server.js

import portfinder from "portfinder"

import { config, links, databases } from "./src/config.js"
import { createBackend } from "./src/backend.js"
import { SubjectsService } from "./src/service.js"
const { schemes } = config

import express from "express"

// Connect to backend
const backend = await createBackend(config)

// this will likely warm up the backend cache as well
// TODO: This is very slow and delays startup by multiple minutes. Find a better solution.
// const { recCount, occCount, vocCount } = await backend.metadata()
// console.log(`Backend contains ${occCount} occurrences from ${recCount} records with ${vocCount} vocabularies.`)

const service = new SubjectsService({backend, schemes, links, databases})

const app = express()
app.set("json spaces", 2)

// Configure view engine to render EJS templates
app.set("views", "./views")
app.set("view engine", "ejs")
app.use(express.static("public"))

// Headers
app.use((req, res, next) => {
  if (req.headers.origin) {
    // Allow all origins by returning the request origin in the header
    res.setHeader("Access-Control-Allow-Origin", req.headers.origin)
  } else {
    // Fallback to * if there is no origin in header
    res.setHeader("Access-Control-Allow-Origin", "*")
  }
  res.setHeader("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept")
  res.setHeader("Access-Control-Allow-Methods", "GET")
  res.setHeader("Access-Control-Expose-Headers", "X-Total-Count, Link", "coli-ana-backend")
  next()
})

// Root path for static page
app.get("/", (req, res) => {
  res.setHeader("Content-Type", "text/html")
  res.render("index", { ...config })
})

// Delegate main API routes to SubjectsService
app.get(["/occurrences","/api"], async (req, res) => {
  res.json(await service.request(req.query))
})

app.get("/subjects", async (req, res) => {
  res.json(await service.subjects(req.query))
})

app.get("/records", async (req, res) => {
  res.json(await service.records(req.query))
})
 
// Supported vocabularies
app.get(["/voc","/api/voc", "/occurrences/voc"], async (req, res) => {
  res.json(schemes)
})

// Supported databases
app.get("/databases", async (req, res) => {
  res.json(databases)
})

// API status
app.get("/status", async (req, res) => {
  try {
    const metadata = await backend.metadata({ counts: false })
    res.json({metadata, ok:1})
  } catch (error) {
    res.json({ok: 0})
  }
})


// start the server
const start = async () => {
  if (config.env == "test") {
    portfinder.basePort = config.port
    config.port = await portfinder.getPortPromise()
  }

  return new Promise(resolve => {
    app.listen(config.port, () => {
      console.log(`subjects api at http://localhost:${config.port}/`)
      resolve(app)
    })
  })
}

export const appStarted = start()