add "HTTP Proxy" preference to support Tor, I2P, or any other proxy

This is the most basic support for channeling all downloads through Tor or
I2P.  This does not include Orbot integration, so the use will have to know
to start Orbot before using this.  I don't know anything about I2P.

closes #2367 https://dev.guardianproject.info/issues/2367
https://f-droid.org/repository/issues/?do=view_issue&issue=404
https://f-droid.org/repository/issues/?do=view_issue&issue=424

CHANGELOG.md

@@ -10,6 +10,8 @@
 
 * use FDroid repos on Tor Hidden Services (.onion addresses)
 
+* support for a HTTP Proxy in Preferences
+
 * directly send installed apps to other devices via Bluetooth and Android Beam
   (NFC+Bluetooth), also compatible with Samsung/HTC S-Beam
 

res/values/strings.xml

@@ -197,6 +197,14 @@
 	<string name="qr_wizard_download_instructions">Scan this QR Code to connect to the website for getting started.</string>
 	<string name="send_fdroid_via_wifi">Send FDroid via WiFi&#8230;</string>
 
+	<string name="proxy">Proxy</string>
+	<string name="enable_proxy_title">Enable HTTP Proxy</string>
+	<string name="enable_proxy_summary">Configure HTTP Proxy for all network requests</string>
+	<string name="proxy_host">Proxy Host</string>
+	<string name="proxy_host_summary">Configure your proxy\'s hostname (e.g. 127.0.0.1)</string>
+	<string name="proxy_port">Proxy Port</string>
+	<string name="proxy_port_summary">Configure your proxy\'s port number (e.g. 8118)</string>
+
 	<!--
 	status_download takes four parameters:
 	  - Repository (url)

res/xml/preferences.xml

@@ -70,4 +70,19 @@
 			android:defaultValue="false"
 			android:key="systemInstaller" />
 	</PreferenceCategory>
+	<PreferenceCategory android:title="@string/proxy" >
+        <CheckBoxPreference
+            android:defaultValue="false"
+            android:key="enableProxy"
+            android:title="@string/enable_proxy_title"
+            android:summary="@string/enable_proxy_summary" />
+        <EditTextPreference
+            android:key="proxyHost"
+            android:title="@string/proxy_host"
+            android:summary="@string/proxy_host_summary" />
+        <EditTextPreference
+            android:key="proxyPort"
+            android:title="@string/proxy_port"
+            android:summary="@string/proxy_port_summary" />
+	</PreferenceCategory>
 </PreferenceScreen>

src/org/fdroid/fdroid/Preferences.java

@@ -53,6 +53,9 @@ public class Preferences implements SharedPreferences.OnSharedPreferenceChangeLi
     public static final String PREF_LOCAL_REPO_BONJOUR = "localRepoBonjour";
     public static final String PREF_LOCAL_REPO_NAME = "localRepoName";
     public static final String PREF_LOCAL_REPO_HTTPS = "localRepoHttps";
+    public static final String PREF_ENABLE_PROXY = "enableProxy";
+    public static final String PREF_PROXY_HOST = "proxyHost";
+    public static final String PREF_PROXY_PORT = "proxyPort";
 
     private static final boolean DEFAULT_COMPACT_LAYOUT = false;
     private static final boolean DEFAULT_ROOTED = true;
@@ -64,6 +67,9 @@ public class Preferences implements SharedPreferences.OnSharedPreferenceChangeLi
     private static final boolean DEFAULT_INCOMP_VER = false;
     private static final boolean DEFAULT_EXPERT = false;
     private static final boolean DEFAULT_PERMISSIONS = false;
+    private static final boolean DEFAULT_ENABLE_PROXY = false;
+    public static final String DEFAULT_PROXY_HOST = "127.0.0.1";
+    public static final int DEFAULT_PROXY_PORT = 8118;
 
     private boolean compactLayout = DEFAULT_COMPACT_LAYOUT;
     private boolean filterAppsRequiringRoot = DEFAULT_ROOTED;
@@ -88,11 +94,11 @@ public class Preferences implements SharedPreferences.OnSharedPreferenceChangeLi
     private void uninitialize(String key) {
         initialized.put(key, false);
     }
-    
+
     public boolean isRootInstallerEnabled() {
         return preferences.getBoolean(PREF_ROOT_INSTALLER, DEFAULT_ROOT_INSTALLER);
     }
-    
+
     public boolean isSystemInstallerEnabled() {
         return preferences.getBoolean(PREF_SYSTEM_INSTALLER, DEFAULT_SYSTEM_INSTALLER);
     }
@@ -126,6 +132,28 @@ public class Preferences implements SharedPreferences.OnSharedPreferenceChangeLi
         return preferences.getString(PREF_LOCAL_REPO_NAME, getDefaultLocalRepoName());
     }
 
+    public boolean isProxyEnabled() {
+        return preferences.getBoolean(PREF_ENABLE_PROXY, DEFAULT_ENABLE_PROXY);
+    }
+
+    public String getProxyHost() {
+        return preferences.getString(PREF_PROXY_HOST, DEFAULT_PROXY_HOST);
+    }
+
+    public int getProxyPort() {
+        String port = preferences.getString(PREF_PROXY_PORT, String.valueOf(DEFAULT_PROXY_PORT));
+        try {
+            return Integer.parseInt(port);
+        } catch (NumberFormatException e) {
+            // hack until this can be a number-only preference
+            try {
+                return Integer.parseInt(port.replaceAll("[^0-9]", ""));
+            } catch (Exception e1) {
+                return DEFAULT_PROXY_PORT;
+            }
+        }
+    }
+
     public boolean hasCompactLayout() {
         if (!isInitialized(PREF_COMPACT_LAYOUT)) {
             initialize(PREF_COMPACT_LAYOUT);

src/org/fdroid/fdroid/net/HttpDownloader.java

@@ -3,12 +3,17 @@ package org.fdroid.fdroid.net;
 import android.content.Context;
 import android.util.Log;
 
+import org.fdroid.fdroid.Preferences;
+
 import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.InputStream;
 import java.net.HttpURLConnection;
+import java.net.InetSocketAddress;
 import java.net.MalformedURLException;
+import java.net.Proxy;
+import java.net.SocketAddress;
 import java.net.URL;
 
 import javax.net.ssl.SSLHandshakeException;
@@ -70,7 +75,14 @@ public class HttpDownloader extends Downloader {
     protected void setupConnection() throws IOException {
         if (connection != null)
             return;
-        connection = (HttpURLConnection) sourceUrl.openConnection();
+        Preferences prefs = Preferences.get();
+        if (prefs.isProxyEnabled()) {
+            SocketAddress sa = new InetSocketAddress(prefs.getProxyHost(), prefs.getProxyPort());
+            Proxy proxy = new Proxy(Proxy.Type.HTTP, sa);
+            connection = (HttpURLConnection) sourceUrl.openConnection(proxy);
+        } else {
+            connection = (HttpURLConnection) sourceUrl.openConnection();
+        }
     }
 
     protected void doDownload() throws IOException, InterruptedException {

src/org/fdroid/fdroid/views/fragments/PreferenceFragment.java

@@ -7,6 +7,8 @@ import android.preference.CheckBoxPreference;
 import android.preference.EditTextPreference;
 import android.preference.ListPreference;
 import android.preference.Preference;
+import android.text.TextUtils;
+
 import org.fdroid.fdroid.Preferences;
 import org.fdroid.fdroid.PreferencesActivity;
 import org.fdroid.fdroid.R;
@@ -34,7 +36,10 @@ public class PreferenceFragment
         Preferences.PREF_CACHE_APK,
         Preferences.PREF_EXPERT,
         Preferences.PREF_ROOT_INSTALLER,
-        Preferences.PREF_SYSTEM_INSTALLER
+        Preferences.PREF_SYSTEM_INSTALLER,
+        Preferences.PREF_ENABLE_PROXY,
+        Preferences.PREF_PROXY_HOST,
+        Preferences.PREF_PROXY_PORT,
     };
 
     @Override
@@ -144,6 +149,35 @@ public class PreferenceFragment
             onoffSummary(key, R.string.system_installer_on,
                     R.string.system_installer_off);
 
+        } else if (key.equals(Preferences.PREF_ENABLE_PROXY)) {
+            CheckBoxPreference pref = (CheckBoxPreference) findPreference(key);
+            pref.setSummary(R.string.enable_proxy_summary);
+            Preference h = findPreference(Preferences.PREF_PROXY_HOST);
+            Preference p = findPreference(Preferences.PREF_PROXY_PORT);
+            if (pref.isChecked()) {
+                h.setEnabled(true);
+                p.setEnabled(true);
+            } else {
+                h.setEnabled(false);
+                p.setEnabled(false);
+            }
+
+        } else if (key.equals(Preferences.PREF_PROXY_HOST)) {
+            EditTextPreference textPref = (EditTextPreference) findPreference(key);
+            String text = Preferences.get().getProxyHost();
+            if (TextUtils.isEmpty(text) || text.equals(Preferences.DEFAULT_PROXY_HOST))
+                textPref.setSummary(R.string.proxy_host_summary);
+            else
+                textPref.setSummary(text);
+
+        } else if (key.equals(Preferences.PREF_PROXY_PORT)) {
+            EditTextPreference textPref = (EditTextPreference) findPreference(key);
+            int port = Preferences.get().getProxyPort();
+            if (port == Preferences.DEFAULT_PROXY_PORT)
+                textPref.setSummary(R.string.proxy_port_summary);
+            else
+                textPref.setSummary(String.valueOf(port));
+
         }
     }