gist/irc/limnoria/titlefetching.md

# A bit opinionated titlefetching

## Preparation

```
load Web
config plugins.web.snarfMultipleUrls True
config plugins.web.snarferShowDomain False
config plugins.web.snarferShowTargetDomain False
config supybot.protocols.http.userAgents "Limnoria UrlPreviewBot"
config supybot.protocols.http.peekSize 1048576
```

* enables the plugin (shipped with Limnoria)
* enables titlefetching for all links on line, not just the first one
* disables showing domain (small protection against multiple titlesfetcherrs
  entering a loop or simply not annoying users with clientside link previews
  (Matrix/Telegram bridges/relays included))
* disables showing redirect target (see previous point)
* sets user-agent to "Limnoria UrlPreviewBot" instead of ['Mozilla/5.0 (compatible; utils.web python module)' from 2005](https://github.com/ProgVal/Limnoria/blame/2990fcd302afdc6a3b741594017c3959fd5da2fd/src/utils/web.py#L120)
  * I have heard that it's bad to pretend to be something you aren't and
    Twitter will only give you HTML `<title>`s if your user-agent contains
    `UrlPreviewBot`, [thanks Tulir's Synapse patch](https://mau.dev/maunium/synapse/-/commit/55d926999cffee893cb4951890a33985beaf70ba)
* search for HTML titles from the first MEGABYTE of the webpage as modern
  web is horrible (looking at you www.hs.fi & www.youtube.com)

## Actually enabling it

```
config channel #CHAN plugins.web.titleSnarfer True
```

* enables titlefetching per-channel, on #CHAN to be accurate
  (avoiding unwanted channels in case of botloop)
  * `"channel #CHAN"` could also be replaced with `network NETWORKNAME` for
    every channel on network or `config` (or omitted entirely) for
    everywhere (channel takes priority over network which *probably* takes
    priority over global)

## Excluding domains from titlefetching

```
config supybot.plugins.Web.nonSnarfingRegexp m/(t.me|matrix.to|facebook.com|instagram.com|imgur.com)/
```

* regexp to block the listed domains, which are the first useless
  examples I have encountered recently. I just stole the regexp from
  [canonical Limnoria](https://github.com/ProgVal/Limnoria/wiki/Canonical-%23limnoria-doc)

## Titlesnarfing ignored users

While I personally don't like to do this, it's possible by

```
config channel #CHAN plugins.web.checkignored False
```

I may have the bot on multiple sides of relay or the user may be ignored due
to abuse so this may result into spam.

## Bonus: Fediverse

If [the Fediverse plugin is configured with secure fetch](https://github.com/progval/Limnoria/tree/master/plugins/Fediverse),
fetching Fediverse profiles/statuses/usernames can be enabled by:

```
channel #CHAN plugins.Fediverse.snarfers.profile true
channel #CHAN plugins.Fediverse.snarfers.status true
channel #CHAN plugins.Fediverse.snarfers.username true
```