_Breaking changes:_

* `jsonfeed`:
  * `jsonfeed_to_activities`: return AS1 objects, not activities.

_Non-breaking changes:_

* `as1`:
  * `activity_changed`: add `displayName`, `summary` fields.
  * `is_public`: return `False` if the object/activity contains `to` that's empty or has only unknown aliases.
* `as2`:
  * Add support for the `Application`, `Block`, `Flag`, and `Link` types.
  * Generalize actor logic in `to/from_as1` across all actor types, not just `Person`.
  * Add new `link_tags` function.
* `atom`:
  * `activities_to_atom`: handle image attachments without `url` field.
* `bluesky`:
  * `to_as1`:
    * Add support for:
      * `app.bsky.embed.record`
      * `app.bsky.embed.recordWithMedia`
      * `app.bsky.feed.defs#notFoundPost`
      * `app.bsky.feed.generator`
      * `app.bsky.graph.block`
      * `app.bsky.graph.list`
      * `app.bsky.graph.listitem`
      * `com.atproto.admin.defs#repoRef`
      * `com.atproto.moderation.createReport#input`
      * `com.atproto.repo.strongRef`
    * Add hashtag facet support.
    * Convert blobs in embeds to `getBlob` image URLs.
    * `app.bsky.actor.profile`: add HTML links for URLs in `summary` ([snarfed/bridgy-fed#1065](snarfed/bridgy-fed#1065)).
    * Escape HTML characters (`<`, `>`, `&`) in `app.bsky.actor.profile` `description` field.
    * Bug fix for `create`/`update` activities with bare string `object`.
  * `from_as1`:
    * Add hashtag, mention, block, and flag support. Interpret `tags` with missing `objectType` as hashtags.
    * Guess missing indices in facets based on content text. Otherwise, if we still don't know a facet's indices, discard it.
    * Extract HTML links (<a> tags) from HTML content and convert to link facets ([snarfed/bridgy-fed#976](snarfed/bridgy-fed#976)).
    * If an output string value is longer than its ``maxGraphemes`` or ``maxLength`` in its lexicon, truncate it with an ``…`` ellipsis character at the end in order to fit. If this happens to post text, include a link embed pointing to the original post.
    * If the object has a video, include an external embed pointing to the original post and mark it as `[Video]` ([snarfed/bridgy-fed#1078](snarfed/bridgy-fed#1078)).
    * If the object has images, add the original post link to the end of the text, since Bluesky doesn't support both image and external embeds in the same post ([bluesky-social/atproto#2575](bluesky-social/atproto#2575), [snarfed/bridgy-fed#1106](snarfed/bridgy-fed#1106)).
    * If a `note` has `summary` - often used for content warnings in the fediverse - add it to `content` as a prefix instead of overriding `content` ([snarfed/bridgy-fed#1001](snarfed/bridgy-fed#1001)).
    * Populate `reply.root` properly in reply posts ([snarfed/bridgy#1696](snarfed/bridgy#1696)).
    * Add new `original_fields_prefix` kwarg to store original data in custom (off-Lexicon) `*OriginalDescription` and `*OriginalUrl` fields in `app.bsky.actor.profile` and `*OriginalText` and `*OriginalUrl` fields in `app.bsky.feed.post` ([snarfed/bridgy-fed#1092](snarfed/bridgy-fed#1092)).
    * Support `lexrpc.Client` as well as `Bluesky` for `client` kwarg.
  * `from_as1_to_strong_ref`:
    * Add `value` boolean kwarg.
    * Change `client` kwarg from `Bluesky` to `lexrpc.Client`.
* `microformats2`:
  * Generalize actor logic across all actor types, not just `person`.
  * `json_to_object`:
    * Strip leading `#` prefix (if present) from hashtag `u-category`s.
    * Bug fix for when `name` property is an object, eg an `h-card`.
  * `object_to_json`:
    * Convert both `id` and `url` inside `inReplyTo` to `in-reply-to.`
* `nostr`:
  * Handle connection closing while sending initial query.
* `source`:
  * `Source.postprocess`: when extracting @-mentions, defer to existing tag if it has the same `displayName` and has `url`.

### Notable changes

* `as1`:
  * `get_owner` bug fix for `post`, `update`, `delete` activities.
  * `activity_changed`: add new `inReplyTo` kwarg.
  * `is_public`: add new `unlisted` kwarg.
* `as2`:
  * `to_as1`: bug fix, preserve `objectType: featured` for banner/header images even when `mediaType` is also set.
  * `is_public`: add new `unlisted` kwarg.
  * `from_as1`:
    * For `icon` field, prefer image types that are [allowed by Mastodon](https://github.com/mastodon/mastodon/blob/b4c332104a8b3748f619de250f77c0acc8e80628/app/models/concerns/account/avatar.rb#L6).
    * Bug fix, handle `stop-following` with string `object` id.
* `atom`:
  * Add new `extract_entries` function.
  * `activity_to_atom`: default actor/author name to username.
  * `atom_to_activities`: support top-level `entry` element as well as `feed`.
  * `atom_to_*`:
    * add `object.author`
    * default `objectType` to `article`/`note` and `verb` to `post`
    * convert `link rel=self`/`alternate` to `url`
    * use `displayName` in objects instead of `title`
    * Interpret entry `link` without `rel` as self link.
  * If `entry.author` doesn't have id or url, default them to feed author's.
* `bluesky`:
  * Implement `create` and `preview`.
  * Fully support both `record` and `object` types in `from_as1` and `to_as1`. Use `to_as1`'s `type` kwarg and `from_as1`'s `out_type` kwarg to disambiguate.
  * Implement `Bluesky.post_id`.
  * Add new `blob_to_url` function.
  * Delete `as1_to_profile`, switch `from_as1` to return `$type: app.bsky.actor.profile`.
  * Convert HTML `summary` and `content` to plain text.
  * Implement `Bluesky.user_to_actor`, `Bluesky.get_actor`.
  * Don't log in (fetch an access token) eagerly in the constructor; wait until the client makes a call.
  * Prefer DID to handle in API calls that accept either.
  * `at_uri_to_web_url`: support lists.
  * `web_url_to_at_uri`: convert profile URLs like `https://bsky.app/profile/snarfed.org` to profile record URIs (`at://snarfed.org/app.bsky.actor.profile/self`) instead of repo URIs (`at://snarfed.org`).
  * Add `from_as1_to_strong_ref`.
  * Allow `:`s in record keys ([atproto#2224](bluesky-social/atproto#2224)).
  * `to_as1`:
    * Convert blobs, [both new and old style](https://atproto.com/specs/data-model#blob-type), to PDS `getBlob` URLs.
    * Add new `uri` kwarg.
    * Translate `handle` to `username`, add new `repo_handle` kwarg.
    * Add support for `app.bsky.feed.repost`, `app.bsky.graph.defs#listView`, `app.bsky.feed.defs#blockedPost`.
    * Add `actor`/`author` based on `repo_did`.
    * Improve `url` field: include custom handles, only use `repo_did/handle` for `app.bsky.actor.profile`.
    * Handle bad facet indices that point inside Unicode code points ([example](https://bsky.app/profile/did:plc:2ythpj4pwwpka2ljkabouubm/post/3kkfszbaiic2g); [discussion](https://discord.com/channels/1097580399187738645/1097580399187738648/1203118842516082848)).
    * Convert [`!no-unauthenticated` label](https://github.com/bluesky-social/atproto/blob/main/packages/api/docs/labels.md#label-behaviors) on profiles to [AS1 `@unlisted` audience target](https://activitystrea.ms/specs/json/targeting/1.0/) ([bridgy-fed#828](snarfed/bridgy-fed#828)).
  * `from_as1`:
    * Add `out_type` kwarg to specify desired output type, eg `app.bsky.actor.profile` vs `app.bsky.actor.defs#profileViewBasic` vs `app.bsky.actor.defs#profileView`.
    * Add `blobs` kwarg to provide blob objects to use for image URLs.
    * Add `client` kwarg to fetch and populate CIDs.
    * Handle mention tags pointing to bare DIDs.
    * Use `parent` as `root` in replies. (Technically wrong in cases where the parent isn't the root, but we don't actually know the root. 🤷)
    * Bug fix: handle bare string URLs in `image` field.
    * Bug fix: handle tags without `url` field.
    * Strip trailing slash from home page URLs in order to remove visible `/` from rel-me verified links on Mastodon etc.
    * Convert `attributedTo` to singular if it has only one element.
    * If `name` isn't set, fall back to `preferredUsername` or infer Webfinger handle from `id` or `url`.
    * Prioritize bsky.app profile URL before handle URL in `url` field ([bridgy#1640](snarfed/bridgy#1640)).
    * Convert `bsky.app` `inReplyTo` URLs to `at://` URIs.
    * Tighten up `datetime` conversion to match the [ATProto recommended format](https://atproto.com/specs/lexicon#datetime).
* `facebook`:
  * Remove `Facebook.fql_stream_to_post`. [Facebook turned down FQL in 2016.](https://en.wikipedia.org/wiki/Facebook_Query_Language#History)
* `github`:
  * When converting data to AS1, use `displayName` in objects instead of `title`.
* `mastodon`:
  * `get_activities` bug fix: use query params for `/api/v1/notifications` API call, not JSON body.
  * Convert HTTP 200 responses with `error` JSON field (eg from Sharkey) to 400/401 exceptions.
  * Prefer `media_attachments.remote_url` when available since it may be more long-lived than `url` for remote statuses ([bridgy#1675](snarfed/bridgy#1675)).
* `microformats2`:
  * `object_to_json` bug fix: handle singular `inReplyTo`.
  * `json_to_object` bug fix: handle list-valued `location`.
* `nostr:`
  * `get_*`: return partial results when the websocket connection is closed prematurely.
  * `to_as1`: handle invalid NIP05 values (eg `{}`)
* `rss`:
  * `to_activities`:
    * Use `objectType: note` if `title` isn't set or is a prefix (possibly ellipsized) of `content`/`description`.
    * Add support for images in `media:content` tags ([#674](#674)).
* `Source`:
  * `postprocess_activity/object`: add `mentions` kwarg to convert @-mentions in HTML links to `mention` tags.

### Notable changes

Nostr, Bluesky `get_activities`, lots of improvements in `as2` and `microformats2`, and more!

_REST API breaking changes:_

[Twitter is dead](https://snarfed.org/2023-04-03_so-long-twitter-api-and-thanks-for-all-the-fish), at least in the REST API.

_Non-breaking changes:_

* Add new `nostr` module!
* `as1`:
  * Add `get_owner`, `targets`.
  * Add `accept`, `reject`, `stop-following` to `VERBS_WITH_OBJECT` and remove `repost`, [it's not an AS1 verb](https://activitystrea.ms/specs/json/schema/activity-schema.html#verbs).
  * Handle `url` field list values (even though it's invalid AS1).
* `as2`:
  * `to_as1`:
    * Improve `Video` handling: support `Link` objects in `url`, extract stream URLs and types from link `tag`s.
    * Coerce non-float `latitude` and `longitude` to float, raise `ValueError` on failure.
    * Put image attachments into `image` as well as `attachments` ([bridgy-fed#429](snarfed/bridgy-fed#429)).
    * Handle Hubzilla's composite object attachment `value`s.
    * Bug fix for null `mediaType` in `attachment` and `tags`.
  * Add new `TYPES_WITH_OBJECT` constant.
  * Add new `get_urls`, `address` functions.
  * Improve `Content-Type` compatibility with `application/ld+json; profile="https://www.w3.org/ns/activitystreams"`.
  * Bug fix for `Undo` activities with bare string id `object`s.
  * Revise HTML in `PropertyValue` attachments on actors to include full URL in anchro text to be compatible with Mastodon's profile link verification.
* `atom`:
  * `activities_to_atom` etc:
    * Switch `content` from XHTML to HTML inside CDATA to support non-XHTML input content ([bridgy-fed#624](snarfed/bridgy-fed#624).
    * Bug fix, handle bare string URL `image` values.
    * Bug fix, emove incorrect `type="application/atom+xml"` from `rel="self"` `link` in `entry`.
    * Render `objectType: comment` attachments.
    * Remove invalid `<a>` element for tags.
  * Bug fixes in `activity_to_atom`/`activities_to_atom` for dict-valued `url` fields.
  * Render images in article/note attachments.
  * Render `objectType: service` attachments, eg Bluesky custom feeds.
* `bluesky`:
  * Implement `Bluesky` API class, including `get_activities`.
  * Drop bundled `app.bsky`/`com.atproto` lexicons, use lexrpc's instead.
  * Convert reposts, quotes, inline links, attached links, and mentions, both directions. Includes Bluesky facet (rich text) support.
  * Handle quote posts with attached images, both directions.
  * Handle likes, both directions.
  * Add new `web_url_to_at_uri` function.
  * `from_as1`: handle link tags without start/end indices.
  * `to_as1`:
    * Add new `type` kwarg.
    * Generate staging.bsky.app profile and post URLs.
    * Propagate profile `did` into actor `id`.
    * Add unimplemented stub for custom feeds, eg `app.bsky.feed.defs#generatorView`.
  * Add `as1_to_profile`.
  * Bug fix for converting follows, both directions: `subject` in `app.bsky.graph.follow` is followee, not follower. ([That field is badly named!](https://discord.com/channels/1097580399187738645/1097580399187738648/1151933384738746478))
* `jsonfeed`:
  * `activities_to_jsonfeed`:
    * Bug fix, handle bare string values for `image` and `stream`.
    * Bug fix: handle non-object `author`.
* `mastodon`:
  * `status_to_object`: add/fix alt text handling for images.
* `microformats2`:
  * `json_to_html`:
    * HTML-escape tag and quote attachment names. Fixes [GHSA-4w4f-g49g-3f7j](GHSA-4w4f-g49g-3f7j); thank you [@janboddez](https://github.com/janboddez)!
  * `json_to_object`:
    * Improve handling of items with multiple types by using [post type discovery](https://indiewebcamp.com/post-type-discovery) more aggressively.
    * Normalize ISO-8601 format of `published` and `updated` timestamps.
  * `object_to_json`:
    * Bug fix, handle bare string URL `image` values.
    * Normalize ISO-8601 format of `published` and `updated` timestamps.
    * Handle bare string ids for `replies ` and `shares` (usually from AS2.)
  * Include `objectType: service` attachments, eg Bluesky custom feeds, in JSON and HTML output.
* `rss`:
  * `from_activities`: handle bare string id `author`.

### Breaking changes

* `as2`:
  * Interpret bare string `object`, `inReplyTo`, etc values as ids, convert them to bare strings or `id` instead of `url`.
* `microformats2`:
  * Convert simple string `in-reply-to`, `repost-of`, `like-of` etc values to AS1 bare strings or `id`s instead of `url`s.

### Non-breaking changes

* Add new `bluesky` module for [Bluesky](https://blueskyweb.org/)/[AT Protocol](https://atproto.com/)!
* `as1`:
  * Add the `organization` object type and `ACTOR_TYPES` constant ([based on AS2](https://www.w3.org/TR/activitystreams-core/#actors)).
  * Add new `get_ids`, `get_object`, and `get_objects` functions.
* `activity_changed`: ignore `inReplyTo.author` ([snarfed/bridgy#1338](snarfed/bridgy#1338))
* `as2`:
  * Support converting between AS1 `stop-following` and AS2 `Undo` `Follow`.
  * Support AS2 `Accept` and `Reject` for follows as well as event RSVPs.
  * Add support for the `Question` (ie poll), `Organization`, and `Delete` object types.
  * Convert `to`/`cc` to/from AS1 `to` for public and unlisted.
  * Handle `type: Document` video attachments like Mastodon emits.
  * `from_as1`: bug fix for image objects with `url` and `value` fields (for alt text).
  * `from_as1`: bug fix, handle bare string URL `image` values.
  * `from_as1`: convert `urls.displayName` to `attachment.name` ([bridgy-fed#331](snarfed/bridgy-fed#331)).
  * `from_as1`: preserve `inReplyTo` object values as objects, inline single-element lists down down to just single element.
  * `to_as1`: use `objectType: featured` for first image in `image` field.
  * `to_as1`: populate `actor` into `object.author` for `Update`s as well as `Create`s.
  * `to_as1`: convert Mastodon profile metadata `PropertyValue` attachments to `url` composite objects with `displayName`.
  * Preserve `to` and `cc` values when converting both directions.
* `atom`:
  * Bug fix for rendering image attachments without `image` field to Atom.
  * Bug fix for `published` and `updated` in entries with objects, eg likes, reposts, RSVPs, bookmarks. Thanks [@gRegorLove](https://gregorlove.com/)! ([#480](#480))
  * Bug fix for content `activity/ies_to_atom` when `object` is present and empty.
  * Bug fix for objects with elements without `objectType` in the `to` field.
* `flickr`:
  * `get_activities`: add support for the `count` kwarg.
* `github`:
  * `get_activities`: add support for the `count` kwarg.
* `jsonfeed`:
  * Switch from `white-space: pre` CSS to converting newlines to `<br>`s because some feed readers follow it strictly and don't even line wrap ([#456](#456)).
* `mastodon`:
  * Add compatibility support for [Truth Social](https://truthsocial.com/).
  * Handle truncated JSON API responses.
* `microformats2`:
  * `json_to_object`: drop backward compatibility support for `like` and `repost` properties. [Background discussion.](https://chat.indieweb.org/dev/2022-12-23#t1671833687984200)
  * `json_to_object`: add new `rel_urls` kwarg to allow attaching `displayName`s to `urls` based on HTML text or `title` attribute ([bridgy-fed#331](snarfed/bridgy-fed#331)).
  * Add new `json_to_activities` function.
  * `hcard_to_html`/`maybe_linked_name`: when `name` is missing, use pretty URL as visible text.
  * Support the `h-card` `org` property.
  * `json_to_object`: handle composite `rsvp` property value.
  * `json_to_object`: bug fix when `fetch_mf2` is True, handle when we run the authorship algorithm and fetch an author URL that has a `u-photo` with `alt`.
* `rss`:
  * `from_activities`: fix item ordering to match input activities.

### Breaking changes

* Drop Python 3.6 support. Python 3.7 is now the minimum required version.
* Twitter, Instagram, Mastodon:
  * Drop `get_activities` `cache` kwarg's support for App Engine memcache interface. It's now only used as a plain `dict`. `get_activities` will now make many small modifications, so if you pass an object that implements those as API calls, you'll probably want to batch those separately.
* Twitter, Mastodon, Flickr, GitHub:
  * `create`/`preview`: support the AS1 `favorite` verb as well as `like`. ([bridgy#1345](snarfed/bridgy#1345))
* Atom:
  * Switch to converting AS1 `id` (instead of `url`) to Atom `id`.
* Reddit:
  * Implement `get_actor`.
* Mastodon:
  * `create`/`preview`: allow non-Mastodon replies, ie activities that include `inReplyTo` URLs even if none of them point to a toot. ([bridgy#1321](snarfed/bridgy#1321))
  * Raise `requests.HTTPError` with `response.status_code` 502 instead of `JSONDecodeError` on non-JSON responses. This is synthetic, but more helpful for error handling.
* microformats2:
  * `object_to_json` and related functions: handle all escaped HTML entities, not just `&` `<` `>`.
  * Unify `microformats2.prefix_image_urls` and `prefix_video_urls` into a new `as1.prefix_urls` function.
* RSS:
  * Remove `itunes:category`. It has to be [one of Apple's explicit categories](https://feedgen.kiesow.be/ext/api.ext.podcast.html#feedgen.ext.podcast.PodcastExtension.itunes_category), which we aren't prepared to validate, so don't try.
* ActivityStreams 2:
  * Translate both `url` and `urls` from AS1 into multi-valued AS2 `url` field.
* Move a number of utility methods from the `Source` class to a new `as1` module: `object_type`, `merge_by_id`, `is_public`, `add_rsvps_to_event`, `get_rsvps_from_event`, `activity_changed`, `append_in_reply_to`, `actor_name`, `original_post_discovery`.
* `as1.original_post_discovery`: remove deprecated `cache` kwarg.

### Non-breaking changes

* ActivityStreams 2:
  * Fix spec compliance bug: [`icon` and `image` are singly valued, not multiply valued](https://www.w3.org/TR/activitystreams-vocabulary/#dfn-icon).
  * Add new `is_public` method and `PUBLIC_AUDIENCE` constant.
  * Prefer `"objectType": "featured"` first in the `image` field when converting from AS1, last in the `icon` field. This matches the ActivityPub (Mastodon) convention of using `icon` for profile pictures and `image` for header images.
  * Propagate `url` values into new `PropertyValue` attachments on `Person` objects; these end up in Mastodon's "profile metadata" link fields.
  * `to_as1`: if an attachment's `mediaType` is `image/...`, override `objectType` and set it to `image`.
* Twitter
  * Trim alt text in line between post preview and creation
  * Correctly trim Twitter alt text
* Facebook
  * Scraping: extract post id and owner id from `data-ft` attribute and `_ft_` query param more often instead of `story_fbid`, which is now an opaque token that changes regularly. ([facebook-atom#27](snarfed/facebook-atom#27))
* Instagram
  * Add new `Instagram.scraped_json_to_activities` method.
* GitHub
  * `create` and `preview`: convert profile URLs to @-mentions, eg `https://github.com/snarfed` to `@snarfed` ([bridgy#1090](snarfed/bridgy#1090)).
    * `get_activities` with `activity_id` now supports `fetch_replies` and `fetch_likes`.
* Reddit
  * Add `cache` support to `get_activities`.
* REST API
  * Add new `/scraped` endpoint that accepts `POST` requests with silo HTML as input. Currently only supports Instagram. Requires `site=instagram`, `output=...` (any supported output format), and HTML as either raw request body or MIME multipart encoded file in the `input` parameter.
* microformats2
  * Add new `extra` and `body_class` kwargs to `activities_to_html`.
  * When converting `u-featured` images to AS1, add new non-standard `"objectType": "featured"` field to distinguish them from `u-photo`.
  * Convert `p-note` to AS1 `summary`.
  * Bug fixes for converting `image` attachments to `photo`.
* `Source.original_post_discovery`: add new `max_redirect_fetches` keyword arg.

### Breaking changes

* Drop Python 3.5 support. Python 3.6 is now the minimum required version.

### Non-breaking changes

* Add new `include_shares` kwarg to `get_activities`, implemented for Twitter and Mastodon. Defaults to `True`. If `False`, shares (retweets in Twitter, boosts in Mastodon) will be discarded and not returned. Also add a corresponding `shares` query param to the REST API.
* RSS:
  * Add support for RSS input via new `rss.to_activities` function.
* Instagram (scraping):
  * Handle media items with no `user` object, add new fetch for comments.
  * Add `Instagram.merge_scraped_comments()`.
* ActivityStreams 2:
  * Handle error when `type` isn't a string.
* Reddit:
  * Implement `get_activities()` to fetch posts by the current user or a user specified with `user_id`.
* Facebook scraping:
  * Skip "Suggested for you" posts.
  * Add `log_html` kwarg to `get_activities`; defaults to False.
  * Miscellaneous bug fixes.
* JSONFeed:
  * Handle malformed `items.author` element.

### Notable changes

* `Source.original_post_discovery`: add new `include_reserved_hosts` kwarg, defaults to `True`.
* Facebook:
  * Scraping: handle pictures, videos, link attachments, and text links in timeline/news feed posts.
* Mastodon:
  * Bug fix for `get_activities()` with `fetch_mentions=True`: handle notifications with `status: null`. Maybe happens when a status is deleted?
  * `create`/`preview_create`: support bookmarks. (Nothing special happens with them; their `content` is posted as a normal toot.)
* microformats2:
  * Stop rendering `image.displayName` as visible text in HTML, since it's already in the `<img>`'s `alt` attribute.
  * Add [`bookmark-of`](https://indieweb.org/bookmark#How_to_markup) support.
  * Add `prefix_image_urls()` function.
  * Handle null `content` in AS1/2 objects.
  * `json_to_object` bug fix for composite `bookmark-of` properties.
* Twitter:
  * `create`/`preview`: [support large videos](https://twittercommunity.com/t/large-file-can-not-be-finalized-synchronously/82929/3) via async upload. We now pass `media_category=tweet_video` to the chunked upload `INIT` stage, and then make blocking `STATUS` calls until the video is finished processing. ([bridgy#1043](snarfed/bridgy#1043))
  * `create`/`preview`: allow bookmarks. ([bridgy#1045](snarfed/bridgy#1045))
  * `create`/`preview`: allow non-Twitter replies, ie activities that include `inReplyTo` URLs even if none of them point to a tweet. ([bridgy#1063](snarfed/bridgy#1063))
  * `get_activities`: support list ids as well as slugs.
  * Bug fixes for removing t.co links to quoted tweets.
  * Bug fix for multiple instances of the same link in tweet text.
  * `get_activities()`: raise `ValueError` on invalid `user_id`.
* REST API: ported web framework from webapp2 to Flask. No user-visible behavior change expected.

release v3.1

### Notable changes

_Breaking changes:_

* _Python 2 is no longer supported!_ Including the [App Engine Standard Python 2 runtime](https://cloud.google.com/appengine/docs/standard/python/). On the plus side, the [Python 3 runtime](https://cloud.google.com/appengine/docs/standard/python3/) is now supported! See this [list of differences](https://cloud.google.com/appengine/docs/standard/python3/python-differences) for more details.

Non-breaking changes:

* Migrate demo app and API to the App Engine Standard Python 3 runtime.
* Instagram:
  * Scraping: fetch 50 likes instead of 24. ([snarfed/bridgy#898](snarfed/bridgy#898))
  * Scraping bug fix for `get_actor()` with `user_id`.
* Twitter:
  * Add [image alt text](https://blog.twitter.com/developer/en_us/a/2016/alt-text-support-for-twitter-cards-and-the-rest-api.html) support to `get_activites()` etc ([#183](#183)).
* RSS:
  * Add `itunes:image`, `itunes:author`, and `itunes:category`.
  * Strip HTML from `title` element ([#177](#177)). [Background.](https://validator.w3.org/feed/docs/warning/ContainsHTML.html)
  * Always include author in items ([#177](#177)).
  * Bug fix: extract feed image from `hfeed` correctly.
  * Bug fix: don't crash on `article` or `mention` tags in items with enclosures.
* Atom:
  * Bug fix: extract feed image from `hfeed` correctly.
* REST API:
  * Add HTTP `HEAD` support.
  * Add support for URL fragments with `input=html`. If a fragment is provided, only that specific element is extracted and converted. ([#185](#185))
* GitHub:
  * Publish: preserve `<code>` tags instead of converting them to \`s so that GitHub renders HTML entities like `&gt;` inside them instead of leaving them escaped. [Background.](https://chat.indieweb.org/dev/2019-12-24#t1577174464779200)
* JSON Feed:
  * Handle malformed attachments better.
* microformats2:
  * Don't crash on string `context` fields.
  * `html_to_activities()`: limit to `h-entry`, `h-event`, and `h-cite` items ([#192](#192)).
* The `cache` kwarg to `Source.original_post_discovery()` now has no effect. `webutil.util.follow_redirects()` has its own built in caching now.
* Added Meetup.com support for publishing RSVPs.

### Notable changes

* Add Mastodon support!
* Add Python 3.7 support, and improve overall Python 3 compatibility.
* Update a number of dependencies.
* Switch from Python's built in `json` module to [`ujson`](https://github.com/esnme/ultrajson/) to speed up JSON parsing and encoding.
* Add `duration` and `size` support to ActivityStreams 1 and 2, RSS, and microformats2 HTML and JSON. [microformats2 support is still emerging for both](https://indieweb.org/podcast#Brainstorming). Both integer seconds and [ISO 8601 string durations](https://en.wikipedia.org/wiki/ISO_8601#Durations) are supported for `duration`. Integer bytes is used for `size` everywhere. microformats2 HTML also includes human-readable strings, eg `5.1 MB`. ([#169](#169))
* Twitter:
  * `[preview]_create()`: detect attempts to upload [images over 5MB](https://developer.twitter.com/en/docs/media/upload-media/uploading-media/media-best-practices#image-specs) and return an error.
* Facebook:
  * Add `get_activities(scrape=True)` for scraping HTML from [m.facebook.com](https://m.facebook.com/). Requires `c_user` and `xs` cookies from a logged in session ([snarfed/bridgy#886](snarfed/bridgy#886)).
  * [Upgrade Graph API version from 2.10 to 4.0.](https://developers.facebook.com/docs/graph-api/changelog)
* Atom:
  * Bug fix for de-duping images in attachments.
* RSS:
  * Wrap all `<description>` element contents in `CDATA` sections.
  * Render images in `<description>` with HTML `<img>` tags ([#175](#175)).
  * `from_activities()` bug fix: don't crash when converting multiple attachments to enclosures in a single item. (RSS only supports one enclosure per item, so we now only include the first, and log a warning if the activity has more.)