[새리] step 5. XHR과 AJAX

build.gradle

@@ -21,6 +21,10 @@ dependencies {
 	// h2 설정
 	implementation ('org.springframework.boot:spring-boot-starter-data-jpa')
 	implementation ('com.h2database:h2')
+
+	// swagger 2
+	compile group: 'io.springfox', name: 'springfox-swagger2', version: '2.9.2'
+	compile group: 'io.springfox', name: 'springfox-swagger-ui', version: '2.9.2'
 }
 
 test {

src/main/java/com/codessquad/qna/CommonExceptionHandler.java

@@ -1,6 +1,8 @@
 package com.codessquad.qna;
 
+import com.codessquad.qna.domain.Result;
 import com.codessquad.qna.exception.IllegalUserAccessException;
+import com.codessquad.qna.exception.NotLoggedInException;
 import com.codessquad.qna.exception.QuestionNotFoundException;
 import com.codessquad.qna.exception.UserNotFoundException;
 import org.springframework.web.bind.annotation.ControllerAdvice;
@@ -23,4 +25,9 @@ public String handleUserNotFoundException() {
     public String handleQuestionNotFoundException() {
         return "redirect:/";
     }
+
+    @ExceptionHandler(NotLoggedInException.class)
+    public Result handleNotLoggedInException() {
+        return Result.fail("Login Needed");
+    }
 }

src/main/java/com/codessquad/qna/QnaApplication.java

@@ -2,12 +2,38 @@
 
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.annotation.Bean;
+import org.springframework.data.jpa.repository.config.EnableJpaAuditing;
+import springfox.documentation.builders.ApiInfoBuilder;
+import springfox.documentation.builders.PathSelectors;
+import springfox.documentation.service.ApiInfo;
+import springfox.documentation.spi.DocumentationType;
+import springfox.documentation.spring.web.plugins.Docket;
+import springfox.documentation.swagger2.annotations.EnableSwagger2;
 
 @SpringBootApplication
+@EnableJpaAuditing
+@EnableSwagger2
 public class QnaApplication {
 
-	public static void main(String[] args) {
-		SpringApplication.run(QnaApplication.class, args);
-	}
+    public static void main(String[] args) {
+        SpringApplication.run(QnaApplication.class, args);
+    }
 
+    @Bean
+    public Docket newsApi () {
+        return new Docket(DocumentationType.SWAGGER_2)
+                .groupName("my-slipp")
+                .apiInfo(apiInfo())
+                .select()
+                .paths(PathSelectors.ant("/api/**"))
+                .build();
+    }
+
+    private ApiInfo apiInfo() {
+        return new ApiInfoBuilder()
+                .title("My Slipp API")
+                .description("My Slipp API")
+                .build();
+    }
 }

src/main/java/com/codessquad/qna/controller/AnswerController.java

@@ -1,20 +1,19 @@
 package com.codessquad.qna.controller;
 
+import com.codessquad.qna.domain.Answer;
+import com.codessquad.qna.domain.Result;
 import com.codessquad.qna.domain.User;
+import com.codessquad.qna.exception.NotLoggedInException;
 import com.codessquad.qna.service.AnswerService;
-import org.springframework.stereotype.Controller;
-import org.springframework.web.bind.annotation.DeleteMapping;
-import org.springframework.web.bind.annotation.PathVariable;
-import org.springframework.web.bind.annotation.PostMapping;
-import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.*;
 
 import javax.servlet.http.HttpSession;
 
 import static com.codessquad.qna.HttpSessionUtils.getUserFromSession;
 import static com.codessquad.qna.HttpSessionUtils.isLoginUser;
 
-@Controller
-@RequestMapping("/questions/{questionId}/answers")
+@RestController
+@RequestMapping("/api/questions/{questionId}/answers")
 public class AnswerController {
     private final AnswerService answerService;
 
@@ -23,25 +22,23 @@ public AnswerController(AnswerService answerService) {
     }
 
     @PostMapping
-    public String create(@PathVariable Long questionId, String contents, HttpSession session) {
+    public Answer create(@PathVariable Long questionId, String contents, HttpSession session) {
         if (!isLoginUser(session)) {
-            return "redirect:/users/login";
+            throw new NotLoggedInException();
         }
 
         User writer = getUserFromSession(session);
-        answerService.save(writer, contents, questionId);
-        return "redirect:/questions/{questionId}";
+        return answerService.save(writer, contents, questionId);
     }
 
     @DeleteMapping("/{id}")
-    public String delete(@PathVariable Long questionId, @PathVariable Long id, HttpSession session) {
+    public Result delete(@PathVariable Long questionId, @PathVariable Long id, HttpSession session) {
         if (!isLoginUser(session)) {
-            return "redirect:/users/login";
+            throw new NotLoggedInException();
         }
-
         User loginUser = getUserFromSession(session);
-        answerService.deleteById(id, loginUser);
 
-        return "redirect:/questions/{questionId}";
+        // Returns either Result.ok() or Result.fail();
+        return answerService.deleteById(id, loginUser);
     }
 }

src/main/java/com/codessquad/qna/domain/AbstractEntity.java

@@ -0,0 +1,58 @@
+package com.codessquad.qna.domain;
+
+import com.fasterxml.jackson.annotation.JsonProperty;
+import org.springframework.data.annotation.CreatedDate;
+import org.springframework.data.annotation.LastModifiedDate;
+import org.springframework.data.jpa.domain.support.AuditingEntityListener;
+
+import javax.persistence.*;
+import java.time.LocalDateTime;
+import java.time.format.DateTimeFormatter;
+import java.util.Objects;
+
+@MappedSuperclass
+@EntityListeners(AuditingEntityListener.class)
+public class AbstractEntity {
+    private static final DateTimeFormatter DATE_TIME_FORMATTER = DateTimeFormatter.ofPattern("yyyy-MM-dd kk:mm");
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    @JsonProperty
+    private Long id;
+
+    @CreatedDate
+    private LocalDateTime createdDate;
+
+    @LastModifiedDate
+    private LocalDateTime modifiedDate = LocalDateTime.now();
+
+    public Long getId() {
+        return id;
+    }
+
+    public String getFormattedCreatedDate() { return createdDate.format(DATE_TIME_FORMATTER); }
+
+    public String getFormattedModifiedDate() { return modifiedDate.format(DATE_TIME_FORMATTER); }
+
+    @Override
+    public String toString() {
+        return "AbstractEntity{" +
+                "id=" + id +
+                ", createdDate=" + getFormattedCreatedDate() +
+                ", modifiedDated=" + getFormattedModifiedDate() +
+                '}';
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        AbstractEntity that = (AbstractEntity) o;
+        return Objects.equals(id, that.id);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(id);
+    }
+}

src/main/java/com/codessquad/qna/domain/Answer.java

@@ -1,20 +1,17 @@
 package com.codessquad.qna.domain;
 
+import com.fasterxml.jackson.annotation.JsonManagedReference;
+
 import javax.persistence.*;
 import java.time.LocalDateTime;
 import java.time.format.DateTimeFormatter;
 import java.util.Objects;
 
 @Entity
-public class Answer {
-    private static final DateTimeFormatter DATE_TIME_FORMATTER = DateTimeFormatter.ofPattern("yyyy-MM-dd kk:mm");
-
-    @Id
-    @GeneratedValue(strategy = GenerationType.IDENTITY)
-    private Long id;
-
+public class Answer extends AbstractEntity {
     @ManyToOne
     @JoinColumn(foreignKey = @ForeignKey(name = "fk_answer_writer"))
+    @JsonManagedReference
     private User writer;
 
     @ManyToOne
@@ -24,20 +21,16 @@ public class Answer {
     @Lob
     private String contents;
 
-    private final LocalDateTime timeCreated = LocalDateTime.now();
-
     private boolean deleted = false;
 
-    protected Answer() {};
+    protected Answer() {}
 
     public Answer(User writer, Question question, String contents) {
         this.writer = writer;
         this.question = question;
         this.contents = contents;
     }
 
-    public Long getId() { return id; }
-
     public User getWriter() {
         return writer;
     }
@@ -50,8 +43,6 @@ public String getContents() {
         return contents;
     }
 
-    public String getFormattedTimeCreated() { return timeCreated.format(DATE_TIME_FORMATTER); }
-
     public boolean isDeleted() {
         return deleted;
     }
@@ -60,28 +51,14 @@ public boolean isAnswerWriter(User writer) {
         return this.writer.equals(writer);
     }
 
-    public void delete() {
+    public void changeDeleteStatus() {
         this.deleted = true;
     }
 
-    @Override
-    public boolean equals(Object o) {
-        if (this == o) return true;
-        if (o == null || getClass() != o.getClass()) return false;
-        Answer answer = (Answer) o;
-        return Objects.equals(id, answer.id) &&
-                Objects.equals(question, answer.question);
-    }
-
-    @Override
-    public int hashCode() {
-        return Objects.hash(id, question);
-    }
-
     @Override
     public String toString() {
         return "Answer{" +
-                "id=" + id +
+                super.toString() +
                 ", writer=" + writer +
                 ", questionId=" + question.getId() +
                 ", contents='" + contents + '\'' +

src/main/java/com/codessquad/qna/domain/Question.java

@@ -1,32 +1,30 @@
 package com.codessquad.qna.domain;
 
+import com.fasterxml.jackson.annotation.JsonBackReference;
+import com.fasterxml.jackson.annotation.JsonManagedReference;
+
 import javax.persistence.*;
 import java.time.LocalDateTime;
 import java.time.format.DateTimeFormatter;
 import java.util.List;
 import java.util.stream.Collectors;
 
 @Entity
-public class Question {
-    private static final DateTimeFormatter DATE_TIME_FORMATTER = DateTimeFormatter.ofPattern("yyyy-MM-dd kk:mm");
-
-    @Id
-    @GeneratedValue(strategy = GenerationType.IDENTITY)
-    private Long id;
+public class Question extends AbstractEntity {
 
     @ManyToOne
     @JoinColumn(foreignKey = @ForeignKey(name = "fk_question_writer"))
+    @JsonManagedReference
     private User writer;
 
     private String title;
 
     @Column(nullable = false, length = 2000)
     private String contents;
 
-    private LocalDateTime timeCreated = LocalDateTime.now();
-
     @OneToMany(mappedBy = "question")
-    @OrderBy("id ASC")
+    @OrderBy("id DESC")
+    @JsonBackReference
     private List<Answer> answers;
 
     private boolean deleted = false;
@@ -51,18 +49,6 @@ public String getContents() {
         return contents;
     }
 
-    public Long getId() {
-        return id;
-    }
-
-    public LocalDateTime getTimeCreated() {
-        return timeCreated;
-    }
-
-    public String getFormattedTimeCreated() {
-        return timeCreated.format(DATE_TIME_FORMATTER);
-    }
-
     public List<Answer> getAnswers() {
         return answers.stream().filter(answer -> !answer.isDeleted()).collect(Collectors.toList());
     }
@@ -71,7 +57,7 @@ public int getAnswerNumber() {
         if (this.answers.isEmpty()) {
             return 0;
         }
-        return this.answers.size();
+        return getAnswers().size();
     }
 
     public Question updateQuestion(Question modifiedQuestion) {
@@ -87,18 +73,17 @@ public boolean isSameUser(User user) {
     public void delete() {
         this.deleted = true;
         for (Answer a : this.answers) {
-            a.delete();
+            a.changeDeleteStatus();
         }
     }
 
     @Override
     public String toString() {
         return "Question{" +
+                super.toString() +
                 "writer='" + writer + '\'' +
                 ", title='" + title + '\'' +
                 ", contents='" + contents + '\'' +
-                ", id=" + id +
-                ", timeCreated='" + timeCreated + '\'' +
                 '}';
     }
 }

src/main/java/com/codessquad/qna/domain/Result.java

@@ -0,0 +1,25 @@
+package com.codessquad.qna.domain;
+
+import com.fasterxml.jackson.annotation.JsonProperty;
+
+public class Result {
+
+    @JsonProperty
+    private boolean valid;
+
+    @JsonProperty
+    private String errorMessage;
+
+    private Result(boolean valid, String errorMessage) {
+        this.valid = valid;
+        this.errorMessage = errorMessage;
+    }
+
+    public static Result ok() {
+        return new Result(true, null);
+    }
+
+    public static Result fail(String errorMessage) {
+        return new Result(false, errorMessage);
+    }
+}