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option.go
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option.go
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package v1
import (
"bytes"
"encoding/json"
"fmt"
"io"
"net/http"
"reflect"
)
type Option struct {
value interface{}
err error
}
type Producer func(o Option) interface{}
type Transformer func(o Option) Option
type ErrorHandler func(err error) error
func Return(option Option) Transformer {
return func(o Option) Option {
return option
}
}
func Wrap(i interface{}, err error) Option {
return Option{
value: i,
err: err,
}
}
func WrapValue(i interface{}) Option {
return Option{
value: i,
}
}
func WrapError(err error) Option {
return Option{
err: err,
}
}
func (o Option) Error() error {
return o.err
}
func (o Option) Value() interface{} {
return o.value
}
func (o Option) Or(i interface{}) interface{} {
if o.err != nil {
return i
}
return nil
}
func (o Option) Read() Option {
if o.err != nil {
return Read(o.value.(io.Reader))
}
return o
}
func (o Option) Slurp() Option {
if o.err != nil {
return o
}
switch o.value.(type) {
case io.ReadCloser:
return Slurp(o.value.(io.ReadCloser))
case io.Reader:
return Read(o.value.(io.Reader))
case *http.Response:
return Slurp(o.value.(*http.Response).Body)
case http.Response:
return Slurp(o.value.(http.Response).Body)
}
return WrapError(fmt.Errorf("couldn't slurp %#v", o))
}
func (o Option) ToString() Option {
if o.err != nil {
return o
}
return Option{
value: string(o.value.([]byte)),
err: o.err,
}
}
func (o Option) Unwrap() interface{} {
if o.err != nil {
panic(o.err)
}
return o.value
}
func (o Option) UnwrapBytes() []byte {
if o.err != nil {
panic(o.err)
}
return o.value.([]byte)
}
func (o Option) UnwrapString() string {
if o.err != nil {
panic(o.err)
}
return string(o.UnwrapBytes())
}
func (o Option) Catch(e ErrorHandler) Option {
if o.err != nil {
return Option{
value: o.value,
err: e(o.err),
}
}
return o
}
func (o Option) Close() Option {
if o.err == nil {
o.err = o.value.(io.Closer).Close()
}
return o
}
func (o Option) WriteTo(w io.Writer) Option {
_, err := w.Write(o.UnwrapBytes())
return Option{
value: o.value,
err: err,
}
}
func (o Option) CopyToWriter(w io.Writer) Option {
if o.err != nil {
return o
}
switch o.value.(type) {
case io.Reader:
_, err := io.Copy(w, o.value.(io.Reader))
return Wrap(o.value, err)
case *http.Response:
_, err := io.Copy(w, o.value.(*http.Response).Body)
return Wrap(o.value, err)
case []byte:
_, err := io.Copy(w, bytes.NewReader(o.value.([]byte)))
return Wrap(o.value, err)
}
return Wrap(o.value, fmt.Errorf("could not handle value of %s type yet", reflect.TypeOf(o.value).Name()))
}
func (o Option) WriteStringTo(w io.StringWriter) Option {
_, err := w.WriteString(o.UnwrapString())
return Option{
value: o.value,
err: err,
}
}
func (o Option) JSON(i interface{}) Option {
b := o.UnwrapBytes()
err := json.Unmarshal(b, &i)
return Option{
value: i,
err: err,
}
}