corrects some pdf download problems with neogeo services

src/app/shared/components/download-button/download-button.component.ts

 import { HttpClient, HttpResponse } from '@angular/common/http';
+import { toBase64String } from '@angular/compiler/src/output/source_map';
 import { Component, Input, OnDestroy, OnInit, OnChanges } from '@angular/core';
 import { Subject } from 'rxjs';
 import { takeUntil } from 'rxjs/operators';
@@ -40,16 +41,49 @@ export class DownloadButtonComponent implements OnInit, OnDestroy, OnChanges {
       takeUntil(this.ngUnsubscribe),
     ).subscribe(
       (response) => {
-        // Create a temporary link and click on it to launch the blob download
         const url = window.URL.createObjectURL(response.body);
-        const a = document.createElement('a');
-        a.href = url;
-        a.rel = 'noopener';
-        a.download = this.fileName;
-        document.body.appendChild(a); // append the element to the dom -> otherwise it will not work in firefox
-        a.click();
-        a.remove();
-        this.loading = false;
+
+        if (response.body.type == 'application/pdf') {
+          var reader = new FileReader();
+          reader.readAsDataURL(response.body);
+          reader.onloadend = () => {
+            const bytes = reader.result.toString();
+            //what we realy have ?
+            const header = bytes.substring(0,bytes.indexOf(',') +1);
+            var str = bytes.substring(bytes.indexOf(',') + 1);
+
+            const b64 = atob(str).replace('"','');
+
+            var newData = '';
+            try {
+              atob(b64.replace('"',''));
+              newData = header + b64.replace('"','');
+            } catch (e) {
+              newData = bytes;
+            }
+            finally {
+
+              const a = document.createElement('a');
+              a.href =  newData;
+              a.rel = 'noopener';
+              a.download = this.fileName;
+              document.body.appendChild(a); // append the element to the dom -> otherwise it will not work in firefox
+              a.click();
+              a.remove();
+              this.loading = false;
+            }
+          }
+        }
+        else {
+          const a = document.createElement('a');
+          a.href =  url;
+          a.rel = 'noopener';
+          a.download = this.fileName;
+          document.body.appendChild(a); // append the element to the dom -> otherwise it will not work in firefox
+          a.click();
+          a.remove();
+          this.loading = false;
+        }
       },
       (err) => {
         let message = notificationMessages.general.failedDownloadFile;