* Not backward compatible: All uses of the ca-auth callback in restconf plugins must be changed
* New version is: `int ca_auth(h, req, auth_type, authp, userp)`
* where `auth_type` is the requested authentication-type (none, client-cert or user-defined)
* `authp` is the returned authentication flag
* `userp` is the returned associated authenticated user
* and the return value is three-valued: -1: Error, 0: not handled, 1: OK
* For more info see [clixon-docs/restconf](https://clixon-docs.readthedocs.io/en/latest/restconf.html)
* evhtp restconf closes session on -1 fatal error (no hang)
* restconf auth-type=none call ca_auth callback
* main example for auth_type=none uses basic auth to get user but without passwd check
* Except `CLICON_RESTCONF_DIR` which remains in clixon-config.yang due to bootstrapping
* -d <dir> option removed
* This applies to both evhtp and fcgi RESTCONF
* Both can also read config from backend, and be started from backend
* You may need to move config as follows (from clixon-config.yang to clixon-restconf.yang)
* CLICON_RESTCONF_PRETTY -> restconf/pretty
* CLICON_RESTCONF_PATH -> restconf/fcgi-path
* Not backward compatible: All uses of the ca-auth callback in restconf plugins must be changed
* New version is: `int ca_auth(h, req, auth_type, authp, userp)`
* where `auth_type` is the requested authentication-type (none, client-cert or user-defined)
* `authp` is the returned authentication flag
* `userp` is the returned associated authenticated user
* and the return value is three-valued: -1: Error, 0: ignored, 1: OK
* For more info see [clixon-docs](https://clixon-docs.readthedocs.io/en/latest/restconf.html)
* New clixon-restconf@2020-12-30.yang revision
* NACM recovery user session is now properly enforced. This means that if `CLICON_NACM_CREDENTIALS` is `except` (default), then a specific `CLICON_NACM_RECOVERY_USER` can make any edits and bypass NACM rules.
* If a default value is replaced by an actual value, RESTCONF return values have changed from `204 No Content` to `201 Created`
* clixon-config.yang: Removed default valude of CLICON_NACM_RECOVERY_USER
* Added: stats RPC for clixon XML and memory statistics.
* Added: restart-plugin RPC for restarting individual plugins without restarting backend.
* xml-stats moved from clixon-config.yang as state data to an rpc `datastats` in clixon-lib.yang
* Experimental: restart_plugin
* Two new plugin callbacks added
* ca_daemon: Called just after a server has "daemonized", ie put in background.
* ca_trans_commit_done: Called when all plugin commits have been done.
* Note: If you have used "end" callback and usign transaction data, you should probably use this instead.
* If you have used, `ys`, add `xml_spec_set(x, ys)` after the statement
* If you have `xml_type_set(x, TYPE)` or `xml_prefix_set(x, PREFIX)` immediately after the statement, you can remove those and set them directly as: `xml_new(name, PREFIX, xp, TYPE)`
Major New features
* New and updated search functions using xpath, api-path and instance-id
* New search functions using api-path and instance_id:
* C search functions: `clixon_find_instance_id()` and `clixon_find_api_path()`
* Binary search optimization in lists for indexed leafs in all three formats.
* This improves search performance to O(logN) which is drastical improvements for large lists.
* You can also register explicit indexes for making binary search (not only list keys)
* For more info, see docs at [paths](https://clixon-docs.readthedocs.io/en/latest/paths.html) and
[search](https://clixon-docs.readthedocs.io/en/latest/xml.html#searching-in-xml)
API changes on existing features (you may need to change your code)
* On failed validation of leafrefs, error message changed from: `No such leaf` to `No leaf <name> matching path <path>`.
* CLI Error message (clicon_rpc_generate_error()) changed when backend returns netconf error to be more descriptive:
* Original: `Config error: Validate failed. Edit and try again or discard changes: Invalid argument`
* New (example): `Netconf error: application operation-failed Identityref validation failed, undefined not derived from acl-base . Validate failed. Edit and try again or discard changes"
Minor changes
* Test framework
* Added `-- -S <file>` command-line to main example to be able to return any state to main example.
* Added `test/cicd` test scripts for running on a set of other hosts
* C-code restructuring
* clixon_yang.c partitioned and moved code into clixon_yang_parse_lib.c and clixon_yang_module.c and move back some code from clixon_yang_type.c.
* partly to reduce size, but most important to limit code that accesses internal yang structures, only clixon_yang.c does this now.
* This occurs in cases where there are more than one XML namespaces in a config tree, such as `augment`:ed trees.
* Affects all parts of the system, including datastore, backend, restconf and cli.
* Invalid api-path syntax (eg non-matching yang) error changed from 412 operation-failed to 400 Bad request invalid-value, or unknown-element.
* New clixon-lib@2019-08-13.yang revision
* Bugfix: If `ietf-netconf.yang` was imported from any yang module, client/backend communication stops working.
* Yang Netconf leaf/leaf-list insert support
* For "ordered-by user" leafs and leaf-lists, the insert and value/key attributes are supported according to RFC7950 Sections 7.7.9 and 7.8.6
* Fixed RESTCONF api-path leaf-list selection was not made properly
* `201 Created` for created resources
* `204 No Content` for replaced resources.
* See [RESTCONF: HTTP return codes are not according to RFC 8040](https://github.com/clicon/clixon/issues/56)
* HTTP `Location:` fields added in RESTCONF POST replies
* Restconf RFC 8040 increased feature compliance
* Cache-Control: no-cache added in HTTP responses (RFC Section 5.5)
* Restconf monitoring capabilities (RFC Section 9.1)
* Added support for Yang extensions
* New plugin callback: ca_extension
* Main backend example includes example code on how to implement a Yang extension in a plugin.
* JSON changes
* Non-pretty-print output removed all extra spaces.
* Example: `{"nacm-example:x": 42}` --> {"nacm-example:x":42}`
* Empty JSON container changed from `null` to `{}`.
* Empty list and leafs remain as `null`
* Removed unnecessary configure dependencies
* libnsl, libcrypt, libm, if_vlan,...
* pseudo-plugin added, to enable callbacks also for main programs. Useful for extensions
* Yang Unique statements with multiple schema identifiers did not work on some platforms due to memory error.
The reason is to be conservative with the API. However, less used functions, such as xpath_vec_bool(), xpath_vec_ctx() and xpath_vec_flag() are changed with a new `nsc`parameter, which should be set to NULL in most cases.
