Add data source for local rss, with tests

api/build.gradle

@@ -56,8 +56,13 @@ dependencies {
     androidTestImplementation 'androidx.test:runner:1.2.0'
     androidTestImplementation 'androidx.test:rules:1.2.0'
     androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'
+    androidTestImplementation 'com.squareup.okhttp3:mockwebserver:4.8.1'
 
-    implementation 'com.squareup.retrofit2:retrofit:2.7.1'
+    implementation 'com.squareup.okhttp3:okhttp:4.8.1'
+
+    implementation('com.squareup.retrofit2:retrofit:2.7.1') {
+        exclude group: 'okhttp3', module: 'okhttp3'
+    }
     implementation('com.squareup.retrofit2:converter-moshi:2.7.1') {
         exclude group: 'moshi', module: 'moshi' // moshi converter uses moshi 1.8.0 which breaks codegen 1.9.2
     }

api/src/androidTest/assets/localfeed/rss_feed.xml

@@ -0,0 +1,57 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<rss version="2.0">
+   <channel>
+      <title>Hacker News</title>
+      <link>https://news.ycombinator.com/</link>
+      <description>Links for the intellectually curious, ranked by readers.</description>
+      <item>
+         <title>Africa declared free of wild polio</title>
+         <link>https://www.bbc.com/news/world-africa-53887947</link>
+         <pubDate>Tue, 25 Aug 2020 17:15:49 +0000</pubDate>
+         <comments>https://news.ycombinator.com/item?id=24273602</comments>
+         <description><![CDATA[<a href="https://news.ycombinator.com/item?id=24273602">Comments</a>]]></description>
+      </item>
+      <item>
+         <title>Palantir S-1</title>
+         <link>https://www.sec.gov/Archives/edgar/data/1321655/000119312520230013/d904406ds1.htm</link>
+         <pubDate>Tue, 25 Aug 2020 21:03:42 +0000</pubDate>
+         <comments>https://news.ycombinator.com/item?id=24276086</comments>
+         <description><![CDATA[<a href="https://news.ycombinator.com/item?id=24276086">Comments</a>]]></description>
+      </item>
+      <item>
+         <title>Openwifi: Linux mac80211 compatible full-stack 802.11/Wi-Fi design based on SDR</title>
+         <link>https://github.com/open-sdr/openwifi</link>
+         <pubDate>Tue, 25 Aug 2020 17:45:19 +0000</pubDate>
+         <comments>https://news.ycombinator.com/item?id=24273919</comments>
+         <description><![CDATA[<a href="https://news.ycombinator.com/item?id=24273919">Comments</a>]]></description>
+      </item>
+      <item>
+         <title>Syllabus for Eric's PhD Students</title>
+         <link>https://docs.google.com/document/d/11D3kHElzS2HQxTwPqcaTnU5HCJ8WGE5brTXI4KLf4dM/edit</link>
+         <pubDate>Tue, 25 Aug 2020 18:55:12 +0000</pubDate>
+         <comments>https://news.ycombinator.com/item?id=24274699</comments>
+         <description><![CDATA[<a href="https://news.ycombinator.com/item?id=24274699">Comments</a>]]></description>
+      </item>
+      <item>
+         <title>WebBundles harmful to content blocking, security tools, and the open web</title>
+         <link>https://brave.com/webbundles-harmful-to-content-blocking-security-tools-and-the-open-web/</link>
+         <pubDate>Tue, 25 Aug 2020 19:18:50 +0000</pubDate>
+         <comments>https://news.ycombinator.com/item?id=24274968</comments>
+         <description><![CDATA[<a href="https://news.ycombinator.com/item?id=24274968">Comments</a>]]></description>
+      </item>
+      <item>
+         <title>Zappos CEO Tony Hsieh is stepping down after 21 years</title>
+         <link>https://footwearnews.com/2020/business/executive-moves/zappos-ceo-tony-hsieh-steps-down-1203045974/</link>
+         <pubDate>Tue, 25 Aug 2020 06:11:42 +0000</pubDate>
+         <comments>https://news.ycombinator.com/item?id=24268522</comments>
+         <description><![CDATA[<a href="https://news.ycombinator.com/item?id=24268522">Comments</a>]]></description>
+      </item>
+      <item>
+         <title>Evgeny Kuznetsov practices with Bauer stick that has hole in the blade</title>
+         <link>https://russianmachineneverbreaks.com/2020/07/17/evgeny-kuznetsov-practices-with-bauer-stick-that-has-hole-in-the-blade/</link>
+         <pubDate>Tue, 25 Aug 2020 19:38:09 +0000</pubDate>
+         <comments>https://news.ycombinator.com/item?id=24275159</comments>
+         <description><![CDATA[<a href="https://news.ycombinator.com/item?id=24275159">Comments</a>]]></description>
+      </item>
+   </channel>
+</rss>

api/src/androidTest/java/com/readrops/api/localfeed/LocalRSSDataSourceTest.kt

@@ -0,0 +1,116 @@
+package com.readrops.api.localfeed
+
+import android.accounts.NetworkErrorException
+import android.content.Context
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import androidx.test.platform.app.InstrumentationRegistry
+import com.readrops.api.utils.HttpManager
+import com.readrops.api.utils.ParseException
+import junit.framework.TestCase.*
+import okhttp3.HttpUrl
+import okhttp3.mockwebserver.MockResponse
+import okhttp3.mockwebserver.MockWebServer
+import org.junit.After
+import org.junit.Before
+import org.junit.Test
+import org.junit.runner.RunWith
+import java.net.HttpURLConnection
+
+
+@RunWith(AndroidJUnit4::class)
+class LocalRSSDataSourceTest {
+
+    private val context: Context = InstrumentationRegistry.getInstrumentation().context
+    private lateinit var url: HttpUrl
+
+    private val mockServer: MockWebServer = MockWebServer()
+    private val localRSSDataSource = LocalRSSDataSource(HttpManager.getInstance().okHttpClient)
+
+    @Before
+    fun before() {
+        mockServer.start()
+        url = mockServer.url("/rss")
+    }
+
+    @After
+    fun tearDown() {
+        mockServer.close()
+    }
+
+    @Test
+    fun successfulQueryTest() {
+        mockServer.enqueue(MockResponse().setResponseCode(HttpURLConnection.HTTP_OK)
+                .addHeader("Content-Type", "application/rss+xml; charset=UTF-8")
+                .setBody(context.resources.assets.open("localfeed/rss_feed.xml").toString()))
+
+
+        val pair = localRSSDataSource.queryRSSResource(url.toString(), null, false)
+
+        assertNotNull(pair?.first)
+        assertNotNull(pair?.second)
+    }
+
+    @Test
+    fun response304Test() {
+        mockServer.enqueue(MockResponse().setResponseCode(HttpURLConnection.HTTP_NOT_MODIFIED))
+
+        val pair = localRSSDataSource.queryRSSResource(url.toString(), null, false)
+
+        assertNull(pair)
+    }
+
+    @Test(expected = NetworkErrorException::class)
+    fun response404Test() {
+        mockServer.enqueue(MockResponse().setResponseCode(HttpURLConnection.HTTP_NOT_FOUND))
+
+        localRSSDataSource.queryRSSResource(url.toString(), null, false)
+    }
+
+    @Test(expected = ParseException::class)
+    fun noContentTypeTest() {
+        mockServer.enqueue(MockResponse().setResponseCode(HttpURLConnection.HTTP_OK))
+
+        localRSSDataSource.queryRSSResource(url.toString(), null, false)
+    }
+
+    @Test(expected = ParseException::class)
+    fun badContentTypeTest() {
+        mockServer.enqueue(MockResponse().setResponseCode(HttpURLConnection.HTTP_OK)
+                .addHeader("Content-Type", ""))
+
+        localRSSDataSource.queryRSSResource(url.toString(), null, false)
+    }
+
+    @Test(expected = ParseException::class)
+    fun badContentTest() {
+        mockServer.enqueue(MockResponse().setResponseCode(HttpURLConnection.HTTP_OK)
+                .addHeader("Content-Type", "application/xml")
+                .setBody("<html>  </html>"))
+
+        localRSSDataSource.queryRSSResource(url.toString(), null, false)
+    }
+
+    @Test
+    fun isUrlResourceSuccessfulTest() {
+        mockServer.enqueue(MockResponse().setResponseCode(HttpURLConnection.HTTP_OK)
+                .addHeader("Content-Type", "application/atom+xml"))
+
+        assertTrue(localRSSDataSource.isUrlRSSResource(url.toString()))
+    }
+
+    @Test
+    fun isUrlRSSResourceFailureTest() {
+        mockServer.enqueue(MockResponse().setResponseCode(HttpURLConnection.HTTP_NOT_FOUND))
+
+        assertFalse(localRSSDataSource.isUrlRSSResource(url.toString()))
+    }
+
+    @Test
+    fun isUrlRSSResourceBadContentTypeTest() {
+        mockServer.enqueue(MockResponse().setResponseCode(HttpURLConnection.HTTP_OK)
+                .addHeader("Content-Type", "application/xml")
+                .setBody("<html> </html>"))
+
+        assertFalse(localRSSDataSource.isUrlRSSResource(url.toString()))
+    }
+}

api/src/debug/AndroidManifest.xml

@@ -3,7 +3,10 @@
 
     <!-- for tests only -->
     <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
+    <uses-permission android:name="android.permission.INTERNET" />
 
-    <application android:requestLegacyExternalStorage="true" />
+    <application
+        android:requestLegacyExternalStorage="true"
+        android:usesCleartextTraffic="true" />
 
 </manifest>

api/src/main/java/com/readrops/api/localfeed/LocalRSSDataSource.kt

@@ -0,0 +1,88 @@
+package com.readrops.api.localfeed
+
+import android.accounts.NetworkErrorException
+import androidx.annotation.WorkerThread
+import com.readrops.api.utils.LibUtils
+import com.readrops.api.utils.ParseException
+import com.readrops.db.entities.Feed
+import com.readrops.db.entities.Item
+import okhttp3.Headers
+import okhttp3.OkHttpClient
+import okhttp3.Request
+import okhttp3.Response
+import java.io.IOException
+import java.io.InputStream
+import java.net.HttpURLConnection
+
+class LocalRSSDataSource(private val httpClient: OkHttpClient) {
+
+    /**
+     * Query RSS url
+     * @param url url to query
+     * @param headers request headers
+     * @param withItems parse items with their feed
+     * @return a Feed object with its items if specified by [withItems]
+     */
+    @WorkerThread
+    fun queryRSSResource(url: String, headers: Headers?, withItems: Boolean): Pair<Feed, List<Item>>? {
+        val response = queryUrl(url, headers)
+
+        return when {
+            response.isSuccessful -> {
+                val header = response.header(LibUtils.CONTENT_TYPE_HEADER)
+                        ?: throw ParseException("Unable to get $url content-type")
+
+                val contentType = LibUtils.parseContentType(header)
+                        ?: throw ParseException("Unable to get $url content-type")
+
+                var type = LocalRSSHelper.getRSSType(contentType)
+
+                // if we can't guess type based on content-type header, we use the content
+                if (type == LocalRSSHelper.RSSType.UNKNOWN) type = LocalRSSHelper.getRSSContentType(response.body?.byteStream()!!)
+                // if we can't guess type even with the content, we are unable to go further
+                if (type == LocalRSSHelper.RSSType.UNKNOWN) throw ParseException("Unable to guess $url RSS type")
+
+                val feed = parseFeed(response, type)
+                val items = if (withItems) parseItems(response.body?.byteStream()!!, type) else listOf()
+
+                return Pair(feed, items)
+            }
+            response.code == HttpURLConnection.HTTP_NOT_MODIFIED -> null
+            else -> throw NetworkErrorException("$url returned ${response.code} code : ${response.message}")
+        }
+    }
+
+    @WorkerThread
+    fun isUrlRSSResource(url: String): Boolean {
+        val response = queryUrl(url, null)
+
+        return if (response.isSuccessful) {
+            val contentType = response.header(LibUtils.CONTENT_TYPE_HEADER)
+                    ?: return false
+
+            var type = LocalRSSHelper.getRSSType(contentType)
+
+            if (type == LocalRSSHelper.RSSType.UNKNOWN)
+                type = LocalRSSHelper.getRSSContentType(response.body?.byteStream()!!) // stream is closed in helper method
+
+            type != LocalRSSHelper.RSSType.UNKNOWN
+        } else false
+    }
+
+    @Throws(IOException::class)
+    private fun queryUrl(url: String, headers: Headers?): Response {
+        val requestBuilder = Request.Builder().url(url)
+        headers?.let { requestBuilder.headers(it) }
+
+        return httpClient.newCall(requestBuilder.build()).execute()
+    }
+
+    private fun parseFeed(response: Response, type: LocalRSSHelper.RSSType): Feed {
+        response.body?.close()
+        return Feed()
+    }
+
+    private fun parseItems(inputStream: InputStream, type: LocalRSSHelper.RSSType): List<Item> {
+        return listOf()
+    }
+}

api/src/main/java/com/readrops/api/utils/LibUtils.java

@@ -4,10 +4,13 @@ import android.content.Context;
 import android.net.Uri;
 
 import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 
 import java.io.FileNotFoundException;
 import java.io.InputStream;
 import java.util.Scanner;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 
 public final class LibUtils {
 
@@ -28,6 +31,8 @@ public final class LibUtils {
     public static final int HTTP_NOT_FOUND = 404;
     public static final int HTTP_CONFLICT = 409;
 
+    private static final String RSS_CONTENT_TYPE_REGEX = "([^;]+)";
+
 
     public static String inputStreamToString(InputStream input) {
         Scanner scanner = new Scanner(input).useDelimiter("\\A");
@@ -44,4 +49,16 @@ public final class LibUtils {
         return type.equals("image") || type.equals("image/jpeg") || type.equals("image/jpg")
                 || type.equals("image/png");
     }
+
+    @Nullable
+    public static String parseContentType(String header) {
+        Matcher matcher = Pattern.compile(RSS_CONTENT_TYPE_REGEX)
+                .matcher(header);
+
+        if (matcher.find()) {
+            return matcher.group(0);
+        } else {
+            return null;
+        }
+    }
 }