update port

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

@@ -0,0 +1,57 @@
+package cc.fascinated.backend.service;
+
+import cc.fascinated.backend.model.Paste;
+import cc.fascinated.backend.exception.impl.ResourceNotFoundException;
+import cc.fascinated.backend.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();
+    }
+}