A VFS_datastore subclass for accessing data in Mongo. More...

#include <VFS_mongo.h>

Inheritance diagram for VFS_mongo:

Public Member Functions
Q_INVOKABLE	VFS_mongo (QString uri, QString db, QString collection, quint64 size=VFS_datastore_cache::DEFAULT_DATACACHE_SIZE, bool debug=false, int flushInterval=5000, int expireInterval=60000, bool createCollection=false)
	Create a VFS_Mongo node. More...

virtual	~VFS_mongo ()

virtual QString	reportDetails ()
	Report the current cache usage. More...

Public Member Functions inherited from VFS_datastore
	VFS_datastore (quint64 size, bool debug=false)

virtual	~VFS_datastore ()

virtual VFS_node *	find (VFS_request *r)

virtual bool	isContainer ()
	All datastore subclasses are containers. More...

Public Member Functions inherited from VFS_node
Q_INVOKABLE	VFS_node ()
	The VFS_node constructor will add its instance to the VFS_node::__allNodes global node registry, observing thread safety rules. More...

virtual	~VFS_node ()
	VFS_node destructor. More...

virtual VFS_node *	append (QString name, VFS_node *node, bool containerCheck=true, QString user="server")
	Append a VFS_node as a child of this node. More...

QString	className ()
	Return the class name of a node. More...

virtual VFS_request *	createRequest (VFS_request::requestType type, QString path, QString user="unknown", QJsonDocument data=QJsonDocument(), QJsonObject metadata=QJsonObject(), bool dontDelete=false)
	Create a new VFS_request with this object as _origin. More...

VFS_node *	find (QString path)
	Find a node by string path. More...

VFS_node *	findChildWithName (QString name)
	Check if a child with a given name exists. More...

virtual VFS_node *	mount ()
	Mount this node. More...

QString	uniqueChildName (QString name)
	Generate a unique child name. More...

virtual VFS_node *	unmount ()
	Unmount this node. More...

virtual bool	validChildName (QString name)
	Check if a node name is valid. More...

Protected Member Functions
bool	createCollection (QString name)
	Create a collection. More...

bool	createDocument (QString path, QJsonObject o, quint64 &size, bool container=false)
	Create a new document in the database if it doesn't exist. More...

virtual QByteArray	icon ()
	The "disk" icon found in the VFS_icons library. More...

virtual void	ls (VFS_request *r)
	List the contents of a collection using a Mongo find() on the path. More...

virtual void	metadata (VFS_request *r)
	Fetch the metadata for a database document. More...

virtual void	read (VFS_request *r)
	Read the contents of a database document. More...

QJsonObject	readDocument (QString path, quint64 &size, bool &container)
	Search for a document by "_path" in the database. More...

bool	removeDocument (QString path)
	Remove a document from the database. More...

virtual void	rm (VFS_request *r)
	Attempt to delete a file. More...

virtual void	submit (VFS_request *r)
	Submit data to a file, applying the data as a diff. More...

virtual void	subscribe (VFS_request *r)
	Subscribe to changes on a database document. More...

virtual void	write (VFS_request *r)
	Write data to a database document. More...

quint64	writeDocument (QString path, QJsonObject o, bool container=false)
	Update a document in the database. More...

Protected Member Functions inherited from VFS_node
virtual void	aclDefaults (VFS_request *r)
	Return default values and features associated wth this node. More...

void	addACLDefault (QJsonObject &acl, bool value, QString description="")
	Add a default value to the acl object. More...

void	addACLFeature (QJsonObject &acl, QString feature, bool value, QString description="")
	Add a feature to the acl object. More...

void	addACLFeatureGroup (QJsonObject &acl, QString feature, QString group, bool value)
	Add a feature group to the acl object. More...

void	addACLFeatureUser (QJsonObject &acl, QString feature, QString user, bool value)
	Add a feature user to the acl object. More...

void	addACLGroup (QJsonObject &acl, QString group, bool value)
	Add a group to the acl object. More...

void	addACLUser (QJsonObject &acl, QString user, bool value)
	Add a user to the acl object. More...

virtual void	issueRequest (VFS_node target, VFS_request t)
	Issue a VFS_request to its target. More...

virtual void	issueRequest (VFS_request *t)
	A convenience function. More...

virtual void	issueResponse (VFS_request *t)
	Once a request has been completed, issue a response. More...

virtual void	releaseLock (VFS_request *r)
	Release a lock on this node. More...

virtual void	report (VFS_request *r)
	Report debugging information about the current state of this node. More...

virtual void	requestLock (VFS_request *r)
	Request a lock on this node. More...

virtual void	unsubscribe (VFS_request *r)
	Remove an entry from this node's _subscription list. More...

virtual void	unsubscribePath (QString path)
	Unsubscribe all references to a subpath. More...

Protected Attributes
int	_expireInterval
	Interval for cache entries to expire, in milliseconds. More...

int	_flushInterval
	Interval for cache entries to flush, in milliseconds. More...

Protected Attributes inherited from VFS_datastore
VFS_datastore_cache	_cache
	The data cache. More...

bool	_debug
	Debug mode. More...

Protected Attributes inherited from VFS_node
VFS_children	_children
	This node's children. More...

QMutex	_lock
	A recursive mutex that is local to this node. More...

VFS_subscriptionType	_subscribers
	This node's subscribers. These subscribers will receive diff notifications. More...

Private Attributes
client	_client
	The Mongo (mongocxx) client object. More...

QString	_collection
	The collection to use. More...

bool	_createCollection
	If a reference is made to a non-existent collection, create it, or throw an error. More...

database	_database
	The Mongo (mongocxx) database object. More...

QString	_databaseName
	The name of the database to use. More...

QString	_url
	The database url for this node to connect to, for instance mongodb://localhost:27017. More...

Static Private Attributes
static instance	_instance = std::move(mongocxx::instance::current())
	The global mongocxx instance. There should only ever be one of these. More...

Friends
class	VFS_mongo_cache_entry

Additional Inherited Members
Public Slots inherited from VFS_node
virtual void	applyDiff (VFS_request *r)
	Apply a diff received via subscription. More...

virtual void	executeRequest (VFS_request *t)
	Based on the VFS_request::requestType, execute the function associated with an operation. More...

void	notifySubscribers (VFS_node origin, VFS_request t)
	Propagate a diff to subscribers. More...

virtual void	receiveResponse (VFS_request *t)
	Once a VFS_request has been completed, a response will be issued back to its _origin. More...

void	remove (bool andDelete)
	Remove a child node. More...

virtual void	remove (VFS_node node=nullptr, QString name=nullptr, QString user="server")
	Remove a child node from this node. More...

virtual void	subtreeRequest (VFS_request *t)
	find() the target of a VFS_request, and execute the request More...

virtual void	unsubscribeAll (VFS_node *n)
	Remove all references to a subscriber from this node. More...

Signals inherited from VFS_node
void	diff (VFS_node origin, VFS_request t)
	Emit a diff, which will trigger notifySubscribers() for a mounted node. More...

void	finished (bool andDelete=false)
	Emitted if a thread fails to create its node, or a node is rm()'d, or any other reason a node has completed its lifecycle. It is deleted if `andDelete==true`. More...

void	mounted ()
	Emitted when a node is mount()ed. More...

void	unmounted (VFS_node *self)
	Emitted when a node is unmount()ed. More...

Static Public Member Functions inherited from VFS_datastore
static QString	applyDeltaDiff (QString data, QJsonObject delta, QString trace="", QString user="server")
	Apply a delta diff to a json object. More...

static QJsonObject	applyJsonDiff (QJsonObject obj, QJsonObject diff, QString trace="", QString user="server")
	Apply a json diff to a json object. More...

Static Public Member Functions inherited from VFS_node
static bool	__isNode (VFS_node *)
	Check to see if a node is in the global registry. More...

static QString	code (QString nodename, QString libname, QString &error)
	Fetch code or any other resource from a node. More...

Detailed Description

A VFS_datastore subclass for accessing data in Mongo.

This plugin requires the mongocxx driver.

This plugin is a drop-in replacement for VFS_HD. It will append a _path field to documents and use that field to emulate a filesystem. Basically _id fields are ignored, and a regex is performed on path values to create listable directories.

The _path field will not be visible in returned documents, but it will appear if a mongo query happens outside of the VFS.

It is recommended to create an index on the _path field. The first time the node is used on a collection, if the collection does not exist it will create the collection and the index if the createCollection flag is set.

More complex queries are possible using the VFS_mongoRDBM plugin, which is in a different repository.

See also: Installing the mongocxx driver

Definition at line 42 of file VFS_mongo.h.

Constructor & Destructor Documentation

◆ VFS_mongo()

VFS_mongo::VFS_mongo	(	QString	url,
		QString	db,
		QString	collection,
		quint64	size = `VFS_datastore_cache::DEFAULT_DATACACHE_SIZE`,
		bool	debug = `false`,
		int	flushInterval = `5000`,
		int	expireInterval = `60000`,
		bool	createCollection = `false`
	)

explicit

Create a VFS_Mongo node.

Parameters

url	The Mongo database uri, for instance "mongodb://localhost:27017"
db	The database name
collection	The collection to use
size	The cache size
debug	Verbose debugging
flushInterval	Interval to flush to the database, in milliseconds.
expireInterval	Interval to expire cache entries, in milliseconds.
createCollection	If a reference is made to a non-existent collection, create it, or throw an error.

Definition at line 261 of file VFS_mongo.cpp.

◆ ~VFS_mongo()

VFS_mongo::~VFS_mongo ( )

virtual

Definition at line 286 of file VFS_mongo.cpp.

Member Function Documentation

◆ createCollection()

bool VFS_mongo::createCollection ( QString name )

protected

Create a collection.

Parameters

name	The collection name.

Returns: Success or failure of the creation request.

Definition at line 488 of file VFS_mongo.cpp.

◆ createDocument()

bool VFS_mongo::createDocument	(	QString	path,
		QJsonObject	o,
		quint64 &	size,
		bool	container = `false`
	)

protected

Create a new document in the database if it doesn't exist.

Parameters

path	The "path" to write to, which will become a field in the document.
o	The new data to write, as a QJsonObject
size	The size of the created document (when converted to a json object).
container	The container flag (false for files, true for directories)

Exceptions

VFS_mongo_directoryException	The path is empty.
VFS_mongo_collectionException	The collection referenced in the path does not exist.
mongocxx::exception	The mongocxx driver has reported a problem.

Returns: Boolean succes of creating the document

If the document already exists, return false and don't update the existing one.

Definition at line 305 of file VFS_mongo.cpp.

◆ icon()

QByteArray VFS_mongo::icon ( )

protectedvirtual

The "disk" icon found in the VFS_icons library.

Returns: The "disk" icon

See also: VFS_node::icon()

Reimplemented from VFS_node.

Definition at line 553 of file VFS_mongo.cpp.

◆ ls()

void VFS_mongo::ls ( VFS_request * r )

protectedvirtual

List the contents of a collection using a Mongo find() on the path.

Parameters

r	The VFS_request object

The resulting list will be of the form:

{
   "entry1":true,
   "entry2":false,
   ... etc.
}

Where the true and false values correspond to whether an entry is a file or directory, which is determined by the existence of an extension on the filename of the path.

The values are sorted alphabetically by the json serializer.

A file entry itself can be used for ls(), but it will return an empty set.

VFS_mongo::ls() does not use the _cache. It will read the underlying database and block during that time.

Optionally, if r->_metadata["sequence"]==true, the resulting list will be collapsed into a sequence view using rutils::sequenceListing().

See also: VFS_node::ls()

Todo:: Use an aggregator for listing directory contents. For instance, listing the root of a collection will query and return the whole collection and waste a lot of resources.

Reimplemented from VFS_node.

Definition at line 604 of file VFS_mongo.cpp.

◆ metadata()

void VFS_mongo::metadata ( VFS_request * r )

protectedvirtual

Fetch the metadata for a database document.

Parameters

r	The VFS_request object

Uses VFS_node_type::getType() to determine a type for a path.

Reimplemented from VFS_node.

Definition at line 883 of file VFS_mongo.cpp.

◆ read()

void VFS_mongo::read ( VFS_request * r )

protectedvirtual

Read the contents of a database document.

Parameters

r	The VFS_request object

If the entry is already in the cache, return the cached value. Otherwise, create a new VFS_mongo_cache_entry and load data into it.

If r->_metadata["createIfMissing"]==true, and the entry does not exist, the read() will be converted to a write() with a VFS_request::create type.

See also: VFS_node::read(); VFS_HD::read()

Reimplemented from VFS_node.

Definition at line 739 of file VFS_mongo.cpp.

◆ readDocument()

QJsonObject VFS_mongo::readDocument	(	QString	path,
		quint64 &	size,
		bool &	container
	)

protected

Search for a document by "_path" in the database.

Parameters

path	The path to read from / search for
size	The size of the document... written back to the caller
container	The container-ness of the document... written back to the caller

Exceptions

VFS_mongo_collectionException	The collection referenced in the path does not exist.
mongocxx::exception	The mongocxx driver has reported a problem.

Returns: The contents of the document, unless an exception was thrown

On a failure, this will throw an exception.

Definition at line 445 of file VFS_mongo.cpp.

◆ removeDocument()

bool VFS_mongo::removeDocument ( QString path )

protected

Remove a document from the database.

Parameters

path	The "path" to remove, which is queried by mongo

Exceptions

VFS_mongo_directoryException	The path does not have two components.
VFS_mongo_collectionException	The collection referenced in the path does not exist.
mongocxx::exception	The mongocxx driver has reported a problem.

On a failure, this will throw an exception. If a parentField is present, this method will execute a mongocxx::collection::find_one_and_delete() instead of the default mongocxx::collection::delete_one().

Definition at line 413 of file VFS_mongo.cpp.

◆ reportDetails()

QString VFS_mongo::reportDetails ( )

virtual

Report the current cache usage.

Returns: Return cache usage and cache entry count.

Reimplemented from VFS_datastore.

Definition at line 563 of file VFS_mongo.cpp.

◆ rm()

void VFS_mongo::rm ( VFS_request * r )

protectedvirtual

Attempt to delete a file.

Parameters

r	The VFS_request object

Attempt to remove (delete) the file from the database, and set r->_success=true if it was possible. The parent directory has changed, so emit a diff() on the parent to notify any subscribers.

An rm() request with an empty r->_path, following all other VFS conventions, removes the VFS_mongo node from the VFS.

In all cases, remove the cache entry for this path.

See also: VFS_node::rm()

Reimplemented from VFS_node.

Definition at line 980 of file VFS_mongo.cpp.

◆ submit()

void VFS_mongo::submit ( VFS_request * r )

protectedvirtual

Submit data to a file, applying the data as a diff.

Parameters

r	The VFS_request object

Fetch or create a cache entry for this file, and call VFS_mongo_cache_entry::getData(). Apply the r->_data as a diff using VFS_datastore::applyJsonDiff().

If r->_success==true, emit a diff() of the applied data to subscribers.

See also: VFS_mongo::write(); VFS_datastore::applyJsonDiff()

Reimplemented from VFS_node.

Definition at line 913 of file VFS_mongo.cpp.

◆ subscribe()

void VFS_mongo::subscribe ( VFS_request * r )

protectedvirtual

Subscribe to changes on a database document.

Parameters

r	The VFS_request object

VFS_node::subscribe() is called, which will pass metadata through to metadata() and read(), and create an empty file if the entry doesn't exist and r->_metadata["createIfMissing"]==true.

See also: VFS_node::subscribe()

Reimplemented from VFS_node.

Definition at line 1044 of file VFS_mongo.cpp.

◆ write()

void VFS_mongo::write ( VFS_request * r )

protectedvirtual

Write data to a database document.

Parameters

r	The VFS_request object

The contents of the data portion of the document will be entirely replaced by r->_data, converted to a bson object.

Because this is a write() operation, a diff() is emitted.

See also: VFS_mongo::read()

Reimplemented from VFS_node.

Definition at line 815 of file VFS_mongo.cpp.

◆ writeDocument()

quint64 VFS_mongo::writeDocument	(	QString	path,
		QJsonObject	o,
		bool	container = `false`
	)

protected

Update a document in the database.

Parameters

path	The "path" to write to, which will become a field in the document.
o	The new data to write, as a QJsonObject
container	The container flag (false for files, true for directories)

Exceptions

VFS_mongo_directoryException	The path is empty.
VFS_mongo_collectionException	The collection referenced in the path does not exist.
mongocxx::exception	The mongocxx driver has reported a problem.

Returns: The number of bytes written (when converted to a json object)

On a failure, this will throw an exception.

Definition at line 369 of file VFS_mongo.cpp.

Friends And Related Function Documentation

◆ VFS_mongo_cache_entry

friend class VFS_mongo_cache_entry

friend

Definition at line 46 of file VFS_mongo.h.

Member Data Documentation

◆ _client

client VFS_mongo::_client

private

The Mongo (mongocxx) client object.

Definition at line 85 of file VFS_mongo.h.

◆ _collection

QString VFS_mongo::_collection

private

The collection to use.

Definition at line 81 of file VFS_mongo.h.

◆ _createCollection

bool VFS_mongo::_createCollection

private

If a reference is made to a non-existent collection, create it, or throw an error.

Definition at line 88 of file VFS_mongo.h.

◆ _database

database VFS_mongo::_database

private

The Mongo (mongocxx) database object.

Definition at line 86 of file VFS_mongo.h.

◆ _databaseName

QString VFS_mongo::_databaseName

private

The name of the database to use.

Definition at line 80 of file VFS_mongo.h.

◆ _expireInterval

int VFS_mongo::_expireInterval

protected

Interval for cache entries to expire, in milliseconds.

Definition at line 56 of file VFS_mongo.h.

◆ _flushInterval

int VFS_mongo::_flushInterval

protected

Interval for cache entries to flush, in milliseconds.

Definition at line 55 of file VFS_mongo.h.

◆ _instance

mongocxx::instance VFS_mongo::_instance = std::move(mongocxx::instance::current())

staticprivate

The global mongocxx instance. There should only ever be one of these.

Definition at line 83 of file VFS_mongo.h.

◆ _url

QString VFS_mongo::_url

private

The database url for this node to connect to, for instance mongodb://localhost:27017.

Definition at line 79 of file VFS_mongo.h.

The documentation for this class was generated from the following files:

Public Member Functions

Protected Member Functions

Protected Attributes

Private Attributes

Static Private Attributes

Friends

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ VFS_mongo()

◆ ~VFS_mongo()

Member Function Documentation

◆ createCollection()

◆ createDocument()

◆ icon()

◆ ls()

◆ metadata()

◆ read()

◆ readDocument()

◆ removeDocument()

◆ reportDetails()

◆ rm()

◆ submit()

◆ subscribe()

◆ write()

◆ writeDocument()

Friends And Related Function Documentation

◆ VFS_mongo_cache_entry

Member Data Documentation

◆ _client

◆ _collection

◆ _createCollection

◆ _database

◆ _databaseName

◆ _expireInterval

◆ _flushInterval

◆ _instance

◆ _url