Share a temporary link

chronozarr share my_store

The command makes a store on your computer reachable through a temporary public address, checks that a browser can read it there, and prints a viewer link. The person who gets the link needs a web browser. They need no Python, no chronozarr and no account.

Temporary or permanent

For a link that lasts, see Publish a permanent link. To look at a store yourself, use chronozarr preview. For data that must stay private, see Private stores.

Before you start

Install cloudflared once. It is a free program from Cloudflare that makes the temporary address. It needs no Cloudflare account and no configuration. On macOS:

brew install cloudflared

chronozarr does not install it for you. If it is missing, share says so and starts nothing.

Share a store

1. Start sharing:

   chronozarr share my_store

   The command prints each stage. With package 0.4.0 the link appears after about a minute and a half, most of it spent waiting for the new public address to work. The command waits up to 90 seconds for it:

   starting local server and quick tunnel...
   waiting for Cloudflare to assign a public address...
   waiting for public access (allowing up to 90 seconds for DNS readiness)...
   checking browser access...
   measuring first transfer...
   sharing my_store through https://bright-sea-example.trycloudflare.com (byte ranges and CORS verified)
   tunnel throughput: first level-0 chunk 1.38 MB in 0.27 s (5.03 MB/s, 1 data request(s)); estimated overview step 0.27 s for 1 cell(s), assuming similar cell-read sizes
   open: https://chronozarr.org/demo/?store=https%3A%2F%2Fbright-sea-example.trycloudflare.com%2Fmy_store
   anyone who can open this link can read this store; press Ctrl-C to stop sharing

   The tunnel throughput line times one chunk through the tunnel. It shows how fast a recipient's views will load. The next release prints the address while it waits and gives the link after about half a minute (measurement).

2. The viewer opens. Choose the date, the product and the part of the map that you want to show.

3. Click Copy link. The copied link holds the store, the date, the product, the band and its display range, the zoom and the map centre. It does not hold the playback speed.

4. Send the copied link. Keep the terminal open and the computer awake while your colleague uses it.

5. Press Ctrl-C in the terminal to stop sharing. The command stops the tunnel and the local server, and the link stops working.

Each run makes a new address. A link from an earlier run does not work again.

What happens

1. share serves the store from your computer on 127.0.0.1. It serves only the store folder, and the viewer folder when you pass --viewer-dir.
2. cloudflared gives that server a public https address on trycloudflare.com.
3. share reads the store through that address, as a browser would, and prints the link only when the read works.

The viewer page comes from chronozarr.org. The data does not: the viewer reads the store through the tunnel, directly from your computer. chronozarr.org holds no copy of your dataset.

Limits

• Anyone who has the link can read the whole store while share runs. Do not share data that must stay private.
• Every view and every timestep that the recipient loads travels over your upload connection. A few viewers are fine. For many viewers, or fast playback of a large area, publish the store.
• If your computer sleeps, loses its network or stops the command, the link stops working.
• A quick tunnel is a free Cloudflare service for testing, with no uptime guarantee.

Options

--port, --viewer, --viewer-dir and --no-open mean the same as for preview. Use --no-open to print the link without opening a browser.

A tunnel targets a port, not a program. share starts its own server and checks that the port serves your store before it starts the tunnel. Do not start a tunnel by hand on a port that you have not checked: if another program owns that port, the tunnel exposes it.

Troubleshooting