Prevent leading slash when serializing relative URIs in JSON-LD

[elichad]

I'm working with JSON-LD data which uses relative URIs as identifiers (example). The identifiers may be paths (like data/results.csv) or local identifiers, which in our case usually start with # (like #alice).

I want to parse this data into a Graph, run SPARQL on it to update it, then serialize it back to JSON-LD.

If I define a base URI (say https://example.org/) and use that both when parsing and serializing the data, I expect that the output will be the same (except for the ordering of @graph). However, I find that the relative @ids are now all prefixed with /, for example:

{
  "@context": "https://w3id.org/ro/crate/1.2/context",
  "@graph": [
    {
      "@id": "/data.csv",
      "@type": "File",
      "name": "Rainfall data for Katoomba, NSW Australia February 2022",
      "encodingFormat": "text/csv",
      "license": {"@id": "https://creativecommons.org/licenses/by-nc-sa/3.0/au/"}
    },
    {
      "@id": "/#local-identifier",
      "@type": "Organization",
      "name": "Blah blah",
    },
    ...
  ]
}

This happens regardless of whether the base URI has a trailing slash.

Is there any way to strip off the leading slash in the relative URIs when serializing?

[edmondchuc]

Could you please provide a reproducible snippet of code?

This is what I get with the following:

import json

from rdflib import Graph

data = {
  "@context": "https://w3id.org/ro/crate/1.2/context",
  "@graph": [
    {
      "@id": "ro-crate-metadata.json",
      "@type": "CreativeWork",
      "conformsTo": {"@id": "https://w3id.org/ro/crate/1.2"},
      "about": {"@id": "./"}
    },
    {
      "@id": "./",
      "@type": "Dataset",
      "name": "Example dataset for RO-Crate specification",
      "description": "Official rainfall readings for Katoomba, NSW 2022, Australia",
      "datePublished": "2022-12-01",
      "publisher": {"@id": "https://ror.org/04dkp1p98"},
      "license": {"@id": "http://spdx.org/licenses/CC0-1.0"},
      "hasPart": [
        {"@id": "data.csv"}
      ]
    },
    {
      "@id": "data.csv",
      "@type": "File",
      "name": "Rainfall data for Katoomba, NSW Australia February 2022",
      "encodingFormat": "text/csv",
      "license": {"@id": "https://creativecommons.org/licenses/by-nc-sa/3.0/au/"}
    },
    {
      "@id": "https://ror.org/04dkp1p98",
      "@type": "Organization",
      "name": "Bureau of Meteorology",
      "description": "Australian Government Bureau of Meteorology",
      "url": "http://www.bom.gov.au/"
    },
    {
      "@id": "https://creativecommons.org/licenses/by-nc-sa/3.0/au/",
      "@type": "CreativeWork",
      "name": "CC BY-NC-SA 3.0 AU",
      "description": "Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Australia"
    }
  ]
}

data_str = json.dumps(data, indent=2)
graph = Graph().parse(data=data_str, format="json-ld", publicID="http://example.com/")
output = graph.serialize(format="json-ld", context="https://w3id.org/ro/crate/1.2/context")
print(output)

Prints:

{
  "@context": "https://w3id.org/ro/crate/1.2/context",
  "@graph": [
    {
      "@id": "http://example.com/",
      "@type": "Dataset",
      "datePublished": "2022-12-01",
      "description": "Official rainfall readings for Katoomba, NSW 2022, Australia",
      "hasPart": {
        "@id": "http://example.com/data.csv"
      },
      "license": {
        "@id": "http://spdx.org/licenses/CC0-1.0"
      },
      "name": "Example dataset for RO-Crate specification",
      "publisher": {
        "@id": "https://ror.org/04dkp1p98"
      }
    },
    {
      "@id": "http://example.com/ro-crate-metadata.json",
      "@type": "CreativeWork",
      "about": {
        "@id": "http://example.com/"
      },
      "conformsTo": {
        "@id": "https://w3id.org/ro/crate/1.2"
      }
    },
    {
      "@id": "https://ror.org/04dkp1p98",
      "@type": "Organization",
      "description": "Australian Government Bureau of Meteorology",
      "name": "Bureau of Meteorology",
      "url": "http://www.bom.gov.au/"
    },
    {
      "@id": "https://creativecommons.org/licenses/by-nc-sa/3.0/au/",
      "@type": "CreativeWork",
      "description": "Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Australia",
      "name": "CC BY-NC-SA 3.0 AU"
    },
    {
      "@id": "http://example.com/data.csv",
      "@type": "File",
      "encodingFormat": "text/csv",
      "license": {
        "@id": "https://creativecommons.org/licenses/by-nc-sa/3.0/au/"
      },
      "name": "Rainfall data for Katoomba, NSW Australia February 2022"
    }
  ]
}

[elichad]

@edmondchuc if you add base="http://example.com/" to the call to graph.serialize, you reproduce the issue.

import json

from rdflib import Graph

data = {
  "@context": "https://w3id.org/ro/crate/1.2/context",
  "@graph": [
    {
      "@id": "ro-crate-metadata.json",
      "@type": "CreativeWork",
      "conformsTo": {"@id": "https://w3id.org/ro/crate/1.2"},
      "about": {"@id": "./"}
    },
    {
      "@id": "./",
      "@type": "Dataset",
      "name": "Example dataset for RO-Crate specification",
      "description": "Official rainfall readings for Katoomba, NSW 2022, Australia",
      "datePublished": "2022-12-01",
      "publisher": {"@id": "https://ror.org/04dkp1p98"},
      "license": {"@id": "http://spdx.org/licenses/CC0-1.0"},
      "hasPart": [
        {"@id": "data.csv"}
      ]
    },
    {
      "@id": "data.csv",
      "@type": "File",
      "name": "Rainfall data for Katoomba, NSW Australia February 2022",
      "encodingFormat": "text/csv",
      "license": {"@id": "https://creativecommons.org/licenses/by-nc-sa/3.0/au/"}
    },
    {
      "@id": "https://ror.org/04dkp1p98",
      "@type": "Organization",
      "name": "Bureau of Meteorology",
      "description": "Australian Government Bureau of Meteorology",
      "url": "http://www.bom.gov.au/"
    },
    {
      "@id": "https://creativecommons.org/licenses/by-nc-sa/3.0/au/",
      "@type": "CreativeWork",
      "name": "CC BY-NC-SA 3.0 AU",
      "description": "Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Australia"
    }
  ]
}

data_str = json.dumps(data, indent=2)
graph = Graph().parse(data=data_str, format="json-ld", publicID="http://example.com/")
output = graph.serialize(format="json-ld", context="https://w3id.org/ro/crate/1.2/context", base="http://example.com/")
print(output)

Produces:

{
  "@context": "https://w3id.org/ro/crate/1.2/context",
  "@graph": [
    {
      "@id": "/data.csv",
      "@type": "File",
      "encodingFormat": "text/csv",
      "license": {
        "@id": "https://creativecommons.org/licenses/by-nc-sa/3.0/au/"
      },
      "name": "Rainfall data for Katoomba, NSW Australia February 2022"
    },
    {
      "@id": "",
      "@type": "Dataset",
      "datePublished": "2022-12-01",
      "description": "Official rainfall readings for Katoomba, NSW 2022, Australia",
      "hasPart": {
        "@id": "/data.csv"
      },
      "license": {
        "@id": "http://spdx.org/licenses/CC0-1.0"
      },
      "name": "Example dataset for RO-Crate specification",
      "publisher": {
        "@id": "https://ror.org/04dkp1p98"
      }
    },
    {
      "@id": "https://ror.org/04dkp1p98",
      "@type": "Organization",
      "description": "Australian Government Bureau of Meteorology",
      "name": "Bureau of Meteorology",
      "url": "http://www.bom.gov.au/"
    },
    {
      "@id": "/ro-crate-metadata.json",
      "@type": "CreativeWork",
      "about": {
        "@id": ""
      },
      "conformsTo": {
        "@id": "https://w3id.org/ro/crate/1.2"
      }
    },
    {
      "@id": "https://creativecommons.org/licenses/by-nc-sa/3.0/au/",
      "@type": "CreativeWork",
      "description": "Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Australia",
      "name": "CC BY-NC-SA 3.0 AU"
    }
  ]
}

[ioggstream]

May be related to #1216 ?