Finished main Resolve FetchType implementation

cfg/gen.cfg

@@ -39,7 +39,7 @@
 #
 # The following values are allowed for this option:
 # 	- Resolve: gets the target IP address by resolving the provided address.
-# 	- RawFetch: gets the target IP address by connecting to the provided
+# 	- PlainText: gets the target IP address by connecting to the provided
 # 	  address that outputs the desired IP address in plain text.
 FetchType=Resolve
 

src/com/luca0n/dual/common/Dual.java

@@ -24,11 +24,15 @@ import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.FileSystems;
 import java.nio.file.Path;
+import java.net.InetAddress;
+import java.util.List;
+import java.util.ArrayList;
 
 import com.luca0n.dual.common.ConfigSyntaxException;
 import com.luca0n.dual.common.NoSuchNamespaceException;
 import com.luca0n.dual.common.NoSuchKeyException;
 import com.luca0n.dual.common.UnsupportedOperatingSystemException;
+import com.luca0n.dual.common.UnknownFetchTypeException;
 import com.luca0n.dual.config.Config;
 import com.luca0n.dual.config.ConfigUtil;
 
@@ -57,7 +61,7 @@ public class Dual {
 	}
 	public static void run() throws ConfigSyntaxException,
 		NoSuchNamespaceException, NoSuchKeyException, IOException,
-		UnsupportedOperatingSystemException {
+		UnsupportedOperatingSystemException, UnknownFetchTypeException {
 		// Read configuration file
 		Config c = ConfigUtil.fromFile(ConfigUtil.DEFAULT_CONFIG);
 
@@ -122,8 +126,17 @@ public class Dual {
 
 		System.out.printf(hostsPath == null ? "%s: using %s settings.\n" : "%s: using custom settings for %s.\n", NAME, os);
 
-		// Open hosts file.
+		// Check FetchType.
+		// TODO: add support for PlainText FetchType.
+		if (type.equals("PlainText"))
+			throw new UnsupportedOperationException("The " + type + " FetchType is currently not supported.");
+		else if (!type.equals("Resolve"))
+			throw new UnknownFetchTypeException("The specified FetchType in the main configuration file (" + type + ") is unknown.");
 
+		String ip = InetAddress.getByName(source).getHostAddress();
+
+		// Open hosts file.
+		// TODO: Use buffered I/O methods.	
 		if (hostsPath == null){
 			boolean isWindows = os.contains(SUPPORTED_OPERATING_SYSTEMS[1]);
 			hostsPath = isWindows ? "C:\\WINDOWS\\System32\\drivers\\etc\\hosts" : "/etc/hosts";
@@ -135,25 +148,39 @@ public class Dual {
 		byte[] fileBytes = Files.readAllBytes(path);
 
 		String[] lines = new String(fileBytes).split(System.lineSeparator());
+		List<String> updatedLines = new ArrayList<>();
 
-		for (String line : lines){
+		for (int x = 0; x < lines.length; x++){
+			String line = lines[x];
+			boolean keepLine = true;
 			// Check if this line is a comment.
 			if (line.startsWith("#"))
 				// Ignore this line.
 				continue;
 			
-			String[] contents = line.split("#")[0];
+			String[] contents = line.split("#");
 			// Check if this line was auto-generated by this program.
 			if (contents.length == 2){
 				// Check line comment.
-				if (contents[1].equals(AUTO_GEN_COMMENT)){
+				if (contents[1].substring(1).equals(AUTO_GEN_COMMENT)){
-					// Remove this entry if we're going to replace it.
+					// This line was auto-generated by this program.
-					
+					// Check if it matches the current hostname.
+					if (contents[0].contains(target))
+						// Remove this entry since we're going to replace it.
+						keepLine = false;
 				}
 			}
-
+			if (keepLine)
-
+				updatedLines.add(line);
 		}
+		// Add a new auto-generated line.
+		updatedLines.add(ip + "	" + target + "	# " + AUTO_GEN_COMMENT);
 
+		// Write all lines to the file.
+		StringBuilder contents = new StringBuilder();
+		for (String line : updatedLines)
+			contents.append(line)
+				.append(System.lineSeparator());
+		Files.write(path, contents.toString().getBytes());
 	}
 }

src/com/luca0n/dual/common/UnknownFetchTypeException.java

@@ -0,0 +1,32 @@
+/*
+Dual: a simple manager for custom hostnames
+
+Copyright (C) 2021 luca0N!
+
+This program is free software: you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free Software
+Foundation, either version 3 of the License, or (at your option) any later
+version.
+
+This program is distributed in the hope that it will be useful, but WITHOUT
+ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License along with
+this program. If not, see <https://www.gnu.org/licenses/>.
+
+Contact me by e-mail via <luca0n [at] luca0n [dot] com>.
+*/
+
+package com.luca0n.dual.common;
+
+import java.lang.Exception;
+
+public class UnknownFetchTypeException extends Exception {
+	public UnknownFetchTypeException(){
+		super();
+	}
+	public UnknownFetchTypeException(String message){
+		super(message);
+	}
+}