Feature/wasm example #85
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This looks like a great start. We might be able to soften the language a bit about the limitations since there are various ways to get around them. For example it should be possible to create a custom persister that uses the cloud or browser storage, and the Mutiny team got around the http(s) only limitation for their lightning wallet by building a proxy https <--> tcp. For this example we should also figure out / demo the solution for bitcoindevkit/bdk#1683. |
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Thanks so much @riverKanies ! @notmandatory I got the retry mechanism working but might be a bit too obscure as we dive into the |
| Any function that requires system time, such as any sort of timestamp, must access system time through a wasm binding to the JavaScript environment. This means some BDK functions that are commonly used in rust won't work in WASM and instead an alternate rust function that takes a timestamp as an argument must be used (I.E. instead of `.apply_update()` we must use `.apply_update_at()`). | ||
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| ### Network access is limited to http(s) | ||
| This effectively means that the blockchain client must be an Esplora instance. Both RPC and Electrum clients require sockets and will not work for BDK in a WASM environment out of the box. |
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@notmandatory I understand very well this limitation for Electrum now but doesn't the Bitcoin node's RPC allow for HTTP? This works fine when I test with my Polar network, so why isn't the client working on the browser ?
curl --location 'http://127.0.0.1:18443' \
--header 'Content-Type: application/json' \
--header 'Authorization: Basic my_auth' \
--data '{
"jsonrpc": "1.0",
"id": "getblockchaininfo",
"method": "getblockchaininfo",
"params": []
}'
docs/cookbook/wasm.md
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| --8<-- "examples/wasm/rust/src/lib.rs:new" | ||
| ``` | ||
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| Notice we are using an in-memory wallet with `.create_wallet_no_persist()`. If you try to use persistence through file or database you will get an error becuase those features require OS access. Instead we have to create a binding to pass the wallet data to the JavaScript environment where we can handle persistence. |
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Here we should mention that you should implement the WalletPersister or AsyncWalletPersister if you want persistence in the browser as not supported currently by BDK.
I implemented a persister myself: https://github.com/darioAnongba/bdk-wasm/blob/main/src/bitcoin/storage.rs. It is very specific to my use case but a LocalStoragePersister would be pretty easy to implement and then you can call create_wallet or create_wallet_async.
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great! yes this is one of the main areas I'm wanting to detail more
| "CC": "/opt/homebrew/opt/llvm/bin/clang" | ||
| }, | ||
| "rust-analyzer.cargo.target": "wasm32-unknown-unknown", | ||
| "rust-analyzer.checkOnSave.allTargets": false |
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I think this one is more optional ?
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@notmandatory ok I hear you, thanks for the feedback! I'll take that into consideration on my next iteration |
Co-authored-by: Dario Anongba Varela <[email protected]>
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I believe this is ready for a final review @notmandatory @thunderbiscuit @darioAnongba The intention is just to be a minimal example of a custom WASM package for bdk, highlighting the particular considerations (limitations) of the WASM env compared to normal rust. We'll have a separate example for using the bdk-wasm package out of the box at some point (hopefully) |
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| // --8<-- [start:store] | ||
| pub fn take_staged(&mut self) -> JsResult<String> { |
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@darioAnongba see use of serde_json here. note I'm converting to json string in this example rn because I'm just saving to localStorage, but you can pas JsValue json and stringify on js side
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Here's the quickstart example in WASM.
The code could use some cleaning but I figured I'd go ahead and get some feedback on the direction here.
Seemed like the most important thing was to highlight some of the limitations of using BDK in wasm
UPDATE:
closer to full wallet than quickstart because wanted to include persistence as it is different in wasm