XML validation and transformation

Available in 3.1.2 and later. Ordinary .xml files still use the text renderer. Install and explicitly enable profiles when your application needs XSD validation and an XSLT-generated document view.

Setup

Install the optional engines and copy their assets from your installed packages:

npm install @file-viewer/web @file-viewer/renderer-text [email protected] [email protected]
npx --no-install file-viewer-xml-assets public/file-viewer/xml

Serve the copied runtime files and licenses from your own origin. The copier checks engine versions and writes a SHA-256 manifest; it never downloads packages. Standard text and Full imports do not load these engines.

import { mountViewer } from '@file-viewer/web'
import { textRenderer } from '@file-viewer/renderer-text'
import { enableFileViewerXmlProfiles } from '@file-viewer/renderer-text/xml-profiles'

const disableProfiles = enableFileViewerXmlProfiles()
mountViewer(document.querySelector('#viewer'), {
  url: '/documents/invoice.xml',
  filename: 'invoice.xml',
  options: {
    renderers: [textRenderer],
    xml: {
      profilesUrl: '/profiles/profiles.json',
      runtime: {
        xsdWorkerUrl: '/file-viewer/xml/xmllint-browser.mjs',
        xsltModuleUrl: '/file-viewer/xml/xslt-wasm.js'
      },
      onDiagnostic: diagnostic => console.info(diagnostic)
    }
  }
})
// Call disableProfiles() when the application's registration is no longer needed.

The component has View Source and View Rendered buttons after a successful transformation. Toggling does not fetch or parse the original again. xml.initialView: 'source' keeps source visible initially. Diagnostic callbacks are optional and do not determine whether rendering succeeds.

Profile manifest

{
  "profiles": [{
    "id": "invoice-v1",
    "match": {
      "rootNamespace": { "enabled": true, "root": "invoice", "namespace": "urn:example:invoice:v1" },
      "xsd": { "enabled": true }
    },
    "xsd": "./invoice.xsd",
    "xslt": "./invoice.xsl"
  }]
}

Resource paths are relative to the manifest URL. Alternatively, supply xml.profiles with xml.baseUrl; do not also set profilesUrl. Every enabled check must pass, and exactly one profile must match. Zero matches, multiple matches, malformed configuration, failed validation, unavailable assets or a transformation error all leave the original XML visible with diagnostics. XSD-only and root/namespace-only profiles are supported; at least one check must be enabled.

XSD uses libxml2 through xmllint-wasm; XSLT 1.0 uses libxslt through xslt-polyfill in a Worker. It does not depend on the browser's native XSLTProcessor. Use HTML output in the stylesheet. XSD imports/includes, XSLT imports/includes, document(), extension instructions, DTDs and external entities are rejected. Flatten schemas and stylesheets into reviewed, self-contained resources before deployment.

Limits and isolation

Resources must be same-origin HTTP(S), without redirects. Runtime URLs are application configuration, never taken from the XML document. The output is sanitized into a sandboxed iframe without scripts or same-origin access; it cannot execute application code or load external resources.

Defaults and hard ceilings are 4 MiB XML, 2 MiB per schema/stylesheet, 8 MiB output, 32 profiles and 16 MiB total fetched resources. xml.limits can lower these limits. timeoutMs defaults to 15 seconds and is capped at 60 seconds. Workers are terminated on timeout, cancellation and unmount. Each WASM engine has a 64 MiB linear-memory ceiling. Larger or unsupported documents fall back to source; no validation result is fabricated.

CSP must allow same-origin assets, blob Workers and WASM compilation. Keep the runtime JavaScript, WASM and license files together when deploying under a subpath, and update the two explicit URLs accordingly. The Demo includes a valid invoice and an invalid invoice to exercise both the rendered view and fallback.