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Use OkHttp to solve the challenge

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This commit is contained in:
inorichi 2019-04-02 00:26:03 +02:00
parent f1f6a2b341
commit ecc1520100
1 changed files with 73 additions and 43 deletions
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116
app/src/main/java/eu/kanade/tachiyomi/network/CloudflareInterceptor.kt
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@ -2,15 +2,16 @@ package eu.kanade.tachiyomi.network
import android.annotation.SuppressLint
import android.content.Context
import android.os.Build
import android.os.Handler
import android.os.HandlerThread
import android.os.Looper
import android.webkit.WebResourceResponse
import android.webkit.WebSettings
import android.webkit.WebView
import eu.kanade.tachiyomi.util.WebViewClientCompat
import okhttp3.Interceptor
import okhttp3.Request
import okhttp3.Response
import timber.log.Timber
import java.io.IOException
import java.util.concurrent.CountDownLatch
import java.util.concurrent.TimeUnit
@ -19,30 +20,33 @@ class CloudflareInterceptor(private val context: Context) : Interceptor {
private val serverCheck = arrayOf("cloudflare-nginx", "cloudflare")
private val handler by lazy {
val thread = HandlerThread("WebViewThread").apply {
uncaughtExceptionHandler = Thread.UncaughtExceptionHandler { _, e ->
Timber.e(e)
}
start()
private val handler = Handler(Looper.getMainLooper())
/**
* When this is called, it initializes the WebView if it wasn't already. We use this to avoid
* blocking the main thread too much. If used too often we could consider moving it to the
* Application class.
*/
private val initWebView by lazy {
if (Build.VERSION.SDK_INT >= 17) {
WebSettings.getDefaultUserAgent(context)
} else {
null
}
Handler(thread.looper)
}
@Synchronized
override fun intercept(chain: Interceptor.Chain): Response {
initWebView
val response = chain.proceed(chain.request())
// Check if Cloudflare anti-bot is on
if (response.code() == 503 && response.header("Server") in serverCheck) {
try {
response.close()
if (resolveWithWebView(chain.request())) {
// Retry original request
return chain.proceed(chain.request())
} else {
throw Exception("Failed resolving Cloudflare challenge")
}
val solutionRequest = resolveWithWebView(chain.request())
return chain.proceed(solutionRequest)
} catch (e: Exception) {
// Because OkHttp's enqueue only handles IOExceptions, wrap the exception so that
// we don't crash the entire app
@ -53,45 +57,55 @@ class CloudflareInterceptor(private val context: Context) : Interceptor {
return response
}
private fun isChallengeResolverUrl(url: String): Boolean {
private fun isChallengeSolutionUrl(url: String): Boolean {
return "chk_jschl" in url
}
@SuppressLint("SetJavaScriptEnabled")
private fun resolveWithWebView(request: Request): Boolean {
private fun resolveWithWebView(request: Request): Request {
// We need to lock this thread until the WebView finds the challenge solution url, because
// OkHttp doesn't support asynchronous interceptors.
val latch = CountDownLatch(1)
var result = false
var isResolvingChallenge = false
var webView: WebView? = null
var solutionUrl: String? = null
var challengeFound = false
val requestUrl = request.url().toString()
val origRequestUrl = request.url().toString()
val headers = request.headers().toMultimap().mapValues { it.value.getOrNull(0) ?: "" }
handler.post {
val view = WebView(context)
webView = view
view.settings.javaScriptEnabled = true
view.settings.userAgentString = request.header("User-Agent")
view.webViewClient = object : WebViewClientCompat() {
override fun shouldOverrideUrlCompat(view: WebView, url: String): Boolean {
if (isChallengeSolutionUrl(url)) {
solutionUrl = url
latch.countDown()
}
return solutionUrl != null
}
override fun shouldInterceptRequestCompat(
view: WebView,
url: String
): WebResourceResponse? {
val isChallengeResolverUrl = isChallengeResolverUrl(url)
if (requestUrl != url && !isChallengeResolverUrl) {
if (solutionUrl != null) {
// Intercept any request when we have the solution.
return WebResourceResponse("text/plain", "UTF-8", null)
}
if (isChallengeResolverUrl) {
isResolvingChallenge = true
}
return null
}
override fun onPageFinished(view: WebView, url: String) {
super.onPageFinished(view, url)
if (isResolvingChallenge && url == requestUrl) {
setResultAndFinish(true)
if (url == origRequestUrl) {
// The first request didn't return the challenge, abort.
if (!challengeFound) {
latch.countDown()
}
}
}
@ -102,27 +116,43 @@ class CloudflareInterceptor(private val context: Context) : Interceptor {
failingUrl: String,
isMainFrame: Boolean
) {
if ((errorCode != 503 && requestUrl == failingUrl) ||
isChallengeResolverUrl(failingUrl)
) {
setResultAndFinish(false)
if (isMainFrame) {
if (errorCode == 503) {
// Found the cloudflare challenge page.
challengeFound = true
} else {
// Unlock thread, the challenge wasn't found.
latch.countDown()
}
}
// Any error on the main frame that isn't the Cloudflare check should unlock
// OkHttp's thread.
if (errorCode != 503 && isMainFrame) {
latch.countDown()
}
}
private fun setResultAndFinish(resolved: Boolean) {
result = resolved
latch.countDown()
view.stopLoading()
view.destroy()
}
}
view.loadUrl(requestUrl, headers)
webView?.loadUrl(origRequestUrl, headers)
}
// Wait a reasonable amount of time to retrieve the solution. The minimum should be
// around 4 seconds but it can take more due to slow networks or server issues.
latch.await(12, TimeUnit.SECONDS)
return result
handler.post {
webView?.stopLoading()
webView?.destroy()
}
val solution = solutionUrl ?: throw Exception("Challenge not found")
return Request.Builder().get()
.url(solution)
.headers(request.headers())
.addHeader("Referer", origRequestUrl)
.addHeader("Accept", "text/html,application/xhtml+xml,application/xml")
.addHeader("Accept-Language", "en")
.build()
}
}