Sharing timelines

Timelines, and the events (moments and durations), searches and views in them, have addresses that open them, previews for social sites and search engines, and embeds for other websites. Everything here applies to timelines on the server; anyone can follow a link to a public timeline, while a private one opens only for its members.

Addresses

Profiles and timelines have addresses like GitHub's (#148):

Everything under a timeline's page is under its address too: /<username>/<slug>/history, …/pulls, …/settings, and its moments' and durations' pages below.

• Choosing a slug: its owner sets it in Sharing & settings, under Address. A slug is 1–64 lowercase letters, digits, hyphens or underscores, starting with a letter or digit, and unique among its owner's timelines. The field suggests one made from the title. Use its ID removes it.
• Other addresses lead to it: its ID, /timelines/<id>, a slug it had before and capitals all redirect to the address, with the rest of the path and the query. A slug it had before keeps leading to it until another of its owner's timelines takes that slug.
• Private timelines: the redirect happens only once the reader may open it, so an address reveals nothing of a private timeline to anyone else. Its pages are not found for them at any address.
• Names the site uses: usernames that are, or may become, the site's own pages (login, admin, timelines, users, settings and others; RESERVED_NAMES in src/addresses.ts) can't be registered. An account that already has one, such as a first administrator named admin, keeps its profile at /users/<username> and its timelines at /timelines/<id>. /users/<username> otherwise redirects to /<username>.
• Names that would pass for the site or its staff can't be registered either (#184): root, moderator, staff, support, noreply, postmaster and others (OFFICIAL_NAMES in src/addresses.ts), any name starting with openchronology, and any of these or the site's own names spelled with hyphens, underscores or a number after them (ad_min, sign-in, admin1, root-2). Accounts that already have such a name keep it and their addresses. The first administrator's name, ADMIN_USERNAME, is the operator's choice and may be any of them.
• Preview images and embeds stay at the timeline's ID (/timelines/<id>/opengraph-image, /embed/<id>).

Links

A timeline's page is at its address. A fragment after it names what to look at:

IDs and words are percent-encoded (#moment/leg%3A2 for leg:2). The address follows what is open: opening a moment adds its fragment, and closing it removes it, so the address bar can be copied at any time. Events also have pages of their own, /<username>/<slug>/moments/<id> and /<username>/<slug>/durations/<id>, which open the timeline at them the same way. They are what Share offers, because social sites and search engines read pages but not fragments.

The same fragments work for embeds (/embed/<id>#moment/…) and in the editor's own address (#timeline/<id>/moment/…). A link to an event that no longer exists opens the timeline and says so.

Share

Share above the timeline, in an event's details, under search results and, for the current view, in the timeline's context menu (Share this view) opens the share dialog:

• Copy link, and the device's own share sheet where the browser has one.
• Facebook, X, LinkedIn, Reddit, Bluesky and email: links to each site's own share page; no script of theirs runs on the platform.
• Embed on a website: the HTML of an embed, in three sizes.

Social sites and embeds are offered for public timelines only. For a private timeline the dialog gives the link (which only members can follow) and, to its owner, a way to make it public. Unsaved moments and edits cannot be shared until they are saved.

Link previews

Timeline, moment and duration pages describe themselves for link previews (Open Graph and Twitter cards) and search engines: a title, a description (the timeline's description, or how many moments it has, over what time and by whom; for a moment, its time and notes), the canonical address, and a 1200 × 630 preview image. The image shows the title and a strip of the timeline's moments, with the shared event marked on it. Facebook, X, LinkedIn, Slack, Discord, iMessage and others show these as a card with a large image.

Previews are made as a guest sees the timeline: a private timeline's preview image is the site's own card, and its pages ask search engines not to index them, so nothing private appears in a preview even when a member shares the link.

A timeline with sensitive-content labels previews as its title and what it is labelled as containing, without its moments or description, and its oEmbed answer has no thumbnail: it opens behind its warning.

Search engines

• /robots.txt lets crawlers read pages but not the API, accounts, the bare editor or embeds, and names the sitemap.
• /sitemap.xml lists public timelines, most recently changed first, and their owners' profiles: up to 45,000 timelines and 4,000 profiles.
• Each timeline page includes its title, description, owner and first 50 moments as text, for screen readers and crawlers; each moment links to its own page.

Embedding

/embed/<id> is a public timeline for other sites to frame: the timeline and its title, with search, zoom, Fit all and an Open on OpenChronology link that follows what is open. It is read-only, and anonymous: it sends no cookies, so it shows what a guest sees even to a visitor who is signed in and owns the timeline. A private timeline is not embedded. The Embed on a website code is an iframe:

<iframe
  src="https://timescale.info/embed/<id>#moment/<moment>"
  title="…"
  width="100%"
  height="480"
  style="border:0;max-width:100%"
  loading="lazy"
  allow="fullscreen"
></iframe>

Any site may frame embeds unless the operator sets EMBED_FRAME_ANCESTORS to a list of origins (see deployment). Other pages of the platform cannot be framed by other sites.

oEmbed

Timeline, moment and duration pages announce an oEmbed endpoint, so services that discover oEmbed from a page (such as Iframely and Embedly, and the sites and editors that use them) can turn a pasted link into the timeline itself:

GET /api/oembed?url=https://timescale.info/<username>/<slug>&maxwidth=600&format=json

It answers a rich embed with the iframe above (opening at the page's event, or at the link's fragment), its size (at most 800 × 480, within maxwidth and maxheight), the title and owner, and the preview image as its thumbnail. Any of a timeline's addresses will do. Only json is available; addresses of other sites, and timelines that are not public, are not found.