Ability to feed the data to the external process via stdin

[p-himik]

There are scenarios when the result of the "Pre JavaScript" is way too large and can't fit into the CLI - that results in the Error: spawn E2BIG in the browser console.

It would be nice if there was a separate option to feed some specific value(s) from [PRE_SCRIPT] to the stdin of the external executable.

[andy-portmen]

The best method is to post data to a local host. The stdin is not meant to handle large data. You can have a simple HTTP server that supports POST and send data to the server from pre-script.

[p-himik]

The stdin is not meant to handle large data.

You mean, stdin of specifically native-client?
What does it mean exactly? And what would it take to make large data (in my case it's anything over 2 MB) be acceptable?

[andy-portmen]

https://developer.chrome.com/docs/apps/nativeMessaging#:~:text=The%20maximum%20size%20of%20a%20single%20message%20from%20the%20native%20messaging%20host%20is%201%20MB

You can run an HTTP server that handles requests at 127.0.0.1:8080, for example. Then on pre-script, send your data with

fetch('127.0.0.1:8080', {
  method: 'POST',
  body: JSON.stringify(data)
});

[p-himik]

Thank you for the link.

However, it says that the limit of 1 MB is for messages sent from a native host to the browser.
But I'm talking about the opposite direction, and there the limit is much larger:

The maximum size of the message sent to the native messaging host is 4 GB.

You can run an HTTP server that handles requests at 127.0.0.1:8080, for example.

I realize that, I'm a web developer myself. But I would like not having to run an umpteenth server on my machine if it can be avoided.

[andy-portmen]

I see. The error you're seeing suggests that the argument list passed to the process is too long. This means that even if you run the same command directly in the terminal, you'll likely see the same error. It also indicates that the browser has already passed the arguments to the native application.

[p-himik]

Indeed, that's why I'm asking about stdin, since it doesn't have the same limitations as the argument list.

[andy-portmen]

The latest commit on EAL extension adds support to @stdin. Each argument that ends with it will be piped to the stdin of the process. You need to update to native client 1.0.1 and try the latest commit of EAL in the developer mode.

andy-portmen/external-application-button@4520c43

[p-himik]

Thank you!

Unfortunately, it doesn't seem like I can test it - I get an document.currentScript is null error even though everything is exactly the same. The only difference is that the extension was loaded from the sources. Maybe some Firefox issue, no idea.

[andy-portmen]

Related FAQ
https://webextension.org/listing/external-application-button.html?rc#faq34

[p-himik]

Seems to be working perfectly, thank you so much!

[rdxfabiano-source]

The best method is to post data to a local host. The stdin is not meant to handle large data. You can have a simple HTTP server that supports POST and send data to the server from pre-script.