feat: Add custom behavior injection (#285)

* support loading custom behaviors from a specified directory via --customBehaviors
* call load() for each behavior incrementally, then call selectMainBehavior() (available in browsertrix-behaviors 0.5.1)
* tests: add tests for multiple custom behaviors

---------
Co-authored-by: Ilya Kreymer <ikreymer@gmail.com>

crawler.js

@@ -21,6 +21,7 @@ import { initRedis } from "./util/redis.js";
 import { logger, errJSON } from "./util/logger.js";
 import { runWorkers } from "./util/worker.js";
 import { sleep, timedRun, secondsElapsed } from "./util/timing.js";
+import { collectAllFileSources } from "./util/file_reader.js";
 
 import { Browser } from "./util/browser.js";
 
@@ -120,6 +121,7 @@ export class Crawler {
 
     this.done = false;
 
+    this.customBehaviors = "";
     this.behaviorLastLine = null;
 
     this.browser = new Browser();
@@ -233,6 +235,10 @@ export class Crawler {
       }
     }
 
+    if (this.params.customBehaviors) {
+      this.customBehaviors = this.loadCustomBehaviors(this.params.customBehaviors);
+    }
+
     let opts = {};
     let redisStdio;
 
@@ -347,6 +353,10 @@ export class Crawler {
       }
       break;
 
+    case "error":
+      logger.error(message, details, "behaviorScript");
+      break;
+
     case "debug":
     default:
       logger.debug(message, details, "behaviorScript");
@@ -399,10 +409,28 @@ export class Crawler {
 
     if (this.params.behaviorOpts) {
       await page.exposeFunction(BEHAVIOR_LOG_FUNC, (logdata) => this._behaviorLog(logdata, page.url(), workerid));
-      await this.browser.addInitScript(page, behaviors + `;\nself.__bx_behaviors.init(${this.params.behaviorOpts});`);
+      await this.browser.addInitScript(page, behaviors);
+
+      const initScript = `
+self.__bx_behaviors.init(${this.params.behaviorOpts}, false);
+${this.customBehaviors}
+self.__bx_behaviors.selectMainBehavior();
+`;
+
+      await this.browser.addInitScript(page, initScript);
     }
   }
 
+  loadCustomBehaviors(filename) {
+    let str = "";
+
+    for (const source of collectAllFileSources(filename, ".js")) {
+      str += `self.__bx_behaviors.load(${source});\n`;
+    }
+
+    return str;
+  }
+
   async crawlPage(opts) {
     await this.writeStats();
 

tests/custom-behavior.test.js

@@ -0,0 +1,23 @@
+import child_process from "child_process";
+
+test("test custom behaviors", async () => {
+  const res = child_process.execSync("docker run -v $PWD/test-crawls:/crawls -v $PWD/tests/custom-behaviors/:/custom-behaviors/ webrecorder/browsertrix-crawler crawl --url https://example.com/ --url https://example.org/ --url https://webrecorder.net/ --customBehaviors /custom-behaviors/ --scopeType page");
+
+  const log = res.toString();
+
+  // custom behavior ran for example.com
+  expect(log.indexOf("{\"state\":{},\"msg\":\"test-stat\",\"page\":\"https://example.com/\",\"workerid\":0}}") > 0).toBe(true);
+
+  // but not for example.org
+  expect(log.indexOf("{\"state\":{},\"msg\":\"test-stat\",\"page\":\"https://example.org/\",\"workerid\":0}}") > 0).toBe(false);
+
+  expect(log.indexOf("{\"state\":{\"segments\":1},\"msg\":\"Skipping autoscroll, page seems to not be responsive to scrolling events\",\"page\":\"https://example.org/\",\"workerid\":0}}") > 0).toBe(true);
+
+  // another custom behavior ran for webrecorder.net
+  expect(log.indexOf("{\"state\":{},\"msg\":\"test-stat-2\",\"page\":\"https://webrecorder.net/\",\"workerid\":0}}") > 0).toBe(true);
+
+
+
+});
+
+

tests/custom-behaviors/custom-2.js

@@ -0,0 +1,22 @@
+class TestBehavior2
+{
+  static init() {
+    return {
+      state: {}
+    };
+  }
+
+  static get id() {
+    return "TestBehavior2";
+  }
+
+  static isMatch() {
+    return window.location.origin === "https://webrecorder.net";
+  }
+
+
+  async* run(ctx) {
+    ctx.log("In Test Behavior 2!");
+    yield ctx.Lib.getState(ctx, "test-stat-2");
+  }
+}

tests/custom-behaviors/custom.js

@@ -0,0 +1,22 @@
+class TestBehavior
+{
+  static init() {
+    return {
+      state: {}
+    };
+  }
+
+  static get id() {
+    return "TestBehavior";
+  }
+
+  static isMatch() {
+    return window.location.origin === "https://example.com";
+  }
+
+
+  async* run(ctx) {
+    ctx.log("In Test Behavior!");
+    yield ctx.Lib.getState(ctx, "test-stat");
+  }
+}

util/argParser.js

@@ -385,7 +385,12 @@ class ArgParser {
         describe: "If set, crawler will fail with exit code 1 if any seed fails",
         type: "boolean",
         default: false
-      }
+      },
+
+      "customBehaviors": {
+        describe: "injects a custom behavior file or set of behavior files in a directory",
+        type: ["string"]
+      },
     };
   }
 

util/file_reader.js

@@ -0,0 +1,33 @@
+import fs from "fs";
+import path from "path";
+
+const MAX_DEPTH = 2;
+
+export function collectAllFileSources(fileOrDir, ext = null, depth = 0) {
+  const resolvedPath = path.resolve(fileOrDir);
+
+  if (depth >= MAX_DEPTH) {
+    console.warn(`WARN: MAX_DEPTH of ${MAX_DEPTH} reached traversing "${resolvedPath}"`);
+    return [];
+  }
+
+  const stat = fs.statSync(resolvedPath);
+
+  if (stat.isFile && (ext === null || path.extname(resolvedPath) === ext)) {
+    const contents = fs.readFileSync(resolvedPath);
+    return [`/* src: ${resolvedPath} */\n\n${contents}`];
+  }
+
+  if (stat.isDirectory) {
+    const files = fs.readdirSync(resolvedPath);
+    return files.reduce((acc, next) => {
+      const nextPath = path.join(fileOrDir, next);
+      return [...acc, ...collectAllFileSources(nextPath, ext, depth + 1)];
+    }, []);
+  }
+
+  if (depth === 0) {
+    console.warn(`WARN: The provided path "${resolvedPath}" is not a .js file or directory.`);
+    return [];
+  }
+}

yarn.lock

@@ -1147,10 +1147,10 @@ browserslist@^4.21.3:
     node-releases "^2.0.6"
     update-browserslist-db "^1.0.9"
 
-browsertrix-behaviors@^0.5.0-beta.0:
-  version "0.5.0-beta.0"
-  resolved "https://registry.yarnpkg.com/browsertrix-behaviors/-/browsertrix-behaviors-0.5.0-beta.0.tgz#d1a7c35cda31d740a374df1e833f36bd1890768d"
-  integrity sha512-RQMQlbV4OBAzYyhTI7imoem8p4MTj2XSDzlIZvA5sC5U89OMnJ0VM5KBAJzET3PUJkQlUQEOTiXtnsnodHXTUQ==
+browsertrix-behaviors@^0.5.1:
+  version "0.5.1"
+  resolved "https://registry.yarnpkg.com/browsertrix-behaviors/-/browsertrix-behaviors-0.5.1.tgz#c4756b349dcabd23e25f851cec804d92e94eb63b"
+  integrity sha512-cNSSpQyQT73Y5NcBn2PFDkZM2ptxHVVcqxstryvtzZNOW9gGqzJlLPo8tmCBY00JHrMyn5rm8qImbFglcG/DKg==
 
 bser@2.1.1:
   version "2.1.1"