save grades to a encrypted cache file, use cache if not older than 24hr

app/build.gradle

@@ -51,7 +51,7 @@ dependencies {
     implementation 'androidx.core:core:1.3.1'
     implementation 'androidx.appcompat:appcompat:1.2.0'
     implementation 'androidx.legacy:legacy-support-v4:1.0.0'
-    implementation 'androidx.constraintlayout:constraintlayout:2.0.0'
+    implementation 'androidx.constraintlayout:constraintlayout:2.0.1'
     implementation 'androidx.swiperefreshlayout:swiperefreshlayout:1.1.0'
     implementation 'androidx.security:security-crypto:1.1.0-alpha02'
     implementation 'com.google.android.material:material:1.2.0'
@@ -66,7 +66,7 @@ dependencies {
     implementation 'org.jsoup:jsoup:1.13.1'
 
     testImplementation 'junit:junit:4.13'
-    androidTestImplementation 'androidx.test:core:1.2.0'
+    androidTestImplementation 'androidx.test:core:1.3.0'
     androidTestImplementation 'androidx.test.ext:junit:1.1.1'
 }
 

app/src/main/java/org/mosad/seil0/projectlaogai/controller/cache/CacheController.kt

@@ -24,21 +24,26 @@ package org.mosad.seil0.projectlaogai.controller.cache
 
 import android.content.Context
 import android.util.Log
+import androidx.security.crypto.EncryptedFile
+import androidx.security.crypto.MasterKey
 import com.google.gson.Gson
 import com.google.gson.GsonBuilder
 import com.google.gson.JsonParser
 import com.google.gson.reflect.TypeToken
 import kotlinx.coroutines.*
+import org.mosad.seil0.projectlaogai.controller.QISPOSParser
 import org.mosad.seil0.projectlaogai.controller.preferences.Preferences
 import org.mosad.seil0.projectlaogai.controller.TCoRAPIController
 import org.mosad.seil0.projectlaogai.controller.preferences.Preferences.cCourse
 import org.mosad.seil0.projectlaogai.controller.preferences.Preferences.coursesCacheTime
+import org.mosad.seil0.projectlaogai.controller.preferences.Preferences.gradesCacheTime
 import org.mosad.seil0.projectlaogai.controller.preferences.Preferences.mensaCacheTime
 import org.mosad.seil0.projectlaogai.controller.preferences.Preferences.timetableCacheTime
 import org.mosad.seil0.projectlaogai.util.*
 import java.io.*
 import java.util.*
 import kotlin.collections.ArrayList
+import kotlin.collections.HashMap
 
 /**
  * The cacheController reads and updates the cache files.
@@ -201,6 +206,25 @@ class CacheController(cont: Context) {
             }
         }
 
+        /**
+         * update the encrypted grades file
+         */
+        fun updateGrades(context: Context): Job {
+            val file = File(context.filesDir, "grades_encrypted")
+            val parser = QISPOSParser(context)
+
+            return GlobalScope.launch(Dispatchers.IO) {
+                if (parser.checkQISPOSStatus() == 200) {
+                    if (file.exists()) { file.delete() }
+
+                    // save cache file and update time
+                    saveEncrypted(context, file, Gson().toJson(parser.parseGrades()))
+                    gradesCacheTime = System.currentTimeMillis() / 1000
+                    Preferences.save(context)
+                }
+            }
+        }
+
         /**
          * save changes in lessonMap and subjectMap,
          * called on addSubject or removeSubject
@@ -223,6 +247,22 @@ class CacheController(cont: Context) {
             }
         }
 
+        private fun saveEncrypted(context: Context, file: File, text: String) {
+            val masterKey = MasterKey.Builder(context)
+                .setKeyScheme(MasterKey.KeyScheme.AES256_GCM)
+                .build()
+            val encryptedFile = EncryptedFile.Builder(
+                context,
+                file,
+                masterKey,
+                EncryptedFile.FileEncryptionScheme.AES256_GCM_HKDF_4KB
+            ).build()
+
+            encryptedFile.openFileOutput().bufferedWriter().use {
+                it.write(text)
+            }
+        }
+
     }
 
     /**
@@ -372,4 +412,40 @@ class CacheController(cont: Context) {
 
     }
 
+    /**
+     * read the encrypted grades file, don't keep them
+     * in CacheController for security reasons
+     * @return the grades as HashMap if the file exists, else a empty HashMap
+     */
+    fun readGrades(): HashMap<String, ArrayList<GradeSubject>> {
+        val file = File(context.filesDir, "grades_encrypted")
+
+        // if the file does not exit, try creating it
+        if (!file.exists()) {
+            runBlocking { updateGrades(context) }
+        }
+
+        if (file.exists()) {
+            val masterKey = MasterKey.Builder(context)
+                .setKeyScheme(MasterKey.KeyScheme.AES256_GCM)
+                .build()
+            val encryptedFile = EncryptedFile.Builder(
+                context,
+                file,
+                masterKey,
+                EncryptedFile.FileEncryptionScheme.AES256_GCM_HKDF_4KB
+            ).build()
+
+            return encryptedFile.openFileInput().bufferedReader().use {
+                GsonBuilder().create()
+                    .fromJson(
+                        it.readLine(),
+                        object : TypeToken<HashMap<String, ArrayList<GradeSubject>>>() {}.type
+                    )
+            }
+        }
+
+        return HashMap()
+    }
+
 }

app/src/main/java/org/mosad/seil0/projectlaogai/controller/cache/TimetableController.kt

@@ -38,9 +38,8 @@ import org.mosad.seil0.projectlaogai.util.TimetableWeek
  *  * add second week
  *  * add configurable week to addSubject() and removeSubject(), updateAdditionalLessons()
  */
-class TimetableController {
+object TimetableController {
 
-    companion object {
     val timetable = ArrayList<TimetableWeek>()
     val lessonMap = HashMap<String, Lesson>() // the key is courseName-subject-lessonID
     val subjectMap = HashMap<String, ArrayList<String>>() // the key is courseName
@@ -126,6 +125,4 @@ class TimetableController {
             timetable[0].days[id[0].toInt()].timeslots[id[1].toInt()].add(lesson)
     }
 
-    }
-
 }

app/src/main/java/org/mosad/seil0/projectlaogai/controller/preferences/Preferences.kt

@@ -36,6 +36,7 @@ object Preferences {
     var coursesCacheTime: Long = 0
     var mensaCacheTime: Long = 0
     var timetableCacheTime: Long = 0
+    var gradesCacheTime: Long = 0
     var cColorPrimary: Int = Color.parseColor("#009688")
     var cColorAccent: Int = Color.parseColor("#0096ff")
     var cCourse = Course(
@@ -67,6 +68,9 @@ object Preferences {
             putLong(context.getString(R.string.save_key_timetableCacheTime),
                 timetableCacheTime
             )
+            putLong(context.getString(R.string.save_key_gradesCacheTime),
+                gradesCacheTime
+            )
             apply()
         }
 
@@ -166,6 +170,9 @@ object Preferences {
         timetableCacheTime = sharedPref.getLong(context.getString(
                 R.string.save_key_timetableCacheTime
             ), 0)
+        gradesCacheTime = sharedPref.getLong(context.getString(
+            R.string.save_key_gradesCacheTime
+        ), 0)
 
         // load saved course
         cCourse = Course(

app/src/main/java/org/mosad/seil0/projectlaogai/fragments/GradesFragment.kt

@@ -35,11 +35,13 @@ import kotlinx.android.synthetic.main.fragment_grades.*
 import kotlinx.coroutines.*
 import org.mosad.seil0.projectlaogai.R
 import org.mosad.seil0.projectlaogai.controller.QISPOSParser
+import org.mosad.seil0.projectlaogai.controller.cache.CacheController
 import org.mosad.seil0.projectlaogai.controller.preferences.EncryptedPreferences
 import org.mosad.seil0.projectlaogai.controller.preferences.Preferences
 import org.mosad.seil0.projectlaogai.uicomponents.DayCardView
 import org.mosad.seil0.projectlaogai.uicomponents.GradeLinearLayout
 import org.mosad.seil0.projectlaogai.uicomponents.dialogs.LoginDialog
+import kotlin.system.measureTimeMillis
 
 /**
  * The grades fragment class
@@ -64,6 +66,7 @@ class GradesFragment : Fragment() {
 
         parser = QISPOSParser(context!!)// init the parser
 
+        // TODO if loading from cache, don't check Qispos state
         if (checkCredentials() && checkQisposStatus()) {
             GlobalScope.launch(Dispatchers.Default) {
                 addGrades()
@@ -125,18 +128,30 @@ class GradesFragment : Fragment() {
         return statusCode == 200
     }
 
-    // add the grades to the layout, async
+    /**
+     * add the grades to the layout, async
+     * TODO this is slow as hell
+     */
     private fun addGrades() = GlobalScope.launch(Dispatchers.Default) {
+        val addGradesTime = measureTimeMillis {
+
             withContext(Dispatchers.Main) {
                 refreshLayout_Grades.isRefreshing = true
             }
 
-        val grades = parser.parseGrades()
+            // if the cache is older than 24hr, update blocking
+            val currentTime = System.currentTimeMillis() / 1000
+            if ((currentTime - Preferences.gradesCacheTime) > 86400) {
+                CacheController.updateGrades(context!!).join()
+            }
+
+            val grades = CacheController(context!!).readGrades()
 
             withContext(Dispatchers.Main) {
                 linLayout_Grades.removeAllViews() // clear layout
             }
 
+            // TODO this loop takes 3/4 of the time
             // for each semester add a new card
             grades.forEach { semester ->
                 val usedSubjects = ArrayList<String>()
@@ -183,8 +198,6 @@ class GradesFragment : Fragment() {
                 }
             }
 
-
-
             val txtViewLegal = TextView(context).apply {
                 text = resources.getString(R.string.without_guarantee)
                 textAlignment = View.TEXT_ALIGNMENT_CENTER
@@ -195,6 +208,9 @@ class GradesFragment : Fragment() {
                 linLayout_Grades.addView(txtViewLegal)
                 refreshLayout_Grades.isRefreshing = false
             }
+
+        }
+        println("startup completed in $addGradesTime ms")
     }
 
 }

app/src/main/java/org/mosad/seil0/projectlaogai/fragments/TimeTableFragment.kt

@@ -33,7 +33,7 @@ import kotlinx.android.synthetic.main.fragment_timetable.*
 import kotlinx.coroutines.*
 import org.mosad.seil0.projectlaogai.R
 import org.mosad.seil0.projectlaogai.controller.cache.TimetableController
-import org.mosad.seil0.projectlaogai.controller.cache.TimetableController.Companion.timetable
+import org.mosad.seil0.projectlaogai.controller.cache.TimetableController.timetable
 import org.mosad.seil0.projectlaogai.controller.preferences.Preferences
 import org.mosad.seil0.projectlaogai.uicomponents.dialogs.AddSubjectDialog
 import org.mosad.seil0.projectlaogai.uicomponents.DayCardView

app/src/main/res/values/strings.xml

@@ -127,6 +127,7 @@
     <string name="save_key_coursesCacheTime" translatable="false">org.mosad.seil0.projectlaogai.coursesCacheTime</string>
     <string name="save_key_mensaCacheTime" translatable="false">org.mosad.seil0.projectlaogai.mensaCacheTime</string>
     <string name="save_key_timetableCacheTime" translatable="false">org.mosad.seil0.projectlaogai.timetableCacheTime</string>
+    <string name="save_key_gradesCacheTime" translatable="false">org.mosad.seil0.projectlaogai.gradesCacheTime</string>
     <string name="save_key_user_email" translatable="false">org.mosad.seil0.projectlaogai.user_email</string>
     <string name="save_key_user_password" translatable="false">org.mosad.seil0.projectlaogai.user_password</string>