Ready to add the file downloader.

rest/matter_service.go

@@ -6,6 +6,9 @@ import (
 	"os"
 	"regexp"
 	"strings"
+	"net/http"
+	"github.com/disintegration/imaging"
+	"strconv"
 )
 
 //@Service
@@ -155,3 +158,97 @@ func (this *MatterService) Upload(file multipart.File, user *User, puuid string,
 
 	return matter
 }
+
+//处理图片下载功能。
+func (this *MatterService) ResizeImage(writer http.ResponseWriter, request *http.Request, matter *Matter, diskFile *os.File) {
+
+	//当前的文件是否是图片，只有图片才能处理。
+	extension := GetExtension(matter.Name)
+	formats := map[string]imaging.Format{
+		".jpg":  imaging.JPEG,
+		".jpeg": imaging.JPEG,
+		".png":  imaging.PNG,
+		".tif":  imaging.TIFF,
+		".tiff": imaging.TIFF,
+		".bmp":  imaging.BMP,
+		".gif":  imaging.GIF,
+	}
+
+	format, ok := formats[extension]
+	if !ok {
+		panic("该图片格式不支持处理")
+	}
+
+	imageResizeM := request.FormValue("imageResizeM")
+	if imageResizeM == "" {
+		imageResizeM = "fit"
+	} else if imageResizeM != "fit" && imageResizeM != "fill" && imageResizeM != "fixed" {
+		panic("imageResizeM参数错误")
+	}
+	imageResizeWStr := request.FormValue("imageResizeW")
+	var imageResizeW int
+	if imageResizeWStr != "" {
+		imageResizeW, err := strconv.Atoi(imageResizeWStr)
+		this.PanicError(err)
+		if imageResizeW < 1 || imageResizeW > 4096 {
+			panic("缩放尺寸不能超过4096")
+		}
+	}
+	imageResizeHStr := request.FormValue("imageResizeH")
+	var imageResizeH int
+	if imageResizeHStr != "" {
+		imageResizeH, err := strconv.Atoi(imageResizeHStr)
+		this.PanicError(err)
+		if imageResizeH < 1 || imageResizeH > 4096 {
+			panic("缩放尺寸不能超过4096")
+		}
+	}
+
+	//单边缩略
+	if imageResizeM == "fit" {
+		//将图缩略成宽度为100，高度按比例处理。
+		if imageResizeW > 0 {
+			src, err := imaging.Decode(diskFile)
+			this.PanicError(err)
+			dst := imaging.Resize(src, imageResizeW, 0, imaging.Lanczos)
+
+			err = imaging.Encode(writer, dst, format)
+			this.PanicError(err)
+		} else if imageResizeH > 0 {
+			//将图缩略成高度为100，宽度按比例处理。
+			src, err := imaging.Decode(diskFile)
+			this.PanicError(err)
+			dst := imaging.Resize(src, 0, imageResizeH, imaging.Lanczos)
+
+			err = imaging.Encode(writer, dst, format)
+
+			this.PanicError(err)
+		} else {
+			panic("单边缩略必须指定imageResizeW或imageResizeH")
+		}
+	} else if imageResizeM == "fill" {
+		//固定宽高，自动裁剪
+		if imageResizeW > 0 && imageResizeH > 0 {
+			src, err := imaging.Decode(diskFile)
+			this.PanicError(err)
+			dst := imaging.Fill(src, imageResizeW, imageResizeH, imaging.Center, imaging.Lanczos)
+			err = imaging.Encode(writer, dst, format)
+			this.PanicError(err)
+		} else {
+			panic("固定宽高，自动裁剪 必须同时指定imageResizeW和imageResizeH")
+		}
+	} else if imageResizeM == "fixed" {
+		//强制宽高缩略
+		if imageResizeW > 0 && imageResizeH > 0 {
+			src, err := imaging.Decode(diskFile)
+			this.PanicError(err)
+			dst := imaging.Resize(src, imageResizeW, imageResizeH, imaging.Lanczos)
+
+			err = imaging.Encode(writer, dst, format)
+			this.PanicError(err)
+		} else {
+			panic("强制宽高缩略必须同时指定imageResizeW和imageResizeH")
+		}
+	}
+
+}