Merge pull request #165 from bcgov/rewrite-preview

trying to bypass blob headers
bcgov · Apr 26, 2024 · c8bb44c · c8bb44c
2 parents e2ed9d9 + 69e0be1
commit c8bb44c
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Showing 3 changed files with 47 additions and 20 deletions.
diff --git a/backend/src/admin/admin.controller.ts b/backend/src/admin/admin.controller.ts
@@ -81,15 +81,18 @@ export class AdminController {
   @Get('preview-template/:id')
   async previewTemplate(@Param('id') id: number, @Res() res) {
     try {
+      // const pdfBuffer = await this.adminService.getPreviewPdf(id);
+      // const streamableFile = new stream.PassThrough();
+      // streamableFile.end(pdfBuffer);
+      // res.set({
+      //   'Content-Type': 'application/pdf',
+      //   'Content-Disposition': 'inline; filename=preview.pdf',
+      //   'Content-Security-Policy': "default-src 'self' https://*.gov.bc.ca data:; frame-src 'self' blob:;",
+      // });
+      // streamableFile.pipe(res);
       const pdfBuffer = await this.adminService.getPreviewPdf(id);
-      const streamableFile = new stream.PassThrough();
-      streamableFile.end(pdfBuffer);
-      res.set({
-        'Content-Type': 'application/pdf',
-        'Content-Disposition': 'inline; filename=preview.pdf',
-        'Content-Security-Policy': "default-src 'self' https://*.gov.bc.ca data:; frame-src 'self' blob:;",
-      });
-      streamableFile.pipe(res);
+      const base64Data = pdfBuffer.toString('base64');
+      res.json({ data: base64Data });
     } catch (error) {
       console.error('Error:', error);
       res.status(500).send('Internal Server Error');

diff --git a/frontend/src/app/common/api.ts b/frontend/src/app/common/api.ts
@@ -130,10 +130,10 @@ export const handleFilePreviewGet = async (url: string, filename: string): Promi
     const getParameters = generateApiParameters(url);
     return new Promise<Blob>((resolve, reject) => {
       fileDownloadGet<Blob>(getParameters)
-        .then(blob => {
+        .then((blob) => {
           resolve(blob);
         })
-        .catch(error => {
+        .catch((error) => {
           console.error('Preview error:', error);
           reject(error);
         });
@@ -153,7 +153,7 @@ export const handleFilePreviewGet = async (url: string, filename: string): Promi
 export const handleFileDownloadGet = async (url: string, filename: string) => {
   const getParameters = generateApiParameters(url);
 
-  console.log(getParameters)
+  console.log(getParameters);
 
   await fileDownloadGet<Blob>(getParameters)
     .then(async (blob) => {

diff --git a/frontend/src/app/common/manage-templates.ts b/frontend/src/app/common/manage-templates.ts
@@ -56,17 +56,36 @@ export const disableProvision = async (provisionId: number): Promise<void> => {
 
 export const previewTemplate = async (id: number, fileName: string): Promise<Blob | null> => {
   const url = `${config.API_BASE_URL}/admin/preview-template/${id}`;
-  const response = await api.handleFilePreviewGet(url, fileName);
-  if (response) {
-    console.log('Preview response:');
-    console.log(response);
-    return response;
-  } else {
-    console.log('Preview response was null or there was an error.');
+  try {
+    const getParameters = api.generateApiParameters(url);
+    const response = await api.get<any>(getParameters);
+    const base64Data = response.data;
+    const blob = base64ToBlob(base64Data, 'application/pdf');
+    return blob;
+  } catch (error) {
+    console.error('Error retrieving preview:', error);
     return null;
   }
 };
 
+// util for previewTemplate
+function base64ToBlob(base64: string, mime: string): Blob {
+  const byteCharacters = atob(base64);
+  const byteArrays = [];
+
+  for (let offset = 0; offset < byteCharacters.length; offset += 512) {
+    const slice = byteCharacters.slice(offset, offset + 512);
+    const byteNumbers = new Array(slice.length);
+    for (let i = 0; i < slice.length; i++) {
+      byteNumbers[i] = slice.charCodeAt(i);
+    }
+    const byteArray = new Uint8Array(byteNumbers);
+    byteArrays.push(byteArray);
+  }
+
+  return new Blob(byteArrays, { type: mime });
+}
+
 export const downloadTemplate = async (id: number, fileName: string): Promise<void> => {
   const url = `${config.API_BASE_URL}/admin/download-template/${id}`;
   const response = await api.handleFileDownloadGet(url, fileName);
@@ -94,8 +113,13 @@ export const uploadTemplate = async (formData: FormData): Promise<void> => {
   await api.post<{ message: string }>(postParameters);
 };
 
-export const editTemplate = async (id: number, documentTypeId: number, documentNo: number, documentName: string): Promise<void> => {
+export const editTemplate = async (
+  id: number,
+  documentTypeId: number,
+  documentNo: number,
+  documentName: string
+): Promise<void> => {
   const url = `${config.API_BASE_URL}/admin/update-template/${id}/${documentTypeId}/${documentNo}/${documentName}`;
   const getParameters = api.generateApiParameters(url);
   await api.get<void>(getParameters);
-}
+};