router/default.go

package router

import (
	"encoding/json"
	"fmt"
	"io"
	"net/http"
)

type DefaultError uint32

type DefaultErrorHandler struct {
	DefaultError
}

func (*DefaultErrorHandler) ErrorResponse(errorResponse ErrorResponse) ErrorResponse {
	return DefaultErrorHandler{errorResponse.(DefaultError)}
}

const (
	DefaultOk                    DefaultError = http.StatusOK
	DefaultErrorNotImplemented   DefaultError = http.StatusNotImplemented
	DefaultErrorMethodNotAllowed DefaultError = http.StatusMethodNotAllowed
	DefaultErrorBadRequest       DefaultError = http.StatusBadRequest
	DefaultErrorUnauthorized     DefaultError = http.StatusUnauthorized
	DefaultErrorServerError      DefaultError = http.StatusInternalServerError
)

func (e DefaultError) Ok() (ok bool) {
	return e == DefaultOk
}

func (e DefaultError) HttpStatus() (code int) {
	return int(e)
}

func (e DefaultError) String() (out string) {
	switch e {
	case DefaultOk:
		out = "ok"
	case DefaultErrorNotImplemented:
		out = "server not implemented"
	case DefaultErrorMethodNotAllowed:
		out = "method not allowed"
	case DefaultErrorBadRequest:
		out = "bad request"
	case DefaultErrorUnauthorized:
		out = "user unauthorized"
	case DefaultErrorServerError:
		out = "internal server error"
	default:
		out = "unhandled error"
	}
	return
}

func (e DefaultError) Error() (out string) {
	return fmt.Sprintf("%s (%d)", e.String(), e.HttpStatus())
}

func (e DefaultError) BodyBytes() (body []byte) {
	body, _ = json.Marshal(struct{ Error string }{Error: e.String()})
	return
}

type DefaultRequestBuilder struct {
	errorHandler   ErrorHandler
	allowedMethods *[]string
	header         struct {
		*Header
		fields header
	}
	values struct {
		*Values
		fields values
	}
	body struct {
		*Body
		fields body
	}
}

func NewDefaultRequestBuilder() *DefaultRequestBuilder {
	return &DefaultRequestBuilder{}
}

func (rb *DefaultRequestBuilder) SetErrorHandler(errorHandler ErrorHandler) *DefaultRequestBuilder {
	rb.errorHandler = errorHandler
	return rb
}

func (rb *DefaultRequestBuilder) SetAllowedMethods(allowedMethods []string) *DefaultRequestBuilder {
	rb.allowedMethods = &allowedMethods
	return rb
}

func (rb *DefaultRequestBuilder) SetHeader(parsed *Header, fields header) *DefaultRequestBuilder {
	rb.header.Header = parsed
	rb.header.fields = fields
	return rb
}

func (rb *DefaultRequestBuilder) SetValues(parsed *Values, fields values) *DefaultRequestBuilder {
	rb.values.Values = parsed
	rb.values.fields = fields
	return rb
}

func (rb *DefaultRequestBuilder) SetBody(parsed *Body, fields body) *DefaultRequestBuilder {
	rb.body.Body = parsed
	rb.body.fields = fields
	return rb
}

func (rb *DefaultRequestBuilder) SetDefaults() *DefaultRequestBuilder {
	if rb.errorHandler == nil {
		rb.errorHandler = &DefaultErrorHandler{}
	}
	if rb.allowedMethods == nil {
		amd := make([]string, 0)
		rb.allowedMethods = &amd
	}
	if rb.header.Header == nil || rb.header.fields == nil {
		hd := make(Header)
		rb.header.Header = &hd
		hfd := struct{ Header }{Header: hd}
		rb.header.fields = &hfd
	}
	if rb.values.Values == nil || rb.values.fields == nil {
		vd := make(Values)
		rb.values.Values = &vd
		vfd := struct{ Values }{Values: vd}
		rb.values.fields = &vfd
	}
	if rb.body.Body == nil || rb.body.fields == nil {
		bd := make(Body, 0)
		rb.body.Body = &bd
		bfd := struct{ Body }{Body: bd}
		rb.body.fields = &bfd
	}
	return rb
}

func (rb *DefaultRequestBuilder) Allowed(method string) (errRes ErrorResponse) {
	var ok bool
	for _, m := range *rb.allowedMethods {
		if m == method {
			ok = true
		}
	}
	if !ok {
		return rb.errorHandler.ErrorResponse(DefaultErrorMethodNotAllowed)
	}
	return DefaultOk
}

func (rb *DefaultRequestBuilder) Header(header Header) (errRes ErrorResponse) {
	err := rb.header.Header.Parse(header)
	if err != nil {
		return rb.errorHandler.ErrorResponse(DefaultErrorBadRequest)
	}
	return rb.errorHandler.ErrorResponse(DefaultOk)
}

func (rb *DefaultRequestBuilder) ReadBody(body io.ReadCloser) (errRes ErrorResponse) {
	defer body.Close()
	json.NewDecoder(body).Decode(rb.body.fields)
	return rb.errorHandler.ErrorResponse(DefaultOk)
}

func (rb *DefaultRequestBuilder) Values(values Values) (errRes ErrorResponse) {
	err := rb.values.Values.Parse(values)
	if err != nil {
		return rb.errorHandler.ErrorResponse(DefaultErrorBadRequest)
	}
	return rb.errorHandler.ErrorResponse(DefaultOk)
}

type DefaultResponse struct {
	header struct {
		*Header
		fields header
	}
	body struct {
		*Body
		fields body
	}
}

func NewDefaultResponse() *DefaultResponse {
	return &DefaultResponse{}
}

func (r *DefaultResponse) SetHeader(parsed *Header, fields header) *DefaultResponse {
	r.header.Header = parsed
	r.header.fields = fields
	return r
}

func (r *DefaultResponse) SetBody(parsed *Body, fields body) *DefaultResponse {
	r.body.Body = parsed
	r.body.fields = fields
	return r
}

func (r *DefaultResponse) SetDefaults() *DefaultResponse {
	if r.header.Header == nil || r.header.fields == nil {
		hd := make(Header)
		r.header.Header = &hd
		hfd := struct{ Header }{Header: hd}
		r.header.fields = &hfd
	}
	if r.body.Body == nil || r.body.fields == nil {
		bd := make(Body, 0)
		r.body.Body = &bd
		bfd := struct{ Body }{Body: bd}
		r.body.fields = &bfd
	}
	return r
}

func (r *DefaultResponse) Header() (header Header) {
	if r.header.Header == nil {
		r.header.Header.Parse(r.header.fields)
	}
	return *r.header.Header
}

func (r *DefaultResponse) BodyBytes() (body []byte) {
	body, _ = json.Marshal(r.body.fields)
	return
}