Issue with getAttachmentContentAsync in Outlook Event-based Add-in

Question

I have developed an event-based Outlook add-in to handle the OnMessageSend event. My goal is to access the attachment content when the event is triggered.

The getAttachmentsAsync method works fine; I can retrieve details like attachment name, ID, and size. However, when I call getAttachmentContentAsync, it does not return any content or error.

Here is the relevant code snippet from my add-in:

function onMessageSendHandler(event) {
    try {
       const item = Office.context.mailbox.item;
       const options = { asyncContext: { currentItem: item } };
     
       // Get attachments asynchronously
       item.getAttachmentsAsync(options, (result) => {
           if (result.status === Office.AsyncResultStatus.Failed) {
               console.log("Error getting attachments:", result.error.message);
               // Complete the event with success to allow sending
               event.completed({ allowEvent: true });
               return;
           }
     
           if (result.value.length <= 0) {
               console.log("Mail item has no attachments.");
               // Complete the event with success to allow sending
               event.completed({
                 allowEvent: false,
                 errorMessage: "Please add attachment(s)"
               });
               return;
           }
     
           const currentItem = result.asyncContext.currentItem;
         
           // Process each attachment
           for (let i = 0; i < result.value.length; i++) {    
               currentItem.getAttachmentContentAsync(result.value[i].id, (asyncResult) => {
                   console.log(asyncResult.status);
                   if (asyncResult.status === Office.AsyncResultStatus.Failed) {
                       console.error("Error getting attachment content:", asyncResult.error.message);
                       return;
                   }    
                   console.log("Attachment content:", asyncResult.value.content);
               });
           }
     
           // Complete the event with success to allow sending
           event.completed({ allowEvent: true });
       });
    } catch (error) {
        console.log("Error Catched", error);
    }
}

// Associate the event handler
Office.actions.associate("onMessageSendHandler", onMessageSendHandler);

In this code:

1. getAttachmentsAsync successfully retrieves attachment details.
2. getAttachmentContentAsync is called with the attachment ID, but it does not return any content or error message.

I am unsure what is causing this behavior. Is there a limitation or a known issue with getAttachmentContentAsync in the OnMessageSend event?

Any insights or suggestions would be greatly appreciated!

Answer 1

Hi @Diluka Hewage 

Glad to hear this issue has been resolved and thanks for the sharing! 

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However, due to a recent update in forum policy, the question author now is not able to accept their own answers.  

So, I have written a brief summary of the solution this issue. Please feel free to ACCEPT it as the Answer, which would benefit others who also have similar issues in the forum.  

Issue: 

When calling getAttachmentContentAsync, it does not return any content or error.

Solution: 

Instead of using getAttachmentContentAsync directly within the OnMessageSend event, using it inside the onMessageAttachmentsChanged event. When the onMessageAttachmentsChanged event is triggered, you can successfully access the attachment content using getAttachmentContentAsync.

Answer 2

I found a solution to this issue!

Instead of using getAttachmentContentAsync directly within the OnMessageSend event, I used it inside the onMessageAttachmentsChanged event. When the onMessageAttachmentsChanged event is triggered, I can successfully access the attachment content using getAttachmentContentAsync.

I’m not sure why getAttachmentContentAsync doesn’t work as expected in the OnMessageSend event, but using it in the onMessageAttachmentsChanged event resolved the problem for me.