@sap/cds/libx/odata/ODataAdapter.js

SAP Cloud Application Programming Model - CDS for Node.js

const cds = require('../../lib')
const LOG = cds.log('odata')

const express = require('express')
const star = express.application.del ? '*' : '{*splat}'

const HttpAdapter = require('../../lib/srv/protocols/http')

const $describe = require('./middleware/service-document')
const $metadata = require('./middleware/metadata')
const $batch = require('./middleware/batch')
const parse4 = require('./middleware/parse')
const operation4 = require('./middleware/operation')
const create4 = require('./middleware/create')
const stream4 = require('./middleware/stream')
const read4 = require('./middleware/read')
const update4 = require('./middleware/update')
const delete4 = require('./middleware/delete')

class ODataAdapter extends HttpAdapter {
  /**
   * Construct express Router for OData service
   */
  get router() {
    const router = super.router
    router.use(this.log_request)
    router.all('/\\$metadata', $metadata(this))
    router.all('/', $describe(this))
    router.use(parse4(this))
    router.all('/\\$batch', $batch(this))
    router.head(star, (_, res) => res.status(405).end())
    router.all(star, operation4(this))
    router.post(star, create4(this))
    router.get(star, stream4(this), read4(this))
    router.put(star, update4(this), create4(this, 'upsert'))
    router.patch(star, update4(this), create4(this, 'upsert'))
    router.delete(star, delete4(this))
    return router
  }

  /**
   * Middleware to log all incoming requests and set OData-Version header.
   * @type {express.RequestHandler}
   */
  log_request(req, res, next) {
    if (req.__proto__.method in { PUT: 1, PATCH: 1 }) return next() // in case of upsert
    let details = Object.keys(req.query).length ? { ...req.query } : ''
    if (req._subrequest) LOG.info('> ' + req.method, req.path, details)
    else LOG.info(req.method, decodeURI(req.baseUrl + req.path), details)
    res.set('OData-Version', '4.0')
    next()
  }

  error(err, req, res, next) {
    let content_id = req.get('content-id')
    if (content_id && typeof err === 'object') err.content_id = content_id
    return super.error(err, req, res, next)
  }

  normalized(err) {
    // Unwrap first of multiple errors for Fiori, and keep the rest as details
    // Note: has to happen before super.normalized(), to ensure proper
    // normalization of the main error's code.
    if (err.details?.map && cds.env.fiori.wrap_multiple_errors == false) {
      const [first, ...tail] = err.details
      err = Object.assign(err, first, {
        message: first.message, // ensure first message override, even if empty
        details: tail.length ? tail : undefined
      })
    }

    // Normalize error using super, which will ensure inferred `code` property
    err = super.normalized(err) // this.normalized() modifies err in-place

    // Ensure all errors have a string code, as expected by OData specification
    for (let e of err.details?.map ? [err, ...err.details] : [err])
      if (typeof e.code !== 'string') e.code = String(e.code || e.status || '')

    if (err.reason) err.innererror = err.reason
    return err
  }

  cleansed(err, content_id = err.content_id) {
    // Extract known OData error properties from the original error object
    const {
      message,
      code,
      target,
      innererror,
      details,
      additionalTargets,
      numericSeverity = 4,
      ...other // all other unknown ones
    } = err

    // Construct and return a new spec-compliant error object
    const error = { message, code, target, innererror }
    if (details) error.details = details.map?.(e => this.cleansed(e, content_id)) ?? details
    if (additionalTargets) error['@Common.additionalTargets'] = additionalTargets
    if (numericSeverity) error['@Common.numericSeverity'] = numericSeverity
    if (content_id) error['@Core.ContentID'] = content_id
    for (let k in other) if (k[0] === '@') error[k] = other[k]
    return error
  }

  request4(args) {
    return new ODataRequest(args)
  }

  sap_messages4(cdsReq, req, res) {
    if (res.headersSent || !cdsReq.messages?.length) return
    const messages = cdsReq.messages.map(err => {
      if (!err.code) err.code = '' // default to empty string if not provided
      const { code, message, numericSeverity, longtextUrl, target, additionalTargets } = this.normalized(err)
      // only return allowed subset of properties
      return { code, message, numericSeverity, longtextUrl, target, additionalTargets }
    })
    const msgs = JSON.stringify(messages).replace(
      /[\u007F-\uFFFF]/g,
      c => '\\u' + c.charCodeAt(0).toString(16).padStart(4, '0')
    )
    res.setHeader('sap-messages', msgs)
  }
}

class ODataRequest extends cds.Request {}
ODataRequest.prototype.protocol = 'odata' // for batch subrequests where prototype is not properly set

module.exports = ODataAdapter