Native-Messaging | Chrome 's native messaging example project for Java | Browser Plugin library

there was some issue with Dead Letter Sinks not being propagated at pre-GA releases. Can you make sure you are using Knative 1.0?

This is working for me as expected using the inmemory channel:

https://gist.github.com/odacremolbap/f6ce029caf4fa6fbb3cc1e829f188788

• curl producing cloud events to a broker
• broker with DLS configured to an event-display
• event display service as DLS receiver
• trigger from broker to a replier service
• replier service (can ack and nack depending on the incoming event)

The solution is:

A starkit is an archive format (based on the Metakit single-file database format) that has been used to distribute Tcl applications and extensions; these can be either platform-specific or cross-platform, depending on what you put inside. Tclkit (or its more modern versions from Kitgen) is a single-file Tcl distribution that can read and execute a starkit; it's naturally platform-specific. A starpack is a combination of tclkit base runtime and starkit-packaged application.

As the whole starkit/tclkit system is based on Tcl's virtualised filesystem support, you can put pretty much anything you want inside a *kit, including extension DLLs. About the only thing that it's not a great idea to put in is a database (such as an SQLite DB file); while you can put a copy inside, you'll need to extract it for use. I mention this because it sounds like including a database would be highly appropriate for your application.

For update, the simplest method is to just have users download a new copy of the application. Since you can make that into one pre-packaged file, this is very easy for them to handle updates for. (You can do automatic updating, but then you have to keep track of the file holding the updates; not all platforms allow updating a running executable.)

Tcl 8.7 will include a packaging technology for doing similar things, though based on a different file format. That's all still alpha though.

At first let me say that you did a good job in transferring data between web extension (Thunderbird add-on) and native application using native messaging. It isn't easy to understand it and set it up, but you managed to transfer required data with some tiny glitches you describe in your question.

... the resulting file contains double quotes (") at the start and the end of the file as well as escaped double quotes (\")

In the add-on you obtain raw email data as a string - console.log(typeof raw) gives string which you then pass to port.postMessage. Although the documentation says it takes JSON object representing the message to send, but it seems to accept single string value which is valid JSON according to some standards. In Delphi code you receive the message via STDIN and parse it using TJSONObject.ParseJSONValue into TJSONValue. It will in fact create instance of TJSONString. You can verify that by examining the value of jsonValue.ClassName. The problem with quotes arises when you use jsonValue.ToString which returns quoted version of the string that is basically the same what you had before parsing. Use the Value property to return raw string value.

Using jsonValue.Value alone will not help you with the encoding issue. The raw message data that you obtain from the e-mail client is in EML format. It conforms to RFC-822 and that means it is ASCII encoded, but it can contain arbitrarily encoded message parts (see your own sample EML). Since you only want to save EML file as is not taking any encoding into account, the best would be to transfer raw bytes of EML, but this isn't out-of-the-box supported by Javascript and native messaging API. Therefore I'd suggest you to send Base64-encoded data string to native application where you decode it into raw bytes that you can write straight to disk.

To encode raw message data as Base64 string in add-on use function btoa:

Basically, the first 32 bits sent from the extension corresponds to the message length, in native order.

Since the first 32 bits are of type int, and I tried to parse JSON objects, Error when communicating with the native messaging host is raised. The documentation mentions that the issue resides within a broken Native Messaging protocol.

The worst part is that I saw it on the Python example, but thought that this was implemented by the programmer who did it.

I stumbled upon this thread on Stack Overflow which helped confirm, (Chrome App fails to communicate with native host on windows).

To debug Chrome in a much more verbose fashion, launch Chrome with --enable-logging=stderr --v=1 in the command line, and all stderr will be outputted there.

The documentation is mentioning it, but the examples found here and there using C# don't include them.

If I have time, I will confirm that this was the issue by editing this answer, and provide code for getting this to work on Visual Studio for macOS.

I managed to have this to work a few days ago. I modified the code so that it works without the while loop, as the StreamReader reads stdin until the end, thus not requesting a while loop (this caused my previous code to hang). The SendMessage method also differs from other seen in other examples. Fewer lines, and works just fine.

My working example: