// Copyright 2012 Google Inc. All Rights Reserved.
//
// 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.google.collide.server.documents;
import com.google.collide.dto.DocOp;
import com.google.collide.dto.DocumentSelection;
import com.google.collide.dto.FileContents;
import com.google.collide.dto.FileContents.ContentType;
import com.google.collide.dto.server.DtoServerImpls.ClientToServerDocOpImpl;
import com.google.collide.dto.server.DtoServerImpls.DocOpComponentImpl;
import com.google.collide.dto.server.DtoServerImpls.DocOpImpl;
import com.google.collide.dto.server.DtoServerImpls.DocumentSelectionImpl;
import com.google.collide.dto.server.DtoServerImpls.FileContentsImpl;
import com.google.collide.dto.server.DtoServerImpls.GetFileContentsImpl;
import com.google.collide.dto.server.DtoServerImpls.GetFileContentsResponseImpl;
import com.google.collide.dto.server.DtoServerImpls.RecoverFromMissedDocOpsImpl;
import com.google.collide.dto.server.DtoServerImpls.RecoverFromMissedDocOpsResponseImpl;
import com.google.collide.dto.server.DtoServerImpls.ServerToClientDocOpImpl;
import com.google.collide.dto.server.DtoServerImpls.ServerToClientDocOpsImpl;
import com.google.collide.json.server.JsonArrayListAdapter;
import com.google.collide.server.documents.VersionedDocument.AppliedDocOp;
import com.google.collide.server.documents.VersionedDocument.DocumentOperationException;
import com.google.collide.server.participants.Participants;
import com.google.collide.server.shared.util.Dto;
import com.google.collide.shared.MimeTypes;
import com.google.common.base.Charsets;
import com.google.common.collect.Lists;
import com.google.common.io.Files;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import org.apache.commons.codec.binary.Base64;
import org.apache.commons.codec.binary.StringUtils;
import org.vertx.java.busmods.BusModBase;
import org.vertx.java.core.Handler;
import org.vertx.java.core.eventbus.Message;
import org.vertx.java.core.json.JsonArray;
import org.vertx.java.core.json.JsonObject;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import java.util.SortedMap;
/**
* Backend service that maintains in-memory edit sessions for documents that are being
* collaboratively edited.
*
* All text mutations and document related changes are handled by this service.
*
*/
public class EditSessions extends BusModBase {
private static final Gson gson = new GsonBuilder().registerTypeAdapter(
DocOpComponentImpl.class, new DocOpComponentDeserializer()).serializeNulls().create();
/**
* Receives Document operations and applies them to the corresponding FileEditSession.
*
* If there is no associated FileEditSession, we need log an error since that probably means we
* have a stale client.
*/
class DocumentMutator implements Handler<Message<JsonObject>> {
private final SelectionTracker selectionTracker = new SelectionTracker();
@Override
public void handle(Message<JsonObject> message) {
ClientToServerDocOpImpl wrappedDocOp =
ClientToServerDocOpImpl.fromJsonString(Dto.get(message));
String resourceId = wrappedDocOp.getFileEditSessionKey();
FileEditSession editSession = editSessions.get(resourceId);
// Apply the DocOp.
if (editSession != null) {
List<String> docOps = ((JsonArrayListAdapter<String>) wrappedDocOp.getDocOps2()).asList();
ServerToClientDocOpsImpl appliedDocOps = applyMutation(
docOps, wrappedDocOp.getClientId(), wrappedDocOp.getCcRevision(),
wrappedDocOp.getSelection(), resourceId, editSession);
message.reply(Dto.wrap(appliedDocOps));
}
}
private List<DocOp> deserializeDocOps(List<String> serializedDocOps) {
List<DocOp> docOps = new ArrayList<DocOp>();
for (String serializedDocOp : serializedDocOps) {
docOps.add(gson.fromJson(serializedDocOp, DocOpImpl.class));
}
return docOps;
}
private ServerToClientDocOpsImpl applyMutation(List<String> serializedDocOps, String authorId,
int ccRevision, DocumentSelection selection, String resourceId, FileEditSession editSession) {
try {
List<DocOp> docOps = deserializeDocOps(serializedDocOps);
VersionedDocument.ConsumeResult result =
editSession.consume(docOps, authorId, ccRevision, selection);
// See if we need to update the selection
checkForSelectionChange(
authorId, resourceId, editSession.getDocument(), result.transformedDocumentSelection);
// Construct the Applied DocOp that we want to broadcast.
SortedMap<Integer, AppliedDocOp> appliedDocOps = result.appliedDocOps;
List<ServerToClientDocOpImpl> appliedDocOpsList = Lists.newArrayList();
for (Entry<Integer, VersionedDocument.AppliedDocOp> entry : appliedDocOps.entrySet()) {
DocOpImpl docOp = (DocOpImpl) entry.getValue().docOp;
ServerToClientDocOpImpl wrappedBroadcastDocOp = ServerToClientDocOpImpl.make()
.setClientId(authorId).setAppliedCcRevision(entry.getKey()).setDocOp2(docOp)
.setFileEditSessionKey(resourceId)
.setFilePath(editSession.getSavedPath());
appliedDocOpsList.add(wrappedBroadcastDocOp);
}
// Add the selection to the last DocOp if there was one.
if (result.transformedDocumentSelection != null && appliedDocOpsList.size() > 0) {
appliedDocOpsList.get(appliedDocOpsList.size() - 1)
.setSelection((DocumentSelectionImpl) result.transformedDocumentSelection);
}
// Broadcast the applied DocOp all the participants, ignoring the sender.
ServerToClientDocOpsImpl broadcastedDocOps =
ServerToClientDocOpsImpl.make().setDocOps(appliedDocOpsList);
vertx.eventBus().send("participants.broadcast", new JsonObject().putString(
Participants.OMIT_SENDER_TAG, authorId).putString(
"payload", broadcastedDocOps.toJson()));
return broadcastedDocOps;
} catch (DocumentOperationException e) {
logger.error(String.format("Failed to apply DocOps [%s]", serializedDocOps));
}
return null;
}
private void checkForSelectionChange(String clientId, String resourceId,
VersionedDocument document, DocumentSelection documentSelection) {
/*
* Currently, doc ops either contain text changes or selection changes (via annotation doc op
* components). Both of these modify the user's selection/cursor.
*/
selectionTracker.selectionChanged(clientId, resourceId, document, documentSelection);
}
}
/**
* Replies with the DocOps that were missed by the requesting client.
*/
class DocOpRecoverer implements Handler<Message<JsonObject>> {
@Override
public void handle(Message<JsonObject> event) {
RecoverFromMissedDocOpsImpl req = RecoverFromMissedDocOpsImpl.fromJsonString(Dto.get(event));
String resourceId = req.getFileEditSessionKey();
FileEditSession editSession = editSessions.get(resourceId);
if (editSession == null) {
logger.error("No edit session for resourceId " + resourceId);
// TODO: This is going to leave the reply handler hanging.
return;
}
List<String> docOps = ((JsonArrayListAdapter<String>) req.getDocOps2()).asList();
// If the client is re-sending any unacked doc ops, apply them first
if (req.getDocOps2().size() > 0) {
documentMutator.applyMutation(
docOps, req.getClientId(), req.getCurrentCcRevision(), null, resourceId, editSession);
}
// Get all the applied doc ops the client doesn't know about
SortedMap<Integer, VersionedDocument.AppliedDocOp> appliedDocOps =
editSession.getDocument().getAppliedDocOps(req.getCurrentCcRevision() + 1);
List<ServerToClientDocOpImpl> appliedDocOpsList = Lists.newArrayList();
for (Entry<Integer, VersionedDocument.AppliedDocOp> entry : appliedDocOps.entrySet()) {
DocOpImpl docOp = (DocOpImpl) entry.getValue().docOp;
ServerToClientDocOpImpl wrappedBroadcastDocOp = ServerToClientDocOpImpl.make()
.setClientId(req.getClientId()).setAppliedCcRevision(entry.getKey()).setDocOp2(docOp)
.setFileEditSessionKey(resourceId)
.setFilePath(editSession.getSavedPath());
appliedDocOpsList.add(wrappedBroadcastDocOp);
}
RecoverFromMissedDocOpsResponseImpl resp =
RecoverFromMissedDocOpsResponseImpl.make().setDocOps(appliedDocOpsList);
event.reply(Dto.wrap(resp));
}
}
/**
* Creates a FileEditSession if there is not one already present and
*/
class EditSessionCreator implements Handler<Message<JsonObject>> {
/**
* Whether or not to provision an edit session if one is missing, before sending the file
* contents
*/
private final boolean provisionEditSession;
EditSessionCreator(boolean provisionEditSession) {
this.provisionEditSession = provisionEditSession;
}
@Override
public void handle(final Message<JsonObject> message) {
final GetFileContentsImpl request = GetFileContentsImpl.fromJsonString(Dto.get(message));
// Resolve the resource IDs from the requested path.
vertx.eventBus().send("tree.getResourceIds",
new JsonObject().putArray("paths", new JsonArray().addString(request.getPath())),
new Handler<Message<JsonObject>>() {
/**
* Sends the contents of a file to the requester. The files will be served out of the
* FileEditSession if the contents are being edited, otherwise they will simply be
* served from disk.
*/
@Override
public void handle(Message<JsonObject> event) {
JsonArray resourceIdArr = event.body.getArray("resourceIds");
Object[] resourceIds = resourceIdArr.toArray();
String resourceId = (String) resourceIds[0];
String currentPath = stripLeadingSlash(request.getPath());
FileEditSession editSession = editSessions.get(resourceId);
// Create the DTO for the file contents response. We will build it up later in the
// method.
String mimeType = MimeTypes.guessMimeType(currentPath, false);
FileContentsImpl fileContentsDto =
FileContentsImpl.make().setMimeType(mimeType).setPath(currentPath);
if (editSession == null) {
// We need to start a new edit session.
String text = "";
File file = new File(currentPath);
try {
text = Files.toString(file, Charsets.UTF_8);
} catch (IOException e) {
logger.error(
String.format("Failed to read text contents for path [%s]", currentPath));
// Send back a no file indicating that file does not exist.
sendContent(message, currentPath, null, false);
return;
}
if (provisionEditSession) {
// Provision a new edit session and fall through.
editSession =
new FileEditSessionImpl(resourceId, currentPath, text, null, logger);
editSessions.put(resourceId, editSession);
// Update the last opened file.
vertx.eventBus().send("workspace.setLastOpenedFile",
new JsonObject().putString("resourceId", resourceId));
} else {
// Just send the contents as they were read from disk and return.
String dataBase64 = MimeTypes.looksLikeImage(mimeType) ? StringUtils
.newStringUtf8(Base64.encodeBase64(text.getBytes())) : null;
fileContentsDto.setContents(dataBase64).setContentType(
dataBase64 == null ? ContentType.UNKNOWN_BINARY : ContentType.IMAGE);
sendContent(message, currentPath, fileContentsDto, true);
return;
}
}
// Populate file contents response Dto with information from the edit session.
fileContentsDto.setFileEditSessionKey(resourceId)
.setCcRevision(editSession.getDocument().getCcRevision())
.setContents(editSession.getContents()).setContentType(ContentType.TEXT);
// Extract the contents from the edit session before sending.
sendContent(message, currentPath, fileContentsDto, true);
}
});
}
}
void sendContent(
Message<JsonObject> event, String path, FileContents fileContents, boolean fileExists) {
GetFileContentsResponseImpl response = GetFileContentsResponseImpl.make()
.setFileExists(fileExists).setFileContents((FileContentsImpl) fileContents);
event.reply(Dto.wrap(response.toJson()));
}
/**
* Iterates through all open, dirty edit sessions and saves them to disk.
*/
class FileSaver implements Handler<Message<JsonObject>> {
@Override
public void handle(Message<JsonObject> message) {
saveAll();
}
void saveAll() {
Set<Entry<String, FileEditSession>> entries = editSessions.entrySet();
Iterator<Entry<String, FileEditSession>> entryIter = entries.iterator();
final JsonArray resourceIds = new JsonArray();
while (entryIter.hasNext()) {
Entry<String, FileEditSession> entry = entryIter.next();
String resourceId = entry.getKey();
FileEditSession editSession = entry.getValue();
if (editSession.hasChanges()) {
resourceIds.addString(resourceId);
}
}
// Resolve the current paths of opened files in case they have been moved.
eb.send("tree.getCurrentPaths", new JsonObject().putArray("resourceIds", resourceIds),
new Handler<Message<JsonObject>>() {
@Override
public void handle(Message<JsonObject> event) {
JsonArray currentPaths = event.body.getArray("paths");
Iterator<Object> pathIter = currentPaths.iterator();
Iterator<Object> resourceIter = resourceIds.iterator();
if (currentPaths.size() != resourceIds.size()) {
logger.error(String.format(
"Received [%d] paths in response to a request specifying [%d] resourceIds",
currentPaths.size(), resourceIds.size()));
}
// Iterate through all the resolved paths and save the files to disk.
while (pathIter.hasNext()) {
String path = (String) pathIter.next();
String resourceId = (String) resourceIter.next();
if (path != null) {
FileEditSession editSession = editSessions.get(resourceId);
if (editSession != null) {
try {
editSession.save(stripLeadingSlash(path));
} catch (IOException e) {
logger.error(String.format("Failed to save file [%s]", path), e);
}
}
}
}
}
});
}
}
/**
* Removes an edit session, and notifies clients that they should reload their opened document.
*/
class EditSessionRemover implements Handler<Message<JsonObject>> {
@Override
public void handle(Message<JsonObject> message) {
String resourceId = message.body.getString("resourceId");
if (resourceId != null) {
editSessions.remove(resourceId);
}
// TODO: Notify clients to reload their opened document.
}
}
private final Map<String, FileEditSession> editSessions = new HashMap<String, FileEditSession>();
private final FileSaver fileSaver = new FileSaver();
private final DocumentMutator documentMutator = new DocumentMutator();
private String addressBase;
@Override
public void start() {
super.start();
this.addressBase = getOptionalStringConfig("address", "documents");
vertx.eventBus().registerHandler(addressBase + ".mutate", documentMutator);
vertx.eventBus().registerHandler(
addressBase + ".createEditSession", new EditSessionCreator(true));
vertx.eventBus().registerHandler(
addressBase + ".getFileContents", new EditSessionCreator(false));
vertx.eventBus().registerHandler(addressBase + ".saveAll", fileSaver);
vertx.eventBus().registerHandler(addressBase + ".removeEditSession", new EditSessionRemover());
vertx.eventBus().registerHandler(addressBase + ".recoverMissedDocop", new DocOpRecoverer());
// TODO: Handle content changes on disk and synthesize a docop to apply to the in-memory edit
// session, and broadcast to all clients.
// Set up a regular save interval to flush to disk.
vertx.setPeriodic(1500, new Handler<Long>() {
@Override
public void handle(Long event) {
fileSaver.saveAll();
}
});
}
/**
* This verticle needs to take "workspace rooted paths", which begin with a leading '/', and make
* them relative to the base directory for the associated classloader for this verticle. That is,
* assume that all paths are relative to what our local view of '.' is on the file system. We
* simply strip the leading slash.
*/
private String stripLeadingSlash(String relative) {
if (relative == null) {
return null;
} else {
return relative.charAt(0) == '/' ? relative.substring(1) : relative;
}
}
}