Navigraph Navigation Data Interface in MSFS

This is a barebones implementation to be able to download up-to-date Navigraph navigation data into MSFS (more specifically into the work folder of the aircraft).

Repository Structure

Here's an overview on the structure of this repository, which is designed to be as simple as possible to use

• examples/
  • Contains sample implementations for using the navigation data interface
  • aircraft/ includes a base aircraft to test in the sim
  • gauge/ includes a very simple TypeScript instrument to communicate with the WASM module
• src/
  • database Includes rust source code for interfacing with a DFD sqlite file (not WASM specific)
  • js Includes source code for the JS interface for using the sdk
  • test Includes code for testing the JS and Rust code using a Node runtime
  • wasm includes the Rust source code for the WASM module which handles the downloading of the database file, and interfacing with the database implementation

Including in Your Aircraft

1. You'll need to either build the WASM module yourself (not recommended, but documented further down) or download it from the latest release (alternatively you can download it off of a commit by looking at the uploaded artifacts).
2. Add the WASM module into your panel folder in PackageSources
3. Add the following entry into panel.cfg (make sure to replace NN with the proper VCockpit ID):

   [VCockpitNN]
   size_mm=0,0
   pixel_size=0,0
   texture=NO_TEXTURE
   htmlgauge00=WasmInstrument/WasmInstrument.html?wasm_module=msfs_navigation_data_interface.wasm&wasm_gauge=navigation_data_interface,0,0,1,1
   

   • Note that if you already have a VCockpit with NO_TEXTURE you can just add another htmlgauge to it, while making sure to increase the index

Building the Sample Aircraft

Before building, make sure you have properly created and set an .env file in examples/gauge! An example can be found in the .env.example file in that directory. Replace with your credentials

1. Download Node.js
2. Open the examples/gauge folder in a terminal
3. Run npm i the first time you build, in order to install dependencies
4. Run npm run build to build into the PackageSources folder of the aircraft sample (or npm run dev to build into the Packages folder of the aircraft and listen to changes in the source).
5. Make sure the WASM module is included in the panel folder! Look at either Including in Your Aircraft or Building the WASM Module Yourself for info on that
6. Open the examples/aircraft/NavigationDataInterfaceAircraftProject.xml file in the simulator and build there

Building the WASM Module Yourself

1. Download Docker Desktop
2. Run npm run build:wasm (must be on Windows)
   • This will take a while to download and build the first time, but subsequent runs will be quicker
3. The compiled WASM module will be copied to out and examples/aircraft/PackageSources/SimObjects/Airplanes/Navigraph_Navigation_Data_Interface_Aircraft/panel

Interfacing with the gauge manually

The navigation data interface acts as its own WASM gauge in sim, so in order to communicate with it, you must use the CommBus.

The gauge communicates using the following event names:

(Any types referenced can be found in wasm/src/json_structs.rs)

• NAVIGRAPH_CallFunction: This event is received by the interface and is used to trigger one of the interfaces functions. It takes in arguments of type CallFunction. The available functions and their expected parameters can be found in the json_structs.rs file
• NAVIGRAPH_FunctionResult: This event is sent by the interface as a response to a previously triggered function. Its result will have the type FunctionResult, with the data field containing the expected return type of the function.
• NAVIGRAPH_Event: This event is sent by the interface to give indications of progress or that the interface is running correctly.

Example

Below is an example of communicating with the interface in JS. (We provide a JS wrapper, the code below is just a basic example to show how it works). Please read the CommBus documentation to determine how to interface with CommBus in your chosen language. src/js contains our JS wrapper, it is also a useful example for implementing a fully fleshed out wrapper.

const queue = []

const listener = RegisterCommBusListener(() => {
  listener.on("NAVIGRAPH_FunctionResult", jsonArgs => {
    const args = JSON.parse(jsonArgs)

    // When a FunctionResult is received, find the item in queue which matches the id, and resolve or reject it
    const queueItem = queue.find(m => m.id === args.id)

    if (queueItem) {
      queue.splice(queue.indexOf(queueItem), 1)
      const data = args.data

      if (args.status === FunctionResultStatus.Success) {
        queueItem.resolve(data)
      } else {
        queueItem.reject(new Error(typeof data === "string" ? data : "Unknown error"))
      }
    }
  })
}) // RegisterCommBusListener is a function provided by sim

function getAirport(ident) {
  const id = Utils.generateGUID() // Utils is a class provided by sim

  const args = {
    function: "GetAirport", // The name of the function being called
    id, // CallFunctions and FunctionResults are tied together with the id field
    data: {
      // The parameters of the function
      ident,
    },
  }

  listener.callWasm("NAVIGRAPH_CallFunction", JSON.stringify(args))

  return new Promise((resolve, reject) => {
    queue.push({
      id,
      resolve: response => resolve(response),
      reject: error => reject(error),
    })
  })
}

function executeSql(sql, params) {
  const id = Utils.generateGUID() // Utils is a class provided by sim

  const args = {
    function: "ExecuteSQLQuery", // The name of the function being called
    id, // CallFunctions and FunctionResults are tied together with the id field
    data: {
      // The parameters of the function
      sql,
      params,
    },
  }

  listener.callWasm("NAVIGRAPH_CallFunction", JSON.stringify(args))

  return new Promise((resolve, reject) => {
    queue.push({
      id,
      resolve: response => resolve(response),
      reject: error => reject(error),
    })
  })
}