func (mfa mockFailingAuthorizer) WithAuthorization() autorest.PrepareDecorator {
	return func(p autorest.Preparer) autorest.Preparer {
		return autorest.PreparerFunc(func(r *http.Request) (*http.Request, error) {
			return r, fmt.Errorf("ERROR: mockFailingAuthorizer returned expected error")
		})
	}
}

// WithAuthorization returns a PrepareDecorator that adds an HTTP Authorization header whose
// value is "Bearer " followed by the AccessToken of the Token.
func (t *Token) WithAuthorization() autorest.PrepareDecorator {
	return func(p autorest.Preparer) autorest.Preparer {
		return autorest.PreparerFunc(func(r *http.Request) (*http.Request, error) {
			return (autorest.WithBearerAuthorization(t.AccessToken)(p)).Prepare(r)
		})
	}
}

// RequestRecorder returns an autorest.PrepareDecorator that records requests
// to ghe given slice.
func RequestRecorder(requests *[]*http.Request) autorest.PrepareDecorator {
	if requests == nil {
		return nil
	}
	var mu sync.Mutex
	return func(p autorest.Preparer) autorest.Preparer {
		return autorest.PreparerFunc(func(req *http.Request) (*http.Request, error) {
			// Save the request body, since it will be consumed.
			reqCopy := *req
			if req.Body != nil {
				var buf bytes.Buffer
				if _, err := buf.ReadFrom(req.Body); err != nil {
					return nil, err
				}
				if err := req.Body.Close(); err != nil {
					return nil, err
				}
				reqCopy.Body = ioutil.NopCloser(&buf)
				req.Body = ioutil.NopCloser(bytes.NewReader(buf.Bytes()))
			}
			mu.Lock()
			*requests = append(*requests, &reqCopy)
			mu.Unlock()
			return req, nil
		})
	}
}

func withInspection() autorest.PrepareDecorator {
	return func(p autorest.Preparer) autorest.Preparer {
		return autorest.PreparerFunc(func(r *http.Request) (*http.Request, error) {
			fmt.Printf("Inspecting Request: %s %s\n", r.Method, r.URL)
			return p.Prepare(r)
		})
	}
}

func (mi *mockInspector) WithInspection() autorest.PrepareDecorator {
	return func(p autorest.Preparer) autorest.Preparer {
		return autorest.PreparerFunc(func(r *http.Request) (*http.Request, error) {
			mi.wasInvoked = true
			return p.Prepare(r)
		})
	}
}

func withErrorPrepareDecorator(e *error) autorest.PrepareDecorator {
	return func(p autorest.Preparer) autorest.Preparer {
		return autorest.PreparerFunc(func(r *http.Request) (*http.Request, error) {
			*e = fmt.Errorf("azure: Faux Prepare Error")
			return r, *e
		})
	}
}

func withInspection() autorest.PrepareDecorator {
	return func(p autorest.Preparer) autorest.Preparer {
		return autorest.PreparerFunc(func(r *http.Request) (*http.Request, error) {
			log.Debug("Azure request", logutil.Fields{
				"method":  r.Method,
				"request": r.URL.String(),
			})
			return p.Prepare(r)
		})
	}
}

// WithAuthorization returns a PrepareDecorator that adds an HTTP Authorization header whose
// value is "Bearer " followed by the AccessToken of the ServicePrincipalToken.
//
// By default, the token will automatically refresh if nearly expired (as determined by the
// RefreshWithin interval). Use the AutoRefresh method to enable or disable automatically refreshing
// tokens.
func (spt *ServicePrincipalToken) WithAuthorization() autorest.PrepareDecorator {
	return func(p autorest.Preparer) autorest.Preparer {
		return autorest.PreparerFunc(func(r *http.Request) (*http.Request, error) {
			if spt.autoRefresh {
				err := spt.EnsureFresh()
				if err != nil {
					return r, fmt.Errorf("azure: Failed to refresh Service Principal Token for request to %s (%v)", r.URL, err)
				}
			}
			return (autorest.WithBearerAuthorization(spt.AccessToken)(p)).Prepare(r)
		})
	}
}

// WithAuthorization is part of the autorest.Authorizer interface.
func (c *cloudSpecAuth) WithAuthorization() autorest.PrepareDecorator {
	return func(p autorest.Preparer) autorest.Preparer {
		return autorest.PreparerFunc(func(r *http.Request) (*http.Request, error) {
			r, err := p.Prepare(r)
			if err != nil {
				return nil, err
			}
			token, err := c.getToken()
			if err != nil {
				return nil, err
			}
			return autorest.CreatePreparer(token.WithAuthorization()).Prepare(r)
		})
	}
}

func withInspection(maxlen int64) autorest.PrepareDecorator {
	return func(p autorest.Preparer) autorest.Preparer {
		return autorest.PreparerFunc(func(r *http.Request) (*http.Request, error) {
			body, bodyString := handleBody(r.Body, maxlen)
			r.Body = body

			log.Print("Azure request", logutil.Fields{
				"method":  r.Method,
				"request": r.URL.String(),
				"body":    bodyString,
			})
			return p.Prepare(r)
		})
	}
}

// WithReturningClientID returns a PrepareDecorator that adds an HTTP extension header of
// x-ms-client-request-id whose value is the passed, undecorated UUID (e.g.,
// "0F39878C-5F76-4DB8-A25D-61D2C193C3CA"). It also sets the x-ms-return-client-request-id
// header to true such that UUID accompanies the http.Response.
func WithReturningClientID(uuid string) autorest.PrepareDecorator {
	preparer := autorest.CreatePreparer(
		WithClientID(uuid),
		WithReturnClientID(true))

	return func(p autorest.Preparer) autorest.Preparer {
		return autorest.PreparerFunc(func(r *http.Request) (*http.Request, error) {
			r, err := p.Prepare(r)
			if err != nil {
				return r, err
			}
			return preparer.Prepare(r)
		})
	}
}

// PrepareDecorator returns an autorest.PrepareDecorator that
// logs requests at trace level.
func PrepareDecorator(logger loggo.Logger) autorest.PrepareDecorator {
	return func(p autorest.Preparer) autorest.Preparer {
		return autorest.PreparerFunc(func(r *http.Request) (*http.Request, error) {
			if logger.IsTraceEnabled() {
				dump, err := httputil.DumpRequest(r, true)
				if err != nil {
					logger.Tracef("failed to dump request: %v", err)
					logger.Tracef("%+v", r)
				} else {
					logger.Tracef("%s", dump)
				}
			}
			return p.Prepare(r)
		})
	}
}