Make the cache provider an injectable dependency

OGParser/src/main/java/com/kedia/ogparser/CacheProvider.kt

@@ -0,0 +1,6 @@
+package com.kedia.ogparser
+
+interface CacheProvider {
+    suspend fun getOpenGraphResult(url: String): OpenGraphResult?
+    suspend fun setOpenGraphResult(openGraphResult: OpenGraphResult, url: String)
+}

OGParser/src/main/java/com/kedia/ogparser/SharedPrefs.kt → OGParser/src/main/java/com/kedia/ogparser/OpenGraphCacheProvider.kt

@@ -5,7 +5,7 @@ import android.content.SharedPreferences
 import android.util.Log
 import androidx.preference.PreferenceManager
 
-class SharedPrefs(context: Context) {
+class OpenGraphCacheProvider(context: Context) : CacheProvider {
 
     private val pm: SharedPreferences = PreferenceManager.getDefaultSharedPreferences(context)
 
@@ -65,7 +65,16 @@ class SharedPrefs(context: Context) {
         return pm.getString(TYPE + "_$link", "") ?: ""
     }
 
-    fun setOpenGraphResult(openGraphResult: OpenGraphResult, url: String) {
+    private fun urlExists(title: String, description: String, image: String): Boolean {
+        return title.isNotEmpty() &&
+                title.equals("null").not() &&
+                description.isNotEmpty() &&
+                description.equals("null").not() &&
+                image.isNotEmpty() &&
+                image.equals("null").not()
+    }
+
+    override suspend fun setOpenGraphResult(openGraphResult: OpenGraphResult, url: String) {
         setTitle(url, openGraphResult.title.toString())
         setDescription(url, openGraphResult.description.toString())
         setImage(url, openGraphResult.image.toString())
@@ -74,26 +83,18 @@ class SharedPrefs(context: Context) {
         setUrl(url, openGraphResult.url.toString())
     }
 
-    fun getOpenGraphResult(url: String): OpenGraphResult {
+    override suspend fun getOpenGraphResult(url: String): OpenGraphResult? {
         val title = getTitle(url)
         val description = getDescription(url)
         val image = getImage(url)
+
+        if (!urlExists(title, description, image)) {
+            return null
+        }
+
         val siteName = getSiteName(url)
         val type = getType(url)
         val url = getUrl(url)
         return OpenGraphResult(title, description, url, image, siteName, type)
     }
-
-    fun urlExists(url: String): Boolean {
-        val title = getTitle(url)
-        val description = getDescription(url)
-        val image = getImage(url)
-        return title.isNotEmpty() &&
-                 title.equals("null").not() &&
-                description.isNotEmpty() &&
-                description.equals("null").not() &&
-                image.isNotEmpty() &&
-                image.equals("null").not()
-    }
-
-}
+}

OGParser/src/main/java/com/kedia/ogparser/OpenGraphParser.kt

@@ -8,11 +8,8 @@ import kotlin.coroutines.CoroutineContext
 class OpenGraphParser(
     private val listener: OpenGraphCallback,
     private var showNullOnEmpty: Boolean = false,
-    context: Context? = null
+    private val cacheProvider: CacheProvider? = null
 ) {
-
-    private val sharedPrefs: SharedPrefs? = context?.let { SharedPrefs(it) }
-
     private var url: String = ""
 
     private val AGENTS = mutableListOf(
@@ -52,15 +49,16 @@ class OpenGraphParser(
         if (!url.contains("http")) {
             url = "http://$url"
         }
-        if (sharedPrefs?.urlExists(url) == true) {
-            return@withContext sharedPrefs?.getOpenGraphResult(url)
+
+        cacheProvider?.getOpenGraphResult(url)?.let {
+            return@withContext it
         }
 
         AGENTS.forEach {
             openGraphResult = jsoupNetworkCall.callUrl(url, it)
             val isResultNull = checkNullParserResult(openGraphResult)
             if (!isResultNull) {
-                openGraphResult?.let { sharedPrefs?.setOpenGraphResult(it, url) }
+                openGraphResult?.let { cacheProvider?.setOpenGraphResult(it, url) }
                 return@withContext openGraphResult
             }
         }
@@ -71,7 +69,7 @@ class OpenGraphParser(
             }
             return@withContext null
         }
-        openGraphResult?.let { sharedPrefs?.setOpenGraphResult(it, url) }
+        openGraphResult?.let { cacheProvider?.setOpenGraphResult(it, url) }
         return@withContext openGraphResult
     }
-}
+}

app/src/main/java/com/kedia/opengraphpreview/MainActivity.kt

@@ -6,11 +6,18 @@ import androidx.appcompat.app.AppCompatActivity
 import com.kedia.ogparser.OpenGraphCallback
 import com.kedia.ogparser.OpenGraphParser
 import com.kedia.ogparser.OpenGraphResult
+import com.kedia.ogparser.OpenGraphCacheProvider
 import kotlinx.android.synthetic.main.activity_main.*
 
 class MainActivity : AppCompatActivity(), OpenGraphCallback {
 
-    private val openGraphParser by lazy { OpenGraphParser(this, showNullOnEmpty = true) }
+    private val openGraphParser by lazy {
+        OpenGraphParser(
+            listener = this,
+            showNullOnEmpty = true,
+            cacheProvider = OpenGraphCacheProvider(this)
+        )
+    }
 
     private val LINKS_TO_TEST = mutableListOf(
         "https://www.linkedin.com/posts/madhusmita-padhy_machinelearning-datascience-activity-6886390508722163712-yhQ0",
@@ -63,4 +70,4 @@ class MainActivity : AppCompatActivity(), OpenGraphCallback {
             LINKS_TO_TEST.removeFirstOrNull()
         }
     }
-}
+}