Adding extension function to extract eTag

Author: marcosholgado

app/src/androidTest/java/com/duckduckgo/app/trackerdetection/api/TrackerDataDownloaderKtTest.kt

@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2021 DuckDuckGo
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.duckduckgo.app.trackerdetection.api
+
+import okhttp3.Headers
+import org.junit.Assert.*
+import org.junit.Test
+
+class TrackerDataDownloaderKtTest {
+
+    @Test
+    fun whenExtractETagAndContainsPrefixAndQuotesThenReturnETag() {
+        val headers = Headers.headersOf("eTag", "W/\"123456789\"")
+        assertEquals(ETAG, headers.extractETag())
+    }
+
+    @Test
+    fun whenExtractETagAndContainsQuotesThenReturnETag() {
+        val headers = Headers.headersOf("eTag", "\"123456789\"")
+        assertEquals(ETAG, headers.extractETag())
+    }
+
+    @Test
+    fun whenExtractETagAndDoesNotContainsQuotesAndPrefixThenReturnETag() {
+        val headers = Headers.headersOf("eTag", "123456789")
+        assertEquals(ETAG, headers.extractETag())
+    }
+
+    companion object {
+        const val ETAG = "123456789"
+    }
+}

app/src/main/java/com/duckduckgo/app/trackerdetection/api/TrackerDataDownloader.kt

@@ -23,10 +23,10 @@ import com.duckduckgo.app.global.store.BinaryDataStore
 import com.duckduckgo.app.trackerdetection.Client.ClientName.*
 import com.duckduckgo.app.trackerdetection.TrackerDataLoader
 import com.duckduckgo.app.trackerdetection.db.TdsMetadataDao
-import com.duckduckgo.app.trackerdetection.db.TdsTrackerDao
 import com.duckduckgo.app.trackerdetection.db.TemporaryTrackingWhitelistDao
 import com.duckduckgo.app.trackerdetection.model.TemporaryTrackingWhitelistedDomain
 import io.reactivex.Completable
+import okhttp3.Headers
 import timber.log.Timber
 import java.io.IOException
 import javax.inject.Inject
@@ -54,10 +54,10 @@ class TrackerDataDownloader @Inject constructor(
             }
 
             val body = response.body()!!
-            val eTag = response.headers()["eTag"]?.removeSurrounding("W/\"", "\"").orEmpty() // removes weak eTag validator
+            val eTag = response.headers().extractETag()
+            Timber.d("Updating tds data from server")
             val oldEtag = metadataDao.eTag()
             if (eTag != oldEtag) {
-                Timber.d("Updating tds data from server")
                 appDatabase.runInTransaction {
                     trackerDataLoader.persistTds(eTag, body)
                     trackerDataLoader.loadTrackers()
@@ -107,3 +107,7 @@ class TrackerDataDownloader @Inject constructor(
         }
     }
 }
+
+fun Headers.extractETag(): String {
+    return this["eTag"]?.removePrefix("W/")?.removeSurrounding("\"", "\"").orEmpty() // removes weak eTag validator
+}