MTConnect-Node

Node.js implementation of an MTConnect agent.

What's New

2013/01/26

• Significant restructuring. Project now runs from run.js.
• Functionality that was in server.js, store.js, and probe.js has now been split between the new agent.js and document.js modules.
• Removed the /test folder. I believe a better approach will be to create an adapter.js that can connect to the MTConnect reference agent adapters.

2012/09/01

• Minor refactoring. Removed some dead code. Fixed error document handling.
• Streams should now return proper firstSequence, lastSequence, nextSequence values.
• The current request now supports at, and validates the parameter.
• The sample request now validates from and count, and supports an arbitrarily-chosen maximum count of 500.
• The store request now accepts multiple DataItem updates in a single request, and returns an error document on failure. See the Usage section.
• Fixed error in loading devices file.
• Working on test/two-axis.js as demo two-axis machine for testing. Currently, this provides two axis data items that move sinusoidally.

2012/08/22

• The current and sample resources now return something that looks like a valid MTConnectStreams document.
• The sample resource now supports from and count parameters.
• The server now supports command-line arguments for port and sender.

What Works, What Doesn't

The server will load device settings from a probe.xml file, and then listen on port 8080. The server will serve an MTConnectDevices document in response to a /probe request. It will serve an MTConnectStreams document in response to a /current or /sample request. All other requests will receive an MTConnectErrors document.

All of the XML documents lack proper xmlns namespace attributes.

Some parameters are not implemented. A /probe request will not recognize a device-specific probe such as http://hostname:port/devicename/probe. A /current request will not recognize path or interval parameters. A /sample request will not recognize path or interval parameters.

Assets are not implemented at all.

Test cases are not yet created.

Installation

1. Install Node.js.
2. Obtain the MTConnect-Node repository.
3. (Optional) Modify the included probe.xml file, which was taken from the MTConnect Institute Agent.

Usage

Running the Agent

From a command prompt in the repository working directory: $ node run.js [port={port}] [sender={sender}] [devices={devices}]

The optional port parameter will be interpreted as the port on which the server should listen. The optional sender parameter will be used as the 'sender' string sent in the document headers. The optional devices parameter will be interpreted as the name of the file to load for Devices XML data.

The server will listen on port 8080 by default.

Sending DataItems to the Agent

Data items may be stored in the agent using the /store resource: http://localhost:8080/store?id={dataItemId}&timestamp={timestamp}&value={value}&condition={condition}

Parameters should be provided as follows:

• dataItemId - the id of the data item.
• timestamp - the UTC timestamp in ISO8601 format e.g. 2012-08-19T21:21:00Z.
• value - the value of the data item.
• condition - (optional) for a CONDITION data item, the condition: one of UNAVAILABLE, NORMAL, WARNING, FAULT.

Multiple data items may be updated in a single request by adding a numeric suffix to the parameters, starting with 1, e.g.: http://localhost:8080/store?id={dataItemId}&timestamp={timestamp}&value={value}&condition={condition}&id1={dataItemId}&timestamp1={timestamp}&value1={value}&condition1={condition}&.... However, the URL should not exceed 2000 characters.

Other parameters will be ignored. Parameters are validated to make sure that the dataItemId exist and that the timestamp is a proper date, but no validation is yet performed to verify that the values are valid, or that a condition is being provided for a condition DataItem.