Class QuerySourceSparql

constructor

• new QuerySourceSparql(
      url: string,
      urlBackup: string,
      context: IActionContext,
      mediatorHttp: MediatorHttp,
      mediatorQuerySerialize: MediatorQuerySerialize,
      bindMethod: BindMethod,
      dataFactory: ComunicaDataFactory,
      algebraFactory: AlgebraFactory,
      bindingsFactory: BindingsFactory,
      forceHttpGet: boolean,
      cacheSize: number,
      countTimeout: number,
      cardinalityCountQueries: boolean,
      cardinalityEstimateConstruction: boolean,
      forceGetIfUrlLengthBelow: number,
      parseUnsupportedVersions: boolean,
      metadata: Record<string, any>,
  ): QuerySourceSparql

  Parameters

  • url: string
  • urlBackup: string
  • context: IActionContext
  • mediatorHttp: MediatorHttp
  • mediatorQuerySerialize: MediatorQuerySerialize
  • bindMethod: BindMethod
  • dataFactory: ComunicaDataFactory
  • algebraFactory: AlgebraFactory
  • bindingsFactory: BindingsFactory
  • forceHttpGet: boolean
  • cacheSize: number
  • countTimeout: number
  • cardinalityCountQueries: boolean
  • cardinalityEstimateConstruction: boolean
  • forceGetIfUrlLengthBelow: number
  • parseUnsupportedVersions: boolean
  • metadata: Record<string, any>

  Returns QuerySourceSparql

Optional ReadonlyextensionFunctions

ReadonlyreferenceValue

estimateOperationCardinality

• estimateOperationCardinality(
      operation: BaseOperation,
  ): Promise<QueryResultCardinality>

  Performs local cardinality estimation for the specified SPARQL algebra operation, which should result in better estimation performance at the expense of accuracy.

  Parameters

  • operation: BaseOperation

    A query operation.

  Returns Promise<QueryResultCardinality>

getFilterFactor

• getFilterFactor(): Promise<number>

  Returns Promise<number>

  A value from 0 to 1 indicating to what respect a source type is able to pre-filter the source based on the pattern. 1 indicates that the source can apply the whole pattern, and 0 indicates that the source can not apply the pattern at all (and local filtering must happen). Plain RDF documents for example have a filter factor of 0, while SPARQL endpoints have a filter factor of 1.

getSelectorShape

• getSelectorShape(): Promise<FragmentSelectorShape>

  Get the selector type that is supported by this source.

  Returns Promise<FragmentSelectorShape>

operationToCountQuery

• operationToCountQuery(
      dataFactory: ComunicaDataFactory,
      algebraFactory: AlgebraFactory,
      operation: BaseOperation,
  ): Promise<string>

  Convert an operation to a count query for the number of matching triples for this pattern.

  Parameters

  • dataFactory: ComunicaDataFactory

    The data factory.

  • algebraFactory: AlgebraFactory

    The algebra factory.

  • operation: BaseOperation

    A query operation.

  Returns Promise<string>

  A count query string.

operationToNormalizedCountQuery

• operationToNormalizedCountQuery(operation: BaseOperation): Promise<string>

  Convert an algebra operation into a query string, and if the operation is a simple triple pattern, then also replace any variables with s, p, and o to increase the chance of cache hits.

  Parameters

  • operation: BaseOperation

    The operation to convert into a query string.

  Returns Promise<string>

  Query string for a COUNT query over the operation.

operationToQuery

• operationToQuery(operation: BaseOperation): Promise<string>

  Convert an operation to a query for this pattern.

  Parameters

  • operation: BaseOperation

    A query operation.

  Returns Promise<string>

  A query string.

operationToSelectQuery

• operationToSelectQuery(
      algebraFactory: AlgebraFactory,
      operation: BaseOperation,
      variables: Variable[],
  ): Promise<string>

  Convert an operation to a select query for this pattern.

  Parameters

  • algebraFactory: AlgebraFactory

    The algebra factory.

  • operation: BaseOperation

    A query operation.

  • variables: Variable[]

    The variables in scope for the operation.

  Returns Promise<string>

  A select query string.

operationUsesPropertyFeatures

• operationUsesPropertyFeatures(operation: BaseOperation): boolean

  Checks whether the provided operation makes use of this endpoint's property features, if the endpoint has property features detected.

  Parameters

  • operation: BaseOperation

    The operation to check.

  Returns boolean

  Whether the operation makes use of property features.

queryBindings

• queryBindings(
      operationIn: BaseOperation,
      context: IActionContext,
      options?: IQueryBindingsOptions,
  ): BindingsStream

  Returns a (possibly lazy) stream that returns all bindings matching the operation.

  Passed operations MUST conform to the query shape exposed by the selector type returned from getSelectorShape. The given operation represents a Linked Data Fragments selector.

  The returned stream MUST expose the property 'metadata' of type MetadataBindings. The implementor is reponsible for handling cases where 'metadata' is being called without the stream being in flow-mode. This metadata object can become invalidated (see metadata.state), in which case the 'metadata' property must and will be updated.

  Parameters

  • operationIn: BaseOperation
  • context: IActionContext

    The query context.

  • Optionaloptions: IQueryBindingsOptions

    Options for querying bindings

  Returns BindingsStream

  The resulting bindings stream.

  See

  https://linkeddatafragments.org/specification/linked-data-fragments/#selectors

queryBindingsRemote

• queryBindingsRemote(
      endpoint: string,
      query: string,
      variables: Variable[],
      context: IActionContext,
      undefVariables: Variable[],
  ): Promise<BindingsStream>

  Send a SPARQL query to a SPARQL endpoint and retrieve its bindings as a stream.

  Parameters

  • endpoint: string

    A SPARQL endpoint URL.

  • query: string

    A SPARQL query string.

  • variables: Variable[]

    The expected variables.

  • context: IActionContext

    The source context.

  • undefVariables: Variable[]

    Variables that may have undefs.

  Returns Promise<BindingsStream>

  A stream of bindings.

queryBoolean

• queryBoolean(operation: Ask, context: IActionContext): Promise<boolean>

  Returns a promise resolving to the ask response of the given operation.

  This method should only be supported if the selector type returned from getSelectorShape supports ask queries.

  Parameters

  • operation: Ask

    The query operation to execute.

  • context: IActionContext

    The query context.

  Returns Promise<boolean>

  The resulting ask reply.

queryQuads

• queryQuads(
      operation: BaseOperation,
      context: IActionContext,
  ): AsyncIterator<Quad>

  Returns a (possibly lazy) stream that returns all quads matching the operation.

  This method should only be supported if the selector type returned from getSelectorShape supports construct queries.

  Parameters

  • operation: BaseOperation

    The query operation to execute.

  • context: IActionContext

    The query context.

  Returns AsyncIterator<Quad>

  The resulting quads stream.

queryVoid

• queryVoid(operation: BaseOperation, context: IActionContext): Promise<void>

  Returns a promise resolving when the given update operation succeeds.

  This method should only be supported if the selector type returned from getSelectorShape supports update queries.

  Parameters

  • operation: BaseOperation

    The query operation to execute.

  • context: IActionContext

    The query context.

  Returns Promise<void>

  The void response.

toString

• toString(): string

  Returns a string representation of this source.

  Returns string

StaticaddBindingsToOperation

• addBindingsToOperation(
      algebraFactory: AlgebraFactory,
      bindMethod: BindMethod,
      operation: BaseOperation,
      addBindings: { bindings: BindingsStream; metadata: MetadataBindings },
  ): Promise<BaseOperation>

  Create an operation that includes the bindings from the given bindings stream.

  Parameters

  • algebraFactory: AlgebraFactory

    The algebra factory.

  • bindMethod: BindMethod

    A method for adding bindings to an operation.

  • operation: BaseOperation

    The operation to bind to.

  • addBindings: { bindings: BindingsStream; metadata: MetadataBindings }

    The bindings to add.

    • bindings: BindingsStream

      The bindings stream.

    • metadata: MetadataBindings

      The bindings metadata.

  Returns Promise<BaseOperation>

StaticgetOperationUndefs

• getOperationUndefs(operation: BaseOperation): Variable[]

  Check if the given operation may produce undefined values.

  Parameters

  • operation: BaseOperation

  Returns Variable[]