New API is as follows:
* `clixon_xml2file()` - Print internal tree as XML to file
* `clixon_xml2cbuf()` - Print internal tree as XML to buffer
* `clixon_json2file()` - Print internal tree as JSON to file
* `clixon_json2cbuf()` - Print internal tree as JSON to buffer
* `clixon_cli2file()` - Print internal tree as CLI format to file
* `clixon_txt2file()` - Print internal tree as text format to file
* Added `skiptop` parameter, if set only apply to children of a node, skip top node
* default is 0
* Functions are merged, ie removed and replaced with more generic functions
* `xml2json_cbuf()`: Added `skiptop` parameter: `xml2json_cbuf(..., int skiptop)`
* `xml2json()` and `xml2json_cb()` merged into `xml2json_file()` with `skiptop`
* Replace `xml2json(...)` with `xml2json_file(..., stdout, 0)`
* Replace `xml2json_cb(...)` with `xml2json_file(..., 0)`
* `clicon_xml2cbuf()`: Added `skiptop` parameter: `clicon_xml2cbuf(..., int skiptop)`
* `xml2cli()`: Added `skiptop` parameter: `xml2cli(..., int skiptop)`
* Load/save JSON config file did not work
* Added rfc7951 parameter to `clixon_json_parse_string()` and `clixon_json_parse_file()`
* If set, honor RFC 7951: JSON Encoding of Data Modeled with YANG, eg it requires module name prefixes
* If not set, parse as regular JSON
* Test: added test_db.sh for datastore format tests
* `clixon_xml_parse_string()`
* `clixon_xml_parse_file()`
* New JSON parsing API, with same signature as XML parsing:
* `clixon_json_parse_string()`
* `clixon_xml_parse_file()`
* XML YANG binding API have been rearranged as follows:
* `xml_bind_yang_rpc()`
* `xml_bind_yang_rpc_reply()`
* `xml_bind_yang()`
* `xml_bind_yang0()`
* C-code changes:
- Replaced stream uri:s w constants
- Replaced large debug print code with single clicon_log_xml
- Restconf put and post handling refactored using new parse API
w-level general upgrades and as a complement to module-specific upgrade.
* Called on startup after initial XML parsing, but before module-specific upgrades
* Enabled by definign the `.ca_datastore_upgrade`
* [General-purpose upgrade documentation](https://clixon-docs.readthedocs.io/en/latest/backend.html#ge
neral-purpose)
* JSON parse error messages change from ` on line x: syntax error,..` to `json_parse: line x: syntax err
or`
* Unknown-element error message is more descriptive, eg from `namespace is: urn:example:clixon` to: `Fai
led to find YANG spec of XML node: x with parent: xp in namespace urn:example:clixon`.
* C-API parse and validation API more capable
* `xml_spec_populate` family of functions extended with three-value return values
* -1: error, 0: parse OK, 1: parse and YANG binding OK.
* `xml_parse` and `json_parse` API changes
* Three value returns: -1: error, 0: parse OK, 1: parse and YANG binding OK.
* Extended `xml_parse_file2` and `xml_parse_string2` extended API functions with all options available.
* New concept called `yang_bind` that defines how XML symbols are bound to YANG after parsing
* Existing API same except `xml_parse_file` `endtag` argument moved to `xml_parse_file2`
* C-API: Added instrumentation: `xml_size` and `xml_stats_get`.
* Fixed: Enabling modstate (CLICON_XMLDB_MODSTATE), changing a revision on a yang, and restarting made the backend daemon exit at start (thanks Matt)
* Also: ensure to load `ietf-yang-library.yang ` if CLICON_XMLDB_MODSTATE is set
* 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.
* For backward compatibility, load of startup and running set CLICON_XML_NS_STRICT to false temporarily.
* Added three-valued return values for several validate functions where -1 is fatal error, 0 is validation failed and 1 is validation OK.
* This includes: `xmldb_put`, `xml_yang_validate_all`, `xml_yang_validate_add`, `xml_yang_validate_rpc`, `api_path2xml`, `api_path2xpath`
* Added new xml functions for specific types: `xml_child_nr_notype`, `xml_child_nr_notype`, `xml_child_i_type`, `xml_find_type`.
Added CLICON_XMLDB_FORMAT option. Default is "xml". If set to "json", XML database files uses JSON format.
Escape " in JSON names and strings and values
Optimized search performance for large lists by sorting and binary search.
