feat(files): add Markdown PDF download

apps/sim/app/api/files/export/[id]/markdown-pdf.test.ts

@@ -0,0 +1,231 @@
+/**
+ * @vitest-environment node
+ */
+import { PDFDocument } from 'pdf-lib'
+import { getDocument, OPS } from 'pdfjs-dist/legacy/build/pdf.mjs'
+import sharp from 'sharp'
+import { describe, expect, it } from 'vitest'
+import { MarkdownPdfLimitError, renderMarkdownPdf } from '@/app/api/files/export/[id]/markdown-pdf'
+
+async function pdfPagesText(buffer: Buffer): Promise<string[]> {
+  const document = await getDocument({ data: new Uint8Array(buffer), disableWorker: true }).promise
+  try {
+    return await Promise.all(
+      Array.from({ length: document.numPages }, async (_, index) => {
+        const page = await document.getPage(index + 1)
+        const content = await page.getTextContent()
+        return content.items.map((item) => ('str' in item ? item.str : '')).join(' ')
+      })
+    )
+  } finally {
+    await document.destroy()
+  }
+}
+
+describe('Markdown PDF rendering', () => {
+  it('creates a valid multi-page PDF with GFM and an embedded image', async () => {
+    const imageKey = 'workspace/ws-1/editor-image.png'
+    const imageUrl = `/api/files/serve/${encodeURIComponent(imageKey)}?context=workspace`
+    const image = await sharp({
+      create: {
+        width: 120,
+        height: 60,
+        channels: 3,
+        background: '#4f46e5',
+      },
+    })
+      .png()
+      .toBuffer()
+    const repeatedParagraphs = Array.from(
+      { length: 70 },
+      (_, index) => `Paragraph ${index + 1} with **bold**, _italic_, and \`inline code\`.`
+    ).join('\n\n')
+    const markdown = `# Export title
+
+> A useful blockquote with a [link](https://sim.ai).
+
+Smart quotes “work” and Greek Ω stays readable.
+
+Common emoji stay readable too: 🚀 😀
+
+中文排版应该清晰易读。 العربية يجب أن تكون متصلة ومقروءة. हिन्दी पाठ स्पष्ट और पठनीय होना चाहिए। עברית צריכה להיות ברורה וקריאה.
+
+- First item
+- Second item
+
+| Name | Value |
+| --- | ---: |
+| Alpha | 1 |
+| Beta | 2 |
+
+\`\`\`ts
+const exported = true
+\`\`\`
+
+![Embedded image](${imageUrl})
+
+<img src="${imageUrl}" alt="Resized image" width="240" height="120">
+
+${repeatedParagraphs}`
+
+    const buffer = await renderMarkdownPdf({
+      markdown,
+      title: 'Export title',
+      images: new Map([[`key:${imageKey}`, image]]),
+    })
+
+    expect(buffer.subarray(0, 4).toString()).toBe('%PDF')
+    expect(buffer.length).toBeGreaterThan(1_000)
+
+    const document = await PDFDocument.load(buffer)
+    expect(document.getTitle()).toBe('Export title')
+    expect(document.getPageCount()).toBeGreaterThan(1)
+
+    const text = (await pdfPagesText(buffer)).join(' ')
+    expect(text).toContain('中文排版应该清晰易读')
+    expect(text).toContain('العربية')
+    // PDF extractors expose visually positioned Indic vowel marks before their base character.
+    expect(text).toMatch(/[\u0900-\u097f]{4,}/u)
+    expect(text).toContain('עברית')
+    expect(text).toContain('[emoji U+1F680]')
+    expect(text).toContain('[emoji U+1F600]')
+    expect(text).not.toContain('�')
+    expect(text).not.toContain('Image: Embedded image')
+
+    const parsed = await getDocument({ data: new Uint8Array(buffer), disableWorker: true }).promise
+    try {
+      let imagePaints = 0
+      for (let pageNumber = 1; pageNumber <= parsed.numPages; pageNumber += 1) {
+        const operators = await (await parsed.getPage(pageNumber)).getOperatorList()
+        imagePaints += operators.fnArray.filter(
+          (operator) =>
+            operator === OPS.paintImageXObject || operator === OPS.paintInlineImageXObject
+        ).length
+      }
+      expect(imagePaints).toBeGreaterThanOrEqual(2)
+    } finally {
+      await parsed.destroy()
+    }
+  })
+
+  it('lets a long table paginate without moving the whole table to a later page', async () => {
+    const rows = Array.from(
+      { length: 90 },
+      (_, index) =>
+        `| Row ${index + 1} | Description ${index + 1} with enough text to exercise wrapping |`
+    ).join('\n')
+    const buffer = await renderMarkdownPdf({
+      markdown: `# Table report\n\n| Name | Value |\n| --- | --- |\n${rows}`,
+      title: 'Table report',
+    })
+
+    const pages = await pdfPagesText(buffer)
+    const tablePages = pages.filter((page) => page.includes('Row '))
+    expect(tablePages.length).toBeGreaterThan(1)
+    expect(pages[0]).toContain('Row 1')
+    expect(pages.join(' ')).toContain('Row 90')
+  })
+
+  it('allows a table row taller than a page to wrap without losing its content', async () => {
+    const cell = `ROW-START ${'wrapping table content '.repeat(900)} ROW-END`
+    const buffer = await renderMarkdownPdf({
+      markdown: `| Name | Value |\n| --- | --- |\n| Tall row | ${cell} |`,
+      title: 'Tall table row',
+    })
+
+    const pages = await pdfPagesText(buffer)
+    expect(pages.length).toBeGreaterThan(1)
+    expect(pages.join(' ')).toContain('ROW-START')
+    expect(pages.join(' ')).toContain('ROW-END')
+  })
+
+  it('renders a table that contains only a header', async () => {
+    const buffer = await renderMarkdownPdf({
+      markdown: '| Name | Value |\n| --- | --- |',
+      title: 'Header-only table',
+    })
+
+    const text = (await pdfPagesText(buffer)).join(' ')
+    expect(text).toContain('Name')
+    expect(text).toContain('Value')
+  })
+
+  it('preserves links on linked-image fallbacks', async () => {
+    const destination = 'https://sim.ai/docs'
+    const buffer = await renderMarkdownPdf({
+      markdown: `[![Documentation badge](https://example.com/badge.svg)](${destination})`,
+      title: 'Linked image',
+    })
+
+    const document = await getDocument({ data: new Uint8Array(buffer), disableWorker: true })
+      .promise
+    try {
+      const annotations = await (await document.getPage(1)).getAnnotations()
+      expect(annotations.some((annotation) => annotation.url === destination)).toBe(true)
+    } finally {
+      await document.destroy()
+    }
+  })
+
+  it('preserves GFM table-cell alignment', async () => {
+    const buffer = await renderMarkdownPdf({
+      markdown: `| LEFTVALUE |
+| :--- |
+| left |
+
+| CENTERVALUE |
+| :---: |
+| center |
+
+| RIGHTVALUE |
+| ---: |
+| right |`,
+      title: 'Aligned tables',
+    })
+
+    const document = await getDocument({ data: new Uint8Array(buffer), disableWorker: true })
+      .promise
+    try {
+      const content = await (await document.getPage(1)).getTextContent()
+      const textX = (value: string) => {
+        const item = content.items.find(
+          (candidate) => 'str' in candidate && candidate.str === value
+        )
+        expect(item && 'transform' in item).toBe(true)
+        return item && 'transform' in item ? item.transform[4] : 0
+      }
+      const leftX = textX('LEFTVALUE')
+      const centerX = textX('CENTERVALUE')
+      const rightX = textX('RIGHTVALUE')
+
+      expect(centerX - leftX).toBeGreaterThan(100)
+      expect(rightX - centerX).toBeGreaterThan(100)
+    } finally {
+      await document.destroy()
+    }
+  })
+
+  it('falls back instead of decoding an image above the pixel ceiling', async () => {
+    const oversizedSvg = Buffer.from(
+      '<svg xmlns="http://www.w3.org/2000/svg" width="20000" height="20000"><rect width="100%" height="100%" fill="red"/></svg>'
+    )
+
+    const buffer = await renderMarkdownPdf({
+      markdown: '![Too large](/api/files/view/image-1)',
+      title: 'Bounded image',
+      images: new Map([['id:image-1', oversizedSvg]]),
+    })
+
+    expect(buffer.subarray(0, 4).toString()).toBe('%PDF')
+    expect((await PDFDocument.load(buffer)).getPageCount()).toBe(1)
+    expect((await pdfPagesText(buffer)).join(' ')).toContain('Image: Too large')
+  })
+
+  it('rejects a pathological number of document blocks before PDF layout', async () => {
+    const markdown = Array.from({ length: 3_001 }, (_, index) => `Paragraph ${index}`).join('\n\n')
+
+    await expect(renderMarkdownPdf({ markdown, title: 'Too many blocks' })).rejects.toBeInstanceOf(
+      MarkdownPdfLimitError
+    )
+  })
+})