Source

plugin.ts

  1. import { Crawler } from "./crawler";
  2. import { Task } from "./index";
  4. export interface PriorityMap {
  5.   before?: number;
  6.   after?: number;
  7.   finish?: number;
  8.   onError?: number;
  9. }
  10. /**
  11.  * Basic plugin structure.
  12.  */
  13. export interface Plugin {
  14.   /**
  15.    * Identifier for the plugin.
  16.    */
  17.   name: string;
  18.   /**
  19.    * Plugin with higher priority will be executed first.
  20.    */
  21.   priority?: number;
  22.   /**
  23.    * Alternative setting for priorities.
  24.    * ```js
  25.    * {
  26.    *  before: 100,
  27.    *  after: 90,
  28.    *  onError: 40
  29.    * }
  30.    * ```
  31.    */
  32.   priorities?: PriorityMap;
  33.   /**
  34.    * Called before task's execution
  35.    */
  36.   before?: (task: Task, crawler: Crawler) => any;
  37.   /**
  38.    * Called after task's execution
  39.    */
  40.   after?: (task: Task, crawler: Crawler) => any;
  41.   /**
  42.    * Called when registered on the Crawler
  43.    */
  44.   start?: (crawler: Crawler) => any;
  45.   /**
  46.    * Called when all tasks are finished.
  47.    */
  48.   finish?: (crawler: Crawler) => any;
  49.   /**
  50.    * Called when an error is throwed during http request.
  51.    */
  52.   onError?: (error: Error, task: Task, crawler: Crawler) => any;
  53. }
  55. export interface PluginMap {
  56.   [name: string]: Plugin;
  57. }
  59. export interface PluginActionMap {
  60.   before: Array<Plugin>;
  61.   after: Array<Plugin>;
  62.   finish: Array<Plugin>;
  63.   onError: Array<Plugin>;
  64. }
  66. function priorityOfPlugin(a: Plugin, pos: string) {
  67.   return (a.priorities && a.priorities[pos]) || a.priority || 0;
  68. }
  69. export function cmpPlugin(a: Plugin, b: Plugin, pos: string) {
  70.   let pa = priorityOfPlugin(a, pos);
  71.   let pb = priorityOfPlugin(b, pos);
  72.   return pa > pb ? -1 : pa < pb ? 1 : 0;
  73. }