71 lines
2.8 KiB
Swift
71 lines
2.8 KiB
Swift
/*
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Copyright 2020 New Vector Ltd
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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import Foundation
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@objcMembers
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final class FormattedBodyParser: NSObject {
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private struct HTMLURLAnchor {
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let link: URL
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let content: String
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}
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private enum Constants {
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static let htmlURLAnchorTagRegexPattern = "<a href=\"(.*?)\">([^<]*)</a>"
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}
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private lazy var htmlURLAnchorRegex: NSRegularExpression? = {
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return try? NSRegularExpression(pattern: Constants.htmlURLAnchorTagRegexPattern, options: .caseInsensitive)
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}()
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private func getHTMLURLAnchors(forURL url: URL, inFormattedBody formattedBody: String) -> [HTMLURLAnchor] {
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// Use regex here self.htmlURLAnchorRegex
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// build and return list with `HTMLURLAnchor`
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guard let regex = htmlURLAnchorRegex else {
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return []
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}
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return regex.matches(in: formattedBody, options: [], range: NSRange(formattedBody.startIndex..., in: formattedBody)).compactMap { (result) -> HTMLURLAnchor? in
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guard result.numberOfRanges > 2 else { return nil }
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guard let urlRange = Range(result.range(at: 1), in: formattedBody) else {
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return nil
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}
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let urlString = String(formattedBody[urlRange])
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guard let contentRange = Range(result.range(at: 2), in: formattedBody) else {
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return nil
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}
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let content = String(formattedBody[contentRange])
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// ignore invalid urls
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guard let link = URL(string: urlString) else { return nil }
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// ignore other links
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guard link == url else { return nil }
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return HTMLURLAnchor(link: link, content: content)
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}
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}
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/// Gets visible url for a given url. Assumes formattedBody has one or more links like: '<a href="https://example.com/given">https://example.com/visible</a>'
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/// - Parameter url: the url given as target
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/// - Parameter formattedBody: html formatted body
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/// - Returns: visible url if found, otherwise nil
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func getVisibleURL(forURL url: URL, inFormattedBody formattedBody: String) -> URL? {
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// TODO: returning first link here. Get url range in formattedBody to detect which link is actually tapped.
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return self.getHTMLURLAnchors(forURL: url, inFormattedBody: formattedBody).compactMap { URL(string: $0.content) }.first
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}
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}
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