---
title: "@cmtx/markdown-it-presigned-url-adapter-nodejs"
category: guide
sidebar_order: 99
sidebar_group: "@cmtx/markdown-it-presigned-url-adapter-nodejs"
lang: en
---

# @cmtx/markdown-it-presigned-url-adapter-nodejs

[![npm version](https://img.shields.io/npm/v/@cmtx/markdown-it-presigned-url-adapter-nodejs.svg)](https://www.npmjs.com/package/@cmtx/markdown-it-presigned-url-adapter-nodejs)

Node.js adapter for `@cmtx/markdown-it-presigned-url`. Implements URL signing and cache management for OSS/COS presigned URLs.

## 1. Installation

```bash
pnpm add @cmtx/markdown-it-presigned-url-adapter-nodejs
```

## 2. Quick Start

```typescript
import { createUrlSigner, createUrlCacheManager } from "@cmtx/markdown-it-presigned-url-adapter-nodejs";
import { createStorage } from "@cmtx/storage";
import MarkdownIt from "markdown-it";
import { presignedUrlPlugin } from "@cmtx/markdown-it-presigned-url";

const storage = createStorage({ provider: "ali-oss", config: { /* ... */ } });
const signer = createUrlSigner(storage);
const cache = createUrlCacheManager();

const md = new MarkdownIt().use(presignedUrlPlugin, { signer, cache });

const html = md.render("![](image.png)");
```

## 3. API

### UrlSigner

Signs image URLs with presigned URLs from the configured storage provider.

```typescript
interface UrlSigner {
  sign(url: string): Promise<string>;
}
```

### UrlCacheManager

Manages a cache of signed URLs to avoid repeated signing requests.

```typescript
interface UrlCacheManager {
  get(url: string): string | undefined;
  set(url: string, signedUrl: string, ttl?: number): void;
  clear(): void;
}
```

### PresignedUrlCache

The underlying cache implementation with TTL support.

## 4. How It Works

1. markdown-it encounters an image URL
2. `@cmtx/markdown-it-presigned-url` intercepts it and delegates to `UrlSigner`
3. The adapter checks `UrlCacheManager` for a cached signed URL
4. If cache miss, it calls storage adapter to generate a presigned URL
5. The signed URL is cached and returned

## 5. Related Packages

- [`@cmtx/markdown-it-presigned-url`](../markdown-it-presigned-url/) — markdown-it plugin
- [`@cmtx/storage`](../storage/) — storage abstraction layer

## 6. Development

```bash
pnpm -F @cmtx/markdown-it-presigned-url-adapter-nodejs build
pnpm -F @cmtx/markdown-it-presigned-url-adapter-nodejs test
```