json-api

JSON API

This example puts method-aware routes, bounded JSON input, validation, error responses, and concurrent in-memory state into one small TODO API. Read the focused binding example first if you only need to compare JSONHandler with manual binding.

Run

From the repository root:

go run ./examples/json-api

Try one write and one read:

curl -sS -X POST http://localhost:8080/todos \
  -H 'Content-Type: application/json' \
  -d '{"title":"Buy groceries"}'

curl -sS http://localhost:8080/todos

What to notice

The method helpers rely on Go's ServeMux, so the mux rejects a wrong method before the handler runs:

app.GET("/todos/{id}", getTodo)
app.PUT("/todos/{id}", updateTodo)
app.DELETE("/todos/{id}", deleteTodo)

Writes use BindJSON rather than an unbounded decoder:

type todoInput struct {
    Title string `json:"title" validate:"required,min=1,max=200"`
}

var input todoInput
if err := hyperserve.BindJSON(r, &input); err != nil {
    sendError(w, http.StatusBadRequest, err.Error())
    return
}

BindJSON limits the body to 1 MiB, rejects unknown fields, and evaluates the validation tags. The example keeps a manual response envelope because a CRUD API needs status codes and error shapes that differ from JSONHandler's short path.

The store uses sync.RWMutex because handlers run concurrently. It is example state, not a persistence recommendation. Authentication, authorization, and rate limiting are intentionally absent so the HTTP and data boundaries remain visible.