewhere go
 * through the CLI (`extenshi media upload`), where the path is on the command
 * line in front of the developer.
 */
import { readFile, realpath, stat } from 'node:fs/promises';
import path from 'node:path';
export const PROJECT_MEDIA_MAX_BYTES = 2 * 1024 * 1024;
export const PROJECT_MEDIA_MIME_TYPES = ['image/png', 'image/jpeg', 'image/webp'];
export class ProjectMediaInputError extends Error {
}
/** Same signatures the BFF accepts. Anything else (SVG, HTML, GIF) → null. */
export function sniffMediaMime(bytes) {
    const b = bytes;
    if (b.length >= 8 && b[0] === 0x89 && b[1] === 0x50 && b[2] === 0x4e && b[3] === 0x47)
        return 'image/png';
    if (b.length >= 3 && b[0] === 0xff && b[1] === 0xd8 && b[2] === 0xff)
        return 'image/jpeg';
    if (b.length >= 12 &&
        String.fromCharCode(b[0], b[1], b[2], b[3]) === 'RIFF' &&
        String.fromCharCode(b[8], b[9], b[10], b[11]) === 'WEBP')
        return 'image/webp';
    return null;
}
const NOT_AN_IMAGE = 'is not a PNG, JPEG or WebP image (checked by content). SVG is not accepted: rasterize it first ' +
    '(npx @extenshi/cli@latest icon store-assets <file.svg>) or pass an inline logo as logoSvg to publish_landing_page.';
/** Read a workspace-local image for upload. `root` is the workspace (default: cwd). */
export async function readWorkspaceImage(filePath, root = process.cwd()) {
    let resolved;
    let rootReal;
    try {
        resolved = await realpath(path.resolve(root, filePath));
        rootReal = await realpath(root);
    }
    catch {
        throw new ProjectMediaInputError(`File not found: ${filePath}`);
    }
    const relative = path.relative(rootReal, resolved);
    if (relative.startsWith('..') || path.isAbsolute(relative)) {
        throw new ProjectMediaInputError(`"${filePath}" is outside the workspace (${rootReal}). upload_project_media only reads files inside it; ` +
            'for other files run `npx @extenshi/cli@latest media upload <file> --project <id>` or send dataBase64.');
    }
    const info = await stat(resolved);
    if (!info.isFile())
        throw new ProjectMediaInputError(`"${filePath}" is not a file.`);
    if (info.size > PROJECT_MEDIA_MAX_BYTES) {
        throw new ProjectMediaInputError(`"${filePath}" is ${(info.size / 1024 / 1024).toFixed(1)} MB; the limit is 2 MB per image.`);
    }
    const bytes = await readFile(resolved);
    const mime = sniffMediaMime(bytes);
    if (!mime)
        throw new ProjectMediaInputError(`"${filePath}" ${NOT_AN_IMAGE}`);
    return { mime, dataBase64: bytes.toString('base64'), bytes: bytes.length };
}
/** Validate an inline payload the same way before it is sent. */
export function checkInlineImage(dataBase64, declared) {
    const bytes = Buffer.from(dataBase64.slice(0, 64), 'base64');
    const mime = sniffMediaMime(bytes);
    if (!mime)
        throw new ProjectMediaInputError(`dataBase64 ${NOT_AN_IMAGE}`);
    if (mime !== declared)
        throw new ProjectMediaInputError(`dataBase64 contains ${mime} but mime says ${declared}.`);
}
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