aboutsummaryrefslogtreecommitdiff
path: root/bg/ResponseProcessor.js
diff options
context:
space:
mode:
Diffstat (limited to 'bg/ResponseProcessor.js')
-rw-r--r--bg/ResponseProcessor.js43
1 files changed, 22 insertions, 21 deletions
diff --git a/bg/ResponseProcessor.js b/bg/ResponseProcessor.js
index 0340a6f..922ff19 100644
--- a/bg/ResponseProcessor.js
+++ b/bg/ResponseProcessor.js
@@ -2,6 +2,7 @@
* GNU LibreJS - A browser add-on to block nonfree nontrivial JavaScript.
*
* Copyright (C) 2018 Giorgio Maone <giorgio@maone.net>
+* Copyright (C) 2022 Yuchen Pei <id@ypei.org>
*
* This file is part of GNU LibreJS.
*
@@ -24,16 +25,16 @@
only the "interesting" HTML and script requests and leaving the other alone
*/
-let { ResponseMetaData } = require('./ResponseMetaData');
+const { ResponseMetaData } = require('./ResponseMetaData');
-let listeners = new WeakMap();
-let webRequestEvent = browser.webRequest.onHeadersReceived;
+const listeners = new WeakMap();
+const webRequestEvent = browser.webRequest.onHeadersReceived;
class ResponseProcessor {
static install(handler, types = ['main_frame', 'sub_frame', 'script']) {
if (listeners.has(handler)) return false;
- let listener =
+ const listener =
async request => await new ResponseTextFilter(request).process(handler);
listeners.set(handler, listener);
webRequestEvent.addListener(
@@ -45,7 +46,7 @@ class ResponseProcessor {
}
static uninstall(handler) {
- let listener = listeners.get(handler);
+ const listener = listeners.get(handler);
if (listener) {
webRequestEvent.removeListener(listener);
}
@@ -62,8 +63,8 @@ Object.assign(ResponseProcessor, {
class ResponseTextFilter {
constructor(request) {
this.request = request;
- let { type, statusCode } = request;
- let md = this.metaData = new ResponseMetaData(request);
+ const { type, statusCode } = request;
+ const md = this.metaData = new ResponseMetaData(request);
this.canProcess = // we want to process html documents and scripts only
(statusCode < 300 || statusCode >= 400) && // skip redirections
!md.disposition && // skip forced downloads
@@ -72,29 +73,29 @@ class ResponseTextFilter {
async process(handler) {
if (!this.canProcess) return ResponseProcessor.ACCEPT;
- let { metaData, request } = this;
- let response = { request, metaData }; // we keep it around allowing callbacks to store state
- if (typeof handler.pre === 'function') {
- let res = await handler.pre(response);
- if (res) return res;
- if (handler.post) handler = handler.post;
- if (typeof handler !== 'function') return ResponseProcessor.ACCEPT;
+ const { metaData, request } = this;
+ const response = { request, metaData }; // we keep it around allowing callbacks to store state
+
+ if (typeof handler.pre !== 'function' || typeof handler.post !== 'function') {
+ throw new Error('handler should have a pre and post function.');
}
+ const res = await handler.pre(response);
+ if (res) return res;
- let { requestId } = request;
- let filter = browser.webRequest.filterResponseData(requestId);
+ const { requestId } = request;
+ const filter = browser.webRequest.filterResponseData(requestId);
let buffer = [];
filter.ondata = event => {
buffer.push(event.data);
};
- filter.onstop = async unused => {
+ filter.onstop = async _ => {
// concatenate chunks
- let size = buffer.reduce((sum, chunk) => sum + chunk.byteLength, 0)
+ const size = buffer.reduce((sum, chunk) => sum + chunk.byteLength, 0)
let allBytes = new Uint8Array(size);
let pos = 0;
- for (let chunk of buffer) {
+ for (const chunk of buffer) {
allBytes.set(new Uint8Array(chunk), pos);
pos += chunk.byteLength;
}
@@ -113,13 +114,13 @@ class ResponseTextFilter {
}
let editedText = null;
try {
- editedText = await handler(response);
+ editedText = await handler.post(response);
} catch (e) {
console.error(e);
}
if (editedText !== null && editedText.indexOf('/* LibreJS: script accepted') !== 0) {
// we changed the content, let's re-encode
- let encoded = new TextEncoder().encode(editedText);
+ const encoded = new TextEncoder().encode(editedText);
// pre-pending the UTF-8 BOM will force the charset per HTML 5 specs
allBytes = new Uint8Array(encoded.byteLength + 3);
allBytes.set(ResponseMetaData.UTF8BOM, 0); // UTF-8 BOM