Add parse file and path

examples/main.go

@@ -2,17 +2,12 @@ package main
 
 import (
 	"fmt"
-	"os"
 
 	imageType "github.com/mushroomsir/image-type"
 )
 
 func main() {
-	file, _ := os.Open("../testdata/test.jpg")
-
-	bytes := make([]byte, 256)
-	file.Read(bytes)
-	res, err := imageType.Parse(bytes)
+	res, err := imageType.ParsePath("../testdata/test.jpg")
 	if err == nil {
 		fmt.Println(res.Type)     // jpg
 		fmt.Println(res.MimeType) // image/jpeg

image.go

@@ -4,6 +4,7 @@ import (
 	"bufio"
 	"errors"
 	"io"
+	"os"
 )
 
 // ImageInfo ...
@@ -14,10 +15,33 @@ type ImageInfo struct {
 	Height   int
 }
 
+var headerLength = 256
+
+// ParsePath ...
+func ParsePath(filePath string) (img *ImageInfo, err error) {
+	file, err := os.Open(filePath)
+	if err != nil {
+		return nil, err
+	}
+	bytes := make([]byte, headerLength)
+	file.Read(bytes)
+	return Parse(bytes)
+}
+
+// ParseFile ...
+func ParseFile(file *os.File) (img *ImageInfo, err error) {
+	bytes := make([]byte, headerLength)
+	_, err = file.Read(bytes)
+	if err != nil {
+		return
+	}
+	return Parse(bytes)
+}
+
 // ParseReader ...
 func ParseReader(rd io.Reader) (img *ImageInfo, err error) {
 	br := bufio.NewReader(rd)
-	bytes, err := br.Peek(256)
+	bytes, err := br.Peek(headerLength)
 	if err != nil {
 		return
 	}

image_test.go

@@ -9,10 +9,7 @@ import (
 
 func TestJPEG(t *testing.T) {
 	assert := assert.New(t)
-	file, _ := os.Open("testdata/test.jpg")
-	bytes := make([]byte, 256)
-	file.Read(bytes)
-	res, err := Parse(bytes)
+	res, err := ParsePath("testdata/test.jpg")
 	if assert.Nil(err) {
 		assert.Equal("jpg", res.Type)
 		assert.Equal("image/jpeg", res.MimeType)
@@ -23,9 +20,7 @@ func TestJPEG(t *testing.T) {
 func TestPng(t *testing.T) {
 	assert := assert.New(t)
 	file, _ := os.Open("testdata/test.png")
-	bytes := make([]byte, 256)
-	file.Read(bytes)
-	res, err := Parse(bytes)
+	res, err := ParseFile(file)
 	if assert.Nil(err) {
 		assert.Equal("png", res.Type)
 		assert.Equal("image/png", res.MimeType)
@@ -37,9 +32,7 @@ func TestPng(t *testing.T) {
 func TestGif(t *testing.T) {
 	assert := assert.New(t)
 	file, _ := os.Open("testdata/test.gif")
-	bytes := make([]byte, 256)
-	file.Read(bytes)
-	res, err := Parse(bytes)
+	res, err := ParseReader(file)
 	if assert.Nil(err) {
 		assert.Equal("gif", res.Type)
 		assert.Equal("image/gif", res.MimeType)