add automatic image resizing

cmd/cli/commands.go

@@ -3,19 +3,129 @@ package main
 import (
 	"fmt"
 	"github.com/urfave/cli/v2"
+	"io"
+	"os"
 )
 
-//func startCmd() *cli.Command {
-//	return &cli.Command{
-//		Name:    "start",
-//		Aliases: []string{"s"},
-//		Usage:   "Start the application service",
-//		Action: func(c *cli.Context) error {
-//
-//			return nil
-//		},
-//	}
-//}
+func resizeCmd() *cli.Command {
+	return &cli.Command{
+		Name:    "resize",
+		Aliases: []string{"r"},
+		Flags: []cli.Flag{
+			&cli.StringFlag{
+				Name:  "output",
+				Value: "./resized.jpg",
+				Usage: "path to output resized file (should be a jpg)",
+				Aliases: []string{
+					"o",
+				},
+			},
+			&cli.StringFlag{
+				Name:    "format",
+				Aliases: []string{"f"},
+				Usage:   "The format to resize the image to wide, tall, or square",
+				Value:   "wide",
+			},
+		},
+		Usage: "Resize an image to a supported size for the API",
+		Action: func(c *cli.Context) error {
+			var needsCleanup bool
+			// get the image
+			// use the first argument as the file name
+			fileLocation, err := getFileLocation(c)
+			if err != nil {
+				return fmt.Errorf("error getting file location | %w", err)
+			}
+
+			// get the format
+			format := c.String("format")
+			if format != "wide" && format != "tall" && format != "square" {
+				return fmt.Errorf("invalid format %s", format)
+			}
+
+			// get output file
+			output := c.String("output")
+
+			// resize the image
+			tempLocation, err := resizeImage(fileLocation, format)
+			if err != nil {
+				return fmt.Errorf("error resizing image | %w", err)
+			}
+
+			if tempLocation != fileLocation {
+				fmt.Printf("Resized image to %s\n", tempLocation)
+				needsCleanup = true
+			}
+
+			// copy the temp image to the output file
+			err = copyFile(tempLocation, output, 1024)
+			if err != nil {
+				return fmt.Errorf("error copying file | %w", err)
+			}
+
+			if needsCleanup {
+				// remove the temp file
+				err = cleanUpTempFile(tempLocation)
+				if err != nil {
+					return fmt.Errorf("error removing temp file | %w", err)
+				}
+			}
+
+			return nil
+		},
+	}
+}
+
+// copyFile copies a file from src to dst
+// BUFFERSIZE is the size of the buffer to use when copying
+// https://opensource.com/article/18/6/copying-files-go
+func copyFile(src, dst string, BUFFERSIZE int64) error {
+	sourceFileStat, err := os.Stat(src)
+	if err != nil {
+		return err
+	}
+
+	if !sourceFileStat.Mode().IsRegular() {
+		return fmt.Errorf("%s is not a regular file.", src)
+	}
+
+	source, err := os.Open(src)
+	if err != nil {
+		return err
+	}
+	defer source.Close()
+
+	_, err = os.Stat(dst)
+	if err == nil {
+		return fmt.Errorf("File %s already exists.", dst)
+	}
+
+	destination, err := os.Create(dst)
+	if err != nil {
+		return err
+	}
+	defer destination.Close()
+
+	if err != nil {
+		panic(err)
+	}
+
+	buf := make([]byte, BUFFERSIZE)
+	for {
+		n, err := source.Read(buf)
+		if err != nil && err != io.EOF {
+			return err
+		}
+		if n == 0 {
+			break
+		}
+
+		if _, err := destination.Write(buf[:n]); err != nil {
+			return err
+		}
+	}
+	return err
+}
 
 func getJobResultCmd() *cli.Command {
 	return &cli.Command{