gistfile1.go

package main

import ( 
	"fmt"
	"time"
	"gopkg.in/mgo.v2"
	"gopkg.in/mgo.v2/bson"
	"encoding/json"
	"os"
)

var configFile string = "config.json"

type Configuration struct {
	Url, Database string
}
var config Configuration = Configuration{}

type Post struct {
	Id string 	`bson="_id"`
	Body string			`bson="body"`
	Title string		`bson:"title"`
	Tags []string		`bson:"tags"`
	Date time.Time		`bson:"date"`
}

type Repository struct {
	databaseName string
	url string
	session *mgo.Session
}

func (repo *Repository) Initialize(url, dbname string) {
	repo.url = url
	repo.databaseName = dbname
	repo.session, _ = mgo.Dial(repo.url)
}

func (repo *Repository) OpenCollection(collection string) *mgo.Collection {
	return repo.session.DB(repo.databaseName).C(collection)
}

func (repo *Repository) Close() {
	repo.session.Close()
}

type PostRepository struct {
	Repository
	collection string
}

func NewPostRepository(config Configuration) *PostRepository {
	postRepo := new(PostRepository)
	postRepo.Initialize(config.Url, config.Database)
	postRepo.collection = "posts"
	return postRepo
}

func (postRepo PostRepository) GetPost(tag string) *Post {
	post := &Post { Id: "1", Body: "Body", Title: "Title", Tags: make([]string,5), Date: time.Now() };
	return post
}

func (postRepo PostRepository) GetPosts(tag string) []Post {
	posts := postRepo.OpenCollection(postRepo.collection)

	postArray := []Post{}
	posts.Find(bson.M{ "tags": tag }).All(&postArray)

	return postArray
}

func init(){
	file, err := os.Open(configFile)

	if err != nil {
		fmt.Println("Error opening json file ", err, configFile)
	}

	decoder := json.NewDecoder(file)
	err2 := decoder.Decode(&config)

	if err2 != nil {
		fmt.Println("error decoding json file", err);
	}
}

func main() {
	postRepo := NewPostRepository(config)
	defer postRepo.Close()

	posts := postRepo.GetPosts("mongodb")

	fmt.Printf("got %d\n", len(posts))

	for _, post := range posts {
		fmt.Println(post.Title)
	}
}