Read embedded server entries from a resource file

The embedded server entries can be very large, and putting them in source code as a string is unwieldy. It makes much more sense for them to be read from a file (and then we can just provide that file to the library consumer).

MobileLibrary/iOS/PsiphonTunnel/PsiphonTunnel/PsiphonTunnel.h

@@ -57,6 +57,7 @@ FOUNDATION_EXPORT const unsigned char PsiphonTunnelVersionString[];
    - `RemoteServerListSignaturePublicKey`
  - Obfuscated server list functionality is also not strictly required, but aids circumvention ability.
    - `ObfuscatedServerListRootURLs`
+   - `RemoteServerListSignaturePublicKey`: This is the same field as above. It is required if either `RemoteServerListURLs` or `ObfuscatedServerListRootURLs` is supplied.
 
  Optional fields (if you don't need them, don't set them):
  - `DataStoreDirectory`: If not set, the library will use a sane location. Override if the client wants to restrict where operational data is kept. If overridden, the directory must already exist and be writable.

MobileLibrary/iOS/SampleApps/TunneledWebRequest/TunneledWebRequest.xcodeproj/project.pbxproj

@@ -16,6 +16,7 @@
 		6626590E1DCB8CF400872F6C /* TunneledWebRequestUITests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6626590D1DCB8CF400872F6C /* TunneledWebRequestUITests.swift */; };
 		662659211DCBC7C300872F6C /* PsiphonTunnel.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 662659201DCBC7C300872F6C /* PsiphonTunnel.framework */; };
 		662659231DCBC8D800872F6C /* PsiphonTunnel.framework in CopyFiles */ = {isa = PBXBuildFile; fileRef = 662659201DCBC7C300872F6C /* PsiphonTunnel.framework */; settings = {ATTRIBUTES = (CodeSignOnCopy, RemoveHeadersOnCopy, ); }; };
+		6682D90E1EB1334000329958 /* psiphon-embedded-server-entries.txt in Resources */ = {isa = PBXBuildFile; fileRef = 6682D90D1EB1334000329958 /* psiphon-embedded-server-entries.txt */; };
 		6688DBB61DCD684B00721A9E /* psiphon-config.json in Resources */ = {isa = PBXBuildFile; fileRef = 6688DBB51DCD684B00721A9E /* psiphon-config.json */; };
 /* End PBXBuildFile section */
 
@@ -64,6 +65,7 @@
 		6626590D1DCB8CF400872F6C /* TunneledWebRequestUITests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TunneledWebRequestUITests.swift; sourceTree = "<group>"; };
 		6626590F1DCB8CF400872F6C /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
 		662659201DCBC7C300872F6C /* PsiphonTunnel.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; path = PsiphonTunnel.framework; sourceTree = "<group>"; };
+		6682D90D1EB1334000329958 /* psiphon-embedded-server-entries.txt */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text; path = "psiphon-embedded-server-entries.txt"; sourceTree = "<group>"; };
 		6688DBB51DCD684B00721A9E /* psiphon-config.json */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.json; path = "psiphon-config.json"; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
@@ -123,6 +125,7 @@
 				662658F61DCB8CF300872F6C /* LaunchScreen.storyboard */,
 				662658F91DCB8CF300872F6C /* Info.plist */,
 				6688DBB51DCD684B00721A9E /* psiphon-config.json */,
+				6682D90D1EB1334000329958 /* psiphon-embedded-server-entries.txt */,
 				662659201DCBC7C300872F6C /* PsiphonTunnel.framework */,
 			);
 			path = TunneledWebRequest;
@@ -260,6 +263,7 @@
 			files = (
 				662658F81DCB8CF300872F6C /* LaunchScreen.storyboard in Resources */,
 				662658F51DCB8CF300872F6C /* Assets.xcassets in Resources */,
+				6682D90E1EB1334000329958 /* psiphon-embedded-server-entries.txt in Resources */,
 				662658F31DCB8CF300872F6C /* Main.storyboard in Resources */,
 				6688DBB61DCD684B00721A9E /* psiphon-config.json in Resources */,
 			);

MobileLibrary/iOS/SampleApps/TunneledWebRequest/TunneledWebRequest/ViewController.swift

@@ -37,7 +37,12 @@ class ViewController: UIViewController {
         // Start up the tunnel and begin connecting.
         // This could be started elsewhere or earlier.
         NSLog("Starting tunnel")
-        let embeddedServerEntries = ""
+
+        guard let embeddedServerEntries = getEmbeddedServerEntries() else {
+            NSLog("getEmbeddedServerEntries failed!")
+            return
+        }
+
         guard let success = self.psiphonTunnel?.start(embeddedServerEntries), success else {
             NSLog("psiphonTunnel.start returned false")
             return
@@ -63,6 +68,22 @@ class ViewController: UIViewController {
                               .replacingOccurrences(of: "\r", with: "")
         self.webView.stringByEvaluatingJavaScript(from: String.init(format: "document.body.innerHTML+='<br><pre>%@</pre><br>'", arguments: [escapedText]))
     }
+
+    /// Read the Psiphon embedded server entries resource file and return the contents.
+    /// * returns: The string of the contents of the file.
+    func getEmbeddedServerEntries() -> String? {
+        guard let psiphonEmbeddedServerEntriesUrl = Bundle.main.url(forResource: "psiphon-embedded-server-entries", withExtension: "txt") else {
+            NSLog("Error getting Psiphon embedded server entries resource file URL!")
+            return nil
+        }
+
+        do {
+            return try String.init(contentsOf: psiphonEmbeddedServerEntriesUrl)
+        } catch {
+            NSLog("Error reading Psiphon embedded server entries resource file!")
+            return nil
+        }
+    }
     
     /// Request URL using URLSession configured to use the current proxy.
     /// * parameters:
@@ -209,7 +230,7 @@ extension ViewController: TunneledAppDelegate {
         do {
             return try String.init(contentsOf: psiphonConfigUrl)
         } catch {
-            NSLog("Error getting Psiphon config resource file URL!")
+            NSLog("Error reading Psiphon config resource file!")
             return nil
         }
     }

MobileLibrary/iOS/SampleApps/TunneledWebRequest/TunneledWebRequest/psiphon-embedded-server-entries.txt.stub

@@ -0,0 +1,2 @@
+Embedded server entries supplied by Psiphon Inc. go here.
+This file should be empty if embedded server entries are not being used. (But they should be used.)