73 lines
2.0 KiB
Swift
73 lines
2.0 KiB
Swift
//
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// FaviconURLFinder.swift
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// Evergreen
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//
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// Created by Brent Simmons on 11/20/17.
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// Copyright © 2017 Ranchero Software. All rights reserved.
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//
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import Foundation
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import RSParser
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import RSWeb
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import RSCore
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// The favicon URL may be specified in the head section of the home page.
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struct FaviconURLFinder {
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static var metadataCache = [String: RSHTMLMetadata]()
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static let serialDispatchQueue = DispatchQueue(label: "FaviconURLFinder")
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static func findFaviconURL(_ homePageURL: String, _ callback: @escaping (String?) -> Void) {
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guard let url = URL(string: homePageURL) else {
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callback(nil)
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return
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}
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downloadUsingCache(url) { (data, response, error) in
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guard let data = data, let response = response, response.statusIsOK else {
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callback(nil)
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return
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}
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// Use the absoluteString of the response’s URL instead of the homePageURL,
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// since the homePageURL might actually have been redirected.
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// Example: Dr. Drang’s feed reports the homePageURL as http://www.leancrew.com/all-this —
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// but it gets redirected to http://www.leancrew.com/all-this/ — which is correct.
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// This way any relative link to a favicon in the page’s metadata
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// will be made absolute correctly.
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let urlToUse = response.url?.absoluteString ?? homePageURL
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faviconURL(urlToUse, data, callback)
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}
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}
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static private func faviconURL(_ url: String, _ webPageData: Data, _ callback: @escaping (String?) -> Void) {
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serialDispatchQueue.async {
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let md5String = (webPageData as NSData).rs_md5HashString()
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if let md5String = md5String, let cachedMetadata = metadataCache[md5String] {
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let cachedURL = cachedMetadata.faviconLink
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DispatchQueue.main.async {
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callback(cachedURL)
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}
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return
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}
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let parserData = ParserData(url: url, data: webPageData)
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let htmlMetadata = RSHTMLMetadataParser.htmlMetadata(with: parserData)
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if let md5String = md5String {
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metadataCache[md5String] = htmlMetadata
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}
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let url = htmlMetadata.faviconLink
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DispatchQueue.main.async {
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callback(url)
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}
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}
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}
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}
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