Initialise Spring API with ShortLink endpoints

backend/src/main/java/services/shay/Halflink.java

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+package services.shay;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+@SpringBootApplication
+public class Halflink {
+
+    @GetMapping("/")
+    String home() {
+        return "Halflink API says hello!";
+    }
+
+    public static void main(String[] args) {
+        SpringApplication.run(Halflink.class, args);
+    }
+
+}

backend/src/main/java/services/shay/shortlink/ShortCodeGenerator.java

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+package services.shay.shortlink;
+
+import java.security.SecureRandom;
+
+public class ShortCodeGenerator {
+
+    private static final String BASE_58_CHARS = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz";
+
+    private static final SecureRandom RANDOM = new SecureRandom();
+
+    public static String generate(int length) {
+        StringBuilder sb = new StringBuilder();
+        for (int i = 0; i < length; i++) {
+            sb.append(BASE_58_CHARS.charAt(RANDOM.nextInt(BASE_58_CHARS.length())));
+        }
+        return sb.toString();
+    }
+
+    public static String generate() {
+        return "abc";
+        // return generate(7);
+    }
+
+}

backend/src/main/java/services/shay/shortlink/ShortLink.java

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+package services.shay.shortlink;
+
+import jakarta.persistence.*;
+import jakarta.validation.constraints.NotNull;
+import jakarta.validation.constraints.Null;
+
+import java.util.Date;
+import java.util.UUID;
+
+@Entity
+@Table(name = "shortlink", uniqueConstraints = { @UniqueConstraint(columnNames = { "code" }) })
+public class ShortLink {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.UUID)
+    private UUID id;
+
+    @NotNull
+    private String url;
+
+    @NotNull
+    private String title;
+
+    private Date createdAt;
+
+    private Integer clicks;
+
+    private String code;
+
+    protected ShortLink() {}
+
+    public ShortLink(String url, String title) {
+        this.url = url;
+        this.title = title;
+    }
+
+    @PrePersist
+    protected void onCreate() {
+        createdAt = new Date();
+        clicks = 0;
+        code = ShortCodeGenerator.generate();
+    }
+
+    public UUID getId() { return id; }
+    public String getUrl() { return url; }
+    public String getTitle() { return title; }
+    public Date getCreatedAt() { return createdAt; }
+    public Integer getClicks() { return clicks; }
+    public String getCode() { return code; }
+
+    public void setId(UUID id) { this.id = id; }
+    public void setUrl(String url) { this.url = url; }
+    public void setTitle(String title) { this.title = title; }
+    public void setCreatedAt(Date createdAt) { this.createdAt = createdAt; }
+    public void setClicks(Integer clicks) { this.clicks = clicks; }
+    public void setCode(String code) { this.code = code; }
+
+}

backend/src/main/java/services/shay/shortlink/ShortLinkController.java

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+package services.shay.shortlink;
+
+import jakarta.validation.Valid;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.*;
+
+import java.net.URI;
+import java.util.UUID;
+
+@RestController
+@RequestMapping("/sl")
+public class ShortLinkController {
+
+    private final ShortLinkRepository shortLinkRepository;
+
+    public ShortLinkController(ShortLinkRepository shortLinkRepository) {
+        this.shortLinkRepository = shortLinkRepository;
+    }
+
+    @GetMapping("/{code}")
+    public ResponseEntity<Void> redirectToUrl(@PathVariable String code) {
+        ShortLink sl = shortLinkRepository.findByCode(code).orElse(null);
+        if (sl != null) {
+            sl.setClicks(sl.getClicks() + 1);
+            shortLinkRepository.save(sl);
+            return ResponseEntity
+                    .status(HttpStatus.FOUND)
+                    .location(URI.create(sl.getUrl()))
+                    .build();
+        }
+        return ResponseEntity.notFound().build();
+    }
+
+    @PostMapping
+    public ShortLink createShortLink(@Valid @RequestBody ShortLink shortLink) {
+        ShortLink savedShortLink = shortLinkRepository.save(shortLink);
+        System.out.println("savedShortLink = " + savedShortLink);
+        return savedShortLink;
+    }
+
+    @DeleteMapping("/{id}")
+    public void deleteShortLink(@PathVariable UUID id) {
+        shortLinkRepository.deleteById(id);
+    }
+
+}

backend/src/main/java/services/shay/shortlink/ShortLinkRepository.java

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+package services.shay.shortlink;
+
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
+
+import java.util.Optional;
+import java.util.UUID;
+
+@Repository
+public interface ShortLinkRepository extends JpaRepository<ShortLink, UUID> {
+
+    Optional<ShortLink> findByCode(String code);
+
+}

backend/src/main/resources/application.properties

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+# Database connection
+spring.datasource.url=jdbc:postgresql://localhost:5432/halflink
+spring.datasource.username=springchatuser
+spring.datasource.password=abcdef
+
+# JPA/Hibernate settings
+spring.jpa.hibernate.ddl-auto=update
+spring.jpa.show-sql=true

backend/src/main/resources/sandbox.http

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+POST http://localhost:8080/sl
+Content-Type: application/json
+
+{
+  "url": "https://docs.spring.io/spring-security/reference/servlet/authentication/index.html",
+  "title": "Spring Security Servlet Authentication"
+}
+
+###
+
+DELETE http://localhost:8080/sl/a0232bf3-245d-4515-8a8b-c10031d21766