fix(react-ui): extract text from PDF attachments in chat and home (#12374)

The React UI read every non-media attachment with file.text(). For a PDF
that decodes the binary bytes as UTF-8, so the model received raw
"%PDF ... stream ... endobj" noise instead of the document. The legacy
Alpine UI ran pdf.js; that step was not ported when the React UI
replaced it, but both file pickers still advertise .pdf.

Add a shared readAttachmentText helper that routes PDFs through
pdfjs-dist and reads other files as before. pdf.js and its worker load
on first use, so the main bundle does not grow. A PDF that cannot be
parsed or has no text layer (scanned, encrypted, damaged) is rejected
with a toast instead of being attached as an empty or garbage file.

Cover the chat and home paths with Playwright specs that build a real
PDF in the test.

Assisted-by: Claude Code:claude-sonnet-5-5 [playwright] [eslint]

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Co-authored-by: Ettore Di Giacinto <mudler@localai.io>

core/http/react-ui/e2e/chat-pdf-attachment.spec.js

@@ -0,0 +1,97 @@
+import { test, expect } from './coverage-fixtures.js'
+
+// Single-page PDF with a real text layer, built byte by byte so the xref
+// offsets are valid and the spec needs no binary fixture.
+function buildPdf(text) {
+  const stream = `BT /F1 18 Tf 20 100 Td (${text}) Tj ET`
+  const objs = [
+    '<< /Type /Catalog /Pages 2 0 R >>',
+    '<< /Type /Pages /Kids [3 0 R] /Count 1 >>',
+    '<< /Type /Page /Parent 2 0 R /MediaBox [0 0 300 200] /Contents 4 0 R /Resources << /Font << /F1 5 0 R >> >> >>',
+    `<< /Length ${stream.length} >>\nstream\n${stream}\nendstream`,
+    '<< /Type /Font /Subtype /Type1 /BaseFont /Helvetica >>',
+  ]
+  let out = '%PDF-1.4\n'
+  const offsets = []
+  objs.forEach((body, i) => {
+    offsets.push(out.length)
+    out += `${i + 1} 0 obj\n${body}\nendobj\n`
+  })
+  const xref = out.length
+  out += `xref\n0 ${objs.length + 1}\n0000000000 65535 f \n`
+  for (const o of offsets) out += `${String(o).padStart(10, '0')} 00000 n \n`
+  out += `trailer\n<< /Size ${objs.length + 1} /Root 1 0 R >>\nstartxref\n${xref}\n%%EOF\n`
+  return Buffer.from(out, 'latin1')
+}
+
+async function openChat(page) {
+  await page.route('**/api/models/capabilities', (route) => {
+    route.fulfill({
+      contentType: 'application/json',
+      body: JSON.stringify({ data: [{ id: 'test-model', capabilities: ['FLAG_CHAT'] }] }),
+    })
+  })
+  await page.goto('/app/chat')
+  await expect(page.getByRole('button', { name: 'test-model' })).toBeVisible({ timeout: 10_000 })
+}
+
+test.describe('Chat - PDF attachments', () => {
+  test('sends the extracted text layer, not the raw PDF bytes', async ({ page }) => {
+    let requestBody = ''
+    await page.route('**/v1/chat/completions', (route) => {
+      requestBody = route.request().postData() || ''
+      route.fulfill({ status: 500, contentType: 'application/json', body: JSON.stringify({ error: { message: 'stop' } }) })
+    })
+    await openChat(page)
+
+    await page.locator('input[type=file]').setInputFiles({
+      name: 'report.pdf',
+      mimeType: 'application/pdf',
+      buffer: buildPdf('Quarterly revenue grew 42 percent'),
+    })
+    await expect(page.locator('.chat-file-name', { hasText: 'report.pdf' })).toBeVisible()
+
+    await page.locator('.chat-input').fill('Summarize')
+    await page.locator('.chat-send-btn').click()
+
+    await expect.poll(() => requestBody).toContain('Quarterly revenue grew 42 percent')
+    expect(requestBody).toContain('File: report.pdf')
+    expect(requestBody).not.toContain('%PDF')
+  })
+
+  test('rejects a PDF that cannot be parsed instead of attaching garbage', async ({ page }) => {
+    await openChat(page)
+
+    await page.locator('input[type=file]').setInputFiles({
+      name: 'broken.pdf',
+      mimeType: 'application/pdf',
+      buffer: Buffer.from('%PDF-1.4 this is not a real document'),
+    })
+
+    await expect(page.getByText('Could not read text from broken.pdf')).toBeVisible({ timeout: 10_000 })
+    await expect(page.locator('.chat-file-name', { hasText: 'broken.pdf' })).toHaveCount(0)
+  })
+})
+
+test.describe('Home - PDF attachments', () => {
+  test('attaches a PDF that has a text layer', async ({ page }) => {
+    await page.goto('/app')
+    await page.locator('input[type=file][accept*="pdf"]').setInputFiles({
+      name: 'notes.pdf',
+      mimeType: 'application/pdf',
+      buffer: buildPdf('Meeting notes for Tuesday'),
+    })
+    await expect(page.locator('.home-file-tag', { hasText: 'notes.pdf' })).toBeVisible({ timeout: 10_000 })
+  })
+
+  test('rejects a PDF that cannot be parsed', async ({ page }) => {
+    await page.goto('/app')
+    await page.locator('input[type=file][accept*="pdf"]').setInputFiles({
+      name: 'broken.pdf',
+      mimeType: 'application/pdf',
+      buffer: Buffer.from('%PDF-1.4 this is not a real document'),
+    })
+    await expect(page.getByText('Could not read text from broken.pdf')).toBeVisible({ timeout: 10_000 })
+    await expect(page.locator('.home-file-tag')).toHaveCount(0)
+  })
+})

core/http/react-ui/package-lock.json

@@ -29,6 +29,7 @@
         "i18next-browser-languagedetector": "^8.2.1",
         "i18next-http-backend": "^3.0.6",
         "marked": "^15.0.7",
+        "pdfjs-dist": "^5.6.205",
         "react": "^19.1.0",
         "react-dom": "^19.1.0",
         "react-i18next": "^17.0.6",
@@ -1021,6 +1022,256 @@
       "resolved": "https://registry.npmjs.org/json-schema-traverse/-/json-schema-traverse-1.0.0.tgz",
       "integrity": "sha512-NM8/P9n3XjXhIZn1lLhkFaACTOURQXjWhV4BA/RnOv8xvgqtqpAX9IO4mRQxSx1Rlo4tqzeqb0sOlruaOy3dug=="
     },
+    "node_modules/@napi-rs/canvas": {
+      "version": "0.1.100",
+      "resolved": "https://registry.npmjs.org/@napi-rs/canvas/-/canvas-0.1.100.tgz",
+      "integrity": "sha512-xglYA6q3XO5P3BNJYxVZ1IV7DLVjp1Py6nwag88YntrS+3vKHyYcMqXVS4ZztJmwz2uGvz1FWhI/4LgbR5uQDA==",
+      "license": "MIT",
+      "optional": true,
+      "workspaces": [
+        "e2e/*"
+      ],
+      "engines": {
+        "node": ">= 10"
+      },
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/Brooooooklyn"
+      },
+      "optionalDependencies": {
+        "@napi-rs/canvas-android-arm64": "0.1.100",
+        "@napi-rs/canvas-darwin-arm64": "0.1.100",
+        "@napi-rs/canvas-darwin-x64": "0.1.100",
+        "@napi-rs/canvas-linux-arm-gnueabihf": "0.1.100",
+        "@napi-rs/canvas-linux-arm64-gnu": "0.1.100",
+        "@napi-rs/canvas-linux-arm64-musl": "0.1.100",
+        "@napi-rs/canvas-linux-riscv64-gnu": "0.1.100",
+        "@napi-rs/canvas-linux-x64-gnu": "0.1.100",
+        "@napi-rs/canvas-linux-x64-musl": "0.1.100",
+        "@napi-rs/canvas-win32-arm64-msvc": "0.1.100",
+        "@napi-rs/canvas-win32-x64-msvc": "0.1.100"
+      }
+    },
+    "node_modules/@napi-rs/canvas-android-arm64": {
+      "version": "0.1.100",
+      "resolved": "https://registry.npmjs.org/@napi-rs/canvas-android-arm64/-/canvas-android-arm64-0.1.100.tgz",
+      "integrity": "sha512-hjhCKhntPv9+t4ckHymdx0phYNcVW+GKQR6Lzw2zE+pOVjOplSmtx9nNNknTjbEDLcuLZqA1y8ufKg1XfgftzQ==",
+      "cpu": [
+        "arm64"
+      ],
+      "license": "MIT",
+      "optional": true,
+      "os": [
+        "android"
+      ],
+      "engines": {
+        "node": ">= 10"
+      },
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/Brooooooklyn"
+      }
+    },
+    "node_modules/@napi-rs/canvas-darwin-arm64": {
+      "version": "0.1.100",
+      "resolved": "https://registry.npmjs.org/@napi-rs/canvas-darwin-arm64/-/canvas-darwin-arm64-0.1.100.tgz",
+      "integrity": "sha512-2PcswRaC7Ly645DGt88///zuFDhJxJYdKAs1uU3mfk1atYkXufgcgLfBpk6Tm12nCQBaNt1wpybuPZ4qOhTo8A==",
+      "cpu": [
+        "arm64"
+      ],
+      "license": "MIT",
+      "optional": true,
+      "os": [
+        "darwin"
+      ],
+      "engines": {
+        "node": ">= 10"
+      },
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/Brooooooklyn"
+      }
+    },
+    "node_modules/@napi-rs/canvas-darwin-x64": {
+      "version": "0.1.100",
+      "resolved": "https://registry.npmjs.org/@napi-rs/canvas-darwin-x64/-/canvas-darwin-x64-0.1.100.tgz",
+      "integrity": "sha512-ePNZtj7pNIva/siZMg+HmbeozkIjqUIYdoymH8HaA3qK7LfzFN4WMBM8G6HQ9ZC+H3+Dnn5pqtiXpgLykaPOhw==",
+      "cpu": [
+        "x64"
+      ],
+      "license": "MIT",
+      "optional": true,
+      "os": [
+        "darwin"
+      ],
+      "engines": {
+        "node": ">= 10"
+      },
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/Brooooooklyn"
+      }
+    },
+    "node_modules/@napi-rs/canvas-linux-arm-gnueabihf": {
+      "version": "0.1.100",
+      "resolved": "https://registry.npmjs.org/@napi-rs/canvas-linux-arm-gnueabihf/-/canvas-linux-arm-gnueabihf-0.1.100.tgz",
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+      "cpu": [
+        "arm"
+      ],
+      "license": "MIT",
+      "optional": true,
+      "os": [
+        "linux"
+      ],
+      "engines": {
+        "node": ">= 10"
+      },
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/Brooooooklyn"
+      }
+    },
+    "node_modules/@napi-rs/canvas-linux-arm64-gnu": {
+      "version": "0.1.100",
+      "resolved": "https://registry.npmjs.org/@napi-rs/canvas-linux-arm64-gnu/-/canvas-linux-arm64-gnu-0.1.100.tgz",
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+        "node": ">= 10"
+      },
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/Brooooooklyn"
+      }
+    },
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+      "version": "0.1.100",
+      "resolved": "https://registry.npmjs.org/@napi-rs/canvas-linux-arm64-musl/-/canvas-linux-arm64-musl-0.1.100.tgz",
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+        "arm64"
+      ],
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+      "optional": true,
+      "os": [
+        "linux"
+      ],
+      "engines": {
+        "node": ">= 10"
+      },
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/Brooooooklyn"
+      }
+    },
+    "node_modules/@napi-rs/canvas-linux-riscv64-gnu": {
+      "version": "0.1.100",
+      "resolved": "https://registry.npmjs.org/@napi-rs/canvas-linux-riscv64-gnu/-/canvas-linux-riscv64-gnu-0.1.100.tgz",
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+      "cpu": [
+        "riscv64"
+      ],
+      "license": "MIT",
+      "optional": true,
+      "os": [
+        "linux"
+      ],
+      "engines": {
+        "node": ">= 10"
+      },
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/Brooooooklyn"
+      }
+    },
+    "node_modules/@napi-rs/canvas-linux-x64-gnu": {
+      "version": "0.1.100",
+      "resolved": "https://registry.npmjs.org/@napi-rs/canvas-linux-x64-gnu/-/canvas-linux-x64-gnu-0.1.100.tgz",
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+        "x64"
+      ],
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+      "optional": true,
+      "os": [
+        "linux"
+      ],
+      "engines": {
+        "node": ">= 10"
+      },
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/Brooooooklyn"
+      }
+    },
+    "node_modules/@napi-rs/canvas-linux-x64-musl": {
+      "version": "0.1.100",
+      "resolved": "https://registry.npmjs.org/@napi-rs/canvas-linux-x64-musl/-/canvas-linux-x64-musl-0.1.100.tgz",
+      "integrity": "sha512-20arT6lnI19S68qNlii73TSEDbECNgzMz2EpldC1V3mZFuRkeujXkcebRk0LRJe9SEUAooYiLokfMViY8IX7yA==",
+      "cpu": [
+        "x64"
+      ],
+      "license": "MIT",
+      "optional": true,
+      "os": [
+        "linux"
+      ],
+      "engines": {
+        "node": ">= 10"
+      },
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/Brooooooklyn"
+      }
+    },
+    "node_modules/@napi-rs/canvas-win32-arm64-msvc": {
+      "version": "0.1.100",
+      "resolved": "https://registry.npmjs.org/@napi-rs/canvas-win32-arm64-msvc/-/canvas-win32-arm64-msvc-0.1.100.tgz",
+      "integrity": "sha512-DZFFT1wIAg37LJw37yhMRFfjATd3vTQzjZ1Yki8u2vhO6Hi5VE6BVaGQ1aaDu7xb4iMErz+9EOwjpS7xcxFeBw==",
+      "cpu": [
+        "arm64"
+      ],
+      "license": "MIT",
+      "optional": true,
+      "os": [
+        "win32"
+      ],
+      "engines": {
+        "node": ">= 10"
+      },
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/Brooooooklyn"
+      }
+    },
+    "node_modules/@napi-rs/canvas-win32-x64-msvc": {
+      "version": "0.1.100",
+      "resolved": "https://registry.npmjs.org/@napi-rs/canvas-win32-x64-msvc/-/canvas-win32-x64-msvc-0.1.100.tgz",
+      "integrity": "sha512-MyT1j3mHC2+Lu4pBi9mKyMJhtP6U7k7EldY7sj/uS5gJA65gTXt8MefJQXLJo5d/vZbuWmfxzkEUNc/urV3pHA==",
+      "cpu": [
+        "x64"
+      ],
+      "license": "MIT",
+      "optional": true,
+      "os": [
+        "win32"
+      ],
+      "engines": {
+        "node": ">= 10"
+      },
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/Brooooooklyn"
+      }
+    },
     "node_modules/@napi-rs/wasm-runtime": {
       "version": "1.1.5",
       "resolved": "https://registry.npmjs.org/@napi-rs/wasm-runtime/-/wasm-runtime-1.1.5.tgz",
@@ -5219,6 +5470,13 @@
         "node": ">=8"
       }
     },
+    "node_modules/node-readable-to-web-readable-stream": {
+      "version": "0.4.2",
+      "resolved": "https://registry.npmjs.org/node-readable-to-web-readable-stream/-/node-readable-to-web-readable-stream-0.4.2.tgz",
+      "integrity": "sha512-/cMZNI34v//jUTrI+UIo4ieHAB5EZRY/+7OmXZgBxaWBMcW2tGdceIw06RFxWxrKZ5Jp3sI2i5TsRo+CBhtVLQ==",
+      "license": "MIT",
+      "optional": true
+    },
     "node_modules/node-releases": {
       "version": "2.0.54",
       "resolved": "https://registry.npmjs.org/node-releases/-/node-releases-2.0.54.tgz",
@@ -5752,6 +6010,19 @@
         "url": "https://opencollective.com/express"
       }
     },
+    "node_modules/pdfjs-dist": {
+      "version": "5.6.205",
+      "resolved": "https://registry.npmjs.org/pdfjs-dist/-/pdfjs-dist-5.6.205.tgz",
+      "integrity": "sha512-tlUj+2IDa7G1SbvBNN74UHRLJybZDWYom+k6p5KIZl7huBvsA4APi6mKL+zCxd3tLjN5hOOEE9Tv7VdzO88pfg==",
+      "license": "Apache-2.0",
+      "engines": {
+        "node": ">=20.19.0 || >=22.13.0 || >=24"
+      },
+      "optionalDependencies": {
+        "@napi-rs/canvas": "^0.1.96",
+        "node-readable-to-web-readable-stream": "^0.4.2"
+      }
+    },
     "node_modules/picocolors": {
       "version": "1.1.1",
       "resolved": "https://registry.npmjs.org/picocolors/-/picocolors-1.1.1.tgz",

core/http/react-ui/package.json

@@ -45,6 +45,7 @@
     "i18next-browser-languagedetector": "^8.2.1",
     "i18next-http-backend": "^3.0.6",
     "marked": "^15.0.7",
+    "pdfjs-dist": "^5.6.205",
     "react": "^19.1.0",
     "react-dom": "^19.1.0",
     "react-i18next": "^17.0.6",

core/http/react-ui/public/locales/en/chat.json

@@ -117,7 +117,8 @@
     "copied": "Copied to clipboard",
     "copyFailed": "Could not copy to clipboard",
     "chatCopied": "Chat copied to clipboard",
-    "forked": "Created a new chat"
+    "forked": "Created a new chat",
+    "pdfReadFailed": "Could not read text from {{name}}. It may be scanned, encrypted or damaged."
   },
   "menu": {
     "trigger": "Chats",

core/http/react-ui/public/locales/en/home.json

@@ -35,7 +35,8 @@
     "enterToSend": "Enter to send",
     "selectModelFirst": "Select a model first",
     "sendMessage": "Send message",
-    "selectModelToast": "Please select a model first"
+    "selectModelToast": "Please select a model first",
+    "pdfReadFailed": "Could not read text from {{name}}. It may be scanned, encrypted or damaged."
   },
   "quickLinks": {
     "manageByChat": "Manage by chat",

core/http/react-ui/src/pages/Chat.jsx

@@ -9,6 +9,7 @@ import { extractCodeArtifacts, renderMarkdownWithArtifacts } from '../utils/arti
 import CanvasPanel from '../components/CanvasPanel'
 import Toggle from '../components/Toggle'
 import { fileToBase64, modelsApi, mcpApi } from '../utils/api'
+import { readAttachmentText } from '../utils/pdf'
 import { CAP_CHAT } from '../utils/capabilities'
 import { useMCPClient } from '../hooks/useMCPClient'
 import MCPAppFrame from '../components/MCPAppFrame'
@@ -842,13 +843,18 @@ export default function Chat() {
       const base64 = await fileToBase64(file)
       const entry = { name: file.name, type: file.type, base64 }
       if (!file.type.startsWith('image/') && !file.type.startsWith('audio/') && !file.type.startsWith('video/')) {
-        entry.textContent = await file.text().catch(() => '')
+        try {
+          entry.textContent = await readAttachmentText(file)
+        } catch {
+          addToast(t('toasts.pdfReadFailed', { name: file.name }), 'error')
+          continue
+        }
       }
       newFiles.push(entry)
     }
     setFiles(prev => [...prev, ...newFiles])
     e.target.value = ''
-  }, [])
+  }, [addToast, t])
 
   const handlePaste = useCallback(async (e) => {
     const items = e.clipboardData?.items

core/http/react-ui/src/pages/Home.jsx

@@ -12,6 +12,7 @@ import HomeConnect from '../components/HomeConnect'
 import { useResources } from '../hooks/useResources'
 import { usePolling } from '../hooks/usePolling'
 import { fileToBase64, backendControlApi, systemApi, modelsApi, mcpApi, nodesApi } from '../utils/api'
+import { readAttachmentText } from '../utils/pdf'
 import { API_CONFIG } from '../utils/config'
 import { greetingKey } from '../utils/greeting'
 import StatusPill from '../components/StatusPill'
@@ -158,12 +159,17 @@ export default function Home() {
       const base64 = await fileToBase64(file)
       const entry = { name: file.name, type: file.type, base64 }
       if (!file.type.startsWith('image/') && !file.type.startsWith('audio/')) {
-        entry.textContent = await file.text().catch(() => '')
+        try {
+          entry.textContent = await readAttachmentText(file)
+        } catch {
+          addToast(t('input.pdfReadFailed', { name: file.name }), 'error')
+          continue
+        }
       }
       newFiles.push(entry)
     }
     setter(prev => [...prev, ...newFiles])
-  }, [])
+  }, [addToast, t])
 
   const removeFile = useCallback((file) => {
     const removeFn = (prev) => prev.filter(f => f !== file)

core/http/react-ui/src/utils/pdf.js

@@ -0,0 +1,48 @@
+export function isPdf(file) {
+  return file?.type === 'application/pdf' || /\.pdf$/i.test(file?.name || '')
+}
+
+// pdf.js and its worker are loaded on first use so the main bundle does not
+// pay for them when nobody attaches a PDF.
+async function loadPdfjs() {
+  const [pdfjs, worker] = await Promise.all([
+    import('pdfjs-dist'),
+    import('pdfjs-dist/build/pdf.worker.min.mjs?url'),
+  ])
+  pdfjs.GlobalWorkerOptions.workerSrc = worker.default
+  return pdfjs
+}
+
+// Returns the text layer of every page, one block per page. Throws when the
+// file cannot be parsed or has no text layer (scanned PDFs): sending an empty
+// attachment to the model would look like success and silently lose the file.
+export async function extractPdfText(file) {
+  const pdfjs = await loadPdfjs()
+  const data = new Uint8Array(await file.arrayBuffer())
+  const doc = await pdfjs.getDocument({ data }).promise
+  try {
+    const pages = []
+    for (let i = 1; i <= doc.numPages; i++) {
+      const page = await doc.getPage(i)
+      const content = await page.getTextContent()
+      let text = ''
+      for (const item of content.items) {
+        text += item.str
+        text += item.hasEOL ? '\n' : ''
+      }
+      pages.push(text.trim())
+    }
+    const text = pages.filter(Boolean).join('\n\n')
+    if (!text) throw new Error('PDF has no extractable text')
+    return text
+  } finally {
+    await doc.destroy()
+  }
+}
+
+// Text of an attached non-media file. PDFs go through pdf.js; everything else
+// is read as UTF-8.
+export async function readAttachmentText(file) {
+  if (isPdf(file)) return extractPdfText(file)
+  return file.text().catch(() => '')
+}