Nostr feed support. (#945)

* Add rust nostr library.

* Build FetchedFeed abstractions to be used for representing fetched feeds.

* Replace some occurrences of SyndFeed with FetchedFeed where needed.

* Add a function for checking a Nostr URI. Modify other occurrences in AbstractRssRepository.

* Add validation for Nostr URIs.

* Actually take Nostr URIs into account when searching for feeds.

* Move fetchFeedFrom() to a companion object instead.

* Update Nostr-sdk library and add Proguard rules for the Nostr sdk library.

* Create a singleton DI module for the Nostr Client.

* Add some fixes for summary, and others.

* Include Jetbrains Markdown library.

* Introduce htmlFromMarkdown(), and use it where needed.

* Revert to using the Nostr URI for the article link, for full content support.

* Implement full content support for Nostr articles, by reusing the content, since it's all the same anyway.

* Switch to throwing an exception when no Nostr feed info is found.

* Add feed syncing for Nostr feeds.

* Use a new Nostr client instance for each syncing feed, to avoid race conditions when using the client.

* Change syncNostrFeed return signature. Improve Nostr feed syncing. Use randomUuid for Nostr article Ids.

* Add OPML feed support for Nostr feeds. Try getting metadata first before saving the feed(else it won't modify it later.)

* Just use the author's profile name as feed title when fetching feed.

* Fix RssHelperTest.

* Fix bug caused by non-differentiation between outlines and sub-outlines when handling sub-outlines.

* Re-use original code for importing feeds from OPML(for GH runner happiness, maybe).

* Revert previous change(just uncommenting code).

* Just return feed with empty article list if nothing is found.

* Manage Nostr Client lifecycle when using it during OPML import.

* Undo changes of previous commit.

app/build.gradle.kts

@@ -176,6 +176,12 @@ dependencies {
     implementation(libs.activity.compose)
     implementation(libs.appcompat)
 
+    // Markdown
+    implementation(libs.jetbrains.markdown)
+
+    // Nostr
+    implementation(libs.rust.nostr)
+
     // Testing
     testImplementation(libs.junit)
     androidTestImplementation(libs.junit.ext)

app/proguard-rules.pro

@@ -37,6 +37,14 @@
 # Provider API
 -keep class me.ash.reader.** { *; }
 
+# Nostr
+-keep class com.sun.jna.** { *; }
+-keep class * implements com.sun.jna.** { *; }
+-dontwarn java.awt.Component
+-dontwarn java.awt.GraphicsEnvironment
+-dontwarn java.awt.HeadlessException
+-dontwarn java.awt.Window
+
 # https://github.com/flutter/flutter/issues/127388
 -dontwarn org.kxml2.io.KXml**
 

app/src/main/java/me/ash/reader/domain/service/AbstractRssRepository.kt

@@ -6,7 +6,6 @@ import androidx.paging.PagingSource
 import androidx.work.CoroutineWorker
 import androidx.work.ListenableWorker
 import androidx.work.WorkManager
-import com.rometools.rome.feed.synd.SyndFeed
 import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.ExperimentalCoroutinesApi
@@ -15,7 +14,6 @@ import kotlinx.coroutines.awaitAll
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.flowOn
 import kotlinx.coroutines.flow.mapLatest
-import kotlinx.coroutines.launch
 import kotlinx.coroutines.supervisorScope
 import kotlinx.coroutines.sync.Semaphore
 import kotlinx.coroutines.sync.withPermit
@@ -32,9 +30,13 @@ import me.ash.reader.domain.repository.GroupDao
 import me.ash.reader.infrastructure.android.NotificationHelper
 import me.ash.reader.infrastructure.preference.KeepArchivedPreference
 import me.ash.reader.infrastructure.preference.SyncIntervalPreference
+import me.ash.reader.infrastructure.rss.FetchedFeed
+import me.ash.reader.infrastructure.rss.NostrFeed
 import me.ash.reader.infrastructure.rss.RssHelper
+import me.ash.reader.infrastructure.rss.SyndFeedDelegate
 import me.ash.reader.ui.ext.currentAccountId
 import me.ash.reader.ui.ext.decodeHTML
+import me.ash.reader.ui.ext.isNostrUri
 import me.ash.reader.ui.ext.spacerDollar
 import java.util.Date
 import java.util.UUID
@@ -63,19 +65,26 @@ abstract class AbstractRssRepository(
     open suspend fun clearAuthorization() {}
 
     open suspend fun subscribe(
-        feedLink: String, searchedFeed: SyndFeed, groupId: String,
+        feedLink: String, searchedFeed: FetchedFeed, groupId: String,
         isNotification: Boolean, isFullContent: Boolean
     ) {
         val accountId = context.currentAccountId
         val feed = Feed(
             id = accountId.spacerDollar(UUID.randomUUID().toString()),
-            name = searchedFeed.title.decodeHTML()!!,
+            name = with(searchedFeed.title){ if (this.isNostrUri()) this else this.decodeHTML()!!},
             url = feedLink,
             groupId = groupId,
             accountId = accountId,
-            icon = searchedFeed.icon?.link
+            icon = searchedFeed.getIconLink()
         )
-        val articles = searchedFeed.entries.map { rssHelper.buildArticleFromSyndEntry(feed, accountId, it) }
+        val articles = when(searchedFeed) {
+            is NostrFeed -> searchedFeed.getArticles().map {
+                rssHelper.buildArticleFromNostrEvent(feed, accountId, it, searchedFeed.getFeedAuthor())
+            }
+            is SyndFeedDelegate -> searchedFeed.getArticles().map {
+                rssHelper.buildArticleFromSyndEntry(feed, accountId, it)
+            }
+        }
         feedDao.insert(feed)
         articleDao.insertList(articles.map {
             it.copy(feedId = feed.id)
@@ -178,17 +187,29 @@ abstract class AbstractRssRepository(
 
     private suspend fun syncFeed(feed: Feed, preDate: Date = Date()): FeedWithArticle {
         val latest = articleDao.queryLatestByFeedId(context.currentAccountId, feed.id)
-        val articles = rssHelper.queryRssXml(feed, "", preDate)
-        if (feed.icon == null) {
-            val iconLink = rssHelper.queryRssIconLink(feed.url)
-            if (iconLink != null) {
-                rssHelper.saveRssIcon(feedDao, feed, iconLink)
+        if (feed.url.isNostrUri()) {
+            val syncedFeed = rssHelper.syncNostrFeed(feed, "", preDate)
+            return FeedWithArticle(
+                feed = syncedFeed.feed
+                    .apply { isNotification = feed.isNotification && syncedFeed.articles.isNotEmpty() },
+                articles = syncedFeed.articles
+            )
+        }
+        else {
+            val articles = rssHelper.queryRssXml(feed, "", preDate)
+            if (feed.icon == null) {
+                val iconLink = rssHelper.queryRssIconLink(feed.url)
+                if (iconLink != null) {
+                    rssHelper.saveRssIcon(feedDao, feed, iconLink)
+                }
             }
+
+            return FeedWithArticle(
+                feed = feed.apply { isNotification = feed.isNotification && articles.isNotEmpty() },
+                articles = articles
+            )
         }
-        return FeedWithArticle(
-            feed = feed.apply { isNotification = feed.isNotification && articles.isNotEmpty() },
-            articles = articles
-        )
+
     }
 
     suspend fun clearKeepArchivedArticles() {

app/src/main/java/me/ash/reader/domain/service/FeverRssService.kt

@@ -5,7 +5,6 @@ import android.util.Log
 import androidx.work.CoroutineWorker
 import androidx.work.ListenableWorker
 import androidx.work.WorkManager
-import com.rometools.rome.feed.synd.SyndFeed
 import dagger.hilt.android.qualifiers.ApplicationContext
 import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.supervisorScope
@@ -27,6 +26,7 @@ import me.ash.reader.infrastructure.di.IODispatcher
 import me.ash.reader.infrastructure.di.MainDispatcher
 import me.ash.reader.infrastructure.exception.FeverAPIException
 import me.ash.reader.infrastructure.html.Readability
+import me.ash.reader.infrastructure.rss.FetchedFeed
 import me.ash.reader.infrastructure.rss.RssHelper
 import me.ash.reader.infrastructure.rss.provider.fever.FeverAPI
 import me.ash.reader.infrastructure.rss.provider.fever.FeverDTO
@@ -86,7 +86,7 @@ class FeverRssService @Inject constructor(
     }
 
     override suspend fun subscribe(
-        feedLink: String, searchedFeed: SyndFeed, groupId: String,
+        feedLink: String, searchedFeed: FetchedFeed, groupId: String,
         isNotification: Boolean, isFullContent: Boolean,
     ) {
         throw FeverAPIException("Unsupported")

app/src/main/java/me/ash/reader/domain/service/GoogleReaderRssService.kt

@@ -5,7 +5,6 @@ import android.util.Log
 import androidx.work.CoroutineWorker
 import androidx.work.ListenableWorker
 import androidx.work.WorkManager
-import com.rometools.rome.feed.synd.SyndFeed
 import dagger.hilt.android.qualifiers.ApplicationContext
 import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.supervisorScope
@@ -25,6 +24,7 @@ import me.ash.reader.infrastructure.di.DefaultDispatcher
 import me.ash.reader.infrastructure.di.IODispatcher
 import me.ash.reader.infrastructure.di.MainDispatcher
 import me.ash.reader.infrastructure.html.Readability
+import me.ash.reader.infrastructure.rss.FetchedFeed
 import me.ash.reader.infrastructure.rss.RssHelper
 import me.ash.reader.infrastructure.rss.provider.greader.GoogleReaderAPI
 import me.ash.reader.infrastructure.rss.provider.greader.GoogleReaderAPI.Companion.ofCategoryIdToStreamId
@@ -97,7 +97,7 @@ class GoogleReaderRssService @Inject constructor(
     }
 
     override suspend fun subscribe(
-        feedLink: String, searchedFeed: SyndFeed, groupId: String,
+        feedLink: String, searchedFeed: FetchedFeed, groupId: String,
         isNotification: Boolean, isFullContent: Boolean,
     ) {
         val accountId = context.currentAccountId

app/src/main/java/me/ash/reader/infrastructure/android/AndroidApp.kt

@@ -22,6 +22,7 @@ import me.ash.reader.ui.ext.del
 import me.ash.reader.ui.ext.getLatestApk
 import me.ash.reader.ui.ext.isGitHub
 import okhttp3.OkHttpClient
+import rust.nostr.sdk.Client
 import javax.inject.Inject
 
 /**
@@ -58,6 +59,9 @@ class AndroidApp : Application(), Configuration.Provider {
     @Inject
     lateinit var rssHelper: RssHelper
 
+    @Inject
+    lateinit var nostrClient: Client
+
     @Inject
     lateinit var notificationHelper: NotificationHelper
 

app/src/main/java/me/ash/reader/infrastructure/di/NostrClientModule.kt

@@ -0,0 +1,19 @@
+package me.ash.reader.infrastructure.di
+
+import dagger.Module
+import dagger.Provides
+import dagger.hilt.InstallIn
+import dagger.hilt.components.SingletonComponent
+import rust.nostr.sdk.Client
+import javax.inject.Singleton
+
+@Module
+@InstallIn(SingletonComponent::class)
+object NostrClientModule {
+
+    @Provides
+    @Singleton
+    fun provideNostrClient(): Client {
+        return Client()
+    }
+}