gno.land/p/moul/txlink

Build a clickable "call this function" link for a realm's Render output, so a page can offer a transaction instead of telling the reader what to type.

1// current realm, one arg
2txlink.Call("AddTodo", "todo", "buy milk")
3// -> /r/moul/home$help&func=AddTodo&todo=buy+milk
4
5// builder, with a send amount
6txlink.NewLink("Donate").
7	AddArgs("message", "thanks").
8	SetSend("1000000ugnot").
9	URL()

The output is the gnoweb $help&func= form: following it opens the help page with the function selected and the arguments pre-filled. The user still signs. Nothing here broadcasts, and nothing here can.

Three prefixes, picked for you

Realm.prefix() decides what the link is relative to:

So txlink.Call(...) in a realm links to itself, and txlink.Realm("gno.land/r/other/x").Call(...) links to a neighbour, without either caller hardcoding a domain. Do not build the string yourself: a hardcoded self-link is wrong the moment the realm moves, which r/moul/demo/render still demonstrates by accident.

Details that bite

• Arguments are key/value pairs, so an odd count panics. AddArgs takes them flat ("k1", "v1", "k2", "v2").
• A key starting with . panics. .send is reserved; use SetSend.
• The builder is nil-safe. NewLink("") returns nil and every method on a nil builder returns nil, so a chain never panics halfway; URL() on it returns "".
• func= is kept first in the query string on purpose, ahead of the url-encoded rest, so the links stay readable.

Related: p/moul/helplink is the fuller version of the same idea; txlink is the streamlined one. For parsing the path on the way in, see p/moul/realmpath.

Part of moul/gno-contracts — moul's versioned gno.land contracts. See the repository for the full catalog, build/test tooling, and usage.

⚠️ Disclaimer: provided as-is, without warranty; not security-audited. Full disclaimer: DISCLAIMER.