resource.go

/*
Copyright 2015 All rights reserved.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package main

import (
	"errors"
	"fmt"
	"strconv"
	"strings"
)

func newResource() *Resource {
	return &Resource{
		Methods: allHTTPMethods,
	}
}

// parse decodes a resource definition
func (r *Resource) parse(resource string) (*Resource, error) {
	if resource == "" {
		return nil, errors.New("the resource has no options")
	}
	for _, x := range strings.Split(resource, "|") {
		kp := strings.Split(x, "=")
		if len(kp) != 2 {
			return nil, errors.New("invalid resource keypair, should be (uri|roles|methods|white-listed)=comma_values")
		}
		switch kp[0] {
		case "uri":
			r.URL = kp[1]
			if !strings.HasPrefix(r.URL, "/") {
				return nil, errors.New("the resource uri should start with a '/'")
			}
		case "methods":
			r.Methods = strings.Split(kp[1], ",")
			if len(r.Methods) == 1 {
				if r.Methods[0] == "any" || r.Methods[0] == "ANY" {
					r.Methods = allHTTPMethods
				}
			}
		case "roles":
			r.Roles = strings.Split(kp[1], ",")
		case "white-listed":
			value, err := strconv.ParseBool(kp[1])
			if err != nil {
				return nil, errors.New("the value of whitelisted must be true|TRUE|T or it's false equivalent")
			}
			r.WhiteListed = value
		default:
			return nil, errors.New("invalid identifier, should be roles, uri or methods")
		}
	}

	return r, nil
}

// valid ensure the resource is valid
func (r *Resource) valid() error {
	if r.Methods == nil {
		r.Methods = make([]string, 0)
	}
	if r.Roles == nil {
		r.Roles = make([]string, 0)
	}
	if strings.HasPrefix(r.URL, oauthURL) {
		return errors.New("this is used by the oauth handlers")
	}
	if r.URL == "" {
		return errors.New("resource does not have url")
	}
	// step: add any of no methods
	if len(r.Methods) <= 0 {
		r.Methods = allHTTPMethods
	}
	// step: check the method is valid
	for _, m := range r.Methods {
		if !isValidHTTPMethod(m) {
			return fmt.Errorf("invalid method %s", m)
		}
	}

	return nil
}

// getRoles returns a list of roles for this resource
func (r Resource) getRoles() string {
	return strings.Join(r.Roles, ",")
}

// String returns a string representation of the resource
func (r Resource) String() string {
	if r.WhiteListed {
		return fmt.Sprintf("uri: %s, white-listed", r.URL)
	}

	roles := "authentication only"
	methods := "ANY"

	if len(r.Roles) > 0 {
		roles = strings.Join(r.Roles, ",")
	}

	if len(r.Methods) > 0 {
		methods = strings.Join(r.Methods, ",")
	}

	return fmt.Sprintf("uri: %s, methods: %s, required: %s", r.URL, methods, roles)
}