Http

Reusable HTTP packages for Go backend services.

Install

go get github.com/go-bumbu/http

Packages

middleware

Composable HTTP middleware using the standard func(next http.Handler) http.Handler pattern. Middleware can be used individually or combined via the Middleware struct which orchestrates all features in a single handler.

Standalone middleware:

Middleware	Import	Description
Logging	middleware.Logging(logger)	Structured request logging via log/slog. Logs at INFO for client errors, ERROR for server errors. Captures error response bodies.
Metrics	middleware.Metrics(hist)	Prometheus histogram recording request duration, method, path, status code, and error flag.
JSONErrors	middleware.JSONErrors(generic)	Intercepts error responses (>= 400) and wraps the body in {"error":"...","code":N}. Optionally replaces messages with generic status text.
GenericErrors	middleware.GenericErrors()	Replaces error response bodies with the standard status text (e.g. "Internal Server Error").
PanicRecover	middleware.PanicRecover(logger)	Recovers from panics, logs a stack trace, and returns 500 to the client.
ReqDelay	middleware.ReqDelay{...}.Delay	Adds a random delay between min/max duration. Useful during development to simulate slow backends.

Combined middleware:

m := middleware.New(middleware.Cfg{
    JsonErrors:   true,
    GenericErrs:  true,
    PanicRecover: true,
    Logger:       slog.Default(),
    PromHisto:    hist,
})
mux.Handle("/", m.Middleware(handler))

The combined Middleware struct runs logging, metrics, error wrapping, and panic recovery in a single pass.

handlers/spa

Single Page Application handler that serves files from an fs.FS (typically embed.FS). Requests for unknown paths fall back to index.html, allowing client-side routing.

spaHandler, err := handlers.NewSpaHAndler(embeddedFS, "dist", "/ui")

Parameters:

• inputFs — the filesystem containing the SPA assets
• fsSubDir — subdirectory within the FS to serve from (empty string for root)
• pathPrefix — URL path prefix where the SPA is mounted

lib/limitio

Internal IO utilities for bounded writes.

• LimitedBuf — A bytes.Buffer that stops accepting data after a configured byte limit (default 2000 in the middleware). Returns ErrBufferLimit when the cap is reached. Used to safely buffer error response bodies for logging without unbounded memory growth.
• LimitWriter — Wraps any io.Writer and caps total bytes written, returning io.EOF at the limit.