feat(file): Added functionality to retrieve magic bytes from files and detect file types using magic bytes.

changelog.md

@@ -1,5 +1,12 @@
 # Changelog
 
+## 2024-11-18 - 3.1.0 - feat(file)
+Added functionality to retrieve magic bytes from files and detect file types using magic bytes.
+
+- Introduced method `getMagicBytes` in `File` and `Bucket` classes to retrieve a specific number of bytes from a file.
+- Enhanced file type detection by utilizing magic bytes in `MetaData` class.
+- Updated dependencies for better performance and compatibility.
+
 ## 2024-11-18 - 3.0.24 - fix(metadata)
 Fix metadata handling to address type assertion and data retrieval.
 

package.json

@@ -19,8 +19,8 @@
     "@push.rocks/tapbundle": "^5.3.0"
   },
   "dependencies": {
-    "@aws-sdk/client-s3": "^3.670.0",
+    "@aws-sdk/client-s3": "^3.693.0",
-    "@push.rocks/smartmime": "^2.0.2",
+    "@push.rocks/smartmime": "^2.0.4",
     "@push.rocks/smartpath": "^5.0.18",
     "@push.rocks/smartpromise": "^4.0.4",
     "@push.rocks/smartrx": "^3.0.7",

ts/00_commitinfo_data.ts

@@ -3,6 +3,6 @@
  */
 export const commitinfo = {
   name: '@push.rocks/smartbucket',
-  version: '3.0.24',
+  version: '3.1.0',
   description: 'A TypeScript library offering simple and cloud-agnostic object storage with advanced features like bucket creation, file and directory management, and data streaming.'
 }

ts/classes.bucket.ts

@@ -232,6 +232,7 @@ export class Bucket {
     if (typeArg === 'webstream') {
       return (await duplexStream.getWebStreams()).readable;
     }
+    throw new Error('unknown typeArg');
   }
 
   /**
@@ -437,4 +438,28 @@ export class Bucket {
     const response = await this.smartbucketRef.s3Client.send(command);
     return response.Contents.length > 0;
   }
+
+  public async getMagicBytes(optionsArg: { path: string; length: number }): Promise<Buffer> {
+    try {
+      const command = new plugins.s3.GetObjectCommand({
+        Bucket: this.name,
+        Key: optionsArg.path,
+        Range: `bytes=0-${optionsArg.length - 1}`,
+      });
+      const response = await this.smartbucketRef.s3Client.send(command);
+      const chunks = [];
+      const stream = response.Body as any; // SdkStreamMixin includes readable stream
+  
+      for await (const chunk of stream) {
+        chunks.push(chunk);
+      }
+      return Buffer.concat(chunks);
+    } catch (error) {
+      console.error(
+        `Error retrieving magic bytes from object at path '${optionsArg.path}' in bucket '${this.name}':`,
+        error
+      );
+      throw error;
+    }
+  }
 }

ts/classes.file.ts

@@ -50,6 +50,10 @@ export class File {
   public parentDirectoryRef: Directory;
   public name: string;
 
+  /**
+   * get the full path to the file
+   * @returns the full path to the file
+   */
   public getBasePath(): string {
     return plugins.path.join(this.parentDirectoryRef.getBasePath(), this.name);
   }
@@ -188,7 +192,7 @@ export class File {
     if (isDirectory) {
       moveToPath = await helpers.reducePathDescriptorToPath({
         ...pathDescriptorArg,
-        path: plugins.path.join(pathDescriptorArg.path, this.name),
+        path: plugins.path.join(pathDescriptorArg.path!, this.name),
       });
     }
     // lets move the file
@@ -230,4 +234,11 @@ export class File {
       contents: JSON.stringify(dataArg),
     });
   }
+
+  public async getMagicBytes(optionsArg: { length: number }): Promise<Buffer> {
+    return this.parentDirectoryRef.bucketRef.getMagicBytes({
+      path: this.getBasePath(),
+      length: optionsArg.length
+    })
+  }
 }

ts/classes.metadata.ts

@@ -31,10 +31,24 @@ export class MetaData {
   public async getFileType(optionsArg?: {
     useFileExtension?: boolean;
     useMagicBytes?: boolean;
-  }): Promise<string> {
+  }): Promise<plugins.smartmime.IFileTypeResult | undefined> {
-    if ((optionsArg && optionsArg.useFileExtension) || optionsArg.useFileExtension === undefined) {
+    if ((optionsArg && optionsArg.useFileExtension) || !optionsArg) {
-      return plugins.path.extname(this.fileRef.name);
+      const fileType = await plugins.smartmime.detectMimeType({
+        path: this.fileRef.name,
+      });
+
+      return fileType;
     }
+    if (optionsArg && optionsArg.useMagicBytes) {
+      const fileType = await plugins.smartmime.detectMimeType({
+        buffer: await this.fileRef.getMagicBytes({
+          length: 100,
+        })
+      });
+
+      return fileType;
+    }
+    throw new Error('optionsArg.useFileExtension and optionsArg.useMagicBytes cannot both be false');
   }
 
   /**