chore: replace query to check if shortlink is available

src/server/modules/user/services/UrlManagementService.ts

@@ -76,8 +76,10 @@ export class UrlManagementService implements interfaces.UrlManagementService {
       shortUrl = await generateShortUrl(API_LINK_RANDOM_STR_LENGTH)
     }
 
-    const owner = await this.userRepository.findUserByUrl(shortUrl)
-    if (owner) {
+    const isShortUrlAvailable = await this.urlRepository.isShortUrlAvailable(
+      shortUrl,
+    )
+    if (!isShortUrlAvailable) {
       throw new AlreadyExistsError(`Short link "${shortUrl}" is already used.`)
     }
 

src/server/repositories/UrlRepository.ts

@@ -175,6 +175,27 @@ export class UrlRepository implements UrlRepositoryInterface {
     return this.urlMapper.persistenceToDto(newUrl)
   }
 
+  /**
+   * @param  {string} shortUrl Short url.
+   * @returns {Promise<boolean>} Returns true if shortUrl is available and false otherwise.
+   */
+  public isShortUrlAvailable: (shortUrl: string) => Promise<boolean> = async (
+    shortUrl,
+  ) => {
+    try {
+      // Cache lookup
+      // if long url does not exist, throws error
+      const longUrl = await this.getLongUrlFromCache(shortUrl)
+      return !longUrl
+    } catch {
+      // Cache failed, look in database
+      const url = await Url.findOne({
+        where: { shortUrl },
+      })
+      return !url
+    }
+  }
+
   public getLongUrl: (shortUrl: string) => Promise<string> = async (
     shortUrl,
   ) => {

src/server/repositories/interfaces/UrlRepositoryInterface.ts

@@ -43,6 +43,12 @@ export interface UrlRepositoryInterface {
     file?: StorableFile,
   ): Promise<StorableUrl>
 
+  /**
+   * Returns true if shortUrl is available, otherwise false.
+   * @param {string} shortUrl The shortUrl.
+   */
+  isShortUrlAvailable: (shortUrl: string) => Promise<boolean>
+
   /**
    * Looks up the longUrl given a shortUrl from the cache, falling back
    * to the database. The cache is re-populated if the database lookup is