54 lines
1.9 KiB
Swift
54 lines
1.9 KiB
Swift
// Copyright © 2022 Rangeproof Pty Ltd. All rights reserved.
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import Foundation
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import GRDB
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import SessionUtilitiesKit
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public struct LinkPreview: Codable, FetchableRecord, PersistableRecord, TableRecord, ColumnExpressible {
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public static var databaseTableName: String { "linkPreview" }
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internal static let interactionForeignKey = ForeignKey(
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[Columns.url],
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to: [Interaction.Columns.linkPreviewUrl]
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)
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internal static let interactions = hasMany(Interaction.self, using: Interaction.linkPreviewForeignKey)
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/// We want to cache url previews to the nearest 100,000 seconds (~28 hours - simpler than 86,400) to ensure the user isn't shown a preview that is too stale
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internal static let timstampResolution: Double = 100000
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public typealias Columns = CodingKeys
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public enum CodingKeys: String, CodingKey, ColumnExpression {
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case url
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case timestamp
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case variant
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case title
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}
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public enum Variant: Int, Codable, DatabaseValueConvertible {
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case standard
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case openGroupInvitation
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}
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/// The url for the link preview
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public let url: String
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/// The number of seconds since epoch rounded down to the nearest 100,000 seconds (~day) - This
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/// allows us to optimise against duplicate urls without having “stale” data last too long
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public let timestamp: TimeInterval
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/// The type of link preview
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public let variant: Variant
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/// The title for the link
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public let title: String?
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}
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// MARK: - Convenience
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public extension LinkPreview {
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static func timestampFor(sentTimestampMs: Double) -> TimeInterval {
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// We want to round the timestamp down to the nearest 100,000 seconds (~28 hours - simpler than 86,400) to optimise
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// LinkPreview storage without having too stale data
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return (floor(sentTimestampMs / 1000 / LinkPreview.timstampResolution) * LinkPreview.timstampResolution)
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}
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}
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