Binding Attributes

Binding attributes connect Go logic and runtime data to JavaScript.
They allow two-way data exchange and data binding between the backend and client runtime.

---

AData

Expose server-side values to JavaScript via $data(name).

type AData struct {
  // Name of the data entry to read via JavaScript with $data(name).
  Name  string
  // Value to expose to the client. Marshaled to JSON.
  Value any
}

Example:

@doors.Script() {
  @doors.AData{
    Name:  "user_profile",
    Value: user, // Go struct or map
  }
  <script>
    const user = $data("user_profile")
    console.log(user.name)
  </script>
}

You can also define multiple entries at once with ADataMap:

type ADataMap map[string]any

@doors.ADataMap{
  "config": config,
  "user":   user,
}

---

AHook

Bind a Go function callable from JavaScript via $hook(name, arg).

type AHook[T any] struct {
  Name      string
  Scope     []Scope
  Indicator []Indicator
  On        func(ctx context.Context, r RHook[T]) (any, bool)
}

• Input arg is sent as JSON, unmarshaled into T.
  
• Return value is marshaled back to JSON.
  
• Return true to remove the hook after completion.
  

Example:

@doors.AHook[string]{
  Name: "length",
  On: func(ctx context.Context, r doors.RHook[string]) (any, bool) {
    return len(r.Data()), false
  },
}

@doors.Script() {
  <script>
    const len = await $hook("length", "hello")
    console.log(len) // 5
    // or await $fetch("length", "hello")
    // to deal with a raw fetch response
  </script>
}

---

ARawHook

Low-level variant of AHook that provides direct access to the HTTP request and body streams.

type ARawHook struct {
  Name      string
  Scope     []Scope
  Indicator []Indicator
  On        func(ctx context.Context, r RRawHook) bool
}

Use for file uploads, raw binary streams, or custom encodings.

Example:

@doors.ARawHook{
  Name: "upload",
  On: func(ctx context.Context, r doors.RRawHook) bool {
    file, _, _ := r.FormFile("file")
    defer file.Close()
    // process file
    return false
  },
}

And from JavaScript:

await $hook("upload", new FormData(document.querySelector("form")))

---

Notes

• Hooks and data bindings are scoped to the closest door parent lifecycle.
  
• $hook calls serialize automatically and return a Promise.
  
• $fetch bypasses JSON and works with any streamable payload.
  
• Both APIs are available only inside <script> rendered by doors.Script().