MoleQueue JSON-RPC Implementation

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The mechanism for handling JSON-RPC transmissions has been simplified. This page may be rewritten at some point.

Language, backends

The MoleQueue JSON-RPC implemention is written in C++, using the JsonCpp parsers. It exposes a Qt 4 interface that provides interprocess communication through a local socket with a visible Qt signal/slot interface.


The implementation consists of the following classes:


Internal class used to generate and handle JSON-RPC requests, responses, and notifications as described in the MoleQueue JSON-RPC Specification.


  • static QByteArray generateJobRequest(const JobRequest &req, unsigned long requestId): Process a JobRequest into a MoleQueue JSON-RPC QByteArray, ready to send to a QLocalSocket.
  • static QByteArray generateJobCancellation(const JobRequest &req, unsigned long requestId)Process a request to cancel a JobRequest into a MoleQueue JSON-RPC QByteArray.
  • static QByteArray generateQueueList(const QueueManager *, unsigned long requestId): Generate a MoleQueue JSON-RPC QByteArray of the available queues/programs.
  • QVector<unsigned long> interpretIncoming(const QByteArray &): Interpret an incoming MoleQueue JSON-RPC packet, identify the type (should be a request), and emit an appropriate signal. Return value is a unique identifier for this packet that can be used later to match the signal to this packet (should be the JSON-RPC packet id). A QVector is used to handle batch requests.
  • static QByteArray generateJobStateChangeNotification(unsigned long moleQueueId, JobState oldState, JobState newState)
  • static bool validateRequest(const QString &)
  • static bool validateResponse(const QString &)
  • static bool validateNotification(const QString &)


  • void queueListRequestReceived(unsigned long packetHandle)
  • void queueListReceived(unsigned long packetHandle, const QList<QPair<QString, QStringList> > &)
  • void jobSubmissionRequestReceived(unsigned long packetHandle, const QHash<QString, QVariant> &options)
  • void successfulSubmissionReceived(unsigned long packetHandle, unsigned long moleQueueId, unsigned long jobId, const QDir &workingDir)
  • void failedSubmissionReceived(unsigned long packetHandle, unsigned long moleQueueId, unsigned long jobId, const QDir &workingDir)
  • void jobCancellationRequestReceived(unsigned long packetHandle, unsigned long moleQueueId)
  • void jobCancellationConfirmationReceived(unsigned long packetHandle, unsigned long moleQueueId)
  • void jobStateChangeReceived(unsigned long packetHandle, unsigned long moleQueueId, JobState oldState, JobState newState)


Client interface providing methods for requesting and monitoring calculations. This class generates and manages JobRequest objects, which are state objects that define a single job's configuration.


  • JobRequest & newJobRequest(): Creates and registers a new JobRequest object with this client.
  • bool submitJobRequest(JobRequest &): Submit a JobRequest to the MoleQueue server.
  • bool cancelJobRequest(JobRequest &): Cancel a JobRequest that has been submitted to the MoleQueue server.


Class describing a single job from the client's side.


  • MoleQueueClient & client(): Return the parent MoleQueueClient.
  • unsigned long id() const: Unique identifier for this job request.
  • unsigned long jobId() const: If set, a queue specific job identifier.
  • Various setters/getters for file path, job options, etc.


  • bool submit(): Equivalent to this->client.submitJobRequest(this).
  • bool cancel(): Equivalent to this->client.cancelJobRequest(this).
  • bool destroy(): Removes a JobRequest from the client. Otherwise the instance will persist for the lifetime of the MoleQueueClient.


  • void stateChanged(JobState oldState, JobState newState): Emitted when the server indicates a change in the job's status.
  • void submitted(): Emitted when the job is successfully submitted to the MoleQueueServer.
  • void error(ErrorCode ec, const QString &err) Emitted if an error is encountered.
  • void finished(): Emitted when the job execution terminates.

ErrorCode values:

  • SUBMISSION_ERROR: Error submitting request to MoleQueueServer.


Server for handling requests from and sending notifications to MoleQueueClient instances. It holds a pointer to a QueueManager and directly sends requests to the appropriate Queue objects.


  • setQueueManager(QueueManager *): Sets the QueueManager.
  • QueueManager * queueManager(): Get the current QueueManager instance.