wordpress webservice

Hi,

I would like to be able to access a web service with some data (links, image url, etc), receive the data on the server side, parse that data and create a new wordpress post using that data, and all of it simply making a post request to a url.

I would also like to download and save an image on my server using a get request from my server to the image url provided. I want the post to include the image which is hosted on my server.

I want to create a family blog (many older family members don’t use facebook or any other social network) in which data from facebook, instegram etc will be posted to my wordpress website by my family members clicking on a facebook post and activating a browser extension that I have created.
I want the browser extension to be able to make a post request to my webservice, and I want the data to be backed up on my server and not on facebook’s…

Any guideness and suggestions for implementing that web service are highly appreciated.

Thanks,
Roy