client.go

package oauth2

import (
	"encoding/json"
	"fmt"
	"io/ioutil"
	"os"
	"sync"
)

type Client struct {
	Id          string
	Secret      string
	BaseUri     string
	Description string
}

func (c *Client) String() string {
	return fmt.Sprintf("client %s for %s", c.Id, c.BaseUri)
}

func NewClient(id, secret, uri, des string) *Client {
	return &Client{id, secret, uri, des}
}

type FileClientStore struct {
	filename string
	locker   *sync.Mutex
	modtime  int64
	m        map[string]*Client
}

func NewFileClientStore(filename string) (*FileClientStore, error) {
	f, err := os.Open(filename)
	if err != nil {
		return nil, err
	}
	c, err := ioutil.ReadAll(f)
	if err != nil {
		return nil, err
	}

	err = f.Close()
	if err != nil {
		return nil, err
	}

	m := make(map[string]*Client)
	err = json.Unmarshal(c, &m)
	if err != nil {
		return nil, err
	}
	info, err := os.Stat(filename)
	if err != nil {
		return nil, err
	}
	return &FileClientStore{filename, new(sync.Mutex), info.ModTime().Unix(),
		m}, nil
}

func (s *FileClientStore) saveFile() error {
	c, err := json.Marshal(s.m)
	if err != nil {
		return err
	}

	f, err := os.Create(s.filename)
	if err != nil {
		return err
	}

	_, err = f.Write(c)
	if err != nil {
		return err
	}

	err = f.Close()
	if err != nil {
		return err
	}

	info, err := os.Stat(s.filename)
	if err != nil {
		return err
	}

	s.modtime = info.ModTime().Unix()
	return nil
}

func (s *FileClientStore) updateMap() error {
	info, err := os.Stat(s.filename)
	if err != nil {
		return err
	}

	if info.ModTime().Unix() > s.modtime {
		f, err := os.Open(s.filename)
		if err != nil {
			return err
		}

		c, err := ioutil.ReadAll(f)
		if err != nil {
			return err
		}

		m := make(map[string]*Client)
		err = json.Unmarshal(c, &m)
		if err != nil {
			return err
		}
		s.m = m
	}
	return nil
}

func (s *FileClientStore) Save(c *Client) (string, error) {
	s.locker.Lock()
	defer s.locker.Unlock()
	err := s.updateMap()
	if err != nil {
		return "", err
	}

	s.m[c.Id] = c

	err = s.saveFile()
	if err != nil {
		return "", err
	}
	return c.Id, nil
}

func (s *FileClientStore) Read(id string) (*Client, error) {
	s.locker.Lock()
	defer s.locker.Unlock()
	err := s.updateMap()
	if err != nil {
		return nil, err
	}
	return s.m[id], nil
}

func (s *FileClientStore) Remove(id string) error {
	s.locker.Lock()
	defer s.locker.Unlock()
	err := s.updateMap()
	if err != nil {
		return err
	}

	delete(s.m, id)

	err = s.saveFile()
	if err != nil {
		return err
	}
	return nil
}