Golang: json.Unmarshal is not returning data correctly

I have a json file (themes/snow/theme.json)

{
    Name:'snow',
    Bgimage:'background.jpg',
    Width:600,
    Height:400,
    Itemrotation:'20,40',
    Text:{
        Fontsize:12,
        Color:'#ff00ff',
        Fontfamily:'verdana',
        Bottommargin:20
    },
    Decoration:[
        {
            Path:'abc.jpg',
            X:2,
            Y:4,
            Rotation:0
        },
        {
            Path:'def.png',
            X:4,
            Y:22,
            Rotation:10
        }
    ]
}

And I have a file that parse the json data

package main

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

const themeDirectory 	= "themes"
const themeJsonFile 	= "theme.json"

type TextInfo struct {
	Fontsize		int
	Color			string
	Fontfamily		string
	Bottommargin	int
}

type DecoInfo struct {
	Path			string
	X				int
	Y				int
	Rotation		int
}

type ThemeInfo struct {
	Name 			string
	Bgimage 		string
	Width 			int
	Height 			int
	Itemrotation	string
	Text 			textInfo
	Decoration		[]decoInfo
}

func main() {
    var tinfo = parseTheme("snow")
        //use tinfo to build graphics
}

func parseTheme(themename string) themeInfo {
	abspath, _ := os.Getwd()
	filename :=  abspath + "/" + themeDirectory + "/" + themename + "/" + themeJsonFile

	//Check this file exists
	if _, error := os.Stat(filename); error != nil {
	    if os.IsNotExist(error) {
			log.Fatal(filename + " does not exist")
			os.Exit(1)
	    }
	} 

	filebyte, error := ioutil.ReadFile(filename) 
 	if error != nil { 
    	log.Fatal("Could not read file " + filename + " to parse")
        os.Exit(1) 
    } 

	var t themeInfo
   	json.Unmarshal(filebyte, &t) 
	fmt.Println(t)
	return t
}

You can see I have 2 lines before the end

 fmt.Println(t)

I am not sure why does it print

{  0 0  {0   0} []}

I expect it should return me themeInfo in a usable way, so that I can use it for further processing.What am I doing wrong here?

As the json package uses reflection to dissect your structs, it can only see fields that are exported. All of your field names begin with lower case letters, therefore they are not exported. Change the names to start with upper case letters and I suspect it will start working for you.

Your JSON is not valid. JavaScript allows single quotes; JSON does not. Further, the object keys must be double quoted:

Valid:

{ "name": "Simon" }

Invalid:

{ name: "Simon" }
{ 'name': "Simon" }
{ "name": 'Simon' }

If you wrap your JSON keys and values with double quotes, you'll see the expected output:

{snow background.jpg 600 400 20,40 {12 #ff00ff verdana 20} [{abc.jpg 2 4 0} {def.png 4 22 10}]}

For exmaple,

const sampleTheme       = `{
    "Name":"snow",
    "Bgimage":"background.jpg",
    "Width":600,
    "Height":400,
    "Itemrotation":"20,40",
    "Text":{
        "Fontsize":12,
        "Color":"#ff00ff",
        "Fontfamily":"verdana",
        "Bottommargin":20
    },
    "Decoration":[
        {
            "Path":"abc.jpg",
            "X":2,
            "Y":4,
            "Rotation":0
        },
        {
            "Path":"def.png",
            "X":4,
            "Y":22,
            "Rotation":10
        }
    ]
}`

For the full program, see: http://play.golang.org/p/SLhaLbJcla