Add new helper class to get RSS feed type, with tests

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

@@ -0,0 +1,68 @@
+package com.readrops.api.localfeed
+
+import com.readrops.api.utils.ParseException
+import java.io.InputStream
+import java.util.regex.Pattern
+
+object LocalRSSHelper {
+
+    private const val RSS_DEFAULT_CONTENT_TYPE = "application/rss+xml"
+    private const val RSS_TEXT_CONTENT_TYPE = "text/xml"
+    private const val RSS_APPLICATION_CONTENT_TYPE = "application/xml"
+    private const val ATOM_CONTENT_TYPE = "application/atom+xml"
+    private const val JSON_CONTENT_TYPE = "application/json"
+    private const val HTML_CONTENT_TYPE = "text/html"
+    
+    private const val RSS_2_REGEX = "rss.*version=\"2.0\""
+
+    private const val ATOM_REGEX = "<feed.* xmlns=\"http://www.w3.org/2005/Atom\""
+
+    /**
+     * Guess RSS type based on content-type header
+     */
+    fun getRSSType(contentType: String): RSSType {
+        return when (contentType) {
+            RSS_DEFAULT_CONTENT_TYPE -> RSSType.RSS_2
+            ATOM_CONTENT_TYPE -> RSSType.ATOM
+            JSON_CONTENT_TYPE -> RSSType.JSONFEED
+            RSS_TEXT_CONTENT_TYPE, RSS_APPLICATION_CONTENT_TYPE, HTML_CONTENT_TYPE -> RSSType.UNKNOWN
+            else -> throw ParseException("Unknown content type")
+        }
+    }
+
+    /**
+     * Guess RSS type based on xml content
+     */
+    fun getRSSContentType(content: InputStream): RSSType {
+        val stringBuffer = StringBuffer()
+        val reader = content.bufferedReader()
+
+        var currentLine = reader.readLine()
+        while (currentLine != null) {
+            stringBuffer.append(currentLine)
+
+            if (Pattern.compile(RSS_2_REGEX).matcher(stringBuffer.toString()).find()) {
+                reader.close()
+                content.close()
+
+                return RSSType.RSS_2
+            } else if (Pattern.compile(ATOM_REGEX).matcher(stringBuffer.toString()).find()) {
+                reader.close()
+                content.close()
+
+                return RSSType.ATOM
+            }
+
+            currentLine = reader.readLine()
+        }
+
+        return RSSType.UNKNOWN
+    }
+
+    enum class RSSType {
+        RSS_2,
+        ATOM,
+        JSONFEED,
+        UNKNOWN
+    }
+}

api/src/test/java/com/readrops/api/LocalRSSHelperTest.kt

@@ -0,0 +1,60 @@
+package com.readrops.api
+
+import com.readrops.api.localfeed.LocalRSSHelper
+import com.readrops.api.utils.ParseException
+import junit.framework.TestCase.assertEquals
+import org.junit.Test
+import java.io.ByteArrayInputStream
+
+class LocalRSSHelperTest {
+
+    @Test
+    fun standardContentTypesTest() {
+        assertEquals(LocalRSSHelper.getRSSType("application/rss+xml"),
+                LocalRSSHelper.RSSType.RSS_2)
+        assertEquals(LocalRSSHelper.getRSSType("application/atom+xml"),
+                LocalRSSHelper.RSSType.ATOM)
+        assertEquals(LocalRSSHelper.getRSSType("application/json"),
+                LocalRSSHelper.RSSType.JSONFEED)
+    }
+
+    @Test
+    fun nonStandardContentTypesTest() {
+        assertEquals(LocalRSSHelper.getRSSType("application/xml"),
+                LocalRSSHelper.RSSType.UNKNOWN)
+        assertEquals(LocalRSSHelper.getRSSType("text/xml"),
+                LocalRSSHelper.RSSType.UNKNOWN)
+        assertEquals(LocalRSSHelper.getRSSType("text/html"),
+                LocalRSSHelper.RSSType.UNKNOWN)
+    }
+
+    @Test(expected = ParseException::class)
+    fun nonSupportedContentTypeTest() {
+        LocalRSSHelper.getRSSType("image/jpeg")
+    }
+
+    @Test
+    fun rssContentTest() {
+        assertEquals(LocalRSSHelper.getRSSContentType(ByteArrayInputStream(
+                """<rss 
+                    xmlns:content="http://purl.org/rss/1.0/modules/content/"
+                    xmlns:wfw="http://wellformedweb.org/CommentAPI/"
+                    xmlns:dc="http://purl.org/dc/elements/1.1/"
+                    version="2.0"
+                    xmlns:atom="http://www.w3.org/2005/Atom"
+                    xmlns:sy="http://purl.org/rss/1.0/modules/syndication/"
+                    xmlns:slash="http://purl.org/rss/1.0/modules/slash/">
+                </rss>""".toByteArray()
+        )), LocalRSSHelper.RSSType.RSS_2)
+    }
+
+    @Test
+    fun atomContentTest() {
+        assertEquals(LocalRSSHelper.getRSSContentType(ByteArrayInputStream(
+                """<feed     xmlns="http://www.w3.org/2005/Atom">
+                    
+                </feed>""".toByteArray()
+        )), LocalRSSHelper.RSSType.ATOM)
+
+    }
+}