75 lines
2.8 KiB
Markdown
75 lines
2.8 KiB
Markdown
# Automerge
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[](https://docs.rs/automerge)
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[](https://crates.io/crates/automerge)
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[](https://travis-ci.org/alexjg/automerge-rs)
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This is a very early, very much work in progress implementation of [automerge](https://github.com/automerge/automerge) in rust. At the moment it implements a simple interface for reading the state of an OpSet, and a really horrendous interface for generating new changes to the Opset.
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## Plans
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We're tentatively working on a plan to write a backend for the current javascript implementation of Automerge in Rust. The javascript Automerge library is split into two parts, a "frontend" and a "backend". The "backend" contains a lot of the more complex logic of the CRDT and also has a fairly small API. Given these facts we think we might be able to write a rust implementation of the backend, which compiles to WASM and can be used as a drop in replacement for the current backend. This same rust implementation could also be used via FFI on a lot of other platforms, which would make language interop much easier. This is all early days but it's very exciting.
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For now though, it's a mostly broken pure rust implementation
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## How to use
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Add this to your dependencies
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```
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automerge = "0.0.2"
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```
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You'll need to export changes from automerge as JSON rather than using the encoding that `Automerge.save` uses. So first do this (in javascript):
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```javascript
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const doc = <your automerge document>
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const changes = Automerge.getHistory(doc).map(h => h.change)
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console.log(JSON.stringify(changes, null, 4))
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```
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Now you can load these changes into automerge like so:
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```rust,no_run
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extern crate automerge;
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fn main() {
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let changes: Vec<automerge::Change> = serde_json::from_str("<paste the changes JSON here>").unwrap();
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let document = automerge::Document::load(changes).unwrap();
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let state: serde_json::Value = document.state().unwrap();
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println!("{:?}", state);
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}
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```
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You can create new changes to the document by doing things like this:
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```rust,no_run
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extern crate automerge;
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fn main() {
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let mut doc = Document::init();
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let json_value: serde_json::Value = serde_json::from_str(
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r#"
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{
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"cards_by_id": {},
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"size_of_cards": 12.0,
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"numRounds": 11.0,
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"cards": [1.0, false]
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}
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"#,
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)
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.unwrap();
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doc.create_and_apply_change(
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Some("Some change".to_string()),
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vec![ChangeRequest::Set {
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path: Path::root().key("the-state".to_string()),
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value: Value::from_json(&json_value),
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}],
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)
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.unwrap();
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}
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```
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Check the docs on `ChangeRequest` for more information on what you can do.
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