Opening a document from the Salesforce Database

1// force-app\main\default\classes\PDFTron_ContentVersionController.cls
2
3//snipped for brevity
4@AuraEnabled(Cacheable=true)
5public static List<ContentVersionWrapper> getAttachments(String recordId){
6  try {
7    List<String> cdIdList = new List<String> ();
8    List<ContentVersionWrapper> cvwList = new List<ContentVersionWrapper> ();
9
10    //Find links between record & document
11    for(ContentDocumentLink cdl : 
12      [   SELECT id, ContentDocumentId, ContentDocument.LatestPublishedVersionId 
13          FROM ContentDocumentLink 
14          WHERE LinkedEntityId = :recordId    ]) {
15            cdIdList.add(cdl.ContentDocumentId);
16    }
17    //Use links to get attachments
18    for(ContentVersion cv : 
19      [   SELECT Id, Title,FileExtension, VersionData 
20          FROM ContentVersion 
21          WHERE ContentDocumentId IN :cdIdList 
22          AND IsLatest = true ]) {
23            cvwList.add(new ContentVersionWrapper(cv));    
24      }
25      
26      return cvwList;
27    } catch (Exception e) {
28            throw new AuraHandledException(e.getMessage());
29    }
30}
31
32//sample wrapper class
33public class ContentVersionWrapper {
34  @AuraEnabled
35  public String name {get; set;}
36  @AuraEnabled
37  public String body {get; set;}
38        
39  public ContentVersionWrapper(ContentVersion contentVer) {
40    this.name = contentVer.Title + '.' + contentVer.FileExtension;
41    this.body = EncodingUtil.base64Encode(contentVer.VersionData);
42  }
43}

1function _base64ToArrayBuffer(base64) {
2  var binary_string =  window.atob(base64);
3  var len = binary_string.length;
4  var bytes = new Uint8Array( len );
5  for (var i = 0; i < len; i++)        {
6      bytes[i] = binary_string.charCodeAt(i);
7  }
8  return bytes.buffer;
9}

1//snipped for brevity
2import { registerListener, unregisterAllListeners } from 'c/pubsub';
3
4connectedCallback() {
5  registerListener('blobSelected', this.handleBlobSelected, this);
6  //register other listeners here
7}
8
9disconnectedCallback() {
10  //unregister all listeners here
11}
12
13handleBlobSelected(record) {
14  record = JSON.parse(record);
15
16  let blobby = new Blob([_base64ToArrayBuffer(record.body)], {
17    type: mimeTypes[record.FileExtension]
18  });
19
20  const payload = {
21    blob: blobby,
22    extension: record.cv.FileExtension,
23    filename: record.cv.Title + "." + record.cv.FileExtension,
24    documentId: record.cv.Id
25  };
26    this.iframeWindow.postMessage({type: 'OPEN_DOCUMENT_BLOB', payload} , '*');
27  }

1//snipped for brevity
2window.addEventListener("message", receiveMessage, false);
3
4function receiveMessage(event) {
5  if (event.isTrusted && typeof event.data === 'object') {
6    switch (event.data.type) {
7      case 'OPEN_DOCUMENT_BLOB':
8        const { blob, extension, filename, documentId } = event.data.payload;
9        instance.loadDocument(blob, { extension, filename, documentId })
10        break;
11      default:
12        break;
13    }
14  }
15}

1//snipped for brevity
2window.addEventListener("message", receiveMessage, false);
3
4function receiveMessage(event) {
5  if (event.isTrusted && typeof event.data === 'object') {
6    switch (event.data.type) {
7      case 'OPEN_DOCUMENT_BLOB':
8        const { blob, extension, filename, documentId } = event.data.payload;
9        event.target.readerControl.loadDocument(blob, { extension, filename, documentId })
10        break;
11      default:
12        break;
13    }
14  }
15}