Add Example

Example/pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xmlns="http://maven.apache.org/POM/4.0.0"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>me.braydon</groupId>
+    <artifactId>Example</artifactId>
+    <version>1.0.0</version>
+
+    <properties>
+        <java.version>17</java.version>
+        <maven.compiler.source>${java.version}</maven.compiler.source>
+        <maven.compiler.target>${java.version}</maven.compiler.target>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    </properties>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>3.8.1</version>
+                <configuration>
+                    <source>${java.version}</source>
+                    <target>${java.version}</target>
+                </configuration>
+            </plugin>
+
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-shade-plugin</artifactId>
+                <version>3.1.0</version>
+                <executions>
+                    <execution>
+                        <phase>package</phase>
+                        <goals>
+                            <goal>shade</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+
+    <dependencies>
+        <!-- Lombok -->
+        <dependency>
+            <groupId>org.projectlombok</groupId>
+            <artifactId>lombok</artifactId>
+            <version>1.18.28</version>
+            <scope>provided</scope>
+        </dependency>
+
+        <!-- Gson -->
+        <dependency>
+            <groupId>com.google.code.gson</groupId>
+            <artifactId>gson</artifactId>
+            <version>2.10.1</version>
+            <scope>compile</scope>
+        </dependency>
+
+        <!-- Oshi -->
+        <dependency>
+            <groupId>com.github.oshi</groupId>
+            <artifactId>oshi-core</artifactId>
+            <version>6.4.2</version>
+            <scope>compile</scope>
+        </dependency>
+    </dependencies>
+</project>

Example/src/main/java/me/braydon/example/LicenseExample.java

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+package me.braydon.example;
+
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonObject;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.NonNull;
+import lombok.ToString;
+import oshi.SystemInfo;
+import oshi.hardware.CentralProcessor;
+import oshi.hardware.ComputerSystem;
+import oshi.hardware.HardwareAbstractionLayer;
+import oshi.software.os.OperatingSystem;
+
+import java.io.*;
+import java.net.HttpURLConnection;
+import java.net.URL;
+import java.nio.charset.StandardCharsets;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * An example of how to interact
+ * with the license server. This
+ * can be conveniently used in
+ * any project by simply copying
+ * the class into your project.
+ *
+ * @author Braydon
+ * @see <a href="https://git.rainnny.club/Rainnny/LicenseServer">License Server</a>
+ * TODO: Convert to okhttp?
+ */
+public final class LicenseExample {
+    /**
+     * The endpoint to check licenses at.
+     */
+    private static final String CHECK_ENDPOINT = "http://localhost:7500/check";
+    
+    /**
+     * The {@link Gson} instance to use.
+     */
+    private static final Gson GSON = new GsonBuilder()
+                                         .serializeNulls()
+                                         .create();
+    
+    @NonNull
+    public static LicenseResponse check(@NonNull String key, @NonNull String product) {
+        String hardwareId = getHardwareId(); // Get the machine's hardware id
+        
+        // Build the body
+        Map<String, Object> body = new HashMap<>();
+        body.put("key", key);
+        body.put("product", product);
+        body.put("hwid", hardwareId);
+        String bodyJson = GSON.toJson(body); // The json body
+        
+        HttpURLConnection connection = null;
+        int responseCode = -1; // The response code
+        try {
+            // Try and send the request to the server
+            connection = (HttpURLConnection) new URL(CHECK_ENDPOINT).openConnection();
+            connection.setRequestMethod("POST"); // Sending a POST request
+            connection.setRequestProperty("Content-Type", "application/json"); // We want JSON as the response
+            connection.setDoOutput(true); // We want to send a body
+            
+            // Write the body to the connection
+            try (OutputStream outputStream = connection.getOutputStream()) {
+                byte[] input = bodyJson.getBytes(StandardCharsets.UTF_8);
+                outputStream.write(input, 0, input.length);
+            }
+            responseCode = connection.getResponseCode(); // Get the response code
+            
+            // If the response code is OK, we can read the response
+            if (responseCode == HttpURLConnection.HTTP_OK) {
+                try (InputStream inputStream = connection.getInputStream();
+                     InputStreamReader inputStreamReader = new InputStreamReader(inputStream);
+                     BufferedReader reader = new BufferedReader(inputStreamReader)
+                ) {
+                    // Read the response
+                    StringBuilder response = new StringBuilder();
+                    String line;
+                    while ((line = reader.readLine()) != null) {
+                        response.append(line);
+                    }
+                    // Parse the response as JSON
+                    JsonObject json = GSON.fromJson(response.toString(), JsonObject.class);
+                    JsonElement description = json.get("description");
+                    JsonElement ownerSnowflake = json.get("ownerSnowflake");
+                    JsonElement ownerName = json.get("ownerName");
+                    JsonElement duration = json.get("duration");
+                    return new LicenseResponse(200, null,
+                        description.isJsonNull() ? null : description.getAsString(),
+                        ownerSnowflake.isJsonNull() ? -1 : ownerSnowflake.getAsLong(),
+                        ownerName.isJsonNull() ? null : ownerName.getAsString(),
+                        duration.isJsonNull() ? -1 : duration.getAsLong()
+                    );
+                }
+            } else { // Otherwise, the request failed
+                // Check if the response has an error message in JSON format
+                try (InputStream errorStream = connection.getErrorStream()) {
+                    if (errorStream != null) { // Read the error response
+                        try (InputStreamReader errorStreamReader = new InputStreamReader(errorStream);
+                             BufferedReader errorReader = new BufferedReader(errorStreamReader)
+                        ) {
+                            
+                            StringBuilder errorResponse = new StringBuilder();
+                            String errorLine;
+                            while ((errorLine = errorReader.readLine()) != null) {
+                                errorResponse.append(errorLine);
+                            }
+                            // Parse the error response as JSON
+                            JsonObject jsonError = GSON.fromJson(errorResponse.toString(), JsonObject.class);
+                            JsonElement errorMessage = jsonError.get("error");
+                            if (!errorMessage.isJsonNull()) { // If the error message isn't null, we can return it
+                                return new LicenseResponse(responseCode, errorMessage.getAsString());
+                            }
+                        }
+                    }
+                }
+            }
+        } catch (IOException ex) {
+            ex.printStackTrace();
+        } finally {
+            // Close the connection if it's open
+            if (connection != null) {
+                connection.disconnect();
+            }
+        }
+        // Didn't find an error message, return an unknown error
+        return new LicenseResponse(responseCode, "An unknown error occurred");
+    }
+    
+    /**
+     * Get the unique hardware
+     * identifier of this machine.
+     *
+     * @return the hardware id
+     */
+    @NonNull
+    private static String getHardwareId() {
+        SystemInfo systemInfo = new SystemInfo();
+        OperatingSystem operatingSystem = systemInfo.getOperatingSystem();
+        HardwareAbstractionLayer hardwareAbstractionLayer = systemInfo.getHardware();
+        CentralProcessor centralProcessor = hardwareAbstractionLayer.getProcessor();
+        ComputerSystem computerSystem = hardwareAbstractionLayer.getComputerSystem();
+        
+        // Retrieve necessary hardware information
+        String vendor = operatingSystem.getManufacturer();
+        String processorSerialNumber = computerSystem.getSerialNumber();
+        String uuid = computerSystem.getHardwareUUID();
+        String processorIdentifier = centralProcessor.getProcessorIdentifier().getIdentifier();
+        int processors = centralProcessor.getLogicalProcessorCount();
+        
+        // Generate a unique hardware id using the retrieved information
+        return String.format("%08x", vendor.hashCode()) + "-"
+                   + String.format("%08x", processorSerialNumber.hashCode()) + "-"
+                   + String.format("%08x", uuid.hashCode()) + "-"
+                   + String.format("%08x", processorIdentifier.hashCode()) + "-" + processors;
+    }
+    
+    @AllArgsConstructor
+    @Getter
+    @ToString
+    public static class LicenseResponse {
+        /**
+         * The status code of the response.
+         */
+        private final long status;
+        
+        /**
+         * The error in the response, null if none.
+         */
+        private String error;
+        
+        /**
+         * The description of the license, present if valid.
+         */
+        private String description;
+        
+        /**
+         * The Discord snowflake of the license owner, present
+         * if valid and there is an owner.
+         */
+        private long ownerSnowflake;
+        
+        /**
+         * The Discord name of the license owner, present
+         * if valid and there is an owner.
+         */
+        private String ownerName;
+        
+        /**
+         * The duration of the license, present if valid.
+         * <p>
+         * If -1, the license will be permanent.
+         * </p>
+         */
+        private long duration;
+        
+        public LicenseResponse(long status, @NonNull String error) {
+            this.status = status;
+            this.error = error;
+        }
+        
+        /**
+         * Check if the license is valid.
+         *
+         * @return true if valid, otherwise false
+         */
+        public boolean isValid() {
+            return status == 200;
+        }
+        
+        /**
+         * Check if the license is permanent.
+         *
+         * @return true if permanent, otherwise false
+         */
+        public boolean isPermanent() {
+            return duration == -1;
+        }
+    }
+}