dav.propfind.depth_infinity --> developer documentation

[mmattel]

WHAT Needs to be Documented?

The new setting in core for 10.9: owncloud/core#38583 ([full-ci] Enable streaming for propfind) may need to find its way into the developer documentation.

WHERE Does This Need To Be Documented (Link)?

Not sure but: https://doc.owncloud.com/server/next/developer_manual/core/apis/ocs-capabilities.html

WHY Should This Change Be Made?

The impact is not only great for the server, but if a client can use the new setting it will bring a lot of benefits. If the client cant use it, there is no change in behaviour.

For a quick and dirty explanation I just sent the answer to my question from deepdiver thru google translate but this gives a hint what it is about.

without streaming:

• server collects all information for the propfind
• information is stored in the RAM
• when everything is collected an xml is built
• the xml is sent to the client
  i.e. client waits until everything is ready

with streaming:

• while the server is still running through the file tree and collecting the information, xml elements are sent directly to the client
• i.e. the client receives the answer immediately and can already process it
• Impact on our clients (who can do that - ios only at the moment): they can immediately parse and process the xml
• effects on the server: significantly lower memory consumption
• the whole thing now allows the initial propfind to be sent with depth infinity
  i.e. the client can process the first sync in a request and does not have to send a request for each folder

(Optional) Which Manual Does This Relate To?

• Admin Manual
• Developer Manual
• User Manual

@EParzefall fyi
@phil-davis mind to help as you have done many updates of the dev docs.

[mmattel]

@phil-davis ping, requesting help as I have no clue how to properly doc this

[michaelstingl]

@mmattel in some scenarios, this is causing more load on the server, and admins wants to avoid this. Maybe also add admin docs how to disable the capability. (see owncloud/core#38583 (comment))

/cc @xoxys

[michaelstingl]

@mmattel in some scenarios, this is causing more load on the server, and admins wants to avoid this. Maybe also add admin docs how to disable the capability. (see owncloud/core#38583 (comment))

/cc @xoxys

Ah, it's already there:
https://doc.owncloud.com/server/10.9/admin_manual/configuration/server/config_sample_php_parameters.html#allow-propfind-depth-infinity