problem

An RFC 7807 compatible error library for Go.

Overview

This library provides a structured way to handle HTTP errors in Go applications, compatible with RFC 7807. It defines custom error types for various HTTP status codes and provides methods to create and manipulate these errors.

Features

• Custom error types for HTTP status codes.
• Methods to create new errors with messages.
• JSON serialization of errors.
• slog Logging support.

Installation

To install the library, run:

go get -u github.com/bnprtr/problem

Usage

To use problem, you should define error constants for the types of your errors. The constant should by typed as one of problem's Status types:

package main

import (
  "errors"
  "net/http"
  "github.com/bnprtr/problem"
)

const (
  InvalidInput problem.StatusBadRequest = "invalid input"
  InvalidJSON problem.StatusBadRequest = "invalid json"

  // always capture stack trace on all InternalServerErrors
  InternalServerError problem.StackTraced[problem.StatusInternalServerError] = "internal server error"
)

type Request struct {
 Name string
 URL  string
}

func MyHandler(w http.ResponseWriter, r *http.Request) {
 if err := handle(r); err != nil {
  var statusCode problem.StatusCode
  if !errors.As(err, &statusCode) {
   // unknown error!
   err = InternalServerError.New("unexpected error occurred.").AddInternalErrors(err)
   statusCode = InternalServerError.StatusCode()
  }
  w.Header().Set("Content-Type", "application/problem+json")
  w.WriteHeader(int(statusCode))
  json.NewEncoder(w).Encode(err)
 }
}

func (r *http.Request) error {
 var req Request
 if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
  return InvalidJSON.New(err.Error()).AddInternalErrors(err)
 }

 if err := validate(req); err != nil {
  panic(err)
 }
 return nil
}

func validate(r Request) error {
 err := InvalidInput.New("request input failed validation")
 var failed bool
 if r.Name == "" {
  failed = true
  err = err.AddDetails(problem.NewFieldDetail("Name", r.Name, "required"))
 }
 if r.URL != "" {
  _, e := url.Parse(r.URL)
  if e != nil {
   failed = true
   err = err.AddInternalErrors(e)
   err = err.AddDetails(problem.NewFieldDetail("URL", r.URL, e.Error()))
  }
 }
 if failed {
  return err
 }
 return nil
}