pdfmerge | learning project , trying to get pdf merge | Document Editor library

I found out that merger is actually working and merging the files but is throwing the exception anyway. I guess to inform the developer or user it is doing a fix? If you read the exception carefully it says the "Cross reference table will be rebuilt." So iText is doing some kind of automated fix.

This exception was triggering a different try catch block and the pdf was never being closed as a result.

Strangely I couldn't find any documentation on this in the iText 7 documentation.

At any rate, a simple try catch around the merge function fixed the issue in my case.

You're missing an indentation when iterating the pages, it should read:

After analyzing the HTML code and with repeated testing, I was able to get rid of the warning message. I had to remove the background-color style in the CSS of the HTML that was related to table , tr and td tags .

You need to subscribe to it. Observables are lazy, and won't actually perform the POST call unless you subscribe to it.

You can add Java to your app by adding the heroku/jvm buildpack like this:

The problem is that you're closing the files before the write.

When you call pdfMerger.append, it doesn't actually read and process the whole file then; it only does so later, when you call pdfMerger.write. Since the files you've appended are closed, it reads no data from each of them, and therefore outputs an empty PDF.

This should actually raise an exception, which would have made the problem and the fix obvious. Apparently this is a bug introduced in version 1.26, and it will be fixed in the next version. Unfortunately, while the fix was implemented in July 2016, there hasn't been a next version since May 2016. (See this issue.)

You could install directly off the github master (and hope there aren't any new bugs), or you could continue to wait for 1.27, or you could work around the bug. How? Simple: just keep the files open until the write is done:

Find out which of the itext7 classes implement IDisposable (from the documentation, or the Visual Studio Object Browser etc), and make sure you use them within using blocks, the same way you already have using blocks for StreamReader.

Edit: @sourkrause's solution can be shortened to:

You need to watch your control flow. Yes, you are creating promises but are not waiting for them to be complete. You could use async/await sync or a Promise library like bluebird

The root problem of your particular code snippet is result.recordset.forEach(element => {, which, basically, runs synchronously and then calls res.end()

Either you can make everything async/await, but you might need to Promisify that request.execute("create_json", callback) call.

Or you can use a Promise library to do something like

The error is in the executa method: