94 lines
2.1 KiB
JavaScript
94 lines
2.1 KiB
JavaScript
const express = require('express')
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const jf = require('jsonfile')
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const fs = require('fs')
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const uuid = require('uuid')
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const router = express.Router()
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router.get('/:id', showComparison)
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router.post('/:id', createComparisonWithId)
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router.post('/', createComparison)
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//return the comparison given an id, if it exsits
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function showComparison(req, res) {
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const id = req.params.id
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return readRecord(res, id)
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}
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// Creates a new comparison
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function createComparison(req, res) {
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//generate a new id
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const id = uuid()
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const {a,b} = req.body
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return writeRecord(res, id, {a,b,id})
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}
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// Creates a new comparison
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function createComparisonWithId(req, res) {
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//use the id provided in the req
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const id = req.params.id
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const {a, b} = req.body
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return writeRecord(res, id, {a, b, id})
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}
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//reads the record from the database
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function readRecord(res, id, data) {
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//generate a filename
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const filename = fnData(id)
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//check if that file exists
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fs.exists(filename, function (exists) {
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//if the file does not exist, return a 404
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if (!exists) return res.status(404).send(`Data id ${id} not found.`)
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//otherwise, read the file as JSON
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jf.readFile(filename, function(err, data) {
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if(err) { return handleError(res, err) }
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//and return
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return res.json(data)
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})
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})
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}
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//writes the record to the database, if it doesn't exist
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function writeRecord(res, id, data) {
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//look up its filename
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var filename = fnData(id)
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//need to test that the file does not exist
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//check if that file exists
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fs.exists(filename, (exists) => {
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//if the file already exists, return a 405
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if (exists) return res.status(405).send(`Data id ${id} is already in use.`)
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//and write it to the filesystem
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jf.writeFile(filename, data, (err) => (
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err ?
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handleError(res, err) :
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//if successful, return the comparison object
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res.status(201).json(data)
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))
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})
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}
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module.exports = router
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function handleError(res, err) {
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console.log(err);
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return res.send(500, err);
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}
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// returns a filename for the given comparison
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function fnData (id) {
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return "./data/" + "id-" + id + ".json";
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}
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