get full path up to given element-CodePudding

I have exported bookmarks from Firefox which in my case is quiet large JSON. I'm interested in the object with guid _0no-4e9woLW in a JSON such as this one:

{
  "foo": {
    "bar": {
      "zoo": {
        "guid": "_0no-4e9woLW",
        "title": "frontend",
        "index": 3,
        "dateAdded": 1614198626454000,
        "lastModified": 1619505016472000,
        "id": 16518,
        "typeCode": 2,
        "type": "text/x-moz-place-container",
        "children": [
          {
            "guid": "2L7ZsYTM2RX0",
            "title": "css child override parent style",
            "index": 0,
            "dateAdded": 1614198648005000,
            "lastModified": 1614198648005000,
            "id": 16519,
            "typeCode": 1,
            "type": "text/x-moz-place",
            "uri": "https://www.google.com/search?client=firefox-b-d&q=css child override parent style"
          },
          {
            "guid": "x3JHTAezzyI8",
            "title": "css child parent inheritance",
            "index": 1,
            "dateAdded": 1614198648096000,
            "lastModified": 1614198648096000,
            "id": 16520,
            "typeCode": 1,
            "type": "text/x-moz-place",
            "uri": "https://www.google.com/search?client=firefox-b-d&q=css child parent inheritance"
          }
        ]
      }
    }
  }
}

Is it possible to get somehow full path up to "guid": "_0no-4e9woLW"? guid keys are uniq in JSON. My goal is to type something like jq '["full path I've somehow previously obtained"]["children"].title'

And I will obtain:

css child override parent style
css child parent inheritance

Of course I could do this manually but I'm too lazy.

CodePudding user response：

Without the whole knowledge of the JSON, something like this should work when using path family of functions i.e. getpath/1

( paths | select(.[-1] == "guid") ) as $p | 
  if getpath($p)  == "_0no-4e9woLW" then getpath($p[:-1]   ["children"])[].title else empty end

The construct above means, select all those paths containing the leaf key named guid and store them in a variable and filter only the path whose value turns out to be "_0no-4e9woLW". On the selected path, trim the child node($p[:-1] removes "guid") and add the node "children" and get the value at the new path constructed (using getpath/1). Extract the .title field from the JSON value

^{jqplay demo}

CodePudding user response：

Using recurse allows to get to the object easily :

jq -r 'recurse |
       select(type=="object" and .guid == "_0no-4e9woLW")
       .children[].title' firefox.json

CodePudding user response：

To access a node by guid:

.. | objects | select( .guid == … )

So you'd use the following to get the title of _0no-4e9woLW's children:

.. | objects | select( .guid == "_0no-4e9woLW" ) | .children[].title

Demo on jqplay

To save a path:

path( … )               # As JSON

path( … ) | join(".")   # As dotted path

Replace … with an expression that returns the node(s) for which you want the path.

For example,

path( .. | objects | select( .guid == "_0no-4e9woLW" ) )   # [ "foo", "bar", "zoo" ]

Demo on jqplay

path( .. | objects | select( .guid == "_0no-4e9woLW" ) ) | join(".")   # "foo.bar.zoo"

Demo on jqplay

To grab an object using its path:

getpath( … )                                      # From JSON

getpath( … | split(".") | map(tonumber? // .) )   # From dotted path

Replace … with an expression that returns the previously saved path.

For example,

getpath( [ "foo", "bar", "zoo" ] ).children[].title

Demo on jqplay

getpath( "foo.bar.zoo" | split(".") | map(tonumber? // .) ).children[].title

Demo on jqplay