Error: "There is no pointer to the root dataset"

[marcolarosa]

I'm now seeing the above error when I wasn't a week or so ago and my templates haven't changed.

I'm using the feature/objectify branch and this is happening when I try to objectify a crate.

Here's an example:

{
    "@graph": [
        {
            "@id": "./",
            "@type": [
                "http://schema.org/Dataset",
                "http://pcdm.org/models#object"
            ],
            "http://paradisec.org.au/adminComment": "",
            "http://paradisec.org.au/bornDigital": "0",
            "http://paradisec.org.au/citeAs": "",
            "http://paradisec.org.au/contentLanguages": { "@id": "_:b0" },
            "http://paradisec.org.au/dialect": "",
            "http://paradisec.org.au/digitisedOn": "2006-02-02T13:00:00.000Z",
            "http://paradisec.org.au/discourseType": "",
            "http://paradisec.org.au/external": "0",
            "http://paradisec.org.au/ingestNotes": "A)  3 3/4ips, NAB eq, 1track of 1/2trk.  Field recordings, speech.  Some high-freq whistle, possibly from dub?\r\nLength: Side A: 0:19:07.\r\nB)  BLANK\r\n",
            "http://paradisec.org.au/languageAsGiven": "Luganda",
            "http://paradisec.org.au/originatedOn": "1958-12-23",
            "http://paradisec.org.au/originatedOnNarrative": "",
            "http://paradisec.org.au/private": "0",
            "http://paradisec.org.au/receivedOn": "",
            "http://paradisec.org.au/subjectLanguages": { "@id": "_:b1" },
            "http://schema.org/additionalType": "item",
            "http://schema.org/contentLocation": { "@id": "_:b2" },
            "http://schema.org/contentUrl": "./",
            "http://schema.org/contributor": [
                { "@id": "_:b4" },
                { "@id": "_:b6" },
                { "@id": "_:b8" }
            ],
            "http://schema.org/dateCreated": "2005-02-27T13:00:00.000Z",
            "http://schema.org/dateModified": "2018-04-05T05:30:59.000Z",
            "http://schema.org/description": "Luganda (Fr Kibéngere)\r\n\r\nside B: blank",
            "http://schema.org/hasPart": [
                { "@id": "AC1-001-A.mp3" },
                { "@id": "AC1-001-A.wav" },
                { "@id": "AC1-001-IMG_02.tif" },
                { "@id": "AC1-001-IMG_02.jpg" },
                { "@id": "AC1-001-IMG_01.tif" },
                { "@id": "AC1-001-IMG_01.jpg" },
                { "@id": "AC1-001-IMG_03.tif" },
                { "@id": "AC1-001-IMG_03.jpg" }
            ],
            "http://schema.org/identifier": [
                { "@id": "_:b10" },
                { "@id": "_:b11" },
                { "@id": "_:b12" },
                { "@id": "_:b13" },
                { "@id": "_:b14" },
                { "@id": "_:b15" }
            ],
            "http://schema.org/license": { "@id": "_:b16" },
            "http://schema.org/memberOf": { "@id": "/paradisec.org.au/AC1" },
            "http://schema.org/name": "Luganda (Fr Kibéngere)",
            "http://schema.org/publisher": { "@id": "_:b17" }
        },
        {
            "@id": "AC1-001-A.mp3",
            "@type": "http://schema.org/MediaObject",
            "http://schema.org/bitrate": "127727",
            "http://schema.org/contentSize": "18327680",
            "http://schema.org/dateCreated": "2005-02-27T13:00:00.000Z",
            "http://schema.org/dateModified": "2017-09-08T02:00:55.000Z",
            "http://schema.org/duration": "1147.93",
            "http://schema.org/encodingFormat": "audio/mpeg",
            "http://schema.org/name": "AC1-001-A.mp3"
        },
        {
            "@id": "AC1-001-A.wav",
            "@type": "http://schema.org/MediaObject",
            "http://schema.org/bitrate": "4609811",
            "http://schema.org/contentSize": "661449946",
            "http://schema.org/dateCreated": "2005-02-27T13:00:00.000Z",
            "http://schema.org/dateModified": "2017-09-08T02:01:13.000Z",
            "http://schema.org/duration": "1147.9",
            "http://schema.org/encodingFormat": "audio/x-wav",
            "http://schema.org/name": "AC1-001-A.wav"
        },
        {
            "@id": "AC1-001-IMG_01.jpg",
            "@type": "http://schema.org/MediaObject",
            "http://schema.org/bitrate": "",
            "http://schema.org/contentSize": "1157474",
            "http://schema.org/dateCreated": "2016-10-11T22:06:34.000Z",
            "http://schema.org/dateModified": "2016-10-12T15:00:26.000Z",
            "http://schema.org/duration": "",
            "http://schema.org/encodingFormat": "image/jpeg",
            "http://schema.org/name": "AC1-001-IMG_01.jpg"
        },
        {
            "@id": "AC1-001-IMG_01.tif",
            "@type": "http://schema.org/MediaObject",
            "http://schema.org/bitrate": "",
            "http://schema.org/contentSize": "29972116",
            "http://schema.org/dateCreated": "2016-10-11T22:06:33.000Z",
            "http://schema.org/dateModified": "2016-10-12T15:00:22.000Z",
            "http://schema.org/duration": "",
            "http://schema.org/encodingFormat": "image/tiff",
            "http://schema.org/name": "AC1-001-IMG_01.tif"
        },
        {
            "@id": "AC1-001-IMG_02.jpg",
            "@type": "http://schema.org/MediaObject",
            "http://schema.org/bitrate": "",
            "http://schema.org/contentSize": "1192048",
            "http://schema.org/dateCreated": "2016-10-11T22:03:26.000Z",
            "http://schema.org/dateModified": "2016-10-12T15:00:17.000Z",
            "http://schema.org/duration": "",
            "http://schema.org/encodingFormat": "image/jpeg",
            "http://schema.org/name": "AC1-001-IMG_02.jpg"
        },
        {
            "@id": "AC1-001-IMG_02.tif",
            "@type": "http://schema.org/MediaObject",
            "http://schema.org/bitrate": "",
            "http://schema.org/contentSize": "29971726",
            "http://schema.org/dateCreated": "2016-10-11T22:03:25.000Z",
            "http://schema.org/dateModified": "2016-10-12T15:00:13.000Z",
            "http://schema.org/duration": "",
            "http://schema.org/encodingFormat": "image/tiff",
            "http://schema.org/name": "AC1-001-IMG_02.tif"
        },
        {
            "@id": "AC1-001-IMG_03.jpg",
            "@type": "http://schema.org/MediaObject",
            "http://schema.org/bitrate": "",
            "http://schema.org/contentSize": "1206492",
            "http://schema.org/dateCreated": "2016-10-11T22:07:13.000Z",
            "http://schema.org/dateModified": "2016-10-12T15:00:34.000Z",
            "http://schema.org/duration": "",
            "http://schema.org/encodingFormat": "image/jpeg",
            "http://schema.org/name": "AC1-001-IMG_03.jpg"
        },
        {
            "@id": "AC1-001-IMG_03.tif",
            "@type": "http://schema.org/MediaObject",
            "http://schema.org/bitrate": "",
            "http://schema.org/contentSize": "29973228",
            "http://schema.org/dateCreated": "2016-10-11T22:07:12.000Z",
            "http://schema.org/dateModified": "2016-10-12T15:00:30.000Z",
            "http://schema.org/duration": "",
            "http://schema.org/encodingFormat": "image/tiff",
            "http://schema.org/name": "AC1-001-IMG_03.tif"
        },
        {
            "@id": "_:b0",
            "@type": "http://schema.org/Language",
            "http://schema.org/alternateName": "lug",
            "http://schema.org/name": "Ganda"
        },
        {
            "@id": "_:b1",
            "@type": "http://schema.org/Language",
            "http://schema.org/alternateName": "lug",
            "http://schema.org/name": "Ganda"
        },
        {
            "@id": "_:b10",
            "@type": "http://schema.org/PropertyValue",
            "http://schema.org/name": "domain",
            "http://schema.org/value": "paradisec.org.au"
        },
        {
            "@id": "_:b11",
            "@type": "http://schema.org/PropertyValue",
            "http://schema.org/name": "id",
            "http://schema.org/value": "/paradisec.org.au/AC1/001"
        },
        {
            "@id": "_:b12",
            "@type": "http://schema.org/PropertyValue",
            "http://schema.org/name": "hashId",
            "http://schema.org/value": "b75a47e81fd8b8de947bbc50bd8487e96b9ba9b0370107905f81d3632358a1156842a698df1320b18943359b771d8a049c4581754fa719058091a703b9ce1e35"
        },
        {
            "@id": "_:b13",
            "@type": "http://schema.org/PropertyValue",
            "http://schema.org/name": "itemIdentifier",
            "http://schema.org/value": "001"
        },
        {
            "@id": "_:b14",
            "@type": "http://schema.org/PropertyValue",
            "http://schema.org/name": "collectionIdentifier",
            "http://schema.org/value": "AC1"
        },
        {
            "@id": "_:b15",
            "@type": "http://schema.org/PropertyValue",
            "http://schema.org/name": "doi",
            "http://schema.org/value": "10.4225/72/56E97C3321C5D"
        },
        {
            "@id": "_:b16",
            "http://schema.org/description": "",
            "http://schema.org/name": "Open (subject to agreeing to PDSC access conditions)"
        },
        {
            "@id": "_:b17",
            "http://schema.org/identifier": "http://nla.gov.au/nla.party-593941",
            "http://schema.org/name": "University of Sydney"
        },
        {
            "@id": "_:b2",
            "@type": "http://schema.org/Place",
            "http://schema.org/geo": { "@id": "_:b3" },
            "http://schema.org/name": ""
        },
        {
            "@id": "_:b3",
            "@type": "http://schema.org/GeoShape",
            "http://schema.org/box": "31.03,-0.995 33.396,1.612"
        },
        {
            "@id": "_:b4",
            "@type": "http://schema.org/Role",
            "http://schema.org/contributor": { "@id": "_:b5" },
            "http://schema.org/name": "collector"
        },
        {
            "@id": "_:b5",
            "@type": "http://schema.org/Person",
            "http://schema.org/givenName": "Arthur",
            "http://schema.org/name": "Arthur Capell"
        },
        {
            "@id": "_:b6",
            "@type": "http://schema.org/Role",
            "http://schema.org/contributor": { "@id": "_:b7" },
            "http://schema.org/name": "operator"
        },
        {
            "@id": "_:b7",
            "@type": "http://schema.org/Person",
            "http://schema.org/givenName": "Frank",
            "http://schema.org/name": "Frank Davey"
        },
        {
            "@id": "_:b8",
            "@type": "http://schema.org/Role",
            "http://schema.org/contributor": { "@id": "_:b9" },
            "http://schema.org/name": "recorder"
        },
        {
            "@id": "_:b9",
            "@type": "http://schema.org/Person",
            "http://schema.org/givenName": "Arthur",
            "http://schema.org/name": "Arthur Capell"
        },
        {
            "@id": "ro-crate-metadata.jsonld",
            "@type": "http://schema.org/CreativeWork",
            "http://schema.org/about": { "@id": "./" },
            "http://schema.org/identifier": "ro-crate-metadata.jsonld",
            "http://schema.org/license": {
                "@id": "https://creativecommons.org/licenses/by-sa/3.0"
            }
        }
    ]
}

Note the last entry in the graph - isn't that the pointer to the root dataset?

[marcolarosa]

So it looks like lines 58 and 59 in lib/rocrate.js are the issue in that they don't handle the fully qualified properties. So, when I change those lines to:

58                 if (t === "http://schema.org/CreativeWork" && item.hasOwnProperty("http://schema.org/identifier")  && item['http://schema.org/identifier'] === this.defaults.roCrateMetadataID) {
 59                     this._rootId = item['http://schema.org/about']["@id"];

The pointer is identified. Thoughts?

The context is that when i write the templates, I use jsonld to flatten them but that's it. Should I also be compacting them to shorten those refs or is the rocrate library supposed to handle crates in that form?

[marcolarosa]

Ok - this is not an issue with the lib. I think what's happened is that (using an earlier version of jsonld) my crates were being compacted at the same time as they were flattened. Looking at the API for jsonld now it seems I need to flatten then compact the crates before writing them out.

You can close this ticket when you're ready.