mali/lib/request.js

Minimalistic gRPC microservice framework

const grpc = require('@grpc/grpc-js')
const CallType = require('@malijs/call-types')
const Metadata = require('./metadata')

/**
 * Mali Request class that encapsulates the request of a call.
 * Clients to not create this. Mali does it for us.
 */
class Request {
  /**
   * Creates a Mali Request instance
   * @param {Object} call the grpc call instance
   * @param {String} type the call type. one of `@malijs/call-types` enums.
   */
  constructor (call, type) {
    this.call = call
    this.type = type
    if (call.metadata instanceof grpc.Metadata) {
      this.metadata = call.metadata.getMap()
    } else {
      this.metadata = call.metadata
    }

    if (type === CallType.RESPONSE_STREAM ||
      type === CallType.UNARY) {
      this.req = call.request
    } else {
      this.req = call
    }
  }

  /**
   * Gets the requests metadata as a `grpc.Metadata` object instance
   * @return {Object} request metadata
   */
  getMetadata () {
    return Metadata.create(this.metadata)
  }

  /**
   * Gets specific request metadata field value
   * @param {*} field the metadata field name
   * @return {*} the metadata value for the field
   * @example
   * console.log(ctx.request.get('foo')) // 'bar'
   */
  get (field) {
    let val
    if (this.metadata) {
      val = this.metadata[field]
    }
    return val
  }
}

/**
 * The internal gRPC call instance reference.
 * @member {Object} call
 * @memberof Request#
 */

/**
 * The call request object or stream.
 * @member {Object|Stream} req
 * @memberof Request#
 * @example
 * console.log(ctx.request.req) // { name: 'Bob' }
 */

/**
 * The call's request metadata plain object if present.
 * @member {Object} metadata
 * @memberof Request#
 * @example
 * console.log(ctx.request.metadata)
 * // { 'user-agent': 'grpc-node/1.7.1 grpc-c/1.7.1 (osx; chttp2)' }
 */

/**
 * The call's type. One of `@malijs/call-types` enums.
 * @member {String} type
 * @memberof Request#
 * @example
 * console.log(ctx.request.type) // 'unary'
 * @example
 * if(ctx.request.type === CallType.DUPLEX) {
 *   console.log('Duplex stream call')
 * }
 */

module.exports = Request