When done compiling, force CSSTree to parse an empty string, so
as to ensure it doesn't keep a reference to that string.
Typically, the string passed to CSSTree is a small slice of a
larger string which is a whole filter list. This means that
holding a reference to the sliced string causes the JS engine
to hold in memory to the whole filter list last parsed.
Reference documentation:
https://adguard.com/kb/general/ad-filtering/create-own-filters/#replace-modifier
This is a network filter option which can only be loaded from a
trusted source.
Since this filter is about modifying the response body, it currently
only works in Firefox.
As discussed with filter list maintainers.
Manual update of one or more lists will cause the most recent version
of these lists to be fetched from the "origin" server, and since the
lists from "origin" servers cannot be updated through differential
update, the lists will be subsequently updated according to their
`Expires` directive.
When the lists are auto-updated, the "CDN" servers will be used,
and as a result the lists will start to be updated trhough
differential updates every 6-hour (currently).
Thus it is recommended and optimal to let the lists auto-update,
since you will benefit from a much shorter delay to get up-to-date
lists (i.e. every 6-hour instead of every 6-day).
You can force the auto-updater to fetch all the lists by clicking
"Purge all caches", then restart uBO without clicking "Update".
This will cause uBO to perform an emergency auto-update at restart
time, after which you will have all the lists which are candidates
for differential update.
The "Update now" button in the "Support" pane will also cause lists
to be fetched from their "origin" server.
Related discussion:
https://github.com/ameshkov/diffupdates
The benefits of diff-patching filter lists is much shorter update
schedule and significantly less bandwidth consumed.
At the moment, only default filter lists are subject to be
diff-patched.
External filter lists can make their lists diff-patchable by
following the specification link above.
Only filter lists fetched by the auto-updater are candidate for
diff-patching.
Forcing a manual update of the filter lists will prevent the
diff-patcher from kicking in until one or more lists are
auto-updated.
Some back-of-the-envelop calculations regarding the load on free
CDN solutions used by uBO to distribute its own filter lists:
Currently, for each CDN (with lists updating after days):
~560 M req/month, ~78 TB/month
With diff-patching lists on a 6-hour schedule:
~390 M req/month, 1 TB/month
Those estimates were done according to statistics shown by
jsDelivr, which is one of 4 CDNs picked randomly when a list
updates:
https://www.jsdelivr.com/package/gh/uBlockOrigin/uAssetsCDN?tab=stats
I worked through some of the websites listed in the google-ima shim
script issue[1], to see what was going wrong. It turned out the
addEventListener method supports an optional context Object, which is
bound to the listener if provided. Some websites make use of that,
and then break when `this` is not bound correctly when events are
dispatched.
See also https://github.com/duckduckgo/tracker-surrogates/pull/24
1 - https://github.com/uBlockOrigin/uBlock-issues/issues/2265
Related discussion:
https://github.com/uBlockOrigin/uBlock-issues/discussions/2895
Changes:
The _content of the My filters_ pane is now considered untrusted by
default, and only uBO's own lists are now trusted by default.
It has been observed that too many people will readily copy-paste
filters from random sources. Copy-pasting filters which require trust
represents a security risk to users with no understanding of how the
filters work and their potential abuse.
Using a filter which requires trust in a filter list from an untrusted
source will cause the filter to be invalid, i.e. shown as an error.
A new advanced setting has been added to control which lists are
considered trustworthy: `trustedListPrefixes`, which is a space-
separated list of tokens. Examples of possible values:
- `ublock-`: trust only uBO lists, exclude everything else including
content of _My filters_ (default value)
- `ublock- user-`: trust uBO lists and content of _My filters_
- `-`: trust no list, essentially disabling all filters requiring
trust (admins or people who don't trust us may want to use this)
One can also decide to trust lists maintained elsewhere. For example,
for stock AdGuard lists add ` adguard-`. To trust stock EasyList lists,
add ` easylist-`.
To trust a specific regional stock list, look-up its token in
assets.json and add to `trustedListPrefixes`.
The matching is made with String.startsWith(), hence why `ublock-`
matches all uBO's own filter lists.
This also allows to trust imported lists, for example add
` https://filters.adtidy.org/extension/ublock/filters/` to trust all
non-stock AdGuard lists.
Add the complete URL of a given imported list to trust only that one
list.
URLs not starting with `https://` or `file:///` will be rejected,
i.e. `http://example.org` will be ignored.
Invalid URLs are rejected.
Related issue:
https://github.com/uBlockOrigin/uBlock-issues/issues/2896
TODO: Eventually, distinguish between filtering profile increasing
or decreasing so as to avoid flushing caches when increasing
filtering, which should not affect the scriptlets cache.
(In addition to in already supported single- and double-quote).
The parsing of (optionally) quoted arguments from an argument
list has been spinned off into a standalone helper in order to
be reused in other parts of the parser eventually.
The `urltransform` option allows to redirect a non-blocked network
request to another URL. There are restrictions on its usage:
- require a trusted source -- thus uBO-maintained lists or user
filters
- the `urltransform` value must start with a `/`
If at least one of these conditions is not fulfilled, the filter
will be invalid and rejected.
The requirement to start with `/` is to enforce that only the path
part of a URL can be modified, thus ensuring the network request
is redirected to the same scheme and authority (as defined at
https://en.wikipedia.org/wiki/Uniform_Resource_Identifier#Syntax).
Usage example (redirect requests for CSS resources to a non-existing
resource, for demonstration purpose):
||iana.org^$css,urltransform=/notfound.css
Name of this option is inspired from DNR API:
https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/API/declarativeNetRequest/URLTransform
This commit required to bring the concept of "trusted source" to
the static network filtering engine.
As per discussion with uBO volunteers.
Volunteers offering support for uBO will be able to craft links with
specially formed URLs, which once clicked will cause uBO to automatically
force an update of specified filter lists.
The URL must be crafted as shown in the example below:
https://ublockorigin.github.io/uAssets/update-lists.html?listkeys=ublock-filters,easylist
Where the `listkeys` parameter is a comma-separated list of tokens
corresponding to filter lists. If a token does not match an enabled
filter list, it will be ignored.
The ability to update filter lists through a specially crafted link
is available only on uBO's own support sites:
- https://github.com/uBlockOrigin/
- https://reddit.com/r/uBlockOrigin/
- https://ublockorigin.github.io/
Additionally, a visual cue has been added in the "Filter lists" pane
to easily spot the filter lists which have been recently updated, where
"recently" is currently defined as less than an hour ago.
