d82b74fb29
Added the necessary room capabilities, too. Support for replies, editing, deletion, and attachments are forthcoming.
98 lines
3.4 KiB
Go
98 lines
3.4 KiB
Go
// mautrix-discord - A Matrix-Discord puppeting bridge.
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// Copyright (C) 2024 Tulir Asokan
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Affero General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Affero General Public License for more details.
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//
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// You should have received a copy of the GNU Affero General Public License
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// along with this program. If not, see <https://www.gnu.org/licenses/>.
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package msgconv
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import (
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"regexp"
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"github.com/bwmarrin/discordgo"
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)
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type BridgeEmbedType int
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const (
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EmbedUnknown BridgeEmbedType = iota
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EmbedRich
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EmbedLinkPreview
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EmbedVideo
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)
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const discordLinkPattern = `https?://[^<\p{Zs}\x{feff}]*[^"'),.:;\]\p{Zs}\x{feff}]`
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// Discord links start with http:// or https://, contain at least two characters afterwards,
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// don't contain < or whitespace anywhere, and don't end with "'),.:;]
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//
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// Zero-width whitespace is mostly in the Format category and is allowed, except \uFEFF isn't for some reason
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var discordLinkRegex = regexp.MustCompile(discordLinkPattern)
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var discordLinkRegexFull = regexp.MustCompile("^" + discordLinkPattern + "$")
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func isActuallyLinkPreview(embed *discordgo.MessageEmbed) bool {
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// Sending YouTube links creates a video embed, but we want to bridge it as a URL preview,
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// so this is a hacky way to detect those.
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return embed.Video != nil && embed.Video.ProxyURL == ""
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}
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// isPlainGifMessage returns whether a Discord message consists entirely of a
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// link to a GIF-like animated image. A single embed must also be present on the
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// message.
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//
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// This helps replicate Discord first-party client behavior, where the link is
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// hidden when these same conditions are fulfilled.
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func isPlainGifMessage(msg *discordgo.Message) bool {
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if len(msg.Embeds) != 1 {
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return false
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}
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embed := msg.Embeds[0]
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isGifVideo := embed.Type == discordgo.EmbedTypeGifv && embed.Video != nil
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isGifImage := embed.Type == discordgo.EmbedTypeImage && embed.Image == nil && embed.Thumbnail != nil && embed.Title == ""
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contentIsOnlyURL := msg.Content == embed.URL || discordLinkRegexFull.MatchString(msg.Content)
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return contentIsOnlyURL && (isGifVideo || isGifImage)
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}
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// getEmbedType determines how a Discord embed should be bridged to Matrix by
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// returning a BridgeEmbedType.
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func getEmbedType(msg *discordgo.Message, embed *discordgo.MessageEmbed) BridgeEmbedType {
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switch embed.Type {
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case discordgo.EmbedTypeLink, discordgo.EmbedTypeArticle:
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return EmbedLinkPreview
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case discordgo.EmbedTypeVideo:
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if isActuallyLinkPreview(embed) {
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return EmbedLinkPreview
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}
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return EmbedVideo
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case discordgo.EmbedTypeGifv:
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return EmbedVideo
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case discordgo.EmbedTypeImage:
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if msg != nil && isPlainGifMessage(msg) {
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return EmbedVideo
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} else if embed.Image == nil && embed.Thumbnail != nil {
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return EmbedLinkPreview
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}
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return EmbedRich
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case discordgo.EmbedTypeRich:
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return EmbedRich
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default:
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return EmbedUnknown
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}
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}
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var hackyReplyPattern = regexp.MustCompile(`^\*\*\[Replying to]\(https://discord.com/channels/(\d+)/(\d+)/(\d+)\)`)
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func isReplyEmbed(embed *discordgo.MessageEmbed) bool {
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return hackyReplyPattern.MatchString(embed.Description)
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}
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