implement caching configuration

.env.example

@@ -31,6 +31,10 @@ PIXIVFE_HOST='127.0.0.1'
 # PIXIVFE_TOKEN_BASE_TIMEOUT=
 # PIXIVFE_TOKEN_MAX_BACKOFF_TIME=
 
+### Caching configuration
+# PIXIVFE_CACHE_SIZE=
+# PIXIVFE_CACHE_TTL=
+
 ### Development options
 # PIXIVFE_DEV=
 # PIXIVFE_RESPONSE_SAVE_LOCATION

config/config.go

@@ -67,6 +67,10 @@ type ServerConfig struct {
 	ProxyCheckInterval time.Duration `env:"PIXIVFE_PROXY_CHECK_INTERVAL,overwrite"`
 	ProxyCheckTimeout  time.Duration `env:"PIXIVFE_PROXY_CHECK_TIMEOUT,overwrite"`
 
+	// Caching configuration
+	CacheSize int           `env:"PIXIVFE_CACHE_SIZE,overwrite"`
+	CacheTTL  time.Duration `env:"PIXIVFE_CACHE_TTL,overwrite"`
+
 	// Development options
 	InDevelopment        bool   `env:"PIXIVFE_DEV"`
 	ResponseSaveLocation string `env:"PIXIVFE_RESPONSE_SAVE_LOCATION,overwrite"`
@@ -133,6 +137,9 @@ func (s *ServerConfig) LoadConfig() error {
 	s.APIBaseTimeout = 500 * time.Millisecond
 	s.APIMaxBackoffTime = 8000 * time.Millisecond
 
+	s.CacheSize = 1000
+	s.CacheTTL = 5 * time.Minute
+
 	s.ResponseSaveLocation = "/tmp/pixivfe/responses"
 
 	s.LogLevel = "info"
@@ -207,6 +214,10 @@ func (s *ServerConfig) LoadConfig() error {
 
 	log.Printf("API request backoff settings: Max retries: %d, Base timeout: %v, Max backoff time: %v\n", s.APIMaxRetries, s.APIBaseTimeout, s.APIMaxBackoffTime)
 
+	// Print cache configuration
+	log.Printf("API response cache size set to: %d items\n", s.CacheSize)
+	log.Printf("API response cache TTL set to: %v\n", s.CacheTTL)
+
 	// Only print ResponseSaveLocation if InDevelopment is set
 	if s.InDevelopment {
 		log.Printf("Response save location: %s\n", s.ResponseSaveLocation)

core/requests.go

@@ -39,9 +39,17 @@ type CachedItem struct {
 var (
 	cache     *lru.Cache
 	cacheLock sync.RWMutex
-	cacheTTL  time.Duration
 )
 
+// initCache initializes the API response cache with the configured size
+func InitCache() {
+	var err error
+	cache, err = lru.New(config.GlobalConfig.CacheSize)
+	if err != nil {
+		panic(i18n.Sprintf("Failed to create cache: %v", err))
+	}
+}
+
 func init() {
 	retryClient = retryablehttp.NewClient()
 	retryClient.RetryMax = config.GlobalConfig.APIMaxRetries
@@ -49,14 +57,6 @@ func init() {
 	retryClient.RetryWaitMax = config.GlobalConfig.APIMaxBackoffTime
 	retryClient.HTTPClient = utils.HttpClient
 	retryClient.Logger = nil // Disables the default logger in go-retryablehttp
-
-	// Initialize cache
-	var err error
-	cache, err = lru.New(1000) // Cache size of 1000 items
-	if err != nil {
-		panic(fmt.Sprintf("Failed to create cache: %v", err))
-	}
-	cacheTTL = 5 * time.Minute // Default TTL of 5 minutes
 }
 
 // Helper function to handle common request logic
@@ -165,7 +165,7 @@ Please refer the following documentation for additional information:
 			cacheLock.Lock()
 			cache.Add(cacheKey, CachedItem{
 				Response:  resp,
-				ExpiresAt: time.Now().Add(cacheTTL),
+				ExpiresAt: time.Now().Add(config.GlobalConfig.CacheTTL),
 			})
 			cacheLock.Unlock()
 			return resp, nil

doc/hosting/environment-variables.md

@@ -197,6 +197,33 @@ Base timeout duration for token management.
 
 Maximum backoff time for token management.
 
+## Caching configuration
+
+PixivFE caches responses from the Pixiv API to improve performance. The following environment variables can be used to configure the caching behavior.
+
+### `PIXIVFE_CACHE_SIZE`
+
+**Required**: No
+
+**Default:** `1000`
+
+Specifies the maximum number of items that can be stored in the cache. This limits the memory usage of the cache.
+
+### `PIXIVFE_CACHE_TTL`
+
+**Required**: No
+
+**Default:** `5m`
+
+Specifies the Time To Live (TTL) for cached items. This is the duration for which an item remains valid in the cache before it's considered stale and needs to be fetched again.
+
+The value should be specified in Go's [`time.Duration`](https://pkg.go.dev/time#ParseDuration) notation.
+
+!!! note
+    While caching improves performance, it also means that changes on Pixiv might not be immediately reflected in PixivFE.
+
+    If you want content updates that are closer to real-time, consider reducing the cache TTL.
+
 ## Network proxy configuration
 
 Used to set the [proxy server](https://en.wikipedia.org/wiki/Proxy_server) that PixivFE will use for all requests. Not to be confused with the image proxy, which is used to comply with the `Referer` check required by `i.pximg.net`.

i18n/locale/en/code.json

@@ -19,6 +19,7 @@
   "core/requests.go:0hOvqlK-HwY": "HTTP status code: %d",
   "core/requests.go:7heLIvyBB2M": "Invalid JSON: %v",
   "core/requests.go:7pvvVOIzWew": "Max retries reached for GET request. Last error: %v",
+  "core/requests.go:Kt44RnMSg6M": "Failed to create cache: %v",
   "core/requests.go:Odhyy2SoIGU": "failed to make request: %w",
   "core/requests.go:XGjPq4l3s2o": "userToken is required for POST requests",
   "core/requests.go:XdMN7Q7DY3k": "failed to proxy request: %w",

main.go

@@ -15,6 +15,7 @@ import (
 	"time"
 
 	"codeberg.org/vnpower/pixivfe/v2/config"
+	"codeberg.org/vnpower/pixivfe/v2/core"
 	"codeberg.org/vnpower/pixivfe/v2/i18n"
 	"codeberg.org/vnpower/pixivfe/v2/server/audit"
 	"codeberg.org/vnpower/pixivfe/v2/server/middleware"
@@ -64,6 +65,10 @@ func main() {
 		log.Println("Skipping proxy checker initialization.")
 	}
 
+	// Initialize cache
+	core.InitCache()
+	log.Println("API response cache initialized.")
+
 	log.Println("Starting server...")
 
 	router := middleware.DefineRoutes()