As IT specialist I want to have a REST API to documents in CooL to automate tasks and link tools

Is your feature request related to a problem? Please describe.

While discussing #4738 I got reminded about a feature I have in mind since a longer time. It would be great, to make document content easily available for modification through a REST API. This would help in different scenarios, some examples:

[dev] Make testing code easy(er), unit tests could make REST calls on a document to add/modify/delete stuff
[biz] Spreadsheet are still powering many business processes, feeding in data from one system into a spreadsheet could automate such processes, also reading from spreadsheet and feed the data into other tools would be helpful
[biz] Having a REST API helps developers to quickly adopt CooL for their needs, it's something people use all over the place (which is not the case for UNO, macros, et al.)
[biz] create web interfaces e.g. for an event sign up that can easily be connected to a spreadsheet
...

Describe the solution you'd like I'd like to have a REST endpoint to easily connect to documents that CooL can manage, the endpoints will differ depending on the document type, some basic examples:

odf/docx

GET /title/3/
PUT /paragraph/3/set/ {"value": "foobar"}
POST /paragraph/3/append/ {"value": " foobar"}
DELETE /title/3/
...

Whereas "3" is the 3rd (or 4th) paragraph/title in the document (maybe there is a better UID that can be used per object in a document, but as an example this should be clear enough).

ods/xlsx

GET /cell/a4/
GET /cell/a4/asINT (to get the value as int, just an example to make the next one more clear)
GET /cell/a4/asPNG (eg. to export a chart)
PUT /cell/a4/ {"value": 42}
DELETE /cell/a4/

Some general considerations I have in mind as well (all file types)

POST /function/replace {"search": "foo", "replace": "bar" } (replace placeholder in a document)
GET /function/download/pdf

I'd love to be able to SET/GET/PUT/DELETE data in this way, e.g. to expose collected data as charts in other places like dashboards, insert data into spreadsheets for analytics/data collection purpose, etc.

Describe alternatives you've considered Writing/parsing files using FODF is an option of course, but that's far more complex for simple document modifications to automate manual processes.

Additional context It's important to expose this feature in a very easy way! I imagine to right click an "object" in a document in CooL (e.g. a title, a paragraph, a table, an index, a picture, a cell, a chart, ...) and get an entry in the context menu that leads to a dialog containing the curl command example, the "UID" of the object and the HTTP verb(s) to use for this object. With that information it would be very easy to automate tedious manual tasks.

CollaboraOnline / online

As IT specialist I want to have a REST API to documents in CooL to automate tasks and link tools #4740