94 lines
2.7 KiB
Go
94 lines
2.7 KiB
Go
//go:build js && wasm
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package rsc
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import (
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"bytes"
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"encoding/gob"
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"syscall/js"
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"kjol/wasmruntime/vdom"
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)
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// Mount connects to a server component by name and returns a render function.
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// The generated client stub for a //gowasm:server component just calls this, so
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// the call site is identical to a client component. It POSTs {name, state,
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// event} to /rsc and swaps (reconciles) the returned render into the DOM. State
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// is opaque and round-trips through the client — the server keeps nothing.
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func Mount(name string) func() *vdom.VNode {
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tree := vdom.NewSignal[*vdom.VNode](nil)
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var state [][]byte
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var post func(kind string, nodeID int, event, value string)
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var convert func(*SNode) *vdom.VNode
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convert = func(sn *SNode) *vdom.VNode {
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if sn == nil {
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return nil
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}
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if sn.Tag == "" {
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return vdom.Text(sn.Text)
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}
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mods := make([]vdom.Mod, 0, len(sn.Attrs)+len(sn.Events)+len(sn.Kids)+1)
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for k, v := range sn.Attrs {
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mods = append(mods, vdom.Attr(k, v))
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}
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if sn.HTML != "" {
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mods = append(mods, vdom.Raw(sn.HTML))
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}
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for _, ev := range sn.Events {
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event, id := ev, sn.ID
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mods = append(mods, vdom.OnEvent(ev, func(e vdom.Event) { post("event", id, event, e.Value()) }))
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}
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for _, k := range sn.Kids {
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if c := convert(k); c != nil {
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mods = append(mods, c)
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}
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}
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return vdom.El(sn.Tag, mods...)
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}
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onArr := js.FuncOf(func(this js.Value, args []js.Value) any {
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arr := js.Global().Get("Uint8Array").New(args[0])
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b := make([]byte, arr.Get("length").Int())
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js.CopyBytesToGo(b, arr)
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var resp Response
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if gob.NewDecoder(bytes.NewReader(b)).Decode(&resp) == nil {
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state = resp.State
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tree.Set(convert(resp.Tree)) // re-render -> reconcile into the DOM
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}
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return nil
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})
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onResp := js.FuncOf(func(this js.Value, args []js.Value) any {
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args[0].Call("arrayBuffer").Call("then", onArr)
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return nil
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})
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loc := js.Global().Get("location")
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url := loc.Get("protocol").String() + "//" + loc.Get("host").String() + "/rsc"
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post = func(kind string, nodeID int, event, value string) {
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var buf bytes.Buffer
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if gob.NewEncoder(&buf).Encode(Request{Kind: kind, Name: name, State: state, NodeID: nodeID, Event: event, Value: value}) != nil {
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return
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}
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body := js.Global().Get("Uint8Array").New(buf.Len())
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js.CopyBytesToJS(body, buf.Bytes())
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opts := js.Global().Get("Object").New()
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opts.Set("method", "POST")
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opts.Set("body", body)
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js.Global().Call("fetch", url, opts).Call("then", onResp)
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}
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started := false
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return func() *vdom.VNode {
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if !started {
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started = true
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post("mount", 0, "", "")
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}
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if t := tree.Get(); t != nil {
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return t
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}
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return vdom.Div(vdom.Attr("class", "text-muted"), vdom.Text("loading server component…"))
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}
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}
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