Merge pull request #24 from mtslzr/feature/cache_settings

Settings for Cache

CHANGELOG.md

@@ -4,6 +4,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+### Added
+- User settings for caching (pokeapi.CacheSettings)
+  - CustomExpire: set a custom cache expiration (in minutes)
+  - UseCache: turn caching on/off
+
 ## [1.3.2] / 2020.04.03
 ### Added
 - Current version to README.

Makefile

@@ -12,6 +12,9 @@ deps: tidy vend
 test:
 	${GOTEST} -v -race ${CODECOVFLAGS} ./...
 
+test-client:
+	${GOTEST} -v ./.
+
 tidy:
 	${GOMOD} tidy -v
 

README.md

@@ -1000,6 +1000,35 @@ As an alternative to `pokeapi.Resource()`, you can use Search to filter resource
 
 ### Caching
 
-Calls are automatically cached to cut down on API traffic to PokeAPI, with subsequent calls (up to five minutes currently) returning local data. You can clear *all* existing cache data with `pokeapi.ClearCache()`.
+Calls are automatically cached to cut down on API traffic to PokeAPI, with subsequent calls returning local data.
 
-Forced non-cached calls and custom cache expiration coming soon.
+#### Clearing Cache
+
+```go
+// Clear all existing cache entries.
+pokeapi.ClearCache()
+```
+
+#### Custom Expiration
+
+Custom cache expiration remains for all calls until changed or unset.
+
+```go
+// Set cache expiration to twenty minutes.
+pokeapi.CacheSettings.CustomExpire = 20
+// Turn custom expiration back off.
+pokeapi.CacheSettings.CustomExpire = 0
+```
+
+#### Disable Cache
+
+_Please be considerate of PokeAPI and be sure to always operate within this requested limits._
+
+As with custom expiration, this setting remains for all calls until changed or unset.
+
+```go
+// Disable checking for cached data
+pokeapi.CacheSettings.UseCache = false
+// Re-enable checking for cached data
+pokeapi.CacheSettings.UseCache = true
+```

cache.go

@@ -0,0 +1,39 @@
+package pokeapi
+
+import "time"
+
+var CacheSettings = Settings{
+	CustomExpire: 0,
+	UseCache: true,
+}
+
+var defaultCacheSettings = defaultSettings{
+	MaxExpire: 10 * time.Minute,
+	MinExpire: 5 * time.Minute,
+}
+
+// defaultSettings are settings not meant to be changed.
+type defaultSettings struct {
+	MaxExpire time.Duration
+	MinExpire time.Duration
+}
+
+// CacheSettings are user settings for cache expiration.
+type Settings struct {
+	CustomExpire time.Duration
+	UseCache     bool
+}
+
+// ClearCache clears all cached data.
+func ClearCache() {
+	c.Flush()
+}
+
+// setCache adds new item to local cache.
+func setCache(endpoint string, body []byte) {
+	if CacheSettings.CustomExpire != 0 {
+		c.Set(endpoint, body, CacheSettings.CustomExpire * time.Minute)
+	} else {
+		c.SetDefault(endpoint, body)
+	}
+}

client.go

@@ -10,23 +10,16 @@ import (
 )
 
 const apiurl = "https://pokeapi.co/api/v2/"
-const cachemin = 5
-const cachemax = 10
 
 var c *cache.Cache
 
 func init() {
-	c = cache.New(cachemin*time.Minute, cachemax*time.Minute)
-}
-
-// ClearCache clears all cached data.
-func ClearCache() {
-	c.Flush()
+	c = cache.New(defaultCacheSettings.MinExpire, defaultCacheSettings.MaxExpire)
 }
 
 func do(endpoint string, obj interface{}) error {
 	cached, found := c.Get(endpoint)
-	if found {
+	if found && CacheSettings.UseCache {
 		return json.Unmarshal(cached.([]byte), &obj)
 	}
 
@@ -47,6 +40,6 @@ func do(endpoint string, obj interface{}) error {
 		return err
 	}
 
-	c.Set(endpoint, body, cache.DefaultExpiration)
+	setCache(endpoint, body)
 	return json.Unmarshal(body, &obj)
 }

client_test.go

@@ -3,6 +3,7 @@ package pokeapi
 import (
 	"encoding/json"
 	"testing"
+	"time"
 
 	"github.com/mtslzr/pokeapi-go/structs"
 	"github.com/stretchr/testify/assert"
@@ -49,3 +50,34 @@ func TestClearCache(t *testing.T) {
 	assert.Equal(t, nil, nocache,
 		"Expect no data after flushing cache.")
 }
+
+func TestCustomExpiration(t *testing.T) {
+	ClearCache()
+	defaultExpire := time.Now().Add(defaultCacheSettings.MinExpire).Minute()
+	_ = do(endpoint, &mockResource)
+	_, expires1, _ := c.GetWithExpiration(endpoint)
+	assert.Equal(t, defaultExpire, expires1.Minute(),
+		"Expect expiration time to match default setting.")
+
+	ClearCache()
+	CacheSettings.CustomExpire = 20
+	customExpire := time.Now().Add(CacheSettings.CustomExpire * time.Minute).Minute()
+	_ = do(endpoint, &mockResource)
+	_, expires2, _ := c.GetWithExpiration(endpoint)
+	assert.Equal(t, customExpire, expires2.Minute(),
+		"Expect expiration time to match custom setting.")
+}
+
+func TestNoCache(t *testing.T) {
+	ClearCache()
+	_ = do(endpoint, &mockResource)
+	_, expires1, found1 := c.GetWithExpiration(endpoint)
+	assert.Equal(t, true, found1,
+		"Expect to have cached data after first call.")
+
+	CacheSettings.UseCache = false
+	_ = do(endpoint, &mockResource)
+	_, expires2, _ := c.GetWithExpiration(endpoint)
+	assert.NotEqual(t, expires1, expires2,
+		"Expect cache expiration not to match first call.")
+}