CLOUD: Add GoogleDriveUploadRequest

Includes NetworkReadStream PATCH method and Headers remembering feature.

8 files changed, 481 insertions, 11 deletions

diff --git a/backends/cloud/googledrive/googledrivestorage.cpp b/backends/cloud/googledrive/googledrivestorage.cpp
index d9db4f7dd8..bb762a4d90 100644
--- a/backends/cloud/googledrive/googledrivestorage.cpp
+++ b/backends/cloud/googledrive/googledrivestorage.cpp
@@ -37,6 +37,7 @@
 #include "googledrivelistdirectoryrequest.h"
 #include "googledrivestreamfilerequest.h"
 #include "googledrivedownloadrequest.h"
+#include "googledriveuploadrequest.h"
 
 namespace Cloud {
 namespace GoogleDrive {
@@ -230,8 +231,7 @@ Networking::Request *GoogleDriveStorage::listDirectoryById(Common::String id, Li
 }
 
 Networking::Request *GoogleDriveStorage::upload(Common::String path, Common::SeekableReadStream *contents, UploadCallback callback, Networking::ErrorCallback errorCallback) {
-	//return addRequest(new GoogleDriveUploadRequest(this, path, contents, callback, errorCallback));
-	return nullptr; //TODO
+	return addRequest(new GoogleDriveUploadRequest(this, path, contents, callback, errorCallback));	
 }
 
 Networking::Request *GoogleDriveStorage::streamFile(Common::String path, Networking::NetworkReadStreamCallback outerCallback, Networking::ErrorCallback errorCallback) {	
diff --git a/backends/cloud/googledrive/googledriveuploadrequest.cpp b/backends/cloud/googledrive/googledriveuploadrequest.cpp
new file mode 100644
index 0000000000..7ab9f2e3c0
--- /dev/null
+++ b/backends/cloud/googledrive/googledriveuploadrequest.cpp
@@ -0,0 +1,341 @@
+/* ScummVM - Graphic Adventure Engine
+*
+* ScummVM is the legal property of its developers, whose names
+* are too numerous to list here. Please refer to the COPYRIGHT
+* file distributed with this source distribution.
+*
+* This program is free software; you can redistribute it and/or
+* modify it under the terms of the GNU General Public License
+* as published by the Free Software Foundation; either version 2
+* of the License, or (at your option) any later version.
+*
+* This program is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+* GNU General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License
+* along with this program; if not, write to the Free Software
+* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+*
+*/
+
+#include "backends/cloud/googledrive/googledriveuploadrequest.h"
+#include "backends/cloud/googledrive/googledrivestorage.h"
+#include "backends/cloud/iso8601.h"
+#include "backends/cloud/storage.h"
+#include "backends/networking/curl/connectionmanager.h"
+#include "backends/networking/curl/curljsonrequest.h"
+#include "backends/networking/curl/networkreadstream.h"
+#include "common/json.h"
+#include "common/debug.h"
+#include "googledrivetokenrefresher.h"
+
+namespace Cloud {
+namespace GoogleDrive {
+
+GoogleDriveUploadRequest::GoogleDriveUploadRequest(GoogleDriveStorage *storage, Common::String path, Common::SeekableReadStream *contents, Storage::UploadCallback callback, Networking::ErrorCallback ecb):
+	Networking::Request(nullptr, ecb), _storage(storage), _savePath(path), _contentsStream(contents), _uploadCallback(callback),
+	_workingRequest(nullptr), _ignoreCallback(false) {
+	start();
+}
+
+GoogleDriveUploadRequest::~GoogleDriveUploadRequest() {
+	_ignoreCallback = true;
+	if (_workingRequest) _workingRequest->finish();
+	delete _contentsStream;
+	delete _uploadCallback;
+}
+
+void GoogleDriveUploadRequest::start() {
+	_ignoreCallback = true;
+	if (_workingRequest) _workingRequest->finish();
+	if (!_contentsStream->seek(0)) {
+		warning("GoogleDriveUploadRequest: cannot restart because stream couldn't seek(0)");
+		finishError(Networking::ErrorResponse(this, false, true, "", -1));
+	}
+	_resolvedId = ""; //used to update file contents
+	_parentId = ""; //used to create file within parent directory
+	_serverReceivedBytes = 0;
+	_ignoreCallback = false;
+
+	resolveId();
+}
+
+void GoogleDriveUploadRequest::resolveId() {
+	//check whether such file already exists
+	Storage::UploadCallback innerCallback = new Common::Callback<GoogleDriveUploadRequest, Storage::UploadResponse>(this, &GoogleDriveUploadRequest::idResolvedCallback);
+	Networking::ErrorCallback innerErrorCallback = new Common::Callback<GoogleDriveUploadRequest, Networking::ErrorResponse>(this, &GoogleDriveUploadRequest::idResolveFailedCallback);
+	_workingRequest = _storage->resolveFileId(_savePath, innerCallback, innerErrorCallback);
+}
+
+void GoogleDriveUploadRequest::idResolvedCallback(Storage::UploadResponse response) {
+	_workingRequest = nullptr;
+	if (_ignoreCallback) return;
+	_resolvedId = response.value.id();
+	startUpload();
+}
+
+void GoogleDriveUploadRequest::idResolveFailedCallback(Networking::ErrorResponse error) {
+	_workingRequest = nullptr;
+	if (_ignoreCallback) return;
+
+	//not resolved => error or no such file
+	if (error.response.contains("no such file found in its parent directory")) {
+		//parent's id after the '\n'
+		Common::String parentId = error.response;
+		for (uint32 i = 0; i < parentId.size(); ++i)
+			if (parentId[i] == '\n') {
+				parentId.erase(0, i + 1);
+				break;
+			}
+
+		_parentId = parentId;
+		startUpload();
+		return;
+	}
+
+	finishError(error);
+}
+
+void GoogleDriveUploadRequest::startUpload() {
+	Common::String name = _savePath;
+	for (uint32 i = name.size(); i > 0; --i) {
+		if (name[i - 1] == '/' || name[i - 1] == '\\') {
+			name.erase(0, i);
+			break;
+		}
+	}
+
+	Common::String url = "https://www.googleapis.com/upload/drive/v3/files";
+	if (_resolvedId != "") url += "/" + _resolvedId;
+	url += "?uploadType=resumable&fields=id,mimeType,modifiedTime,name,size";
+	Networking::JsonCallback callback = new Common::Callback<GoogleDriveUploadRequest, Networking::JsonResponse>(this, &GoogleDriveUploadRequest::startUploadCallback);
+	Networking::ErrorCallback failureCallback = new Common::Callback<GoogleDriveUploadRequest, Networking::ErrorResponse>(this, &GoogleDriveUploadRequest::startUploadErrorCallback);
+	Networking::CurlJsonRequest *request = new GoogleDriveTokenRefresher(_storage, callback, failureCallback, url.c_str());
+	request->addHeader("Authorization: Bearer " + _storage->accessToken());
+	request->addHeader("Content-Type: application/json");
+	if (_resolvedId != "") request->usePatch();
+
+	Common::JSONObject jsonRequestParameters;
+	if (_resolvedId != "") jsonRequestParameters.setVal("id", new Common::JSONValue(_resolvedId));
+	else {
+		Common::JSONArray parentsArray;
+		parentsArray.push_back(new Common::JSONValue(_parentId));
+		jsonRequestParameters.setVal("parents", new Common::JSONValue(parentsArray));
+	}
+	jsonRequestParameters.setVal("name", new Common::JSONValue(name));
+
+	Common::JSONValue value(jsonRequestParameters);
+	request->addPostField(Common::JSON::stringify(&value));
+
+	_workingRequest = ConnMan.addRequest(request);
+}
+
+void GoogleDriveUploadRequest::startUploadCallback(Networking::JsonResponse response) {
+	_workingRequest = nullptr;
+	if (_ignoreCallback) return;
+
+	Networking::ErrorResponse error(this, false, true, "", -1);
+	Networking::CurlJsonRequest *rq = (Networking::CurlJsonRequest *)response.request;
+	if (rq) {
+		const Networking::NetworkReadStream *stream = rq->getNetworkReadStream();
+		if (stream) {
+			long code = stream->httpResponseCode();
+			Common::String headers = stream->responseHeaders();
+			if (code == 200) {
+				const char *cstr = headers.c_str();
+				const char *position = strstr(cstr, "Location: ");
+
+				if (position) {
+					Common::String result = "";
+					char c;
+					for (const char *i = position + 10; c = *i, c != 0; ++i) {
+						if (c == '\n' || c == '\r') break;
+						result += c;
+					}
+					_uploadUrl = result;
+					uploadNextPart();
+					return;
+				}
+			}
+
+			error.httpResponseCode = code;
+		}
+	}
+
+	Common::JSONValue *json = response.value;	
+	delete json;
+
+	finishError(error);
+}
+
+void GoogleDriveUploadRequest::startUploadErrorCallback(Networking::ErrorResponse error) {
+	_workingRequest = nullptr;
+	if (_ignoreCallback) return;
+	finishError(error);
+}
+
+void GoogleDriveUploadRequest::uploadNextPart() {
+	const uint32 UPLOAD_PER_ONE_REQUEST = 10 * 1024 * 1024;
+	Common::String url = _uploadUrl;
+	
+	Networking::JsonCallback callback = new Common::Callback<GoogleDriveUploadRequest, Networking::JsonResponse>(this, &GoogleDriveUploadRequest::partUploadedCallback);
+	Networking::ErrorCallback failureCallback = new Common::Callback<GoogleDriveUploadRequest, Networking::ErrorResponse>(this, &GoogleDriveUploadRequest::partUploadedErrorCallback);
+	Networking::CurlJsonRequest *request = new GoogleDriveTokenRefresher(_storage, callback, failureCallback, url.c_str());
+	request->addHeader("Authorization: Bearer " + _storage->accessToken());	
+	request->usePut();
+
+	uint32 oldPos = _contentsStream->pos();
+	if (oldPos != _serverReceivedBytes) {
+		if (!_contentsStream->seek(_serverReceivedBytes)) {
+			warning("GoogleDriveUploadRequest: cannot upload because stream couldn't seek(%u)", _serverReceivedBytes);
+			finishError(Networking::ErrorResponse(this, false, true, "", -1));
+			return;
+		}
+		oldPos = _serverReceivedBytes;
+	}
+
+	byte *buffer = new byte[UPLOAD_PER_ONE_REQUEST];
+	uint32 size = _contentsStream->read(buffer, UPLOAD_PER_ONE_REQUEST);
+	request->setBuffer(buffer, size);
+
+	//request->addHeader(Common::String::format("Content-Length: %u", size));
+	if (_uploadUrl != "")
+		request->addHeader(Common::String::format("Content-Range: bytes %u-%u/%u", oldPos, _contentsStream->pos()-1, _contentsStream->size()));	;
+	
+	_workingRequest = ConnMan.addRequest(request);
+}
+
+namespace {
+uint64 atoull(Common::String s) {
+	uint64 result = 0;
+	for (uint32 i = 0; i < s.size(); ++i) {
+		if (s[i] < '0' || s[i] > '9') break;
+		result = result * 10L + (s[i] - '0');
+	}
+	return result;
+}
+}
+
+bool GoogleDriveUploadRequest::handleHttp308(const Networking::NetworkReadStream *stream) {
+	//308 Resume Incomplete, with Range: X-Y header
+	if (!stream) return false;
+	if (stream->httpResponseCode() != 308) return false; //seriously	
+	
+	Common::String headers = stream->responseHeaders();
+	const char *cstr = headers.c_str();	
+	for (int rangeTry = 0; rangeTry < 2; ++rangeTry) {
+		const char *needle = (rangeTry==0 ? "Range: 0-" : "Range: bytes=0-");
+		uint32 needleLength = (rangeTry == 0 ? 9 : 15);
+
+		const char *position = strstr(cstr, needle); //if it lost the first part, I refuse to talk with it
+
+		if (position) {
+			Common::String result = "";
+			char c;
+			for (const char *i = position + needleLength; c = *i, c != 0; ++i) {
+				if (c == '\n' || c == '\r') break;
+				result += c;
+			}
+			_serverReceivedBytes = atoull(result) + 1;			
+			uploadNextPart();
+			return true;
+		}
+	}
+
+	return false;
+}
+
+void GoogleDriveUploadRequest::partUploadedCallback(Networking::JsonResponse response) {	
+	_workingRequest = nullptr;
+	if (_ignoreCallback) return;
+		
+	Networking::ErrorResponse error(this, false, true, "", -1);
+	Networking::CurlJsonRequest *rq = (Networking::CurlJsonRequest *)response.request;	
+	if (rq) {
+		const Networking::NetworkReadStream *stream = rq->getNetworkReadStream();
+		if (stream) {
+			long code = stream->httpResponseCode();
+			error.httpResponseCode = code;
+			if (code == 308 && handleHttp308(stream)) {
+				delete (Common::JSONValue *)response.value;
+				return;
+			}
+		}
+	}
+
+	Common::JSONValue *json = response.value;
+	if (json) {
+		debug("%s", json->stringify(true).c_str());		
+		if (json->isObject()) {
+			Common::JSONObject object = json->asObject();
+
+			if (object.contains("error")) {
+				warning("GoogleDrive returned error: %s", json->stringify(true).c_str());
+				delete json;
+				error.response = json->stringify(true);
+				finishError(error);
+				return;
+			}
+
+			if (object.contains("id") && object.contains("name")) {
+				//finished
+				Common::String id = object.getVal("id")->asString();
+				Common::String name = object.getVal("name")->asString();
+				bool isDirectory = (object.getVal("mimeType")->asString() == "application/vnd.google-apps.folder");
+				uint32 size = 0, timestamp = 0;
+				if (object.contains("size") && object.getVal("size")->isString())
+					size = atoull(object.getVal("size")->asString());
+				if (object.contains("modifiedTime") && object.getVal("modifiedTime")->isString())
+					timestamp = ISO8601::convertToTimestamp(object.getVal("modifiedTime")->asString());
+
+				//as we list directory by id, we can't determine full path for the file, so we leave it empty
+				finishSuccess(StorageFile(id, _savePath, name, size, timestamp, isDirectory));
+				return;
+			}
+		}
+
+		if (_contentsStream->eos() || _contentsStream->pos() >= _contentsStream->size() - 1) {
+			warning("no file info to return");
+			finishSuccess(StorageFile(_savePath, 0, 0, false));
+		} else {
+			uploadNextPart();
+		}
+	} else {
+		warning("null, not json");
+		finishError(error);
+	}
+
+	delete json;
+}
+
+void GoogleDriveUploadRequest::partUploadedErrorCallback(Networking::ErrorResponse error) {	
+	_workingRequest = nullptr;
+	if (_ignoreCallback) return;
+	
+	Networking::CurlJsonRequest *rq = (Networking::CurlJsonRequest *)error.request;
+	if (rq) {
+		const Networking::NetworkReadStream *stream = rq->getNetworkReadStream();
+		if (stream) {
+			long code = stream->httpResponseCode();			
+			if (code == 308 && handleHttp308(stream)) {				
+				return;
+			}
+		}
+	}
+
+	finishError(error);
+}
+
+void GoogleDriveUploadRequest::handle() {}
+
+void GoogleDriveUploadRequest::restart() { start(); }
+
+void GoogleDriveUploadRequest::finishSuccess(StorageFile file) {
+	Request::finishSuccess();
+	if (_uploadCallback) (*_uploadCallback)(Storage::UploadResponse(this, file));
+}
+
+} // End of namespace GoogleDrive
+} // End of namespace Cloud
diff --git a/backends/cloud/googledrive/googledriveuploadrequest.h b/backends/cloud/googledrive/googledriveuploadrequest.h
new file mode 100644
index 0000000000..e417403542
--- /dev/null
+++ b/backends/cloud/googledrive/googledriveuploadrequest.h
@@ -0,0 +1,70 @@
+/* ScummVM - Graphic Adventure Engine
+*
+* ScummVM is the legal property of its developers, whose names
+* are too numerous to list here. Please refer to the COPYRIGHT
+* file distributed with this source distribution.
+*
+* This program is free software; you can redistribute it and/or
+* modify it under the terms of the GNU General Public License
+* as published by the Free Software Foundation; either version 2
+* of the License, or (at your option) any later version.
+*
+* This program is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+* GNU General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License
+* along with this program; if not, write to the Free Software
+* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+*
+*/
+
+#ifndef BACKENDS_CLOUD_GOOGLEDRIVE_GOOGLEDRIVEUPLOADREQUEST_H
+#define BACKENDS_CLOUD_GOOGLEDRIVE_GOOGLEDRIVEUPLOADREQUEST_H
+
+#include "backends/cloud/storage.h"
+#include "backends/networking/curl/curljsonrequest.h"
+#include "backends/networking/curl/request.h"
+#include "common/callback.h"
+
+namespace Cloud {
+namespace GoogleDrive {
+class GoogleDriveStorage;
+
+class GoogleDriveUploadRequest: public Networking::Request {
+	GoogleDriveStorage *_storage;
+	Common::String _savePath;
+	Common::SeekableReadStream *_contentsStream;
+	Storage::UploadCallback _uploadCallback;
+	Request *_workingRequest;
+	bool _ignoreCallback;
+	Common::String _resolvedId, _parentId;
+	Common::String _uploadUrl;
+	uint64 _serverReceivedBytes;
+	
+	void start();
+	void resolveId();
+	void idResolvedCallback(Storage::UploadResponse response);
+	void idResolveFailedCallback(Networking::ErrorResponse error);
+	void startUpload();
+	void startUploadCallback(Networking::JsonResponse response);
+	void startUploadErrorCallback(Networking::ErrorResponse error);
+	void uploadNextPart();
+	void partUploadedCallback(Networking::JsonResponse response);
+	void partUploadedErrorCallback(Networking::ErrorResponse error);
+	bool handleHttp308(const Networking::NetworkReadStream *stream);
+	void finishSuccess(StorageFile status);
+
+public:
+	GoogleDriveUploadRequest(GoogleDriveStorage *storage, Common::String path, Common::SeekableReadStream *contents, Storage::UploadCallback callback, Networking::ErrorCallback ecb);
+	virtual ~GoogleDriveUploadRequest();
+
+	virtual void handle();
+	virtual void restart();
+};
+
+} // End of namespace GoogleDrive
+} // End of namespace Cloud
+
+#endif
diff --git a/backends/module.mk b/backends/module.mk
index 817c82970c..95334fef65 100644
--- a/backends/module.mk
+++ b/backends/module.mk
@@ -40,6 +40,7 @@ MODULE_OBJS += \
 	cloud/googledrive/googledrivestorage.o \
 	cloud/googledrive/googledrivestreamfilerequest.o \
 	cloud/googledrive/googledrivetokenrefresher.o \
+	cloud/googledrive/googledriveuploadrequest.o \
 	cloud/onedrive/onedrivestorage.o \
 	cloud/onedrive/onedrivecreatedirectoryrequest.o \
 	cloud/onedrive/onedrivetokenrefresher.o \
diff --git a/backends/networking/curl/curlrequest.cpp b/backends/networking/curl/curlrequest.cpp
index a3f997a4ff..6ef0e346af 100644
--- a/backends/networking/curl/curlrequest.cpp
+++ b/backends/networking/curl/curlrequest.cpp
@@ -31,7 +31,8 @@
 namespace Networking {
 
 CurlRequest::CurlRequest(DataCallback cb, ErrorCallback ecb, Common::String url):
-	Request(cb, ecb), _url(url), _stream(nullptr), _headersList(nullptr), _bytesBuffer(nullptr), _bytesBufferSize(0), _uploading(false) {}
+	Request(cb, ecb), _url(url), _stream(nullptr), _headersList(nullptr), _bytesBuffer(nullptr),
+	_bytesBufferSize(0), _uploading(false), _usingPatch(false) {}
 
 CurlRequest::~CurlRequest() {
 	delete _stream;
@@ -40,11 +41,10 @@ CurlRequest::~CurlRequest() {
 
 NetworkReadStream *CurlRequest::makeStream() {
 	if (_bytesBuffer)
-		return new NetworkReadStream(_url.c_str(), _headersList, _bytesBuffer, _bytesBufferSize, _uploading, true);
-	return new NetworkReadStream(_url.c_str(), _headersList, _postFields, _uploading);
+		return new NetworkReadStream(_url.c_str(), _headersList, _bytesBuffer, _bytesBufferSize, _uploading, _usingPatch, true);
+	return new NetworkReadStream(_url.c_str(), _headersList, _postFields, _uploading, _usingPatch);
 }
 
-
 void CurlRequest::handle() {
 	if (!_stream) _stream = makeStream();	
 
@@ -99,6 +99,8 @@ void CurlRequest::setBuffer(byte *buffer, uint32 size) {
 
 void CurlRequest::usePut() { _uploading = true; }
 
+void CurlRequest::usePatch() { _usingPatch = true; }
+
 NetworkReadStreamResponse CurlRequest::execute() {
 	if (!_stream) {
 		_stream = makeStream();
diff --git a/backends/networking/curl/curlrequest.h b/backends/networking/curl/curlrequest.h
index 5737078b2d..5c06b58107 100644
--- a/backends/networking/curl/curlrequest.h
+++ b/backends/networking/curl/curlrequest.h
@@ -45,6 +45,7 @@ protected:
 	byte *_bytesBuffer;
 	uint32 _bytesBufferSize;
 	bool _uploading; //using PUT method
+	bool _usingPatch; //using PATCH method
 
 	virtual NetworkReadStream *makeStream();
 
@@ -70,6 +71,9 @@ public:
 	/** Remembers to use PUT method when it would create NetworkReadStream. */
 	virtual void usePut();
 
+	/** Remembers to use PATCH method when it would create NetworkReadStream. */
+	virtual void usePatch();
+
 	/**
 	 * Starts this Request with ConnMan.
 	 * @return its NetworkReadStream in NetworkReadStreamResponse.
diff --git a/backends/networking/curl/networkreadstream.cpp b/backends/networking/curl/networkreadstream.cpp
index 283e5e667f..ccfb3d5a29 100644
--- a/backends/networking/curl/networkreadstream.cpp
+++ b/backends/networking/curl/networkreadstream.cpp
@@ -41,16 +41,24 @@ static size_t curlReadDataCallback(char *d, size_t n, size_t l, void *p) {
 	return 0;
 }
 
-NetworkReadStream::NetworkReadStream(const char *url, curl_slist *headersList, Common::String postFields, bool uploading):
-	NetworkReadStream(url, headersList, (byte *)postFields.c_str(), postFields.size(), uploading, false) {}
+static size_t curlHeadersCallback(char *d, size_t n, size_t l, void *p) {
+	NetworkReadStream *stream = (NetworkReadStream *)p;
+	if (stream) return stream->addResponseHeaders(d, n*l);
+	return 0;
+}
 
-NetworkReadStream::NetworkReadStream(const char *url, curl_slist *headersList, byte *buffer, uint32 bufferSize, bool uploading, bool post):
+NetworkReadStream::NetworkReadStream(const char *url, curl_slist *headersList, Common::String postFields, bool uploading, bool usingPatch):
+	NetworkReadStream(url, headersList, (byte *)postFields.c_str(), postFields.size(), uploading, usingPatch, false) {}
+
+NetworkReadStream::NetworkReadStream(const char *url, curl_slist *headersList, byte *buffer, uint32 bufferSize, bool uploading, bool usingPatch, bool post):
 	_easy(0), _eos(false), _requestComplete(false), _sendingContentsBuffer(nullptr), _sendingContentsSize(0), _sendingContentsPos(0) {
 	_easy = curl_easy_init();
 	curl_easy_setopt(_easy, CURLOPT_WRITEFUNCTION, curlDataCallback);
 	curl_easy_setopt(_easy, CURLOPT_WRITEDATA, this); //so callback can call us
 	curl_easy_setopt(_easy, CURLOPT_PRIVATE, this); //so ConnectionManager can call us when request is complete
 	curl_easy_setopt(_easy, CURLOPT_HEADER, 0L);
+	curl_easy_setopt(_easy, CURLOPT_HEADERDATA, this);
+	curl_easy_setopt(_easy, CURLOPT_HEADERFUNCTION, curlHeadersCallback);
 	curl_easy_setopt(_easy, CURLOPT_URL, url);
 	curl_easy_setopt(_easy, CURLOPT_VERBOSE, 0L);
 	curl_easy_setopt(_easy, CURLOPT_FOLLOWLOCATION, 1L); //probably it's OK to have it always on
@@ -61,6 +69,8 @@ NetworkReadStream::NetworkReadStream(const char *url, curl_slist *headersList, b
 		curl_easy_setopt(_easy, CURLOPT_READFUNCTION, curlReadDataCallback);
 		_sendingContentsBuffer = buffer;
 		_sendingContentsSize = bufferSize;
+	} else if (usingPatch) {		
+		curl_easy_setopt(_easy, CURLOPT_CUSTOMREQUEST, "PATCH");
 	} else {
 		if (post || bufferSize != 0) {
 			curl_easy_setopt(_easy, CURLOPT_POSTFIELDSIZE, bufferSize);
@@ -101,6 +111,20 @@ long NetworkReadStream::httpResponseCode() const {
 	return responseCode;
 }
 
+Common::String NetworkReadStream::currentLocation() const {
+	Common::String result = "";
+	if (_easy) {
+		char *pointer;
+		curl_easy_getinfo(_easy, CURLINFO_EFFECTIVE_URL, &pointer);
+		result = Common::String(pointer);
+	}
+	return result;
+}
+
+Common::String NetworkReadStream::responseHeaders() const {
+	return _responseHeaders;
+}
+
 uint32 NetworkReadStream::fillWithSendingContents(char *bufferToFill, uint32 maxSize) {
 	uint32 size = _sendingContentsSize - _sendingContentsPos;
 	if (size > maxSize) size = maxSize;
@@ -111,4 +135,9 @@ uint32 NetworkReadStream::fillWithSendingContents(char *bufferToFill, uint32 max
 	return size;
 }
 
+uint32 NetworkReadStream::addResponseHeaders(char *buffer, uint32 size) {
+	_responseHeaders += Common::String(buffer, size);
+	return size;
+}
+
 } // End of namespace Cloud
diff --git a/backends/networking/curl/networkreadstream.h b/backends/networking/curl/networkreadstream.h
index d48d01b198..991fdb346d 100644
--- a/backends/networking/curl/networkreadstream.h
+++ b/backends/networking/curl/networkreadstream.h
@@ -38,10 +38,11 @@ class NetworkReadStream: public Common::MemoryReadWriteStream {
 	byte *_sendingContentsBuffer;
 	uint32 _sendingContentsSize;
 	uint32 _sendingContentsPos;
+	Common::String _responseHeaders;
 
 public:	
-	NetworkReadStream(const char *url, curl_slist *headersList, Common::String postFields, bool uploading = false);
-	NetworkReadStream(const char *url, curl_slist *headersList, byte *buffer, uint32 bufferSize, bool uploading = false, bool post = true);
+	NetworkReadStream(const char *url, curl_slist *headersList, Common::String postFields, bool uploading = false, bool usingPatch = false);
+	NetworkReadStream(const char *url, curl_slist *headersList, byte *buffer, uint32 bufferSize, bool uploading = false, bool usingPatch = false, bool post = true);
 	virtual ~NetworkReadStream();
 
 	/**
@@ -87,6 +88,21 @@ public:
 	long httpResponseCode() const;
 
 	/**
+	* Return current location URL from inner CURL handle.
+	* "" is returned to indicate there is no inner handle.
+	*
+	* @note This method should be called when eos() == true.
+	*/
+	Common::String currentLocation() const;
+
+	/**
+	* Return response headers.
+	*
+	* @note This method should be called when eos() == true.
+	*/
+	Common::String responseHeaders() const;
+
+	/**
 	 * Fills the passed buffer with _sendingContentsBuffer contents.
 	 * It works similarly to read(), expect it's not for reading
 	 * Stream's contents, but for sending our own data to the server.
@@ -94,6 +110,13 @@ public:
 	 * @returns how many bytes were actually read (filled in)
 	 */
 	uint32 fillWithSendingContents(char *bufferToFill, uint32 maxSize);
+
+	/**
+	* Remembers headers returned to CURL in server's response.
+	*
+	* @returns how many bytes were actually read
+	*/
+	uint32 addResponseHeaders(char *buffer, uint32 size);
 };
 
 } // End of namespace Networking