withcode.go

// GoToSocial
// Copyright (C) GoToSocial Authors admin@gotosocial.org
// SPDX-License-Identifier: AGPL-3.0-or-later
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package gtserror

import (
	"errors"
	"net/http"
	"strings"
)

// Custom http response codes + text that
// aren't included in the net/http package.
const (
	StatusClientClosedRequest     = 499
	StatusTextClientClosedRequest = "Client Closed Request"
)

// WithCode wraps an internal error with an http code, and a 'safe' version of
// the error that can be served to clients without revealing internal business logic.
//
// A typical use of this error would be to first log the Original error, then return
// the Safe error and the StatusCode to an API caller.
type WithCode interface {
	// Unwrap returns the original error.
	// This should *NEVER* be returned to a client as it may contain sensitive information.
	Unwrap() error

	// Error serializes the original internal error for debugging within the GoToSocial logs.
	// This should *NEVER* be returned to a client as it may contain sensitive information.
	Error() string

	// Safe returns the API-safe version of the error for serialization towards a client.
	// There's not much point logging this internally because it won't contain much helpful information.
	Safe() string

	// Code returns the status code for serving to a client.
	Code() int
}

type withCode struct {
	original error
	safe     error
	code     int
}

func (e withCode) Unwrap() error {
	return e.original
}

func (e withCode) Error() string {
	return e.original.Error()
}

func (e withCode) Safe() string {
	return e.safe.Error()
}

func (e withCode) Code() int {
	return e.code
}

// NewErrorBadRequest returns an ErrorWithCode 400 with the given original error and optional help text.
func NewErrorBadRequest(original error, helpText ...string) WithCode {
	safe := http.StatusText(http.StatusBadRequest)
	if helpText != nil {
		safe = safe + ": " + strings.Join(helpText, ": ")
	}
	return withCode{
		original: original,
		safe:     errors.New(safe),
		code:     http.StatusBadRequest,
	}
}

// NewErrorUnauthorized returns an ErrorWithCode 401 with the given original error and optional help text.
func NewErrorUnauthorized(original error, helpText ...string) WithCode {
	safe := http.StatusText(http.StatusUnauthorized)
	if helpText != nil {
		safe = safe + ": " + strings.Join(helpText, ": ")
	}
	return withCode{
		original: original,
		safe:     errors.New(safe),
		code:     http.StatusUnauthorized,
	}
}

// NewErrorForbidden returns an ErrorWithCode 403 with the given original error and optional help text.
func NewErrorForbidden(original error, helpText ...string) WithCode {
	safe := http.StatusText(http.StatusForbidden)
	if helpText != nil {
		safe = safe + ": " + strings.Join(helpText, ": ")
	}
	return withCode{
		original: original,
		safe:     errors.New(safe),
		code:     http.StatusForbidden,
	}
}

// NewErrorNotFound returns an ErrorWithCode 404 with the given original error and optional help text.
func NewErrorNotFound(original error, helpText ...string) WithCode {
	safe := http.StatusText(http.StatusNotFound)
	if helpText != nil {
		safe = safe + ": " + strings.Join(helpText, ": ")
	}
	return withCode{
		original: original,
		safe:     errors.New(safe),
		code:     http.StatusNotFound,
	}
}

// NewErrorInternalError returns an ErrorWithCode 500 with the given original error and optional help text.
func NewErrorInternalError(original error, helpText ...string) WithCode {
	safe := http.StatusText(http.StatusInternalServerError)
	if helpText != nil {
		safe = safe + ": " + strings.Join(helpText, ": ")
	}
	return withCode{
		original: original,
		safe:     errors.New(safe),
		code:     http.StatusInternalServerError,
	}
}

// NewErrorConflict returns an ErrorWithCode 409 with the given original error and optional help text.
func NewErrorConflict(original error, helpText ...string) WithCode {
	safe := http.StatusText(http.StatusConflict)
	if helpText != nil {
		safe = safe + ": " + strings.Join(helpText, ": ")
	}
	return withCode{
		original: original,
		safe:     errors.New(safe),
		code:     http.StatusConflict,
	}
}

// NewErrorNotAcceptable returns an ErrorWithCode 406 with the given original error and optional help text.
func NewErrorNotAcceptable(original error, helpText ...string) WithCode {
	safe := http.StatusText(http.StatusNotAcceptable)
	if helpText != nil {
		safe = safe + ": " + strings.Join(helpText, ": ")
	}
	return withCode{
		original: original,
		safe:     errors.New(safe),
		code:     http.StatusNotAcceptable,
	}
}

// NewErrorUnprocessableEntity returns an ErrorWithCode 422 with the given original error and optional help text.
func NewErrorUnprocessableEntity(original error, helpText ...string) WithCode {
	safe := http.StatusText(http.StatusUnprocessableEntity)
	if helpText != nil {
		safe = safe + ": " + strings.Join(helpText, ": ")
	}
	return withCode{
		original: original,
		safe:     errors.New(safe),
		code:     http.StatusUnprocessableEntity,
	}
}

// NewErrorGone returns an ErrorWithCode 410 with the given original error and optional help text.
func NewErrorGone(original error, helpText ...string) WithCode {
	safe := http.StatusText(http.StatusGone)
	if helpText != nil {
		safe = safe + ": " + strings.Join(helpText, ": ")
	}
	return withCode{
		original: original,
		safe:     errors.New(safe),
		code:     http.StatusGone,
	}
}

// NewErrorClientClosedRequest returns an ErrorWithCode 499 with the given original error.
// This error type should only be used when an http caller has already hung up their request.
// See: https://en.wikipedia.org/wiki/List_of_HTTP_status_codes#nginx
func NewErrorClientClosedRequest(original error) WithCode {
	return withCode{
		original: original,
		safe:     errors.New(StatusTextClientClosedRequest),
		code:     StatusClientClosedRequest,
	}
}

// NewErrorRequestTimeout returns an ErrorWithCode 408 with the given original error.
// This error type should only be used when the server has decided to hang up a client
// request after x amount of time, to avoid keeping extremely slow client requests open.
func NewErrorRequestTimeout(original error) WithCode {
	return withCode{
		original: original,
		safe:     errors.New(http.StatusText(http.StatusRequestTimeout)),
		code:     http.StatusRequestTimeout,
	}
}