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infinite refresh redirection issue fix #151

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infinite refresh redirection issue fix #151

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28 changes: 10 additions & 18 deletions Sources/StringExtension.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -82,6 +82,13 @@ extension String {
}

// Substring

func getSubstring(_ start: Int, end: Int) -> String {
let startIndex = self.index(self.startIndex, offsetBy: start)
let endIndex = self.index(startIndex, offsetBy: end)
return String(self[startIndex..<endIndex])
}

func substring(_ start: Int, end: Int) -> String {

return self.substring(NSRange(location: start, length: end - start))
Expand All @@ -100,27 +107,12 @@ extension String {
// Check if url is an image
func isImage() -> Bool {

let possible = ["gif", "jpg", "jpeg", "png", "bmp"]
if let url = URL(string: self),
possible.contains(url.pathExtension) {
return true
}

return false
}
return Regex.test(self, regex: Regex.imagePattern)

func isOpenGraphImage() -> Bool {
return Regex.test(self, regex: Regex.openGraphImagePattern)
}

func isVideo() -> Bool {
let possible = ["mp4", "mov", "mpeg", "avi", "m3u8"]
if let url = URL(string: self),
possible.contains(url.pathExtension) {
return true
}

return false
return Regex.test(self, regex: Regex.videoTagPattern)
}

// Split into substring of equal length
Expand Down
100 changes: 55 additions & 45 deletions Sources/SwiftLinkPreview.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -33,7 +33,8 @@ open class SwiftLinkPreview: NSObject {
// MARK: - Vars
static let titleMinimumRelevant: Int = 15
static let decriptionMinimumRelevant: Int = 100

static let maxHtmlCharacter = 300000

public var session: URLSession
public let workQueue: DispatchQueue
public let responseQueue: DispatchQueue
Expand Down Expand Up @@ -118,7 +119,7 @@ open class SwiftLinkPreview: NSObject {
successResponseQueue(result)
} else {

self.unshortenURL(url, cancellable: cancellable, completion: { unshortened in
self.unshortenURL(url, cancellable: cancellable, completion: { unshortened in
if let result = self.cache.slp_getCachedResponse(url: unshortened.absoluteString) {
successResponseQueue(result)
} else {
Expand All @@ -129,7 +130,6 @@ open class SwiftLinkPreview: NSObject {
result.canonicalUrl = self.extractCanonicalURL(unshortened)

self.extractInfo(response: result, cancellable: cancellable, completion: {

result.title = $0.title
result.description = $0.description
result.image = $0.image
Expand Down Expand Up @@ -243,7 +243,7 @@ extension SwiftLinkPreview {
}

// Unshorten URL by following redirections
fileprivate func unshortenURL(_ url: URL, cancellable: Cancellable, completion: @escaping (URL) -> Void, onError: @escaping (PreviewError) -> Void) {
fileprivate func unshortenURL(_ url: URL, cancellable: Cancellable, isRedirectURL: Bool = false, completion: @escaping (URL) -> Void, onError: @escaping (PreviewError) -> Void) {

if cancellable.isCancelled {return}

Expand All @@ -254,7 +254,6 @@ extension SwiftLinkPreview {
task = session.dataTask(with: request, completionHandler: { data, response, error in
guard !cancellable.isCancelled
else { return }

if error != nil {
self.workQueue.async {
if !cancellable.isCancelled {
Expand All @@ -271,7 +270,6 @@ extension SwiftLinkPreview {
self.session.dataTask( with: request, completionHandler: { data, response, error in
guard !cancellable.isCancelled
else { return }

if error != nil {
self.workQueue.async {
if !cancellable.isCancelled {
Expand All @@ -286,24 +284,36 @@ extension SwiftLinkPreview {
String.Encoding( rawValue: CFStringConvertEncodingToNSStringEncoding(
CFStringConvertIANACharSetNameToEncoding( $0 as CFString ) ) )
} ?? .utf8
if let html = String( data: data, encoding: encoding ) {
for meta in Regex.pregMatchAll( html, regex: Regex.metatagPattern, index: 1 ) {
if var html = String( data: data, encoding: encoding ) {
if html.count > SwiftLinkPreview.maxHtmlCharacter {
html = html.getSubstring(0, end: SwiftLinkPreview.maxHtmlCharacter-1)
}
html = html.deleteTagByPattern(Regex.commentPattern)
let metas = Regex.pregMatchAll( html, regex: Regex.metatagPattern, index: 1 )
var shouldRefresh = true
if metas.contains(where: { $0.contains("property=\"og:title\"") || $0.contains("property='og:title'")}) {
shouldRefresh = false
}
for meta in metas {
if (meta.contains( "http-equiv=\"refresh\"" ) || meta.contains( "http-equiv='refresh'" )),
let value = Regex.pregMatchFirst( meta, regex: Regex.metatagContentPattern, index: 2 )?.decoded.extendedTrim,
let redirectString = value.split( separator: ";" )
.first( where: { $0.lowercased().starts( with: "url=" ) } )?
.split( separator: "=", maxSplits: 1 ).last,
let redirectURL = URL( string: self.addImagePrefixIfNeeded( String( redirectString ), url: url ) ) {
self.unshortenURL( redirectURL, cancellable: cancellable, completion: completion, onError: onError )
return
if shouldRefresh && !isRedirectURL {
self.unshortenURL( redirectURL, cancellable: cancellable, isRedirectURL: true, completion: completion, onError: onError )
return
}
}
}
}
}

self.workQueue.async {
if !cancellable.isCancelled {
completion( url )
completion( url)
task = nil
}
}
} ).resume()
Expand All @@ -319,7 +329,7 @@ extension SwiftLinkPreview {
} else {
task?.cancel()
task = nil
self.unshortenURL(finalResult, cancellable: cancellable, completion: completion, onError: onError)
self.unshortenURL(finalResult, cancellable: cancellable, isRedirectURL: true, completion: completion, onError: onError)
}
} else {
self.workQueue.async {
Expand Down Expand Up @@ -372,7 +382,6 @@ extension SwiftLinkPreview {

completion(result)
} else {

guard let sourceUrl = url.scheme == "http" || url.scheme == "https" ? url: URL( string: "http://\(url)" )
else {
if !cancellable.isCancelled { onError(.invalidURL(url.absoluteString)) }
Expand All @@ -393,7 +402,11 @@ extension SwiftLinkPreview {
let source = NSString( data: data, encoding:
CFStringConvertEncodingToNSStringEncoding( CFStringConvertIANACharSetNameToEncoding( encoding as CFString ) ) ) {
if !cancellable.isCancelled {
self.parseHtmlString(source as String, response: response, completion: completion)
var sourceStr = source as String
if sourceStr.count > SwiftLinkPreview.maxHtmlCharacter {
sourceStr = sourceStr.getSubstring(0, end: SwiftLinkPreview.maxHtmlCharacter-1)
}
self.parseHtmlString(sourceStr, response: response, completion: completion)
}
} else {
do {
Expand All @@ -403,7 +416,11 @@ extension SwiftLinkPreview {

if let source = source {
if !cancellable.isCancelled {
self.parseHtmlString(source as String, response: response, completion: completion)
var sourceStr = source as String
if sourceStr.count > SwiftLinkPreview.maxHtmlCharacter {
sourceStr = sourceStr.getSubstring(0, end: SwiftLinkPreview.maxHtmlCharacter-1)
}
self.parseHtmlString(sourceStr, response: response, completion: completion)
}
} else {
onError(.cannotBeOpened(sourceUrl.absoluteString))
Expand Down Expand Up @@ -556,7 +573,7 @@ extension SwiftLinkPreview {
let value = value.decoded.extendedTrim
if tag == "image" {
let value = addImagePrefixIfNeeded(value, result: result)
if value.isOpenGraphImage(){ result.set(value, for: key) }
if value.isImage() { result.set(value, for: key) }
} else if tag == "video" {
let value = addImagePrefixIfNeeded(value, result: result)
if value.isVideo() { result.set(value, for: key) }
Expand Down Expand Up @@ -621,25 +638,23 @@ extension SwiftLinkPreview {
let images = result.images

if images == nil || images?.isEmpty ?? true {

// Should look for <meta property="og:image" content=""/> first instead of <img/> tag.
let values = Regex.pregMatchAll(htmlCode, regex: Regex.secondaryImageTagPattern, index: 2)
let values = Regex.pregMatchAll(htmlCode, regex: Regex.imageTagPattern, index: 2)
if !values.isEmpty {
result.images = values
result.image = values.first
} else {
// If no OpenGraph image found pick any from <img/> tag to show.
let values = Regex.pregMatchAll(htmlCode, regex: Regex.imageTagPattern, index: 2)
let imgs = values.map { self.addImagePrefixIfNeeded($0, result: result) }

result.images = imgs
result.image = imgs.first
}
else{
let values = Regex.pregMatchAll(htmlCode, regex: Regex.secondaryImageTagPattern, index: 1)
if !values.isEmpty {
let imgs = values.map { self.addImagePrefixIfNeeded($0, result: result) }
result.images = imgs
result.image = imgs.first
result.images = values
result.image = values.first
}
}

}
} else {
let values = Regex.pregMatchAll(htmlCode, regex: Regex.secondaryImageTagPattern, index: 2)
let values = Regex.pregMatchAll(htmlCode, regex: Regex.secondaryImageTagPattern, index: 1)
if !values.isEmpty {
result.images = values
result.image = values.first
Expand Down Expand Up @@ -680,27 +695,21 @@ extension SwiftLinkPreview {
var image = image

// TODO: account for HTML <base>
if let canonicalUrl = canonicalUrl, let finalUrl = finalUrl, let proto = finalUrl.split(separator: ":").first {
if image.hasPrefix("/") {
if let canonicalUrl = canonicalUrl, let finalUrl = finalUrl {
if finalUrl.hasPrefix("https:") {
if image.hasPrefix("//") {
// image url is //domain/path
image = proto + ":" + image
} else {
// image url is /path relative to base url
image = proto + "://" + canonicalUrl + image
}
} else if !image.contains("://") {
// image is relative to request url
let requestUrl = removeSuffixIfNeeded(finalUrl)
if requestUrl.hasSuffix("/") {
image = requestUrl + image
} else {
image = (requestUrl as NSString).deletingLastPathComponent + "/" + image
image = "https:" + image
} else if image.hasPrefix("/") {
image = "https://" + canonicalUrl + image
}
} else if image.hasPrefix("//") {
image = "http:" + image
} else if image.hasPrefix("/") {
image = "http://" + canonicalUrl + image
}
}

return image
return removeSuffixIfNeeded(image)

}

Expand Down Expand Up @@ -807,3 +816,4 @@ extension SwiftLinkPreview: URLSessionDataDelegate {
}

}