UPDATE v2, 2015-10-31

Note that v2 is a potentially breaking change from v1 as the underlying code has changed significantly. V2 is simpler to use and does more than v1 but you may need to reset some parameters in your node instances.

node-red-contrib-globalgetset

Node-Red Node that can get/set a context.global variable. This saves you having to use a function node with JavaScript.

You can easily pass in a msg containing an element to store in the global variables. In this case, assuming there are no errors, the msg will be passed through unchanged.

You can also use the node to retrieve something from the global variables and add it to the msg (or indeed to another global variable). This allows you to then process it it downstream. For example, the following node could be a switch node that could switch output depending on the variable.

Finally, you could use this node to duplicate something from the input msg to a different element on the output msg. Note however that currently, you can only do this at the first sub-level of msg (e.g. msg.mything) not any lower (e.g. msg.mysub.mything doesn't work, you would get instead msg["mysub.mything"]). Use in combination with the change node if you want anything more complex.

Note

Future updates to Node-Red will better expose the context and context.global variables. When that happens (estimated currently at around NR v0.12) this node will require changing to use the full features and to expose the context part that is currently disabled.

Installation

Run the following command in the root directory of your Node-RED install

npm install node-red-contrib-globalgetset

While in development, install with:

npm install https://github.com/TotallyInformation/node-red-contrib-globalgetset/tarball/master

Usage

The node defaults to input from the context.global.temporary and output to msg.payload.

The parameters to the node are:

Input

Context - The input context (AKA prefix). Currently only allows global (meaning context.global) or msg.
Variable - The name of the input variable.
- Leave this blank if you want to use the incoming msg.topic as the variable name (note however that not all valid topic names may be valid variable names).

Output

Context - The ouput context (prefix). Currently only allows global (meaning context.global) or msg.
Variable - The name of the ouput variable
- Leave this blank if you want to use the incoming msg.topic as the variable name (note however that not all valid topic names may be valid variable names).

Other

topic - Optional. Change the topic for the outbound msg.
name - Optional. Standard Node-Red name field. Names the instance of the node.

For both the input and output, context and variable are catenated to make, for example, msg.payload or context.global.temporary, etc.

License

This code is Open Source under an Apache 2 License. Please see the apache2-license.txt file for details.

You may not use this code except in compliance with the License. You may obtain an original 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. Please see the License for the specific language governing permissions and limitations under the License.

Author

Julian Knight (Totally Information), https://github.com/totallyinformation

Feedback and Support

Please report any issues or suggestions via the Github Issues list for this repository.

For more information, feedback, or community support see the Node-Red Google groups forum at https://groups.google.com/forum/#!forum/node-red