The use case of this problem is very simple but i struggle to find a good solution for it.

I want to allow my users (through a webapp) fill some pdf files stored in server (pdf with forms, which begin more and more popular).

Actually, app like chrome or acrobat reader are able to fill them perfectly whe its open locally.

I already allow this functionnality for docx and xlsx files, for that i use Webdav and the custom protocols ms-word ad ms-excel. It works perfectly.

For pdf, I didnt found equivalent. Its look the mains pdf reader/editor doesn't implement this protocol. Whe we open distant file with these tools, they failed for write permission when save or they try to save the file locally) .

Another option i take a look was the new file system access api (https://web.dev/file-system-access/). But again i wasn't able to make it working properly. The main problem here is how we can edit the file.? Im able with this api to dowload the file locally and keep the filehandler to retrieve the updates, but i blocked on how i can edit the file ? like an option on the fileHandler to say "Open this file with default editor on the OS". this would be perfect. But for now to edit the file i have to manually open it on the eplorer. i can't ask my end user to do that there is too many risk they edit the wrong file.

Another option on the table is the different javascript library for editing PDF, but these last one looks all very expensive, usually very heavy on the client side, with advanced features definitively i don't need. I just want to fill the forms and retrieve the pdf completed. So i would like to avoid this option.

Last option i take a look, i already use pdf.js (from mozilla) and pdf-lib.js in my app for some drawing features. I was thinking

• rendering the pdf with pdf.js
• retrieve all the forms fields (id, type, size, position) of the pdf with pdf-lib
• generate html input write on the top of the pdf with the informations given by pdf-lib
• i let the users fill the input and click on a save button whe he finished
• on the save, i edit my pdf with pdf lib, i set the value of all my forms fields by taking value of the corresponding html input, and i retrieved the pdf updated. This solution look for me the more "feasible". But im afraid of the volume of development, on how it will render, deal with zoom, rotation, etc. i would like to not have my custom solution.

I precise my webapp target chrome so it make me crazy to not be able to use the chrome pdf viewer/editor to do what i want.

PS : i struggle to post this question on stackoverflow. the previous one was deleted witout i had precise reasons. i try to be more specific on this one, but please if its such a dumb question, please answer it