dsh-drawio

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A plugin for DeepSeek Harness (DSH) that previews .drawio files as diagrams in the Web Sidebar: open one from the file tree and it renders as the diagram you drew, instead of opening as mxGraph XML source.

Editing needs dsh-drawioedit. The two are independent packages; the limitations below say when this preview is enough.

What it does

• Read-only and inert. The file is decoded and laid out offscreen; the pane receives an SVG data: URL, never an engine instance or a live DOM, so a diagram's content cannot script the page.
• Both draw.io save formats. Plain mxGraph XML, and draw.io's compressed body (base64 + raw DEFLATE + percent escape). A multi-page <mxfile> renders its first page.
• Nothing leaves the machine, and the styling is draw.io's. Rendering is fully local, unlike a hosted viewer. The renderer applies a stylesheet matching draw.io's defaults, so a cell whose style string omits a color does not inherit the storage engine's own palette; a cell's own style still wins.

Install

The built lib/ is committed, so the repository installs and runs with no build step on your machine. dsh plugin adds the dependency and the profile's bundle entry together — do not edit the profile manifest by hand.

# a checkout over HTTPS or SSH, or a local one — pnpm links a local checkout, so a rebuilt
# lib/ reaches the host on the next start
npx @deepseek-ai/dsh plugin --profile web add git+https://github.com/zhang-guo-wen/dsh-drawio.git
npx @deepseek-ai/dsh plugin --profile web add git+ssh://git@github.com/zhang-guo-wen/dsh-drawio.git
npx @deepseek-ai/dsh plugin --profile web add /absolute/path/to/dsh-drawio

# then restart the host
npx @deepseek-ai/dsh web

Remove it, dependency and layer together, with dsh plugin --profile web remove @zhang-guo-wen/dsh-drawio.

The profile must already compose @deepseek-ai/dsh-client-ui-sidebar-documentpreview, which owns the registry this plugin contributes to. Every shipped web profile does.

Known limitations

Edge routing and edge-label placement do not match draw.io. A .drawio file stores an edge's endpoints and its edgeStyle name, but not the path between them:

<mxCell id="e4" style="edgeStyle=orthogonalEdgeStyle;…" edge="1" source="n4" target="n5">
  <mxGeometry relative="1" as="geometry" />   <!-- no points, no label offset -->
</mxCell>

Both viewers therefore compute the bend points and the label position at render time from the same inputs, with different code: draw.io's editor adds its own routing and label-avoidance behaviour on top of the shared engine, and this plugin's engine does not carry it. Where the gap between two nodes is narrower than the label — 50px apart, 66px label — the label cannot clear both boxes without moving a node, and an opaque background would only paint over the text it covers.

Workaround. Drag the label where you want it in draw.io: the editor writes an explicit <mxPoint as="offset"> into the file, which every viewer honours. Widening the gap between the two nodes works equally well. Both fix the diagram at its source rather than in one viewer.

Shapes outside the engine's set are drawn as plain rectangles, never omitted: draw.io ships several hundred stencil shapes and the bundled engine carries a smaller set of its own.

Development

The repository root is the plugin package: its root package.json is @zhang-guo-wen/dsh-drawio. npm install <git-url> and dsh plugin add both package the repository root, so a plugin under packages/* would install as the wrong thing.

npm install
npm run build      # host half via tsdown; browser half via build-client.mjs
npm run typecheck  # tsc against the PUBLISHED @deepseek-ai/* packages
npm test           # loads the built bundle the way the browser does

Re-run npm run build and commit lib/ whenever you change src/.

The harness monorepo builds its client bundles with a script it does not publish, so this repository bundles the browser half itself. platform: 'browser' is set explicitly: under the bundler's node platform, a library whose exports lists a platform condition before import gets its server entry inlined, and that entry can call createRequire('module') at module scope — a require("module") the browser module table cannot answer. Only react and the DSH client packages stay external, so the deployed bundle carries no install-time dependency; npm test loads it with a module table holding nothing else and fails if it asks for more.

License

Apache License 2.0 — see LICENSE. Bundled third-party code is attributed in NOTICE. "draw.io" is a trademark of its owner; this package is not affiliated with or endorsed by draw.io.