fake 이미지, 동영상 파일 검증하는 로직 (중간단계 개발중)

projects/ucap-webmessenger-api-common/src/lib/services/common-api.service.ts

@@ -223,6 +223,65 @@ export class CommonApiService {
     };
   }
 
+  public mimeCheckForImageAndVideoFiles(files: File[]) {
+    files.forEach(file => {
+      console.log(file);
+      const fileReader = new FileReader();
+      fileReader.onloadend = () => {
+        const arr = new Uint8Array(fileReader.result as ArrayBuffer).subarray(
+          0,
+          4
+        );
+        let header = '';
+        for (let i = 0; i < arr.length; i++) {
+          header += arr[i].toString(16);
+        }
+        console.log('File header: ' + header);
+
+        // Check the file signature against known types
+        var type = 'unknown';
+        // http://forensic-proof.com/archives/300?ckattempt=1
+
+        if (header.startsWith('89504e47')) {
+          // 89504E470D0A1A0A
+          type = 'image/png';
+        } else if (header.startsWith('47494638')) {
+          // 474946383761
+          // 474946383961
+          type = 'image/gif';
+        } else if (header.startsWith('ffd8ffe')) {
+          // ffd8ffe0
+          // ffd8ffe1
+          // ffd8ffe2
+          // ffd8ffe8
+          type = 'image/jpeg';
+        } else if (header.startsWith('424d')) {
+          type = 'image/bmp';
+        } else if (header.startsWith('4d4d') || header.startsWith('4949')) {
+          type = 'image/tiff';
+        } else if (header.startsWith('4F676753')) {
+          // 4F67675300020000
+          type = 'image/ogg';
+        } else if (header.startsWith('38425053')) {
+          // 38 42 50 53
+          type = 'image/psd';
+        } else if (header.startsWith('25504446')) {
+          // 38 42 50 53
+          type = 'image/ai';
+        } else if (header.startsWith('52494646')) {
+          // avi
+          type = 'video/x-msvideo';
+        } else if (header.startsWith('00000018')) {
+          // 0000001866747970
+          type = 'video/x-msvideo';
+        }
+
+        console.log('type', type);
+      };
+      fileReader.readAsArrayBuffer(file);
+    });
+  }
+
   public fileTalkShare(
     req: FileTalkShareRequest
   ): Observable<FileTalkShareResponse> {

projects/ucap-webmessenger-app/src/app/layouts/messenger/components/messages.component.ts

@@ -1107,6 +1107,10 @@ export class MessagesComponent implements OnInit, OnDestroy, AfterViewInit {
       }
     }
 
+    // this.commonApiService.mimeCheckForImageAndVideoFiles(
+    //   fileUploadItems.map(fui => fui.file)
+    // );
+
     const checkExt = this.commonApiService.acceptableExtensionForFileTalk(
       fileUploadItems.map(fui => FileUtil.getExtension(fui.file.name))
     );