Need Help

[mannyd209]

I'm using your code for a project I'm working on. I'm trying to use a raspberry pi to be accessible as an Epson printer for my POS. Instead of printing out the receipt, I want to decode the data sent from the POS and print it out on a self hosted webpage on my pi. Can you help if possible? Thanks & great work btw.

[juergenpabel]

Just to make sure I correctly understand what you're trying to achieve here: you want to use a Pi Pico with this software to not "relay" the printjob (a receipt?) to some (real) printer but instead provide it via HTTP (on the local network) so that (another system) can fetch that from the Pi Pico and presumably render it on a display that's shown to customers?

Please confirm or correct.

Presuming I did get you right, this is how I would go about it: Due to memory constraints with the Pico (or pretty much any embedded device), I would "offload" the ESC/POS parsing to the device that's showing the result on the display; from your description I understand that that device is capable of rendering HTML (and showing it on a display); so if that device is actually running a somewhat recent (less than 10 years old) browser, than all the ESC/POS parsing could be done in javascrip on that device. So this approach splits the task into two parts:

1. running a HTTP-server on the Pico, serving the ESC/POS data (an presumably also the HTML+JS files for part 2)
2. running a HTTP-client on some other device (that the customer-facing display is connected to) that will (presumably) load the HTML-page from the Pico, run the Javascript which fetches the ESC/POS data from the Pico and than parses and renders it as HTML, which is than shown on the display.

My implementation approach (for this software) would be to add a new printer implementation, which would simply serve the most recent printjob data via HTTP; additionally, this would also serve the HTML+JS files that the client than runs in order to fetch, parse and render the printjob. These files would ideally be just files in some sub-folder on the micropython partition of the Pico, thus customizations should be easily done. The only part of this approach that I can't immediately confirm to be trivially implementable is the javascript-based parsing of ESC/POS in order to render it as HTML. After a quick search on github, it seems that there are JS libraries that implement that functionality - but this is something I would have to look a bit into (most libs seem to be for node.js - which would introduce another runtime component and thus should be avoided if possible).