initial commit

src/main/java/cc/fascinated/Main.java

@@ -0,0 +1,30 @@
+package cc.fascinated;
+
+import lombok.SneakyThrows;
+import lombok.extern.log4j.Log4j2;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+import java.io.File;
+import java.nio.file.Files;
+import java.nio.file.StandardCopyOption;
+import java.util.Objects;
+
+@Log4j2(topic = "Main")
+@SpringBootApplication
+public class Main {
+    @SneakyThrows
+    public static void main(String[] args) {
+        File config = new File("application.yml");
+        if (!config.exists()) { // Saving the default config if it doesn't exist locally
+            Files.copy(Objects.requireNonNull(Main.class.getResourceAsStream("/application.yml")), config.toPath(), StandardCopyOption.REPLACE_EXISTING);
+            log.info("Saved the default configuration to '{}', please re-launch the application", // Log the default config being saved
+                    config.getAbsolutePath()
+            );
+            return;
+        }
+        log.info("Found configuration at '{}'", config.getAbsolutePath()); // Log the found config
+
+        SpringApplication.run(Main.class, args); // Start the application
+    }
+}

src/main/java/cc/fascinated/controller/PasteController.java

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+package cc.fascinated.controller;
+
+import cc.fascinated.model.Paste;
+import cc.fascinated.service.PasteService;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.*;
+
+import java.util.Map;
+
+@RestController
+@RequestMapping(value = "/")
+public class PasteController {
+
+    private final PasteService pasteService;
+
+    @Autowired
+    public PasteController(PasteService pasteService) {
+        this.pasteService = pasteService;
+    }
+
+    @GetMapping(value = "/")
+    public ResponseEntity<?> home() {
+        return ResponseEntity.ok(Map.of(
+                "status", "OK"
+        ));
+    }
+
+    @PostMapping(value = "/upload")
+    public ResponseEntity<?> uploadPaste(@RequestBody String content) {
+        String id = pasteService.createPaste(content);
+        return ResponseEntity.ok(Map.of("id", id));
+    }
+
+    @GetMapping(value = "/{id}")
+    public ResponseEntity<Paste> getPaste(@PathVariable String id) {
+        Paste paste = pasteService.getPaste(id);
+        return ResponseEntity.ok(paste);
+    }
+}

src/main/java/cc/fascinated/exception/ExceptionControllerAdvice.java

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+package cc.fascinated.exception;
+
+import cc.fascinated.model.response.ErrorResponse;
+import io.micrometer.common.lang.NonNull;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.ControllerAdvice;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.bind.annotation.ResponseStatus;
+import org.springframework.web.servlet.resource.NoResourceFoundException;
+
+@ControllerAdvice
+public final class ExceptionControllerAdvice {
+
+    /**
+     * Handle a raised exception.
+     *
+     * @param ex the raised exception
+     * @return the error response
+     */
+    @ExceptionHandler(Exception.class)
+    public ResponseEntity<?> handleException(@NonNull Exception ex) {
+        HttpStatus status = null; // Get the HTTP status
+        if (ex instanceof NoResourceFoundException) { // Not found
+            status = HttpStatus.NOT_FOUND;
+        } else if (ex instanceof UnsupportedOperationException) { // Not implemented
+            status = HttpStatus.NOT_IMPLEMENTED;
+        }
+        if (ex.getClass().isAnnotationPresent(ResponseStatus.class)) { // Get from the @ResponseStatus annotation
+            status = ex.getClass().getAnnotation(ResponseStatus.class).value();
+        }
+        String message = ex.getLocalizedMessage(); // Get the error message
+        if (message == null) { // Fallback
+            message = "An internal error has occurred.";
+        }
+        // Print the stack trace if no response status is present
+        if (status == null) {
+            ex.printStackTrace();
+        }
+        if (status == null) { // Fallback to 500
+            status = HttpStatus.INTERNAL_SERVER_ERROR;
+        }
+        return new ResponseEntity<>(new ErrorResponse(status, message), status);
+    }
+}

src/main/java/cc/fascinated/exception/impl/BadRequestException.java

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+package cc.fascinated.exception.impl;
+
+import org.springframework.http.HttpStatus;
+import org.springframework.web.bind.annotation.ResponseStatus;
+
+@ResponseStatus(HttpStatus.BAD_REQUEST)
+public class BadRequestException extends RuntimeException {
+
+    public BadRequestException(String message) {
+        super(message);
+    }
+}

src/main/java/cc/fascinated/exception/impl/ResourceNotFoundException.java

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+package cc.fascinated.exception.impl;
+
+import lombok.experimental.StandardException;
+import org.springframework.http.HttpStatus;
+import org.springframework.web.bind.annotation.ResponseStatus;
+
+@StandardException
+@ResponseStatus(HttpStatus.NOT_FOUND)
+public class ResourceNotFoundException extends RuntimeException { }

src/main/java/cc/fascinated/model/Paste.java

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+package cc.fascinated.model;
+
+import io.micrometer.common.lang.NonNull;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import org.springframework.data.annotation.Id;
+
+@AllArgsConstructor
+@Getter
+public class Paste {
+    /**
+     * The id of the paste.
+     */
+    @Id @NonNull
+    private final String id;
+
+    /**
+     * The content of the paste.
+     */
+    @NonNull
+    private final String content;
+}

src/main/java/cc/fascinated/model/response/ErrorResponse.java

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+package cc.fascinated.model.response;
+
+import io.micrometer.common.lang.NonNull;
+import lombok.EqualsAndHashCode;
+import lombok.Getter;
+import lombok.ToString;
+import org.springframework.http.HttpStatus;
+
+import java.util.Date;
+
+@Getter @ToString @EqualsAndHashCode
+public class ErrorResponse {
+    /**
+     * The status code of this error.
+     */
+    @NonNull
+    private final HttpStatus status;
+
+    /**
+     * The HTTP code of this error.
+     */
+    private final int code;
+
+    /**
+     * The message of this error.
+     */
+    @NonNull private final String message;
+
+    /**
+     * The timestamp this error occurred.
+     */
+    @NonNull private final Date timestamp;
+
+    public ErrorResponse(@NonNull HttpStatus status, @NonNull String message) {
+        this.status = status;
+        code = status.value();
+        this.message = message;
+        timestamp = new Date();
+    }
+}

src/main/java/cc/fascinated/repository/PasteRepository.java

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+package cc.fascinated.repository;
+
+import cc.fascinated.model.Paste;
+import org.springframework.data.mongodb.repository.MongoRepository;
+
+/**
+ * A repository for {@link Paste}s.
+ */
+public interface PasteRepository extends MongoRepository<Paste, String> { }

src/main/java/cc/fascinated/service/PasteService.java

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+package cc.fascinated.service;
+
+import cc.fascinated.exception.impl.ResourceNotFoundException;
+import cc.fascinated.model.Paste;
+import cc.fascinated.repository.PasteRepository;
+import org.apache.commons.lang3.RandomStringUtils;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.stereotype.Service;
+
+import java.util.Optional;
+
+@Service
+public class PasteService {
+
+    /**
+     * The {@link PasteRepository} instance.
+     */
+    private final PasteRepository pasteRepository;
+
+    /**
+     * The length of the paste id.
+     */
+    @Value("${paste.id-length}")
+    private int idLength;
+
+    @Autowired
+    public PasteService(PasteRepository pasteRepository) {
+        this.pasteRepository = pasteRepository;
+    }
+
+    /**
+     * Creates a new paste with the specified content.
+     *
+     * @param content The content of the paste.
+     * @return The id of the paste.
+     */
+    public String createPaste(String content) {
+        return pasteRepository.save(new Paste(RandomStringUtils.randomAlphabetic(idLength), content)).getId();
+    }
+
+    /**
+     * Gets the content of the paste with the specified id.
+     *
+     * @param id The id of the paste.
+     * @return The content of the paste.
+     */
+    public Paste getPaste(String id) {
+        Optional<Paste> paste = pasteRepository.findById(id);
+
+        // The paste does not exist.
+        if (paste.isEmpty()) {
+            throw new ResourceNotFoundException("Paste with id '%s' not found".formatted(id));
+        }
+        return paste.get();
+    }
+}