1주차 과제 - ToDo REST API 만들기

app/src/main/java/com/codesoom/assignment/App.java

@@ -1,10 +1,29 @@
 package com.codesoom.assignment;
 
+import com.codesoom.assignment.handler.TaskHandler;
+import com.sun.net.httpserver.HttpHandler;
+import com.sun.net.httpserver.HttpServer;
+
+import java.io.IOException;
+import java.net.InetSocketAddress;
+
 public class App {
     public String getGreeting() {
         return "Hello World!";
     }
 
     public static void main(String[] args) {
+        System.out.println(new App().getGreeting());
+        InetSocketAddress address = new InetSocketAddress(8000);
+
+        try {
+            HttpServer server = HttpServer.create(address , 0);
+            HttpHandler handler = new TaskHandler();
+            server.createContext("/" , handler);
+            server.start();
+
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
     }
 }

app/src/main/java/com/codesoom/assignment/converter/TaskConverter.java

@@ -0,0 +1,61 @@
+package com.codesoom.assignment.converter;
+
+import com.codesoom.assignment.models.Task;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.StringJoiner;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+public class TaskConverter {
+
+    public static TaskConverter getInstance(){
+        return LazyHolder.INSTANCE;
+    }
+
+    private static class LazyHolder{
+        public static final TaskConverter INSTANCE = new TaskConverter();
+    }
+
+    public Task newTask(String content , Long taskId){
+        Map<String , String> map = jsonToMap(content);
+        String title = map.get("title");
+        return new Task(taskId , title);
+    }
+
+    public String convert(Task task){
+        return String.format("{\"id\":%d,\"title\":\"%s\"}" , task.getId() , task.getTitle());
+    }
+
+    public String convert(Map<Long , Task> tasks){
+        StringBuilder sb = new StringBuilder();
+        StringJoiner sj = new StringJoiner(",");
+        sb.append("[");
+        for(Task task : new ArrayList<>(tasks.values())){
+            sj.add(convert(task));
+        }
+        sb.append(sj);
+        sb.append("]");
+        return sb.toString();
+    }
+
+    public Map<String , String> jsonToMap(String content){
+        Map<String , String> map = new HashMap<>();
+        String[] contents = content.split(",");
+        Pattern pattern = Pattern.compile("\"(.*?)\"");
+        for(String test : contents){
+            Matcher matcher = pattern.matcher(test);
+            String key = getContent(matcher);
+            String value = getContent(matcher);
+            map.put(key , value);
+        }
+        return map;
+    }
+
+    public String getContent(Matcher matcher){
+        if(!matcher.find())
+            return "";
+        return matcher.group().replace("\"" , "");
+    }
+}

app/src/main/java/com/codesoom/assignment/enums/HttpMethod.java

@@ -0,0 +1,12 @@
+package com.codesoom.assignment.enums;
+
+/**
+ * HTTP Method를 관리한다 <a href="https://datatracker.ietf.org/doc/html/rfc7231#section-4.3">RFC7231</a>
+ */
+public enum HttpMethod {
+    GET,
+    POST,
+    PUT,
+    PATCH,
+    DELETE;
+}

app/src/main/java/com/codesoom/assignment/enums/HttpResponse.java

@@ -0,0 +1,24 @@
+package com.codesoom.assignment.enums;
+
+/**
+ * HTTP Response Status Code를 관리한다 <a href="https://datatracker.ietf.org/doc/html/rfc9110#section-15">RFC9110</a>
+ *
+ * @see HttpResponse#getCode() Response Status Code를 반환한다
+ */
+public enum HttpResponse {
+    OK(200),
+    CREATED(201),
+    BAD_REQUEST(400),
+    NO_CONTENT(204),
+    NOT_FOUND(404);
+
+    private final int code;
+
+    HttpResponse(int code) {
+        this.code = code;
+    }
+
+    public int getCode(){
+        return code;
+    }
+}

app/src/main/java/com/codesoom/assignment/exceptions/ParameterNotFoundException.java

@@ -0,0 +1,7 @@
+package com.codesoom.assignment.exceptions;
+
+public class ParameterNotFoundException extends Exception{
+    public ParameterNotFoundException(String msg){
+        super(msg);
+    }
+}

app/src/main/java/com/codesoom/assignment/handler/TaskHandler.java

@@ -0,0 +1,114 @@
+package com.codesoom.assignment.handler;
+
+import com.codesoom.assignment.converter.TaskConverter;
+import com.codesoom.assignment.enums.HttpMethod;
+import com.codesoom.assignment.enums.HttpResponse;
+import com.codesoom.assignment.exceptions.ParameterNotFoundException;
+import com.codesoom.assignment.models.Path;
+import com.codesoom.assignment.models.Task;
+import com.sun.net.httpserver.Headers;
+import com.sun.net.httpserver.HttpExchange;
+import com.sun.net.httpserver.HttpHandler;
+
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.io.InputStreamReader;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.stream.Collectors;
+
+public class TaskHandler implements HttpHandler {
+
+    public static Map<Long , Task> tasks = new ConcurrentHashMap<>();
+    public static AtomicLong taskId = new AtomicLong(1L);
+    public TaskConverter taskConverter = TaskConverter.getInstance();
+
+    @Override
+    public void handle(HttpExchange exchange) throws IOException {
+        final HttpMethod method = HttpMethod.valueOf(exchange.getRequestMethod());
+        final Path path = new Path(exchange.getRequestURI().getPath());
+        System.out.printf("[method] : %s , [path] : %s%n", method , path.fullPath);
+        if(!path.hasResource() || !path.resourceEquals("tasks")) {
+            send(exchange, HttpResponse.OK.getCode() , "");
+        }
+
+        if(path.hasPathVariable()){
+            handleUsingTaskId(exchange , method , Long.parseLong(path.pathVariable));
+        }
+        else{
+            handleTask(exchange , method);
+        }
+    }
+
+    private void handleUsingTaskId(HttpExchange exchange, HttpMethod method , Long id) throws IOException {
+        String content = "";
+        Task task = tasks.get(id);
+        if(task == null){
+            send(exchange , HttpResponse.NOT_FOUND.getCode(), content);
+            return;
+        }
+
+        HttpResponse response = HttpResponse.OK;
+        if ("GET".equals(method.name())) {
+            content = taskConverter.convert(task);
+        } else if ("PUT".equals(method.name()) || "PATCH".equals(method.name())) {
+            content = updateTask(exchange, id);
+        } else if ("DELETE".equals(method.name())) {
+            tasks.remove(id);
+            response = HttpResponse.NO_CONTENT;
+        }
+
+        send(exchange , response.getCode(), content);
+    }
+
+    private void handleTask(HttpExchange exchange, HttpMethod method) throws IOException {
+        String content = "";
+        HttpResponse response = HttpResponse.OK;
+        if ("GET".equals(method.name())) {
+            content = taskConverter.convert(tasks);
+        } else if ("POST".equals(method.name())) {
+            content = createTask(exchange);
+            response = HttpResponse.CREATED;
+        }
+        send(exchange, response.getCode() , content);
+    }
+
+    private String createTask(HttpExchange exchange) throws IOException {
+        long taskId = getNextId();
+        Task task = taskConverter.newTask(getBody(exchange.getRequestBody()) , taskId);
+        tasks.put(taskId, task);
+        return taskConverter.convert(task);
+    }
+
+    private void send(HttpExchange exchange, int code, String content) throws IOException {
+        Headers responseHeaders = exchange.getResponseHeaders();
+        responseHeaders.set("Content-Type" , "application/json; charset=UTF-8");
+        exchange.sendResponseHeaders(code , content.getBytes().length);
+        OutputStream outputStream = exchange.getResponseBody();
+        outputStream.write(content.getBytes());
+        outputStream.flush();
+        outputStream.close();
+    }
+
+    private String updateTask(HttpExchange exchange, Long id) {
+        String content;
+        Task newTask = taskConverter.newTask(getBody(exchange.getRequestBody()) , id);
+        tasks.replace(id, newTask);
+        content = taskConverter.convert(newTask);
+        return content;
+    }
+
+    private String getBody(InputStream inputStream){
+        return new BufferedReader(new InputStreamReader(inputStream))
+                .lines()
+                .collect(Collectors.joining("\n"));
+    }
+
+    private long getNextId(){
+        return taskId.getAndIncrement();
+    }
+}

app/src/main/java/com/codesoom/assignment/models/Path.java

@@ -0,0 +1,28 @@
+package com.codesoom.assignment.models;
+
+import com.codesoom.assignment.exceptions.ParameterNotFoundException;
+
+public class Path {
+    public final String fullPath;
+    public final String resource;
+    public final String pathVariable;
+
+    public Path(String path){
+        this.fullPath = path;
+        String[] pathArr = path.split("/");
+        this.resource = pathArr.length >= 2 ? pathArr[1] : null;
+        this.pathVariable = pathArr.length >= 3 ? pathArr[2] : null;
+    }
+
+    public boolean hasPathVariable(){
+        return this.pathVariable != null;
+    }
+    public boolean hasResource(){
+        return this.resource != null;
+    }
+
+    public boolean resourceEquals(String resource){
+        return this.resource.equals(resource);
+    }
+
+}

app/src/main/java/com/codesoom/assignment/models/Task.java

@@ -0,0 +1,30 @@
+package com.codesoom.assignment.models;
+
+public class Task {
+    private Long id;
+    private String title;
+
+    public Task(){}
+
+    public Task(Long id , String title){
+        this.id = id;
+        this.title = title;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public String getTitle() {
+        return title;
+    }
+
+    @Override
+    public String toString() {
+        final StringBuilder sb = new StringBuilder("Task{");
+        sb.append("id=").append(id);
+        sb.append(", title='").append(title).append('\'');
+        sb.append('}');
+        return sb.toString();
+    }
+}

app/src/test/java/com/codesoom/assignment/converter/TaskConverterJsonToMapTest.java

@@ -0,0 +1,84 @@
+package com.codesoom.assignment.converter;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+import java.util.Map;
+
+public class TaskConverterJsonToMapTest {
+
+    @Test
+    @DisplayName(" JSON형식에 맞지 않아도 [\"]로 감싸준다면 Map에 키 또는 값으로 저장된다")
+    void notJson1(){
+        // given
+        String json = "[\"title1\"=\"테스트1\" ,\"title2\"=\"테스트2\"]";
+        TaskConverter converter = new TaskConverter();
+
+        // when
+        Map<String , String> map = converter.jsonToMap(json);
+
+        // then
+        Assertions.assertEquals(map.get("title1") , "테스트1");
+        Assertions.assertEquals(map.get("title2") , "테스트2");
+    }
+
+    @Test
+    @DisplayName(" [,]로 키:값 Entry가 구분되어 있지 않다면 첫 번째 키와 값만 가져온다")
+    void notJson2(){
+        // given
+        String json = "{\"title1\":\"테스트1\" \"title2\":\"테스트2\"}";
+        TaskConverter converter = new TaskConverter();
+
+        // when
+        Map<String , String> map = converter.jsonToMap(json);
+
+        // then
+        Assertions.assertEquals(map.get("title1") , "테스트1");
+    }
+
+    @Test
+    @DisplayName("JSON문자열에 키가 중복되지 않는다면 Map에 각각 저장된다")
+    void jsonhasMultiKey(){
+        // given
+        String json = "{\"title1\": \"테스트1\",\"title2\": \"테스트2\"}";
+        TaskConverter converter = new TaskConverter();
+
+        // when
+        Map<String , String> map = converter.jsonToMap(json);
+
+        // then
+        Assertions.assertEquals(map.get("title1"), "테스트1");
+        Assertions.assertEquals(map.get("title2"), "테스트2");
+    }
+
+    @Test
+    @DisplayName("JSON문자열에 숫자 값이 있을 때 구분하지 못 한다")
+    void jsonInNumeric(){
+        // given
+        String json = "{\"id\": 1,\"title\": \"테스트1\"}";
+        TaskConverter converter = new TaskConverter();
+
+        // when
+        Map<String , String> map = converter.jsonToMap(json);
+
+        // then
+        Assertions.assertEquals(map.get("id"), "");
+    }
+
+    @Test
+    @DisplayName("JSON객체가 여러 개일 때 title은 덮어씌워진다")
+    void jsons(){
+        // given
+        String jsons = "[{\"id\": 1,\"title\": \"테스트1\"},{\"id\": 2,\"title\": \"테스트2\"}]";
+        TaskConverter converter = new TaskConverter();
+
+        // when
+        Map<String , String> map = converter.jsonToMap(jsons);
+
+        // then
+        Assertions.assertEquals(map.get("title") , "테스트2");
+    }
+
+
+}