Access context from custom node editor code (.html file)

Developing Nodes
1

I want to access the global context from a custom node I'm creating. I want to do this from the editor code (html file) in the onprepare function. I read in (javascript - Send data on configuration - Stack Overflow) that in order to access the context (runtime) from the editor code (which runs in the browser), I can create a RED api in my js file, and call that api from my editor code.

However I don't know how I can access the context from that API I'm creating. this.context().global is not available there (see below).

module.exports = function (RED) {
  function ModelConfigurationNode(config) {
    RED.nodes.createNode(this, config);
    this.name = config.name;
    this.models = config.models;
  }
  RED.nodes.registerType("model-configuration", ModelConfigurationNode);

  // api to be able to communicate between editor and runtime to read the global context
  RED.httpAdmin.post(
    "/custompath/models",
    RED.auth.needsPermission("model-configuration.read"),
    function (req, res) {
      // read body of the request
      var body = req.body;
      // ACCESS CONTEXT ????
    }
  );
};
2

Have a look at the uib-cache node in uibuilder:

I pass the store type in from the Editor. this.storeContext could be "context", "flow" or "global".

image
image619×269 20.5 KB

3

Julian, he is trying to access the context outside the node.

Get your node (RED.nodes.getNode(id)) and then access the context (node.context()).

Or read the context directly in the editor - no need your own endpoint.

6

Thank you for your answer.
Can you provide some more information?
My requirement is to write some data to the global context whenever a user saves some properties in the edit dialog of my custom node.
How can I read the context from the editor? Can I also write to it?

7

You can get the value from the editor like this:

$.getJSON("context/global", function(data) {
  console.log(data);
});

But you cannot write.
Since you want to write, then you will have to use your endpoint:

RED.httpAdmin.post(
    "/custompath/models/:id",
    RED.auth.needsPermission("model-configuration.read"),
    function (req, res) {
      // read body of the request
      const body = req.body;
      const id = req.params.id
      // ACCESS CONTEXT ????
      const node = RED.nodes.getNode(id);
      if (node) {
        const context = node.context();
      }
    }
  );
8

I tried your code but it never finds the node even though the id is correctly sent from the editor:
image

function (req, res) {
      // read body of the request
      var body = req.body;
      const id = req.params.id;
      const node = RED.nodes.getNode(id);
      if (node) {
        res.sendStatus(200);
      }
      else {
        res.sendStatus(404); // always get a 404, since node is not found
      }
    }

I also tried getting the context through below code, but this also does not work.

RED.nodes.getContext('global') // TypeError: RED.nodes.getContext is not a function
9

The id comes from a deployed node? If the node only exists in the editor, this is normal.

RED.nodes.getContext is not exported.

10

Well... since you are only looking for the global context you can simplify it like this:

let globalContext;
RED.httpAdmin.post(
  "/custompath/models",
  RED.auth.needsPermission("model-configuration.read"),
  function (req, res) {
    const body = req.body;

    if (!globalContext) {
        RED.nodes.eachNode((node) =>
          globalContext = node.context().global;
          return false; // Not sure but should breaks the loop
        );
    } else {
      // Write your code here
    }
  }
);