app/src/main/java/com/stoutner/privacybrowser/backgroundtasks/GetSourceBackgroundTask.kt

   1 /*
   2  * Copyright © 2017-2023 Soren Stoutner <soren@stoutner.com>.
   3  *
   4  * This file is part of Privacy Browser Android <https://www.stoutner.com/privacy-browser-android>.
   5  *
   6  * Privacy Browser Android is free software: you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation, either version 3 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * Privacy Browser Android is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with Privacy Browser Android.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 package com.stoutner.privacybrowser.backgroundtasks
  21
  22 import android.annotation.SuppressLint
  23 import android.content.ContentResolver
  24 import android.graphics.Typeface
  25 import android.net.Uri
  26 import android.text.SpannableStringBuilder
  27 import android.text.Spanned
  28 import android.text.style.StyleSpan
  29 import android.webkit.CookieManager
  30
  31 import com.stoutner.privacybrowser.viewmodels.WebViewSource
  32
  33 import java.io.BufferedInputStream
  34 import java.io.BufferedReader
  35 import java.io.ByteArrayOutputStream
  36 import java.io.IOException
  37 import java.io.InputStream
  38 import java.io.InputStreamReader
  39
  40 import java.net.HttpURLConnection
  41 import java.net.Proxy
  42 import java.net.URL
  43
  44 import java.security.SecureRandom
  45 import java.security.cert.X509Certificate
  46
  47 import javax.net.ssl.HostnameVerifier
  48 import javax.net.ssl.HttpsURLConnection
  49 import javax.net.ssl.SSLContext
  50 import javax.net.ssl.SSLSession
  51 import javax.net.ssl.TrustManager
  52 import javax.net.ssl.X509TrustManager
  53
  54
  55 class GetSourceBackgroundTask {
  56     fun acquire(urlString: String, userAgent: String, localeString: String, proxy: Proxy, contentResolver: ContentResolver, webViewSource: WebViewSource, ignoreSslErrors: Boolean):
  57             Array<SpannableStringBuilder> {
  58
  59         // Initialize the spannable string builders.
  60         val requestHeadersBuilder = SpannableStringBuilder()
  61         val responseMessageBuilder = SpannableStringBuilder()
  62         val responseHeadersBuilder = SpannableStringBuilder()
  63         val responseBodyBuilder = SpannableStringBuilder()
  64
  65         if (urlString.startsWith("content://")) {  // This is a content URL.
  66             // Attempt to read the content data.  Return an error if this fails.
  67             try {
  68                 // Get a URI for the content URL.
  69                 val contentUri = Uri.parse(urlString)
  70
  71                 // Get a cursor with metadata about the content URL.
  72                 val contentCursor = contentResolver.query(contentUri, null, null, null, null)!!
  73
  74                 // Move the content cursor to the first row.
  75                 contentCursor.moveToFirst()
  76
  77                 // Populate the response header.
  78                 for (i in 0 until contentCursor.columnCount) {
  79                     // Add a new line if this is not the first entry.
  80                     if (i > 0)
  81                         responseHeadersBuilder.append(System.getProperty("line.separator"))
  82
  83                     // Add each header to the string builder.
  84                     responseHeadersBuilder.append(contentCursor.getColumnName(i), StyleSpan(Typeface.BOLD), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE)
  85                     responseHeadersBuilder.append(":  ")
  86                     responseHeadersBuilder.append(contentCursor.getString(i))
  87                 }
  88
  89                 // Close the content cursor.
  90                 contentCursor.close()
  91
  92                 // Create a buffered string reader for the content data.
  93                 val bufferedReader = BufferedReader(InputStreamReader(contentResolver.openInputStream(contentUri)))
  94
  95                 // Create a buffered string reader for the content data.
  96                 var contentLineString: String?
  97
  98                 // Get the data from the buffered reader one line at a time.
  99                 while (bufferedReader.readLine().also { contentLineString = it } != null) {
 100                     // Add the line to the response body builder.
 101                     responseBodyBuilder.append(contentLineString)
 102
 103                     // Append a new line.
 104                     responseBodyBuilder.append("\n")
 105                 }
 106             } catch (exception: Exception) {
 107                 // Return the error message.
 108                 webViewSource.returnError(exception.toString())
 109             }
 110         } else {  // This is not a content URL.
 111             // Because everything relating to requesting data from a webserver can throw errors, the entire section must catch `IOExceptions`.
 112             try {
 113                 // Get the current URL from the main activity.
 114                 val url = URL(urlString)
 115
 116                 // Open a connection to the URL.  No data is actually sent at this point.
 117                 val httpUrlConnection = url.openConnection(proxy) as HttpURLConnection
 118
 119                 // Set the `Host` header property.
 120                 httpUrlConnection.setRequestProperty("Host", url.host)
 121
 122                 // Add the `Host` header to the string builder and format the text.
 123                 requestHeadersBuilder.append("Host", StyleSpan(Typeface.BOLD), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE)
 124                 requestHeadersBuilder.append(":  ")
 125                 requestHeadersBuilder.append(url.host)
 126
 127
 128                 // Set the `Connection` header property.
 129                 httpUrlConnection.setRequestProperty("Connection", "keep-alive")
 130
 131                 // Add the `Connection` header to the string builder and format the text.
 132                 requestHeadersBuilder.append(System.getProperty("line.separator"))
 133                 requestHeadersBuilder.append("Connection", StyleSpan(Typeface.BOLD), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE)
 134                 requestHeadersBuilder.append(":  keep-alive")
 135
 136
 137                 // Set the `Upgrade-Insecure-Requests` header property.
 138                 httpUrlConnection.setRequestProperty("Upgrade-Insecure-Requests", "1")
 139
 140                 // Add the `Upgrade-Insecure-Requests` header to the string builder and format the text.
 141                 requestHeadersBuilder.append(System.getProperty("line.separator"))
 142                 requestHeadersBuilder.append("Upgrade-Insecure-Requests", StyleSpan(Typeface.BOLD), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE)
 143                 requestHeadersBuilder.append(":  1")
 144
 145
 146                 // Set the `User-Agent` header property.
 147                 httpUrlConnection.setRequestProperty("User-Agent", userAgent)
 148
 149                 // Add the `User-Agent` header to the string builder and format the text.
 150                 requestHeadersBuilder.append(System.getProperty("line.separator"))
 151                 requestHeadersBuilder.append("User-Agent", StyleSpan(Typeface.BOLD), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE)
 152                 requestHeadersBuilder.append(":  ")
 153                 requestHeadersBuilder.append(userAgent)
 154
 155
 156                 // Set the `Sec-Fetch-Site` header property.
 157                 httpUrlConnection.setRequestProperty("Sec-Fetch-Site", "none")
 158
 159                 // Add the `Sec-Fetch-Site` header to the string builder and format the text.
 160                 requestHeadersBuilder.append(System.getProperty("line.separator"))
 161                 requestHeadersBuilder.append("Sec-Fetch-Site", StyleSpan(Typeface.BOLD), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE)
 162                 requestHeadersBuilder.append(":  none")
 163
 164
 165                 // Set the `Sec-Fetch-Mode` header property.
 166                 httpUrlConnection.setRequestProperty("Sec-Fetch-Mode", "navigate")
 167
 168                 // Add the `Sec-Fetch-Mode` header to the string builder and format the text.
 169                 requestHeadersBuilder.append(System.getProperty("line.separator"))
 170                 requestHeadersBuilder.append("Sec-Fetch-Mode", StyleSpan(Typeface.BOLD), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE)
 171                 requestHeadersBuilder.append(":  navigate")
 172
 173
 174                 // Set the `Sec-Fetch-User` header property.
 175                 httpUrlConnection.setRequestProperty("Sec-Fetch-User", "?1")
 176
 177                 // Add the `Sec-Fetch-User` header to the string builder and format the text.
 178                 requestHeadersBuilder.append(System.getProperty("line.separator"))
 179                 requestHeadersBuilder.append("Sec-Fetch-User", StyleSpan(Typeface.BOLD), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE)
 180                 requestHeadersBuilder.append(":  ?1")
 181
 182
 183                 // Set the `Accept` header property.
 184                 httpUrlConnection.setRequestProperty("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3")
 185
 186                 // Add the `Accept` header to the string builder and format the text.
 187                 requestHeadersBuilder.append(System.getProperty("line.separator"))
 188                 requestHeadersBuilder.append("Accept", StyleSpan(Typeface.BOLD), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE)
 189                 requestHeadersBuilder.append(":  ")
 190                 requestHeadersBuilder.append("text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3")
 191
 192
 193                 // Set the `Accept-Language` header property.
 194                 httpUrlConnection.setRequestProperty("Accept-Language", localeString)
 195
 196                 // Add the `Accept-Language` header to the string builder and format the text.
 197                 requestHeadersBuilder.append(System.getProperty("line.separator"))
 198                 requestHeadersBuilder.append("Accept-Language", StyleSpan(Typeface.BOLD), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE)
 199                 requestHeadersBuilder.append(":  ")
 200                 requestHeadersBuilder.append(localeString)
 201
 202
 203                 // Get the cookies for the current domain.
 204                 val cookiesString = CookieManager.getInstance().getCookie(url.toString())
 205
 206                 // Only process the cookies if they are not null.
 207                 if (cookiesString != null) {
 208                     // Add the cookies to the header property.
 209                     httpUrlConnection.setRequestProperty("Cookie", cookiesString)
 210
 211                     // Add the cookie header to the string builder and format the text.
 212                     requestHeadersBuilder.append(System.getProperty("line.separator"))
 213                     requestHeadersBuilder.append("Cookie", StyleSpan(Typeface.BOLD), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE)
 214                     requestHeadersBuilder.append(":  ")
 215                     requestHeadersBuilder.append(cookiesString)
 216                 }
 217
 218
 219                 // `HttpUrlConnection` sets `Accept-Encoding` to be `gzip` by default.  If the property is manually set, than `HttpUrlConnection` does not process the decoding.
 220                 // Add the `Accept-Encoding` header to the string builder and format the text.
 221                 requestHeadersBuilder.append(System.getProperty("line.separator"))
 222                 requestHeadersBuilder.append("Accept-Encoding", StyleSpan(Typeface.BOLD), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE)
 223                 requestHeadersBuilder.append(":  gzip")
 224
 225                 // Ignore SSL errors if requested.
 226                 if (ignoreSslErrors) {
 227                     // Create a new host name verifier that allows all host names without checking for SSL errors.
 228                     val hostnameVerifier = HostnameVerifier { _: String?, _: SSLSession? -> true }
 229
 230                     // Create a new trust manager.  Lint wants to warn us that it is hard to securely implement an X509 trust manager.
 231                     // But the point of this trust manager is that it should accept all certificates no matter what, so that isn't an issue in our case.
 232                     @SuppressLint("CustomX509TrustManager") val trustManager = arrayOf<TrustManager>(
 233                         object : X509TrustManager {
 234                             @SuppressLint("TrustAllX509TrustManager")
 235                             override fun checkClientTrusted(chain: Array<X509Certificate>, authType: String) {
 236                                 // Do nothing, which trusts all client certificates.
 237                             }
 238
 239                             @SuppressLint("TrustAllX509TrustManager")
 240                             override fun checkServerTrusted(chain: Array<X509Certificate>, authType: String) {
 241                                 // Do nothing, which trusts all server certificates.
 242                             }
 243
 244                             override fun getAcceptedIssuers(): Array<X509Certificate>? {
 245                                 return null
 246                             }
 247                         }
 248                     )
 249
 250                     // Get an SSL context.  `TLS` provides a base instance available from API 1.  <https://developer.android.com/reference/javax/net/ssl/SSLContext>
 251                     val sslContext = SSLContext.getInstance("TLS")
 252
 253                     // Initialize the SSL context with the blank trust manager.
 254                     sslContext.init(null, trustManager, SecureRandom())
 255
 256                     // Get the SSL socket factory with the blank trust manager.
 257                     val socketFactory = sslContext.socketFactory
 258
 259                     // Set the HTTPS URL Connection to use the blank host name verifier.
 260                     (httpUrlConnection as HttpsURLConnection).hostnameVerifier = hostnameVerifier
 261
 262                     // Set the HTTPS URL connection to use the socket factory with the blank trust manager.
 263                     httpUrlConnection.sslSocketFactory = socketFactory
 264                 }
 265
 266                 // The actual network request is in a `try` bracket so that `disconnect()` is run in the `finally` section even if an error is encountered in the main block.
 267                 try {
 268                     // Get the response code, which causes the connection to the server to be made.
 269                     val responseCode = httpUrlConnection.responseCode
 270
 271                     // Populate the response message string builder.
 272                     responseMessageBuilder.append(responseCode.toString(), StyleSpan(Typeface.BOLD), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE)
 273                     responseMessageBuilder.append(":  ")
 274                     responseMessageBuilder.append(httpUrlConnection.responseMessage)
 275
 276                     // Initialize the iteration variable.
 277                     var i = 0
 278
 279                     // Iterate through the received header fields.
 280                     while (httpUrlConnection.getHeaderField(i) != null) {
 281                         // Add a new line if there is already information in the string builder.
 282                         if (i > 0)
 283                             responseHeadersBuilder.append(System.getProperty("line.separator"))
 284
 285                         // Add the header to the string builder and format the text.
 286                         responseHeadersBuilder.append(httpUrlConnection.getHeaderFieldKey(i), StyleSpan(Typeface.BOLD), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE)
 287                         responseHeadersBuilder.append(":  ")
 288                         responseHeadersBuilder.append(httpUrlConnection.getHeaderField(i))
 289
 290                         // Increment the iteration variable.
 291                         i++
 292                     }
 293
 294                     // Get the correct input stream based on the response code.
 295                     val inputStream: InputStream = if (responseCode == 404)  // Get the error stream.
 296                         BufferedInputStream(httpUrlConnection.errorStream)
 297                     else  // Get the response body stream.
 298                         BufferedInputStream(httpUrlConnection.inputStream)
 299
 300                     // Initialize the byte array output stream and the conversion buffer byte array.
 301                     val byteArrayOutputStream = ByteArrayOutputStream()
 302                     val conversionBufferByteArray = ByteArray(1024)
 303
 304                     // Define the buffer length variable.
 305                     var bufferLength: Int
 306
 307                     try {
 308                         // Attempt to read data from the input stream and store it in the conversion buffer byte array.  Also store the amount of data read in the buffer length variable.
 309                         while (inputStream.read(conversionBufferByteArray).also { bufferLength = it } > 0) {  // Proceed while the amount of data stored in the buffer is > 0.
 310                             // Write the contents of the conversion buffer to the byte array output stream.
 311                             byteArrayOutputStream.write(conversionBufferByteArray, 0, bufferLength)
 312                         }
 313                     } catch (exception: IOException) {
 314                         // Return the error message.
 315                         webViewSource.returnError(exception.toString())
 316                     }
 317
 318                     // Close the input stream.
 319                     inputStream.close()
 320
 321                     // Populate the response body string with the contents of the byte array output stream.
 322                     responseBodyBuilder.append(byteArrayOutputStream.toString())
 323                 } finally {
 324                     // Disconnect HTTP URL connection.
 325                     httpUrlConnection.disconnect()
 326                 }
 327             } catch (exception: Exception) {
 328                 // Return the error message.
 329                 webViewSource.returnError(exception.toString())
 330             }
 331         }
 332
 333         // Return the spannable string builders.
 334         return arrayOf(requestHeadersBuilder, responseMessageBuilder, responseHeadersBuilder, responseBodyBuilder)
 335     }
 336 }