Implement Redis caching for Reddit image fetching

2025-07-22 12:13:38 -04:00
parent 8d0f11e681
commit 88ef0c23a0
5 changed files with 280 additions and 156 deletions
--- a/reddit/fetcher.go
+++ b/reddit/fetcher.go
@@ -0,0 +1,132 @@
+package reddit
+
+import (
+	"context"
+	"github.com/labstack/echo/v4"
+	"github.com/siteworxpro/top-wallpaper/redis"
+	"github.com/siteworxpro/top-wallpaper/resize"
+	"io"
+	"net/http"
+	"net/url"
+	"os"
+	"strconv"
+	"strings"
+	"time"
+)
+
+func Fetch(ctx context.Context) {
+	const defaultImageSize = 1600
+	const minImageSize = 100
+
+	rc, err := redis.FromContext(ctx)
+	if err != nil {
+		panic("Redis client not found in context: " + err.Error())
+	}
+
+	l := ctx.Value("logger").(echo.Logger)
+
+	var size int
+	if sizeS, ok := os.LookupEnv("MAX_SIZE"); ok {
+		size, err = strconv.Atoi(sizeS)
+		if err != nil {
+			size = defaultImageSize
+		}
+	} else {
+		size = defaultImageSize
+	}
+
+	if size < minImageSize {
+		size = defaultImageSize
+	}
+
+	for {
+		select {
+		case <-ctx.Done():
+
+			l.Info("Stopping Reddit fetcher...")
+			_ = rc.Close()
+
+			return
+		default:
+
+			val, err := rc.Get(redis.CacheKey)
+			if val != "" {
+				l.Info("Reddit image fetched from cache...")
+
+				break
+			}
+
+			l.Info("Fetching latest image from Reddit...")
+
+			latestImageVal, err := GetLatestImage(func(u string) (*http.Response, error) {
+
+				request := &http.Request{
+					Method: http.MethodGet,
+					Header: http.Header{
+						"User-Agent": []string{"Mozilla/5.0 (compatible; RedditBot/1.0; +https://www.reddit.com/wiki/redditauth)"},
+					},
+					URL: &url.URL{
+						Scheme: "https",
+						Host:   "www.reddit.com",
+						Path:   strings.TrimPrefix(u, "https://www.reddit.com"),
+					},
+				}
+
+				httpClient := &http.Client{
+					Timeout: 10 * time.Second,
+				}
+
+				response, err := httpClient.Do(request)
+
+				if err != nil {
+					l.Error("Error fetching image from Reddit: ", err)
+					return nil, err
+				}
+
+				if response.StatusCode != http.StatusOK {
+					l.Error("Error fetching image from Reddit: ", response.Status)
+					return nil, &echo.HTTPError{
+						Code:    response.StatusCode,
+						Message: "Error fetching image from Reddit",
+					}
+				}
+
+				return response, nil
+			})
+
+			response, err := http.Get(latestImageVal)
+			if err != nil {
+				l.Error("Error fetching image from Reddit: ", err)
+
+				break
+			}
+
+			if response.StatusCode != http.StatusOK {
+				l.Error("Error fetching image from Reddit: ", response.Status)
+
+				break
+			}
+
+			imageDataBytes, err := io.ReadAll(response.Body)
+			if err != nil {
+				l.Error("Error reading image data: ", err)
+				_ = response.Body.Close()
+				break
+			}
+
+			_ = response.Body.Close()
+
+			imageData := string(imageDataBytes)
+			resized, err := resize.Shrink(imageData, uint(size), 70)
+
+			err = rc.Set(redis.CacheKey, resized, 10*time.Minute)
+			if err != nil {
+				l.Warn("could not cache image")
+			}
+
+			l.Info("Reddit image fetched and resized successfully, cached for 10 minutes.")
+		}
+
+		time.Sleep(10 * time.Minute)
+	}
+}