kws-sdk/src/index.ts

import querystring = require('querystring');
import aws = require('aws4');
import request = require('request-promise');

declare namespace KWS {

  interface headers {
    [key: string]: string
  }

  export interface Query {
    [key: string]: string;
  }

  export interface AWSRequest {
    host: string;
    method: string;
    headers: headers;
    service: string;
    region: string;
    path: string;
    body?: string;
    signQuery?: boolean;
  }

  export interface AWSCredentials {
    accessKeyId: string;
    secretAccessKey: string;
  }

  export interface RequestARGS {
    query?: Query;
    body?: any;
  }

  export interface ARGS {
    ak: string;
    sk: string;
    uniqname: string;
    app: string;
    host?: string;
    region?: string;
  }

  export interface Api {
    action: string;
    service: string;
    version: string;
  }
}

function buildBody(body?: any) {
  if (!body) {
    return '';
  }
  return JSON.stringify(body);
}

function buildAWSPath(query: KWS.Query = {}): string {
  const keys = Object.keys(query);
  if (keys.length === 0) {
    return '/';
  }
  return '/?' + querystring.stringify(query);
}

class KWS implements KWS.ARGS {
  ak: string;
  sk: string;
  host: string;
  region: string;
  uniqname: string;
  app: string;

  constructor(args: KWS.ARGS) {
    Object.assign(this, args);
    if (!this.region) {
      this.region = 'cn-beijing-6'
    }
  }

  buildHost(service: string) {
    return this.host || `${service}.${this.region}.api.ksyun.com`;
  }

  buildAWSRequest(method: string, service: string, query: KWS.Query, body: any): KWS.AWSRequest {
    return {
      host: this.buildHost(service),
      method,
      service,
      headers: {},
      region: this.region,
      path: buildAWSPath(query),
      body,
      signQuery: true
    };
  }

  buildAWSCredentials(): KWS.AWSCredentials {
    return {
      accessKeyId: this.ak,
      secretAccessKey: this.sk
    };
  }

  buildQuery(action: string, version: string, query: Object): KWS.Query {
    return Object.assign({
      Action: action,
      Version: version,
      App: this.app,
      UniqName: this.uniqname
    }, query);
  }

  sign(method: string, api: KWS.Api, data: KWS.RequestARGS = {}) {
    data.query = data.query || {};
    const body = buildBody(data.body);
    const query: KWS.Query = this.buildQuery(api.action, api.version, data.query);
    const AWSRequest = this.buildAWSRequest(method, api.service, query, body);
    const AWSCredentials = this.buildAWSCredentials();
    return aws.sign(AWSRequest, AWSCredentials);
  }

  request(method: string, api: KWS.Api, data: KWS.RequestARGS = {}) {
    const sign = this.sign(method, api, data);
    const option = {
      uri: `https://${sign.host}${sign.path}`,
      method: method,
      headers: sign.headers,
      body: ''
    };
    if (data.body) {
      option.method = 'POST';
      option.body = JSON.stringify(data.body);
    } else {
      delete option.body;
    }
    return request(option);
  }
}

export = KWS;