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https://issues.apache.org/jira/browse/JENA-712?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Andy Seaborne resolved JENA-712.
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Resolution: Fixed
Fix Version/s: Jena 2.12.0
Assignee: Andy Seaborne
Patch applied - awaiting verification that it addresses the root issue.
> ARQ serialises queries and updates using relative URIs but does not include a
> BASE clause
> -----------------------------------------------------------------------------------------
>
> Key: JENA-712
> URL: https://issues.apache.org/jira/browse/JENA-712
> Project: Apache Jena
> Issue Type: Bug
> Components: ARQ
> Affects Versions: Jena 2.11.2
> Reporter: Rob Vesse
> Assignee: Andy Seaborne
> Fix For: Jena 2.12.0
>
> Attachments: JENA-712-AlwaysWriteBase.patch,
> JENA-712-ConfigurableOutputImplictBase.patch,
> JENA-712-ConfigurableOutputImplictBaseOnByDefault.patch,
> JENA-712-UseBaseOnlyIfExplicit.patch, SparqlRelativeUriTreatment.java
>
>
> An internal discussion with [~harschware] has raised what we think is a bug
> in ARQs behaviour though it is somewhat open to interpretation so may be
> controversial.
> The code I will attach demonstrates the issue.
> The problem arises as follows:
> 1 - When given a query/update with a relative URI ARQ resolves it against an
> implicit Base URI of the current working directory
> 2 - When applying {{toString()}} on the parsed {{Query}} or {{UpdateRequest}}
> the implicit Base URI is used and relative URIs are output but no `BASE`
> clause is output
> 3 - The query is transmitted to a different system which has a different
> working directory and so interprets it differently resulting in unexpected
> behaviour/errors
> This causes us issues because the relative URIs are valid relative to the
> working directory of the client but not relative to the working directory of
> the server so we want absolute URIs to be transmitted to the server.
> For example given the following query string:
> {noformat}
> SELECT * WHERE { <path/to/thing> a ?type }
> {noformat}
> Calling {{toString()}} on the resulting {{Query}} object gives the following:
> {noformat}
> SELECT *
> WHERE
> { <path/to/thing> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> ?type }
> {noformat}
> Which does not include the `BASE` declaration, if we however force the
> `Query` object to have a null base via `setBaseURI((String)null)` ARQ prints
> the following when `toString()` is called:
> {noformat}
> BASE <file:///Users/rvesse/Documents/Work/Code/jena-playground/>
> SELECT *
> WHERE
> { <path/to/thing> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> ?type }
> {noformat}
> More generally it seems that whenever an implicit Base URI is used or where a
> Base URI is passed only to the {{QueryFactory.create()}} or
> {{UpdateFactory.create()}} call a {{BASE}} declaration is never written i.e.
> when there is an {{IRIResolver}} set but not a specific Base URI no {{BASE}}
> declaration will be written but URIs will be serialised in relative form.
> We can appreciate that other people may have use cases where leaving relative
> URIs as-is and not including a `BASE` is desirable but our feeling is that in
> the more general case this does more harm than good and lets users shoot
> themselves in the foot unwittingly as we have done in this example.
> We would like to propose that the default behaviour should be for a `BASE`
> declaration to always be written if relative URIs are being output. Or at
> the very least we would like the behaviour to be configurable.
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