Cache reactions for 100 posts

app.go

@@ -7,6 +7,7 @@ import (
 
 	shutdowner "git.jlel.se/jlelse/go-shutdowner"
 	ts "git.jlel.se/jlelse/template-strings"
+	"github.com/dgraph-io/ristretto"
 	ct "github.com/elnormous/contenttype"
 	"github.com/go-fed/httpsig"
 	"github.com/hacdias/indieauth/v2"
@@ -73,6 +74,10 @@ type goBlog struct {
 	mediaStorage     mediaStorage
 	// Minify
 	min minify.Minifier
+	// Reactions
+	reactionsInit  sync.Once
+	reactionsCache *ristretto.Cache
+	reactionsSfg   singleflight.Group
 	// Regex Redirects
 	regexRedirects []*regexRedirect
 	// Sessions

reactions.go

@@ -3,8 +3,10 @@ package main
 import (
 	"encoding/json"
 	"errors"
+	"io"
 	"net/http"
 
+	"github.com/dgraph-io/ristretto"
 	"github.com/samber/lo"
 	"go.goblog.app/app/pkgs/bufferpool"
 	"go.goblog.app/app/pkgs/contenttype"
@@ -29,6 +31,17 @@ func (a *goBlog) reactionsEnabledForPost(post *post) bool {
 	return a.reactionsEnabled() && post != nil && post.firstParameter(reactionsPostParam) != "false"
 }
 
+func (a *goBlog) initReactions() {
+	a.reactionsInit.Do(func() {
+		a.reactionsCache, _ = ristretto.NewCache(&ristretto.Config{
+			NumCounters:        1000,
+			MaxCost:            100, // Cache reactions for 100 posts
+			BufferItems:        64,
+			IgnoreInternalCost: true,
+		})
+	})
+}
+
 func (a *goBlog) postReaction(w http.ResponseWriter, r *http.Request) {
 	path := r.FormValue("path")
 	reaction := r.FormValue("reaction")
@@ -48,6 +61,11 @@ func (a *goBlog) saveReaction(reaction, path string) error {
 	if !lo.Contains(allowedReactions, reaction) {
 		return errors.New("reaction not allowed")
 	}
+	// Init
+	a.initReactions()
+	// Delete from cache
+	defer a.reactionsSfg.Forget(path)
+	defer a.reactionsCache.Del(path)
 	// Insert reaction
 	_, err := a.db.exec("insert into reactions (path, reaction, count) values (?, ?, 1) on conflict (path, reaction) do update set count=count+1", path, reaction)
 	return err
@@ -68,38 +86,57 @@ func (a *goBlog) getReactions(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 	w.Header().Set(contentType, contenttype.JSONUTF8)
-	_ = a.min.Get().Minify(contenttype.JSON, w, buf)
+	_, _ = io.Copy(w, buf)
 }
 
 func (a *goBlog) getReactionsFromDatabase(path string) (map[string]int, error) {
-	sqlBuf := bufferpool.Get()
-	defer bufferpool.Put(sqlBuf)
-	sqlArgs := []any{}
-	sqlBuf.WriteString("select reaction, count from reactions where path=? and reaction in (")
-	sqlArgs = append(sqlArgs, path)
-	for i, reaction := range allowedReactions {
-		if i > 0 {
-			sqlBuf.WriteString(",")
-		}
-		sqlBuf.WriteString("?")
-		sqlArgs = append(sqlArgs, reaction)
+	// Init
+	a.initReactions()
+	// Check cache
+	if val, cached := a.reactionsCache.Get(path); cached {
+		// Return from cache
+		return val.(map[string]int), nil
 	}
-	sqlBuf.WriteString(") and path not in (select path from post_parameters where parameter=? and value=?)")
-	sqlArgs = append(sqlArgs, reactionsPostParam, "false")
-	rows, err := a.db.query(sqlBuf.String(), sqlArgs...)
-	if err != nil {
-		return nil, err
-	}
-	defer rows.Close()
-	reactions := map[string]int{}
-	for rows.Next() {
-		var reaction string
-		var count int
-		err = rows.Scan(&reaction, &count)
+	// Get reactions
+	res, err, _ := a.reactionsSfg.Do(path, func() (interface{}, error) {
+		// Build query
+		sqlBuf := bufferpool.Get()
+		defer bufferpool.Put(sqlBuf)
+		sqlArgs := []any{}
+		sqlBuf.WriteString("select reaction, count from reactions where path=? and reaction in (")
+		sqlArgs = append(sqlArgs, path)
+		for i, reaction := range allowedReactions {
+			if i > 0 {
+				sqlBuf.WriteString(",")
+			}
+			sqlBuf.WriteString("?")
+			sqlArgs = append(sqlArgs, reaction)
+		}
+		sqlBuf.WriteString(") and path not in (select path from post_parameters where parameter=? and value=?)")
+		sqlArgs = append(sqlArgs, reactionsPostParam, "false")
+		// Execute query
+		rows, err := a.db.query(sqlBuf.String(), sqlArgs...)
 		if err != nil {
 			return nil, err
 		}
-		reactions[reaction] = count
+		// Build result
+		defer rows.Close()
+		reactions := map[string]int{}
+		for rows.Next() {
+			var reaction string
+			var count int
+			err = rows.Scan(&reaction, &count)
+			if err != nil {
+				return nil, err
+			}
+			reactions[reaction] = count
+		}
+		// Cache result
+		a.reactionsCache.Set(path, reactions, 1)
+		return reactions, nil
+	})
+	if err != nil || res == nil {
+		return nil, err
 	}
-	return reactions, nil
+	return res.(map[string]int), nil
 }

reactions_test.go

@@ -136,13 +136,13 @@ func Test_reactionsHighLevel(t *testing.T) {
 	rec = httptest.NewRecorder()
 	app.getReactions(rec, req)
 	assert.Equal(t, http.StatusOK, rec.Code)
-	assert.Equal(t, `{"❤️":1}`, rec.Body.String())
+	assert.Equal(t, "{\"❤️\":1}\n", rec.Body.String())
 
 	// Get reactions for a non-existing post
 	req = httptest.NewRequest(http.MethodGet, "/?path=/non-existing-post", nil)
 	rec = httptest.NewRecorder()
 	app.getReactions(rec, req)
 	assert.Equal(t, http.StatusOK, rec.Code)
-	assert.Equal(t, `{}`, rec.Body.String())
+	assert.Equal(t, "{}\n", rec.Body.String())
 
 }