Initial commit

backend/main.go

@@ -0,0 +1,137 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"net/http"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+
+	"github.com/labstack/echo"
+	"github.com/labstack/echo/middleware"
+	"github.com/google/uuid"
+)
+
+// VideoDownloadRequest represents the request structure for video download
+type VideoDownloadRequest struct {
+	URL     string `json:"url"`
+	Quality string `json:"quality"`
+}
+
+// getBestFormat fetches and returns the best format for the given quality
+func getBestFormats(url string, targetResolution string) (string, string, error) {
+    log.Printf("Getting best formats for URL: %s, target resolution: %s", url, targetResolution)
+
+    cmd := exec.Command("yt-dlp", "--list-formats", url)
+    output, err := cmd.CombinedOutput()
+    if err != nil {
+        return "", "", fmt.Errorf("failed to list formats: %v\nOutput: %s", err, string(output))
+    }
+
+    lines := strings.Split(strings.TrimSpace(string(output)), "\n")
+    var bestVideoFormat, bestAudioFormat string
+    targetHeight := strings.TrimSuffix(targetResolution, "p")
+
+    for _, line := range lines {
+        fields := strings.Fields(line)
+        if len(fields) < 3 {
+            continue
+        }
+
+        if strings.Contains(line, targetHeight) && strings.Contains(line, "mp4") && bestVideoFormat == "" {
+            bestVideoFormat = fields[0]
+        }
+
+        if strings.Contains(line, "audio only") && strings.Contains(line, "m4a") && bestAudioFormat == "" {
+            bestAudioFormat = fields[0]
+        }
+
+        if bestVideoFormat != "" && bestAudioFormat != "" {
+            break
+        }
+    }
+
+    if bestVideoFormat == "" || bestAudioFormat == "" {
+        return "", "", fmt.Errorf("no suitable formats found for resolution: %s", targetResolution)
+    }
+
+    log.Printf("Selected video format: %s, audio format: %s", bestVideoFormat, bestAudioFormat)
+    return bestVideoFormat, bestAudioFormat, nil
+}
+
+func downloadVideo(c echo.Context) error {
+    req := new(VideoDownloadRequest)
+    if err := c.Bind(req); err != nil {
+        return err
+    }
+    if req.URL == "" || req.Quality == "" {
+        return echo.NewHTTPError(http.StatusBadRequest, "URL and Quality are required")
+    }
+
+    // Get the best video and audio formats
+    videoFormat, audioFormat, err := getBestFormats(req.URL, req.Quality)
+    if err != nil {
+        return echo.NewHTTPError(http.StatusInternalServerError, fmt.Sprintf("Failed to get best formats: %v", err))
+    }
+
+    // Create a temporary directory for downloading files
+    tmpDir, err := os.MkdirTemp("", "downlink")
+    if err != nil {
+        return echo.NewHTTPError(http.StatusInternalServerError, fmt.Sprintf("Failed to create temporary directory: %v", err))
+    }
+    defer func() {
+        if err := os.RemoveAll(tmpDir); err != nil {
+            log.Printf("Failed to clean up temporary directory: %v", err)
+        }
+    }()
+
+    uid := uuid.New().String()
+    videoPath := filepath.Join(tmpDir, fmt.Sprintf("video_%s.mp4", uid))
+    audioPath := filepath.Join(tmpDir, fmt.Sprintf("audio_%s.m4a", uid))
+    outputPath := filepath.Join(tmpDir, fmt.Sprintf("output_%s.mp4", uid))
+
+    // Download video
+    cmdVideo := exec.Command("yt-dlp", "-f", videoFormat, "-o", videoPath, req.URL)
+    if err := cmdVideo.Run(); err != nil {
+        return echo.NewHTTPError(http.StatusInternalServerError, fmt.Sprintf("Failed to download video: %v", err))
+    }
+
+    // Download audio
+    cmdAudio := exec.Command("yt-dlp", "-f", audioFormat, "-o", audioPath, req.URL)
+    if err := cmdAudio.Run(); err != nil {
+        return echo.NewHTTPError(http.StatusInternalServerError, fmt.Sprintf("Failed to download audio: %v", err))
+    }
+
+    // Combine video and audio using ffmpeg
+    cmdMerge := exec.Command("ffmpeg", "-i", videoPath, "-i", audioPath, "-c", "copy", outputPath)
+    if err := cmdMerge.Run(); err != nil {
+        return echo.NewHTTPError(http.StatusInternalServerError, fmt.Sprintf("Failed to merge video and audio: %v", err))
+    }
+
+    // Serve the file with appropriate headers
+    return c.Attachment(outputPath, fmt.Sprintf("video_%s.mp4", uid))
+}
+
+func main() {
+	e := echo.New()
+
+	// Middleware
+	e.Use(middleware.Logger())
+	e.Use(middleware.Recover())
+	e.Use(middleware.CORSWithConfig(middleware.CORSConfig{
+		AllowOrigins: []string{"*"},
+		AllowMethods: []string{http.MethodGet, http.MethodPost, http.MethodPut, http.MethodDelete},
+	}))
+
+	// Routes
+	e.GET("/downlink/", func(c echo.Context) error {
+		return c.String(http.StatusOK, "Backend for DownLink is running.\n")
+	})
+
+	e.POST("/downlink/download", downloadVideo)
+
+	// Start server
+	e.Logger.Fatal(e.Start(":8080"))
+}