X-Git-Url: https://gerrit.onap.org/r/gitweb?a=blobdiff_plain;f=docs%2Fcps-path.rst;h=0271d07e1d42744b49c36ad2028dd8774e418bd1;hb=f0527c58c17963d940535d0ce0eb934c2b4c635c;hp=aec87cd4362c76e22ae4d12d84bdea2b65b77b17;hpb=6355b212de77e658b16614eb775f03c7713c8460;p=cps.git diff --git a/docs/cps-path.rst b/docs/cps-path.rst index aec87cd43..0271d07e1 100644 --- a/docs/cps-path.rst +++ b/docs/cps-path.rst @@ -14,8 +14,8 @@ CPS Path Introduction ============ -Several CPS APIs use the cps-path (or cpsPath in Java API) parameter. -The CPS Path parameter is used for querying xpaths. CPS Path is insprired by the `XML Path Language (XPath) 3.1. `_ +Several CPS APIs use the CPS path (or cpsPath in Java API) parameter. +The CPS path parameter is used for querying xpaths. CPS path is inspired by the `XML Path Language (XPath) 3.1. `_ This section describes the functionality currently supported by CPS Path. @@ -28,104 +28,137 @@ The xml below describes some basic data to be used to illustrate the CPS Path fu - Chapters - - - - - - - - - - - + Chapters + + + + + + 1968 + 2018 + + + + 1965 + + + + + + + + -**Note.** 'categories' is a Yang List and 'code' is its key leaf. All other data nodes are Yang Containers +**Note.** 'categories' is a Yang List and 'code' is its key leaf. All other data nodes are Yang Containers. 'label' and 'edition' are both leaf-lists. General Notes ============= -- String values must be wrapped in quotation marks (U+0022) or apostrophes (U+0027). +- String values must be wrapped in quotation marks ``"`` (U+0022) or apostrophes ``'`` (U+0027). - String comparisons are case sensitive. +- List key-fields containing ``\`` or ``@[`` will not be processed correctly when being referenced with such key values in absolute or descendant paths. This means such entries will be omitted from any query result. See `CPS-500 `_ Special Character Limitations of cpsPath Queries -Supported Queries -================= +Query Syntax +============ -Get List Elements by Any Attribute Value ----------------------------------------- +``( | ) [ ] [ ] [ ]`` -**Syntax**: ``/[@=]`` - - ``xpath``: The xpath to the parent of the target node including all ancestors. - - ``target-node``: The name of the (list) node which elements will queried. - - ``leaf-name``: The name of the leaf which value needs to be compared. - - ``leaf-value``: The required value of the leaf. +Each CPS path expression need to start with an 'absolute' or 'descendant' xpath. + +absolute-path +------------- + +**Syntax**: ``'/' ( '[' ']' )? ( '/' ( '[' ']' )? )*`` + + - ``container name``: Any yang container or list. + - ``list-key``: One or more key-value pairs, each preceded by the ``@`` symbol, combined using the ``and`` keyword. + - The above van repeated any number of times. **Examples** - - ``/shops/bookstore/categories[@numberOfBooks=1]`` - - ``/shops/bookstore/categories[@name="Kids"]`` - - ``/shops/bookstore/categories[@name='Kids']`` + - ``/shops/bookstore`` + - ``/shops/bookstore/categories[@code=1]`` + - ``/shops/bookstore/categories[@code=1]/book`` **Limitations** - - Only one list (last descendant) can be queried for a non-key value. Any ancestor list will have to be referenced by its key name-value pair(s). - - Only one attribute can be queried. - - Only string and integer values are supported (boolean and float values are not supported). + - Absolute paths must start with the top element (data node) as per the model tree. + - Each list reference must include a valid instance reference to the key for that list. Except when it is the last element. -**Notes** - - For performance reasons it does not make sense to query using key leaf as attribute. If the key value is known it is better to execute a get request with the complete xpath. +descendant-path +--------------- -Get Any Descendant ------------------- +**Syntax**: ``'//' ( '[' ']' )? ( '/' ( '[' ']' )? )*`` -**Syntax**: ``//`` - - ``direct-ancestors``: Optional path to direct ancestors of the target node. This can contain zero to many ancestor nodes separated by a /. - - ``target-node``: The name of the (list) node from which element will be selected. If the target node is a Yang List he element needs to be specified using the key as normal e.g. ``categories[@code=1]``. + - The syntax of a descendant path is identical to a absolute path except that it is preceded by a double slash ``//``. **Examples** - - ``//book`` - - ``//books/book`` - - ``//categories[@code=1]`` - - ``//categories[@code=1]/books`` + - ``//bookstore`` + - ``//categories[@code=1]/book`` + - ``//bookstore/categories`` **Limitations** - - List elements can only be addressed using the list key leaf. + - Each list reference must include a valid instance reference to the key for that list. Except when it is the last element. -Get Any Descendant by Any Attribute Value ------------------------------------------ +leaf-conditions +--------------- -**Syntax**: ``//[@=]`` - - ``direct-ancestors``: Optional path to direct ancestors of the target node. This can contain zero to many ancestor nodes separated by a /. - - ``target-node``: The name of the (list) node which elements will queried. - - ``leaf1-name .. leafN-name:``: One or more leaves whose value needs to be compared. - - ``leaf1-value .. leafN-value:``: One or more required leaf values (multiple condition can be combined using the 'and' keyword). +**Syntax**: `` '[' @ '=' ( ' and ' @ '=' )* ']'`` + - ``xpath``: Absolute or descendant or xpath to the (list) node which elements will be queried. + - ``leaf-name``: The name of the leaf which value needs to be compared. + - ``leaf-value``: The required value of the leaf. **Examples** + - ``/shops/bookstore/categories[@numberOfBooks=1]`` + - ``//categories[@name="Kids"]`` - ``//categories[@name='Kids']`` - - ``//categories[@name='Kids' and @numberOfBooks=1]`` + - ``//categories[@code=1]/book[@title='Dune' and price=5]`` **Limitations** - - Only string and integer values are supported (boolean and float values are not supported). - - Multiple attributes can only be combined using 'and'. 'or' and bracketing is not supported. + - Only the last list or container can be queried leaf values. Any ancestor list will have to be referenced by its key name-value pair(s). + - Multiple attributes can only be combined using ``and``. ``or`` and bracketing is not supported. + - Only leaves can be used, leaf-list are not supported. + - Only string and integer values are supported, boolean and float values are not supported. + +**Notes** + - For performance reasons it does not make sense to query using key leaf as attribute. If the key value is known it is better to execute a get request with the complete xpath. + +text()-condition +---------------- + +The text()-condition can be added to any CPS path query. -Query Extensions -================ +**Syntax**: `` ( '/' '[text()=' ']' )?`` + - ``cps-path``: Any CPS path query. + - ``leaf-name``: The name of the leaf or leaf-list which value needs to be compared. + - ``string-value``: The required value of the leaf or leaf-list element as a string wrapped in quotation marks (U+0022) or apostrophes (U+0027). This wil still match integer values. + +**Examples** + - ``//book/label[text()="classic"]`` + - ``//book/edition[text()="1965"]`` + +**Limitations** + - Only the last list or container can be queried for leaf values with a text() condition. Any ancestor list will have to be referenced by its key name-value pair(s). + - Only one leaf or leaf-list can be tested. + - Only string and integer values are supported, boolean and float values are not supported. + - Since CPS cannot return individual leaves it will always return the container with all its leaves. Ancestor-axis can be used to specify a parent higher up the tree. + - When querying a leaf value (instead of leaf-list) it is better, more performant to use a text value condition use @ as described above. -Ancestor Axis +ancestor-axis ------------- -The ancestor axis can be added to any CPS path query. +The ancestor axis can be added to any CPS path query but has to be the last part. -**Syntax**: ``///ancestor::`` +**Syntax**: `` ( '/ancestor::' )?`` - ``cps-path``: Any CPS path query. - - ``ancestor-path``: Partial path to ancestors of the target node. This can contain one or more ancestor nodes separated by a /. + - ``ancestor-path``: Partial path to ancestors of the target node. This can contain one or more ancestor nodes separated by a ``/``. **Examples** - ``//book/ancestor::categories`` - ``//categories[@genre="SciFi"]/book/ancestor::bookstore`` - ``book/ancestor::categories[@code=1]/books`` + - ``//book/label[text()="classic"]/ancestor::shop`` **Limitations** - Ancestor list elements can only be addressed using the list key leaf. - - List elements with compound keys are not supported. \ No newline at end of file + - List elements with compound keys are not supported.