mobilithek-to-csv (binary downloader)

This is a small, fully static index.html tool that:

• extracts all <binary> elements from a Mobilithek XML response
• Base64-decodes them
• optionally gunzips them (when the decoded bytes are gzip)
• extracts FuelPricePublication time series and exports CSV (and keeps raw binaries downloadable)

Use

Option A (recommended): start the local Ruby helper + UI

On macOS you can just double-click start.command.

Or run it manually:

ruby server.rb

This serves the UI at http://127.0.0.1:5173 and provides /api/fetch so the page can fetch Mobilithek using your .p12/.pfx client certificate (mTLS).

Option B: decode an existing XML response (no server)

1. Open index.html in a modern browser (anywhere, including file://).
2. Get a Mobilithek response:
   • Click Open endpoint in new tab (browser will handle client-certificate selection), then save/copy the XML.
   • Or click Try fetch:
     • with a selected .p12/.pfx: uses the local helper server (recommended)
     • without a certificate: uses browser fetch() (often blocked by CORS)
3. Paste the XML into the textarea (or load the saved XML file) and click Decode binaries.
4. Download CSV from the Fuel prices (time series) section, or download decoded binaries as decoded_binaries.json / decoded_binaries.xml to inspect before CSV conversion.

Helper server notes

• The browser cannot use a user-selected .p12/.pfx for mTLS from JavaScript, and Mobilithek responses are often blocked by CORS. The Ruby helper server is the portable workaround.
• You can change bind address/port:

HOST=127.0.0.1 PORT=5173 ruby server.rb

If you opened index.html via file:// and still want to use the helper server, open:

• index.html?helper=http://127.0.0.1:5173

Notes / limitations

• Pure client-side fetch() cannot attach a user-selected .p12/.pfx for mTLS, and cross-origin responses are often blocked by CORS. Use the helper server if you need one-click fetching with the certificate.
• Gzip decompression uses DecompressionStream('gzip'). If your browser doesn’t support it, the tool will still let you download the Base64-decoded bytes (often a .gz).