Blog Client with Factory and Validator

This implements a simple initial blog client that covers the basic blog
actions, but no deletion/removal of blogs, yet.

Classes for Blogs and Blog Post Headers have been introduced along with
the associated factories.

A `BlogPostValidator` has been added that validates incoming blog posts.

Closes #402
Closes #404

briar-api/build.gradle

@@ -7,14 +7,16 @@ apply plugin: 'witness'
 dependencies {
 	compile "com.google.dagger:dagger:2.0.2"
 	compile 'com.google.dagger:dagger-compiler:2.0.2'
+	compile 'org.jetbrains:annotations-java5:15.0'
 }
 
 dependencyVerification {
 	verify = [
 			'com.google.dagger:dagger:84c0282ed8be73a29e0475d639da030b55dee72369e58dd35ae7d4fe6243dcf9',
 			'com.google.dagger:dagger-compiler:b74bc9de063dd4c6400b232231f2ef5056145b8fbecbf5382012007dd1c071b3',
-			'com.google.dagger:dagger-producers:99ec15e8a0507ba569e7655bc1165ee5e5ca5aa914b3c8f7e2c2458f724edd6b',
+			'org.jetbrains:annotations-java5:c84e6e9947f802ec2183bdc415dd496df02a749cac92e805f697e60f628a1e24',
 			'javax.inject:javax.inject:91c77044a50c481636c32d916fd89c9118a72195390452c81065080f957de7ff',
+			'com.google.dagger:dagger-producers:99ec15e8a0507ba569e7655bc1165ee5e5ca5aa914b3c8f7e2c2458f724edd6b',
 			'com.google.guava:guava:d664fbfc03d2e5ce9cab2a44fb01f1d0bf9dfebeccc1a473b1f9ea31f79f6f99',
 	]
 }

briar-api/src/org/briarproject/api/blogs/Blog.java

+package org.briarproject.api.blogs;
+
+import org.briarproject.api.forum.Forum;
+import org.briarproject.api.identity.Author;
+import org.briarproject.api.sync.Group;
+import org.jetbrains.annotations.NotNull;
+
+public class Blog extends Forum {
+
+	@NotNull
+	private final String description;
+	@NotNull
+	private final Author author;
+
+	public Blog(@NotNull Group group, @NotNull String name,
+			@NotNull String description, @NotNull Author author) {
+		super(group, name, null);
+
+		this.description = description;
+		this.author = author;
+	}
+
+	@NotNull
+	public String getDescription() {
+		return description;
+	}
+
+	@NotNull
+	public Author getAuthor() {
+		return author;
+	}
+}

briar-api/src/org/briarproject/api/blogs/BlogConstants.java

+package org.briarproject.api.blogs;
+
+import static org.briarproject.api.sync.SyncConstants.MAX_MESSAGE_BODY_LENGTH;
+
+public interface BlogConstants {
+
+	/** The maximum length of a blogs's name in UTF-8 bytes. */
+	int MAX_BLOG_TITLE_LENGTH = 100;
+
+	/** The length of a blogs's description in UTF-8 bytes. */
+	int MAX_BLOG_DESC_LENGTH = 240;
+
+	/** The maximum length of a blog post's content type in UTF-8 bytes. */
+	int MAX_CONTENT_TYPE_LENGTH = 50;
+
+	/** The length of a blog post's title in UTF-8 bytes. */
+	int MAX_BLOG_POST_TITLE_LENGTH = 100;
+
+	/** The length of a blog post's teaser in UTF-8 bytes. */
+	int MAX_BLOG_POST_TEASER_LENGTH = 240;
+
+	/** The maximum length of a blog post's body in bytes. */
+	int MAX_BLOG_POST_BODY_LENGTH = MAX_MESSAGE_BODY_LENGTH - 1024;
+
+	// Metadata keys
+	String KEY_DESCRIPTION = "description";
+	String KEY_TITLE = "title";
+	String KEY_TEASER = "teaser";
+	String KEY_HAS_BODY = "hasBody";
+	String KEY_TIMESTAMP = "timestamp";
+	String KEY_PARENT = "parent";
+	String KEY_AUTHOR_ID = "id";
+	String KEY_AUTHOR_NAME = "name";
+	String KEY_PUBLIC_KEY = "publicKey";
+	String KEY_AUTHOR = "author";
+	String KEY_CONTENT_TYPE = "contentType";
+	String KEY_READ = "read";
+
+}

briar-api/src/org/briarproject/api/blogs/BlogFactory.java

+package org.briarproject.api.blogs;
+
+import org.briarproject.api.FormatException;
+import org.briarproject.api.identity.Author;
+import org.briarproject.api.sync.Group;
+import org.jetbrains.annotations.NotNull;
+
+public interface BlogFactory {
+
+	/** Creates a blog with the given name, description and author. */
+	Blog createBlog(@NotNull String name, @NotNull String description,
+			@NotNull Author author);
+
+	/** Parses a blog with the given Group and description */
+	Blog parseBlog(@NotNull Group g, @NotNull String description)
+			throws FormatException;
+}

briar-api/src/org/briarproject/api/blogs/BlogManager.java

+package org.briarproject.api.blogs;
+
+import org.briarproject.api.FormatException;
+import org.briarproject.api.db.DbException;
+import org.briarproject.api.db.Transaction;
+import org.briarproject.api.identity.LocalAuthor;
+import org.briarproject.api.sync.ClientId;
+import org.briarproject.api.sync.GroupId;
+import org.briarproject.api.sync.MessageId;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.Collection;
+
+public interface BlogManager {
+
+	/** Returns the unique ID of the blog client. */
+	ClientId getClientId();
+
+	/** Creates a new Blog. */
+	Blog addBlog(LocalAuthor localAuthor, String name, String description)
+			throws DbException;
+
+	/** Stores a local blog post. */
+	void addLocalPost(BlogPost p) throws DbException;
+
+	/** Returns the blog with the given ID. */
+	Blog getBlog(GroupId g) throws DbException;
+
+	/** Returns the blog with the given ID. */
+	Blog getBlog(Transaction txn, GroupId g) throws DbException;
+
+	/** Returns all blogs to which the localAuthor created. */
+	Collection<Blog> getBlogs(LocalAuthor localAuthor) throws DbException;
+
+	/** Returns all blogs to which the user subscribes. */
+	Collection<Blog> getBlogs() throws DbException;
+
+	/** Returns the body of the blog post with the given ID. */
+	@Nullable
+	byte[] getPostBody(MessageId m) throws DbException;
+
+	/** Returns the headers of all posts in the given blog. */
+	Collection<BlogPostHeader> getPostHeaders(GroupId g) throws DbException;
+
+	/** Marks a blog post as read or unread. */
+	void setReadFlag(MessageId m, boolean read) throws DbException;
+
+}

briar-api/src/org/briarproject/api/blogs/BlogPost.java

+package org.briarproject.api.blogs;
+
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import org.briarproject.api.forum.ForumPost;
+import org.briarproject.api.identity.Author;
+import org.briarproject.api.sync.Message;
+import org.briarproject.api.sync.MessageId;
+
+public class BlogPost extends ForumPost {
+
+	@Nullable
+	private final String title;
+	@NotNull
+	private final String teaser;
+	private final boolean hasBody;
+
+	public BlogPost(@Nullable String title, @NotNull String teaser,
+			boolean hasBody, @NotNull Message message,
+			@Nullable MessageId parent, @NotNull Author author,
+			@NotNull String contentType) {
+		super(message, parent, author, contentType);
+
+		this.title = title;
+		this.teaser = teaser;
+		this.hasBody = hasBody;
+	}
+
+	@Nullable
+	public String getTitle() {
+		return title;
+	}
+
+	@NotNull
+	public String getTeaser() {
+		return teaser;
+	}
+
+	public boolean hasBody() {
+		return hasBody;
+	}
+}

briar-api/src/org/briarproject/api/blogs/BlogPostFactory.java

+package org.briarproject.api.blogs;
+
+import org.briarproject.api.FormatException;
+import org.briarproject.api.identity.LocalAuthor;
+import org.briarproject.api.sync.GroupId;
+import org.briarproject.api.sync.MessageId;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.security.GeneralSecurityException;
+
+public interface BlogPostFactory {
+
+	BlogPost createBlogPost(@NotNull GroupId groupId, @Nullable String title,
+			@NotNull String teaser, long timestamp, @Nullable MessageId parent,
+			@NotNull LocalAuthor author, @NotNull String contentType,
+			@Nullable byte[] body)
+			throws FormatException, GeneralSecurityException;
+}

briar-api/src/org/briarproject/api/blogs/BlogPostHeader.java

+package org.briarproject.api.blogs;
+
+import org.briarproject.api.clients.PostHeader;
+import org.briarproject.api.identity.Author;
+import org.briarproject.api.identity.Author.Status;
+import org.briarproject.api.sync.MessageId;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+public class BlogPostHeader extends PostHeader {
+
+	@Nullable
+	private final String title;
+	@NotNull
+	private final String teaser;
+	private final boolean hasBody;
+
+	public BlogPostHeader(@Nullable String title, @NotNull String teaser,
+			boolean hasBody, @NotNull MessageId id,
+			@Nullable MessageId parentId, long timestamp,
+			@NotNull Author author,	@NotNull Status authorStatus,
+			@NotNull String contentType, boolean read) {
+		super(id, parentId, timestamp, author, authorStatus, contentType, read);
+
+		this.title = title;
+		this.teaser = teaser;
+		this.hasBody = hasBody;
+	}
+
+	@Nullable
+	public String getTitle() {
+		return title;
+	}
+
+	@NotNull
+	public String getTeaser() {
+		return teaser;
+	}
+
+	public boolean hasBody() {
+		return hasBody;
+	}
+}

briar-api/src/org/briarproject/api/clients/PostHeader.java

+package org.briarproject.api.clients;
+
+import org.briarproject.api.identity.Author;
+import org.briarproject.api.sync.MessageId;
+
+public abstract class PostHeader {
+
+	private final MessageId id;
+	private final MessageId parentId;
+	private final long timestamp;
+	private final Author author;
+	private final Author.Status authorStatus;
+	private final String contentType;
+	private final boolean read;
+
+	public PostHeader(MessageId id, MessageId parentId, long timestamp,
+			Author author, Author.Status authorStatus, String contentType,
+			boolean read) {
+		this.id = id;
+		this.parentId = parentId;
+		this.timestamp = timestamp;
+		this.author = author;
+		this.authorStatus = authorStatus;
+		this.contentType = contentType;
+		this.read = read;
+	}
+
+	public MessageId getId() {
+		return id;
+	}
+
+	public Author getAuthor() {
+		return author;
+	}
+
+	public Author.Status getAuthorStatus() {
+		return authorStatus;
+	}
+
+	public String getContentType() {
+		return contentType;
+	}
+
+	public long getTimestamp() {
+		return timestamp;
+	}
+
+	public boolean isRead() {
+		return read;
+	}
+
+	public MessageId getParentId() {
+		return parentId;
+	}
+}

briar-api/src/org/briarproject/api/forum/ForumPostHeader.java

 package org.briarproject.api.forum;
 
 import org.briarproject.api.clients.MessageTree;
+import org.briarproject.api.clients.PostHeader;
 import org.briarproject.api.identity.Author;
 import org.briarproject.api.sync.MessageId;
 
-public class ForumPostHeader implements MessageTree.MessageNode {
-
-	private final MessageId id;
-	private final MessageId parentId;
-	private final long timestamp;
-	private final Author author;
-	private final Author.Status authorStatus;
-	private final String contentType;
-	private final boolean read;
+public class ForumPostHeader extends PostHeader
+		implements MessageTree.MessageNode {
 
 	public ForumPostHeader(MessageId id, MessageId parentId, long timestamp,
 			Author author, Author.Status authorStatus, String contentType,
 			boolean read) {
-		this.id = id;
-		this.parentId = parentId;
-		this.timestamp = timestamp;
-		this.author = author;
-		this.authorStatus = authorStatus;
-		this.contentType = contentType;
-		this.read = read;
-	}
-
-	public MessageId getId() {
-		return id;
-	}
-
-	public Author getAuthor() {
-		return author;
-	}
-
-	public Author.Status getAuthorStatus() {
-		return authorStatus;
+		super(id, parentId, timestamp, author, authorStatus, contentType, read);
 	}
 
-	public String getContentType() {
-		return contentType;
-	}
-
-	public long getTimestamp() {
-		return timestamp;
-	}
-
-	public boolean isRead() {
-		return read;
-	}
-
-	public MessageId getParentId() {
-		return parentId;
-	}
 }

briar-api/src/org/briarproject/api/identity/IdentityManager.java

@@ -2,6 +2,7 @@ package org.briarproject.api.identity;
 
 import org.briarproject.api.db.DbException;
 import org.briarproject.api.db.Transaction;
+import org.briarproject.api.identity.Author.Status;
 
 import java.util.Collection;
 
@@ -25,6 +26,9 @@ public interface IdentityManager {
 	/** Removes a local pseudonym and all associated state. */
 	void removeLocalAuthor(AuthorId a) throws DbException;
 
+	/** Returns the trust-level status of the author */
+	Status getAuthorStatus(AuthorId a) throws DbException;
+
 	interface AddIdentityHook {
 		void addingIdentity(Transaction txn, LocalAuthor a) throws DbException;
 	}

briar-core/src/org/briarproject/CoreEagerSingletons.java

 package org.briarproject;
 
+import org.briarproject.blogs.BlogsModule;
 import org.briarproject.contact.ContactModule;
 import org.briarproject.crypto.CryptoModule;
 import org.briarproject.db.DatabaseExecutorModule;
@@ -15,6 +16,8 @@ import org.briarproject.transport.TransportModule;
 
 public interface CoreEagerSingletons {
 
+	void inject(BlogsModule.EagerSingletons init);
+
 	void inject(ContactModule.EagerSingletons init);
 
 	void inject(CryptoModule.EagerSingletons init);

briar-core/src/org/briarproject/CoreModule.java

 package org.briarproject;
 
+import org.briarproject.blogs.BlogsModule;
 import org.briarproject.clients.ClientsModule;
 import org.briarproject.contact.ContactModule;
 import org.briarproject.crypto.CryptoModule;
@@ -26,6 +27,7 @@ import org.briarproject.transport.TransportModule;
 import dagger.Module;
 
 @Module(includes = {
+		BlogsModule.class,
 		ClientsModule.class,
 		ContactModule.class,
 		CryptoModule.class,
@@ -52,6 +54,7 @@ import dagger.Module;
 public class CoreModule {
 
 	public static void initEagerSingletons(CoreEagerSingletons c) {
+		c.inject(new BlogsModule.EagerSingletons());
 		c.inject(new ContactModule.EagerSingletons());
 		c.inject(new CryptoModule.EagerSingletons());
 		c.inject(new DatabaseExecutorModule.EagerSingletons());

briar-core/src/org/briarproject/blogs/BlogFactoryImpl.java

+package org.briarproject.blogs;
+
+import org.briarproject.api.FormatException;
+import org.briarproject.api.blogs.Blog;
+import org.briarproject.api.blogs.BlogFactory;
+import org.briarproject.api.clients.ClientHelper;
+import org.briarproject.api.data.BdfList;
+import org.briarproject.api.identity.Author;
+import org.briarproject.api.identity.AuthorFactory;
+import org.briarproject.api.sync.Group;
+import org.briarproject.api.sync.GroupFactory;
+import org.jetbrains.annotations.NotNull;
+
+import javax.inject.Inject;
+
+class BlogFactoryImpl implements BlogFactory {
+
+	private final GroupFactory groupFactory;
+	private final AuthorFactory authorFactory;
+	private final ClientHelper clientHelper;
+
+	@Inject
+	BlogFactoryImpl(GroupFactory groupFactory, AuthorFactory authorFactory,
+			ClientHelper clientHelper) {
+
+		this.groupFactory = groupFactory;
+		this.authorFactory = authorFactory;
+		this.clientHelper = clientHelper;
+	}
+
+	@Override
+	public Blog createBlog(@NotNull String name, @NotNull String description,
+			@NotNull Author author) {
+		try {
+			BdfList blog = BdfList.of(
+					name,
+					author.getName(),
+					author.getPublicKey()
+			);
+			byte[] descriptor = clientHelper.toByteArray(blog);
+			Group g = groupFactory
+					.createGroup(BlogManagerImpl.CLIENT_ID, descriptor);
+			return new Blog(g, name, description, author);
+		} catch (FormatException e) {
+			throw new RuntimeException(e);
+		}
+	}
+
+	@Override
+	public Blog parseBlog(@NotNull Group g, @NotNull String description)
+			throws FormatException {
+
+		byte[] descriptor = g.getDescriptor();
+		// Blog Name, Author Name, Public Key
+		BdfList blog = clientHelper.toList(descriptor, 0, descriptor.length);
+		Author a =
+				authorFactory.createAuthor(blog.getString(1), blog.getRaw(2));
+		return new Blog(g, blog.getString(0), description, a);
+	}
+
+}

briar-core/src/org/briarproject/blogs/BlogManagerImpl.java

+package org.briarproject.blogs;
+
+import org.briarproject.api.FormatException;
+import org.briarproject.api.blogs.Blog;
+import org.briarproject.api.blogs.BlogFactory;
+import org.briarproject.api.blogs.BlogManager;
+import org.briarproject.api.blogs.BlogPost;
+import org.briarproject.api.blogs.BlogPostHeader;
+import org.briarproject.api.clients.ClientHelper;
+import org.briarproject.api.data.BdfDictionary;
+import org.briarproject.api.data.BdfEntry;
+import org.briarproject.api.data.BdfList;
+import org.briarproject.api.db.DatabaseComponent;
+import org.briarproject.api.db.DbException;
+import org.briarproject.api.db.Transaction;
+import org.briarproject.api.identity.Author;
+import org.briarproject.api.identity.Author.Status;
+import org.briarproject.api.identity.AuthorId;
+import org.briarproject.api.identity.IdentityManager;
+import org.briarproject.api.identity.LocalAuthor;
+import org.briarproject.api.sync.ClientId;
+import org.briarproject.api.sync.Group;
+import org.briarproject.api.sync.GroupId;
+import org.briarproject.api.sync.MessageId;
+import org.briarproject.util.StringUtils;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.logging.Logger;
+
+import javax.inject.Inject;
+
+import static org.briarproject.api.blogs.BlogConstants.KEY_AUTHOR;
+import static org.briarproject.api.blogs.BlogConstants.KEY_AUTHOR_ID;
+import static org.briarproject.api.blogs.BlogConstants.KEY_AUTHOR_NAME;
+import static org.briarproject.api.blogs.BlogConstants.KEY_CONTENT_TYPE;
+import static org.briarproject.api.blogs.BlogConstants.KEY_DESCRIPTION;
+import static org.briarproject.api.blogs.BlogConstants.KEY_HAS_BODY;
+import static org.briarproject.api.blogs.BlogConstants.KEY_PARENT;
+import static org.briarproject.api.blogs.BlogConstants.KEY_PUBLIC_KEY;
+import static org.briarproject.api.blogs.BlogConstants.KEY_READ;
+import static org.briarproject.api.blogs.BlogConstants.KEY_TEASER;
+import static org.briarproject.api.blogs.BlogConstants.KEY_TIMESTAMP;
+import static org.briarproject.api.blogs.BlogConstants.KEY_TITLE;
+
+class BlogManagerImpl implements BlogManager {
+
+	private static final Logger LOG =
+			Logger.getLogger(BlogManagerImpl.class.getName());
+
+	static final ClientId CLIENT_ID = new ClientId(StringUtils.fromHexString(
+			"dafbe56f0c8971365cea4bb5f08ec9a6" +
+					"1d686e058b943997b6ff259ba423f613"));
+
+	private final DatabaseComponent db;
+	private final IdentityManager identityManager;
+	private final ClientHelper clientHelper;
+	private final BlogFactory blogFactory;
+
+	@Inject
+	BlogManagerImpl(DatabaseComponent db, IdentityManager identityManager,
+			ClientHelper clientHelper, BlogFactory blogFactory) {
+
+		this.db = db;
+		this.identityManager = identityManager;
+		this.clientHelper = clientHelper;
+		this.blogFactory = blogFactory;
+	}
+
+	@Override
+	public ClientId getClientId() {
+		return CLIENT_ID;
+	}
+
+	@Override
+	public Blog addBlog(LocalAuthor localAuthor, String name,
+			String description) throws DbException {
+
+		Blog b = blogFactory
+				.createBlog(name, description, localAuthor);
+		BdfDictionary metadata = BdfDictionary.of(
+				new BdfEntry(KEY_DESCRIPTION, b.getDescription())
+		);
+
+		Transaction txn = db.startTransaction(false);
+		try {
+			db.addGroup(txn, b.getGroup());
+			clientHelper.mergeGroupMetadata(txn, b.getId(), metadata);
+			txn.setComplete();
+		} catch (FormatException e) {
+			throw new DbException(e);
+		} finally {
+			db.endTransaction(txn);
+		}
+		return b;
+	}
+
+	@Override
+	public void addLocalPost(BlogPost p) throws DbException {
+		try {
+			BdfDictionary meta = new BdfDictionary();
+			if (p.getTitle() != null) meta.put(KEY_TITLE, p.getTitle());
+			meta.put(KEY_TEASER, p.getTeaser());
+			meta.put(KEY_TIMESTAMP, p.getMessage().getTimestamp());
+			meta.put(KEY_HAS_BODY, p.hasBody());
+			if (p.getParent() != null) meta.put(KEY_PARENT, p.getParent());
+
+			Author a = p.getAuthor();
+			BdfDictionary authorMeta = new BdfDictionary();
+			authorMeta.put(KEY_AUTHOR_ID, a.getId());
+			authorMeta.put(KEY_AUTHOR_NAME, a.getName());
+			authorMeta.put(KEY_PUBLIC_KEY, a.getPublicKey());
+			meta.put(KEY_AUTHOR, authorMeta);
+
+			meta.put(KEY_CONTENT_TYPE, p.getContentType());
+			meta.put(KEY_READ, true);
+			clientHelper.addLocalMessage(p.getMessage(), CLIENT_ID, meta, true);
+		} catch (FormatException e) {
+			throw new RuntimeException(e);
+		}
+	}
+
+	@Override
+	public Blog getBlog(GroupId g) throws DbException {
+		Blog blog;
+		Transaction txn = db.startTransaction(true);
+		try {
+			blog = getBlog(txn, g);
+			txn.setComplete();
+		} finally {
+			db.endTransaction(txn);
+		}
+		return blog;
+	}
+
+	@Override
+	public Blog getBlog(Transaction txn, GroupId g) throws DbException {
+		try {
+			Group group = db.getGroup(txn, g);
+			String description = getBlogDescription(txn, g);
+			return blogFactory.parseBlog(group, description);
+		} catch (FormatException e) {
+			throw new DbException(e);
+		}
+	}
+
+	@Override
+	public Collection<Blog> getBlogs(LocalAuthor localAuthor)
+			throws DbException {
+
+		Collection<Blog> allBlogs = getBlogs();
+		List<Blog> blogs = new ArrayList<Blog>();
+		for (Blog b : allBlogs) {
+			if (b.getAuthor().equals(localAuthor)) {
+				blogs.add(b);
+			}
+		}
+		return Collections.unmodifiableList(blogs);
+	}
+
+	@Override
+	public Collection<Blog> getBlogs() throws DbException {
+		try {
+			List<Blog> blogs = new ArrayList<Blog>();
+			Collection<Group> groups;
+			Transaction txn = db.startTransaction(true);
+			try {
+				groups = db.getGroups(txn, CLIENT_ID);
+				for (Group g : groups) {
+					String description = getBlogDescription(txn, g.getId());
+					blogs.add(blogFactory.parseBlog(g, description));
+				}
+				txn.setComplete();
+			} finally {
+				db.endTransaction(txn);
+			}
+			return Collections.unmodifiableList(blogs);
+		} catch (FormatException e) {
+			throw new DbException(e);
+		}
+	}
+
+	@Override
+	@Nullable
+	public byte[] getPostBody(MessageId m) throws DbException {
+		try {
+			// content, signature
+			// content: parent, contentType, title, teaser, body, attachments
+			BdfList message = clientHelper.getMessageAsList(m);
+			BdfList content = message.getList(0);
+			return content.getRaw(4);
+		} catch (FormatException e) {
+			throw new DbException(e);
+		}
+	}
+
+	@Override
+	public Collection<BlogPostHeader> getPostHeaders(GroupId g)
+			throws DbException {
+
+		Map<MessageId, BdfDictionary> metadata;
+		try {
+			metadata = clientHelper.getMessageMetadataAsDictionary(g);
+		} catch (FormatException e) {
+			throw new DbException(e);
+		}
+		Collection<BlogPostHeader> headers = new ArrayList<BlogPostHeader>();
+		for (Entry<MessageId, BdfDictionary> entry : metadata.entrySet()) {
+			try {
+				BdfDictionary meta = entry.getValue();
+				String title = meta.getOptionalString(KEY_TITLE);
+				String teaser = meta.getString(KEY_TEASER);
+				boolean hasBody = meta.getBoolean(KEY_HAS_BODY);
+				long timestamp = meta.getLong(KEY_TIMESTAMP);
+				MessageId parentId = null;
+				if (meta.containsKey(KEY_PARENT))
+					parentId = new MessageId(meta.getRaw(KEY_PARENT));
+
+				BdfDictionary d = meta.getDictionary(KEY_AUTHOR);
+				AuthorId authorId = new AuthorId(d.getRaw(KEY_AUTHOR_ID));
+				String name = d.getString(KEY_AUTHOR_NAME);
+				byte[] publicKey = d.getRaw(KEY_PUBLIC_KEY);
+				Author author = new Author(authorId, name, publicKey);
+				Status authorStatus = identityManager.getAuthorStatus(authorId);
+
+				String contentType = meta.getString(KEY_CONTENT_TYPE);
+				boolean read = meta.getBoolean(KEY_READ);
+				headers.add(new BlogPostHeader(title, teaser, hasBody,
+						entry.getKey(), parentId, timestamp, author,
+						authorStatus, contentType, read));
+			} catch (FormatException e) {
+				throw new DbException(e);
+			}
+		}
+		return headers;
+	}
+
+	@Override
+	public void setReadFlag(MessageId m, boolean read) throws DbException {
+		try {
+			BdfDictionary meta = new BdfDictionary();
+			meta.put(KEY_READ, read);
+			clientHelper.mergeMessageMetadata(m, meta);
+		} catch (FormatException e) {
+			throw new RuntimeException(e);
+		}
+	}
+
+	private String getBlogDescription(Transaction txn, GroupId g)
+			throws DbException, FormatException {
+		BdfDictionary d = clientHelper.getGroupMetadataAsDictionary(txn, g);
+		return d.getString(KEY_DESCRIPTION);
+	}
+
+}

briar-core/src/org/briarproject/blogs/BlogPostFactoryImpl.java

+package org.briarproject.blogs;
+
+import org.briarproject.api.FormatException;
+import org.briarproject.api.blogs.BlogPost;
+import org.briarproject.api.blogs.BlogPostFactory;
+import org.briarproject.api.clients.ClientHelper;
+import org.briarproject.api.crypto.CryptoComponent;
+import org.briarproject.api.crypto.KeyParser;
+import org.briarproject.api.crypto.PrivateKey;
+import org.briarproject.api.crypto.Signature;
+import org.briarproject.api.data.BdfList;
+import org.briarproject.api.identity.LocalAuthor;
+import org.briarproject.api.sync.GroupId;
+import org.briarproject.api.sync.Message;
+import org.briarproject.api.sync.MessageId;
+import org.briarproject.util.StringUtils;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.security.GeneralSecurityException;
+
+import javax.inject.Inject;
+
+import static org.briarproject.api.blogs.BlogConstants.MAX_BLOG_POST_BODY_LENGTH;
+import static org.briarproject.api.blogs.BlogConstants.MAX_BLOG_POST_TEASER_LENGTH;
+import static org.briarproject.api.blogs.BlogConstants.MAX_BLOG_POST_TITLE_LENGTH;
+import static org.briarproject.api.blogs.BlogConstants.MAX_CONTENT_TYPE_LENGTH;
+
+class BlogPostFactoryImpl implements BlogPostFactory {
+
+	private final CryptoComponent crypto;
+	private final ClientHelper clientHelper;
+
+	@Inject
+	BlogPostFactoryImpl(CryptoComponent crypto, ClientHelper clientHelper) {
+		this.crypto = crypto;
+		this.clientHelper = clientHelper;
+	}
+
+	@Override
+	public BlogPost createBlogPost(@NotNull GroupId groupId,
+			@Nullable String title, @NotNull String teaser,	long timestamp,
+			@Nullable MessageId parent,	@NotNull LocalAuthor author,
+			@NotNull String contentType, @Nullable byte[] body)
+			throws FormatException, GeneralSecurityException {
+
+		// Validate the arguments
+		if (title != null &&
+				StringUtils.toUtf8(title).length > MAX_BLOG_POST_TITLE_LENGTH)
+			throw new IllegalArgumentException();
+		if (StringUtils.toUtf8(teaser).length > MAX_BLOG_POST_TEASER_LENGTH)
+			throw new IllegalArgumentException();
+		if (StringUtils.toUtf8(contentType).length > MAX_CONTENT_TYPE_LENGTH)
+			throw new IllegalArgumentException();
+		if (body != null && body.length > MAX_BLOG_POST_BODY_LENGTH)
+			throw new IllegalArgumentException();
+
+		// Serialise the data to be signed
+		BdfList content =
+				BdfList.of(parent, contentType, title, teaser, body, null);
+		BdfList signed = BdfList.of(groupId, timestamp, content);
+
+		// Generate the signature
+		Signature signature = crypto.getSignature();
+		KeyParser keyParser = crypto.getSignatureKeyParser();
+		PrivateKey privateKey =
+				keyParser.parsePrivateKey(author.getPrivateKey());
+		signature.initSign(privateKey);
+		signature.update(clientHelper.toByteArray(signed));
+		byte[] sig = signature.sign();
+
+		// Serialise the signed message
+		BdfList message = BdfList.of(content, sig);
+		Message m = clientHelper.createMessage(groupId, timestamp, message);
+		return new BlogPost(title, teaser, body != null, m, parent, author,
+				contentType);
+	}
+}

briar-core/src/org/briarproject/blogs/BlogPostValidator.java

+package org.briarproject.blogs;
+
+import org.briarproject.api.FormatException;
+import org.briarproject.api.UniqueId;
+import org.briarproject.api.blogs.Blog;
+import org.briarproject.api.blogs.BlogFactory;
+import org.briarproject.api.clients.BdfMessageContext;
+import org.briarproject.api.clients.ClientHelper;
+import org.briarproject.api.crypto.CryptoComponent;
+import org.briarproject.api.crypto.KeyParser;
+import org.briarproject.api.crypto.PublicKey;
+import org.briarproject.api.crypto.Signature;
+import org.briarproject.api.data.BdfDictionary;
+import org.briarproject.api.data.BdfList;
+import org.briarproject.api.data.MetadataEncoder;
+import org.briarproject.api.identity.Author;
+import org.briarproject.api.sync.Group;
+import org.briarproject.api.sync.InvalidMessageException;
+import org.briarproject.api.sync.Message;
+import org.briarproject.api.sync.MessageId;
+import org.briarproject.api.system.Clock;
+import org.briarproject.clients.BdfMessageValidator;
+
+import java.security.GeneralSecurityException;
+import java.util.Collection;
+import java.util.Collections;
+
+import static org.briarproject.api.blogs.BlogConstants.KEY_CONTENT_TYPE;
+import static org.briarproject.api.blogs.BlogConstants.KEY_HAS_BODY;
+import static org.briarproject.api.blogs.BlogConstants.KEY_PARENT;
+import static org.briarproject.api.blogs.BlogConstants.KEY_READ;
+import static org.briarproject.api.blogs.BlogConstants.KEY_TEASER;
+import static org.briarproject.api.blogs.BlogConstants.KEY_TIMESTAMP;
+import static org.briarproject.api.blogs.BlogConstants.KEY_TITLE;
+import static org.briarproject.api.blogs.BlogConstants.MAX_BLOG_POST_BODY_LENGTH;
+import static org.briarproject.api.blogs.BlogConstants.MAX_BLOG_POST_TEASER_LENGTH;
+import static org.briarproject.api.blogs.BlogConstants.MAX_BLOG_POST_TITLE_LENGTH;
+import static org.briarproject.api.blogs.BlogConstants.MAX_CONTENT_TYPE_LENGTH;
+import static org.briarproject.api.identity.AuthorConstants.MAX_SIGNATURE_LENGTH;
+
+class BlogPostValidator extends BdfMessageValidator {
+
+	private final CryptoComponent crypto;
+	private final BlogFactory blogFactory;
+
+	BlogPostValidator(CryptoComponent crypto, BlogFactory blogFactory,
+			ClientHelper clientHelper, MetadataEncoder metadataEncoder,
+			Clock clock) {
+		super(clientHelper, metadataEncoder, clock);
+
+		this.crypto = crypto;
+		this.blogFactory = blogFactory;
+	}
+
+	@Override
+	protected BdfMessageContext validateMessage(Message m, Group g,
+			BdfList body) throws InvalidMessageException, FormatException {
+
+		// Content, Signature
+		checkSize(body, 2);
+		BdfList content = body.getList(0);
+
+		// Content: Parent ID, content type, title (optional), teaser,
+		//          post body (optional), attachments (optional)
+		checkSize(body, 6);
+		// Parent ID is optional
+		byte[] parent = content.getOptionalRaw(0);
+		checkLength(parent, UniqueId.LENGTH);
+		// Content type
+		String contentType = content.getString(1);
+		checkLength(contentType, 0, MAX_CONTENT_TYPE_LENGTH);
+		// Blog post title is optional
+		String title = content.getOptionalString(2);
+		checkLength(contentType, 0, MAX_BLOG_POST_TITLE_LENGTH);
+		// Blog teaser
+		String teaser = content.getString(3);
+		// TODO make sure that there is only text in the teaser
+		checkLength(contentType, 0, MAX_BLOG_POST_TEASER_LENGTH);
+		// Blog post body is optional
+		byte[] postBody = content.getOptionalRaw(4);
+		checkLength(postBody, 0, MAX_BLOG_POST_BODY_LENGTH);
+		// Attachments
+		BdfDictionary attachments = content.getOptionalDictionary(5);
+		// TODO handle attachments somehow
+
+		// Signature
+		byte[] sig = body.getRaw(1);
+		checkLength(sig, 0, MAX_SIGNATURE_LENGTH);
+		// Verify the signature
+		try {
+			// Get the blog author
+			Blog b = blogFactory.parseBlog(g, ""); // description doesn't matter
+			Author a = b.getAuthor();
+			// Parse the public key
+			KeyParser keyParser = crypto.getSignatureKeyParser();
+			PublicKey key = keyParser.parsePublicKey(a.getPublicKey());
+			// Serialise the data to be signed
+			BdfList signed = BdfList.of(g.getId(), m.getTimestamp(), content);
+			// Verify the signature
+			Signature signature = crypto.getSignature();
+			signature.initVerify(key);
+			signature.update(clientHelper.toByteArray(signed));
+			if (!signature.verify(sig)) {
+				throw new InvalidMessageException("Invalid signature");
+			}
+		} catch (GeneralSecurityException e) {
+			throw new InvalidMessageException("Invalid public key");
+		}
+
+		// Return the metadata and dependencies
+		BdfDictionary meta = new BdfDictionary();
+		Collection<MessageId> dependencies = null;
+		if (title != null) meta.put(KEY_TITLE, title);
+		meta.put(KEY_TEASER, teaser);
+		meta.put(KEY_HAS_BODY, postBody != null);
+		meta.put(KEY_TIMESTAMP, m.getTimestamp());
+		if (parent != null) {
+			meta.put(KEY_PARENT, parent);
+			dependencies = Collections.singletonList(new MessageId(parent));
+		}
+		meta.put(KEY_CONTENT_TYPE, contentType);
+		meta.put(KEY_READ, false);
+		return new BdfMessageContext(meta, dependencies);
+	}
+}

briar-core/src/org/briarproject/blogs/BlogsModule.java

+package org.briarproject.blogs;
+
+import org.briarproject.api.blogs.BlogFactory;
+import org.briarproject.api.blogs.BlogManager;
+import org.briarproject.api.blogs.BlogPostFactory;
+import org.briarproject.api.clients.ClientHelper;
+import org.briarproject.api.crypto.CryptoComponent;
+import org.briarproject.api.data.MetadataEncoder;
+import org.briarproject.api.db.DatabaseComponent;
+import org.briarproject.api.identity.AuthorFactory;
+import org.briarproject.api.identity.IdentityManager;
+import org.briarproject.api.sync.GroupFactory;
+import org.briarproject.api.sync.ValidationManager;
+import org.briarproject.api.system.Clock;
+
+import javax.inject.Inject;
+import javax.inject.Singleton;
+
+import dagger.Module;
+import dagger.Provides;
+
+@Module
+public class BlogsModule {
+
+	public static class EagerSingletons {
+		@Inject
+		BlogPostValidator blogPostValidator;
+	}
+
+	@Provides
+	@Singleton
+	BlogManager provideBlogManager(BlogManagerImpl blogManager) {
+		return blogManager;
+	}
+
+	@Provides
+	BlogPostFactory provideBlogPostFactory(CryptoComponent crypto,
+			ClientHelper clientHelper) {
+		return new BlogPostFactoryImpl(crypto, clientHelper);
+	}
+
+	@Provides
+	BlogFactory provideBlogFactory(GroupFactory groupFactory,
+			AuthorFactory authorFactory, ClientHelper clientHelper) {
+		return new BlogFactoryImpl(groupFactory, authorFactory, clientHelper);
+	}
+
+	@Provides
+	@Singleton
+	BlogPostValidator provideBlogPostValidator(
+			ValidationManager validationManager, CryptoComponent crypto,
+			BlogFactory blogFactory, ClientHelper clientHelper,
+			MetadataEncoder metadataEncoder, Clock clock) {
+
+		BlogPostValidator validator = new BlogPostValidator(crypto,
+				blogFactory, clientHelper, metadataEncoder, clock);
+		validationManager.registerMessageValidator(
+				BlogManagerImpl.CLIENT_ID, validator);
+
+		return validator;
+	}
+
+}

briar-core/src/org/briarproject/forum/ForumManagerImpl.java

@@ -2,7 +2,6 @@ package org.briarproject.forum;
 
 import org.briarproject.api.FormatException;
 import org.briarproject.api.clients.ClientHelper;
-import org.briarproject.api.contact.Contact;
 import org.briarproject.api.data.BdfDictionary;
 import org.briarproject.api.data.BdfList;
 import org.briarproject.api.db.DatabaseComponent;
@@ -14,8 +13,9 @@ import org.briarproject.api.forum.ForumManager;
 import org.briarproject.api.forum.ForumPost;
 import org.briarproject.api.forum.ForumPostHeader;
 import org.briarproject.api.identity.Author;
+import org.briarproject.api.identity.Author.Status;
 import org.briarproject.api.identity.AuthorId;
-import org.briarproject.api.identity.LocalAuthor;
+import org.briarproject.api.identity.IdentityManager;
 import org.briarproject.api.sync.ClientId;
 import org.briarproject.api.sync.Group;
 import org.briarproject.api.sync.GroupId;
@@ -25,11 +25,9 @@ import org.briarproject.util.StringUtils;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
-import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
-import java.util.Set;
 import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.logging.Logger;
 
@@ -45,8 +43,6 @@ import static org.briarproject.api.forum.ForumConstants.KEY_PUBLIC_NAME;
 import static org.briarproject.api.forum.ForumConstants.KEY_READ;
 import static org.briarproject.api.forum.ForumConstants.KEY_TIMESTAMP;
 import static org.briarproject.api.identity.Author.Status.ANONYMOUS;
-import static org.briarproject.api.identity.Author.Status.UNKNOWN;
-import static org.briarproject.api.identity.Author.Status.VERIFIED;
 
 class ForumManagerImpl implements ForumManager {
 
@@ -58,15 +54,17 @@ class ForumManagerImpl implements ForumManager {
 					+ "795af837abbf8c16d750b3c2ccc186ea"));
 
 	private final DatabaseComponent db;
+	private final IdentityManager identityManager;
 	private final ClientHelper clientHelper;
 	private final ForumFactory forumFactory;
 	private final List<RemoveForumHook> removeHooks;
 
 	@Inject
-	ForumManagerImpl(DatabaseComponent db, ClientHelper clientHelper,
-			ForumFactory forumFactory) {
+	ForumManagerImpl(DatabaseComponent db, IdentityManager identityManager,
+			ClientHelper clientHelper, ForumFactory forumFactory) {
 
 		this.db = db;
+		this.identityManager = identityManager;
 		this.clientHelper = clientHelper;
 		this.forumFactory = forumFactory;
 		removeHooks = new CopyOnWriteArrayList<RemoveForumHook>();
@@ -183,24 +181,12 @@ class ForumManagerImpl implements ForumManager {
 	@Override
 	public Collection<ForumPostHeader> getPostHeaders(GroupId g)
 			throws DbException {
-		Set<AuthorId> localAuthorIds = new HashSet<AuthorId>();
-		Set<AuthorId> contactAuthorIds = new HashSet<AuthorId>();
+
 		Map<MessageId, BdfDictionary> metadata;
-		Transaction txn = db.startTransaction(true);
 		try {
-			// Load the IDs of the user's identities
-			for (LocalAuthor a : db.getLocalAuthors(txn))
-				localAuthorIds.add(a.getId());
-			// Load the IDs of contacts' identities
-			for (Contact c : db.getContacts(txn))
-				contactAuthorIds.add(c.getAuthor().getId());
-			// Load the metadata
-			metadata = clientHelper.getMessageMetadataAsDictionary(txn, g);
-			txn.setComplete();
+			metadata = clientHelper.getMessageMetadataAsDictionary(g);
 		} catch (FormatException e) {
 			throw new DbException(e);
-		} finally {
-			db.endTransaction(txn);
 		}
 		// Parse the metadata
 		Collection<ForumPostHeader> headers = new ArrayList<ForumPostHeader>();
@@ -209,7 +195,7 @@ class ForumManagerImpl implements ForumManager {
 				BdfDictionary meta = entry.getValue();
 				long timestamp = meta.getLong(KEY_TIMESTAMP);
 				Author author = null;
-				Author.Status authorStatus = ANONYMOUS;
+				Status authorStatus = ANONYMOUS;
 				MessageId parentId = null;
 				if (meta.containsKey(KEY_PARENT))
 					parentId = new MessageId(meta.getRaw(KEY_PARENT));
@@ -219,11 +205,8 @@ class ForumManagerImpl implements ForumManager {
 					String name = d1.getString(KEY_NAME);
 					byte[] publicKey = d1.getRaw(KEY_PUBLIC_NAME);
 					author = new Author(authorId, name, publicKey);
-					if (localAuthorIds.contains(authorId))
-						authorStatus = VERIFIED;
-					else if (contactAuthorIds.contains(authorId))
-						authorStatus = VERIFIED;
-					else authorStatus = UNKNOWN;
+					authorStatus =
+							identityManager.getAuthorStatus(author.getId());
 				}
 				String contentType = meta.getString(KEY_CONTENT_TYPE);
 				boolean read = meta.getBoolean(KEY_READ);

briar-core/src/org/briarproject/forum/ForumModule.java

@@ -11,6 +11,7 @@ import org.briarproject.api.forum.ForumManager;
 import org.briarproject.api.forum.ForumPostFactory;
 import org.briarproject.api.forum.ForumSharingManager;
 import org.briarproject.api.identity.AuthorFactory;
+import org.briarproject.api.identity.IdentityManager;
 import org.briarproject.api.lifecycle.LifecycleManager;
 import org.briarproject.api.sync.GroupFactory;
 import org.briarproject.api.sync.ValidationManager;
@@ -38,9 +39,8 @@ public class ForumModule {
 
 	@Provides
 	@Singleton
-	ForumManager provideForumManager(DatabaseComponent db,
-			ClientHelper clientHelper, ForumFactory forumFactory) {
-		return new ForumManagerImpl(db, clientHelper, forumFactory);
+	ForumManager provideForumManager(ForumManagerImpl forumManager) {
+		return forumManager;
 	}
 
 	@Provides
@@ -88,7 +88,7 @@ public class ForumModule {
 			LifecycleManager lifecycleManager,
 			ContactManager contactManager,
 			MessageQueueManager messageQueueManager,
-			ForumManager forumManager, ForumFactory forumFactory,
+			ForumManager forumManager,
 			ForumSharingManagerImpl forumSharingManager) {
 
 		lifecycleManager.registerClient(forumSharingManager);