Merge pull request #12 from Tpt/service-improvements

Service support improvements

lib/src/lib.rs

@@ -27,9 +27,8 @@
 //! assert_eq!(vec![quad], results.unwrap());
 //!
 //! // SPARQL query
-//! let prepared_query = connection.prepare_query("SELECT ?s WHERE { ?s ?p ?o }", None).unwrap();
+//! let prepared_query = connection.prepare_query("SELECT ?s WHERE { ?s ?p ?o }", QueryOptions::default()).unwrap();
-//! let options = QueryOptions::default();
+//! let results = prepared_query.exec().unwrap();
-//! let results = prepared_query.exec(&options).unwrap();
 //! if let QueryResult::Bindings(results) = results {
 //!     assert_eq!(results.into_values_iter().next().unwrap().unwrap()[0], Some(ex.into()));
 //! }

lib/src/repository.rs

@@ -1,5 +1,5 @@
 use crate::model::*;
-use crate::sparql::{GraphPattern, PreparedQuery};
+use crate::sparql::{GraphPattern, PreparedQuery, QueryOptions};
 use crate::{DatasetSyntax, GraphSyntax, Result};
 use std::io::BufRead;
 
@@ -30,9 +30,8 @@ use std::io::BufRead;
 /// assert_eq!(vec![quad], results.unwrap());
 ///
 /// // SPARQL query
-/// let prepared_query = connection.prepare_query("SELECT ?s WHERE { ?s ?p ?o }", None).unwrap();
+/// let prepared_query = connection.prepare_query("SELECT ?s WHERE { ?s ?p ?o }", QueryOptions::default()).unwrap();
-/// let options = QueryOptions::default();
+/// let results = prepared_query.exec().unwrap();
-/// let results = prepared_query.exec(&options).unwrap();
 /// if let QueryResult::Bindings(results) = results {
 ///     assert_eq!(results.into_values_iter().next().unwrap().unwrap()[0], Some(ex.into()));
 /// }
@@ -76,24 +75,19 @@ pub trait RepositoryConnection: Clone {
     /// connection.insert(&Quad::new(ex.clone(), ex.clone(), ex.clone(), None));
     ///
     /// // SPARQL query
-    /// let prepared_query = connection.prepare_query("SELECT ?s WHERE { ?s ?p ?o }", None).unwrap();
+    /// let prepared_query = connection.prepare_query("SELECT ?s WHERE { ?s ?p ?o }", QueryOptions::default()).unwrap();
-    /// let options = QueryOptions::default();
+    /// let results = prepared_query.exec().unwrap();
-    /// let results = prepared_query.exec(&options).unwrap();
     /// if let QueryResult::Bindings(results) = results {
     ///     assert_eq!(results.into_values_iter().next().unwrap().unwrap()[0], Some(ex.into()));
     /// }
     /// ```
-    fn prepare_query<'a>(
+    fn prepare_query(&self, query: &str, options: QueryOptions) -> Result<Self::PreparedQuery>;
-        &'a self,
-        query: &str,
-        base_iri: Option<&'a str>,
-    ) -> Result<Self::PreparedQuery>;
 
     /// This is similar to `prepare_query`, but useful if a SPARQL query has already been parsed, which is the case when building `ServiceHandler`s for federated queries with `SERVICE` clauses. For examples, look in the tests.
-    fn prepare_query_from_pattern<'a>(
+    fn prepare_query_from_pattern(
-        &'a self,
+        &self,
-        graph_pattern: &'a GraphPattern,
+        graph_pattern: &GraphPattern,
-        base_iri: Option<&str>,
+        options: QueryOptions,
     ) -> Result<Self::PreparedQuery>;
 
     /// Retrieves quads with a filter on each quad component

lib/src/sparql/mod.rs

@@ -18,7 +18,6 @@ use crate::sparql::plan::{DatasetView, PlanNode};
 use crate::sparql::plan_builder::PlanBuilder;
 use crate::store::StoreConnection;
 use crate::Result;
-use failure::format_err;
 use rio_api::iri::Iri;
 use std::fmt;
 
@@ -31,7 +30,7 @@ pub use crate::sparql::model::Variable;
 /// A prepared [SPARQL query](https://www.w3.org/TR/sparql11-query/)
 pub trait PreparedQuery {
     /// Evaluates the query and returns its results
-    fn exec<'a>(&'a self, options: &'a QueryOptions<'a>) -> Result<QueryResult<'a>>;
+    fn exec(&self) -> Result<QueryResult>;
 }
 
 /// An implementation of `PreparedQuery` for internal use
@@ -59,10 +58,9 @@ enum SimplePreparedQueryAction<S: StoreConnection> {
 }
 
 impl<'a, S: StoreConnection + 'a> SimplePreparedQuery<S> {
-    pub(crate) fn new(connection: S, query: &str, base_iri: Option<&'a str>) -> Result<Self> {
+    pub(crate) fn new(connection: S, query: &str, options: QueryOptions) -> Result<Self> {
-        let dataset = DatasetView::new(connection);
+        let dataset = DatasetView::new(connection, options.default_graph_as_union);
-        //TODO avoid inserting terms in the Repository StringStore
+        Ok(Self(match read_sparql_query(query, options.base_iri)? {
-        Ok(Self(match read_sparql_query(query, base_iri)? {
             QueryVariants::Select {
                 algebra,
                 dataset: _,
@@ -72,7 +70,7 @@ impl<'a, S: StoreConnection + 'a> SimplePreparedQuery<S> {
                 SimplePreparedQueryAction::Select {
                     plan,
                     variables,
-                    evaluator: SimpleEvaluator::new(dataset, base_iri),
+                    evaluator: SimpleEvaluator::new(dataset, base_iri, options.service_handler),
                 }
             }
             QueryVariants::Ask {
@@ -83,7 +81,7 @@ impl<'a, S: StoreConnection + 'a> SimplePreparedQuery<S> {
                 let (plan, _) = PlanBuilder::build(dataset.encoder(), &algebra)?;
                 SimplePreparedQueryAction::Ask {
                     plan,
-                    evaluator: SimpleEvaluator::new(dataset, base_iri),
+                    evaluator: SimpleEvaluator::new(dataset, base_iri, options.service_handler),
                 }
             }
             QueryVariants::Construct {
@@ -100,7 +98,7 @@ impl<'a, S: StoreConnection + 'a> SimplePreparedQuery<S> {
                         &construct,
                         variables,
                     )?,
-                    evaluator: SimpleEvaluator::new(dataset, base_iri),
+                    evaluator: SimpleEvaluator::new(dataset, base_iri, options.service_handler),
                 }
             }
             QueryVariants::Describe {
@@ -111,7 +109,7 @@ impl<'a, S: StoreConnection + 'a> SimplePreparedQuery<S> {
                 let (plan, _) = PlanBuilder::build(dataset.encoder(), &algebra)?;
                 SimplePreparedQueryAction::Describe {
                     plan,
-                    evaluator: SimpleEvaluator::new(dataset, base_iri),
+                    evaluator: SimpleEvaluator::new(dataset, base_iri, options.service_handler),
                 }
             }
         }))
@@ -121,62 +119,77 @@ impl<'a, S: StoreConnection + 'a> SimplePreparedQuery<S> {
     pub(crate) fn new_from_pattern(
         connection: S,
         pattern: &GraphPattern,
-        base_iri: Option<&'a str>,
+        options: QueryOptions,
     ) -> Result<Self> {
-        let dataset = DatasetView::new(connection);
+        let dataset = DatasetView::new(connection, options.default_graph_as_union);
         let (plan, variables) = PlanBuilder::build(dataset.encoder(), pattern)?;
-        let base_iri = base_iri.map(|str_iri| Iri::parse(str_iri.to_string()));
+        let base_iri = if let Some(base_iri) = options.base_iri {
-        match base_iri {
+            Some(Iri::parse(base_iri.to_string())?)
-            Some(Err(_)) => Err(format_err!("Failed to parse base_iri")),
+        } else {
-            Some(Ok(base_iri)) => Ok(Self(SimplePreparedQueryAction::Select {
+            None
+        };
+        Ok(Self(SimplePreparedQueryAction::Select {
             plan,
             variables,
-                evaluator: SimpleEvaluator::new(dataset, Some(base_iri)),
+            evaluator: SimpleEvaluator::new(dataset, base_iri, options.service_handler),
-            })),
+        }))
-            None => Ok(Self(SimplePreparedQueryAction::Select {
-                plan,
-                variables,
-                evaluator: SimpleEvaluator::new(dataset, None),
-            })),
-        }
     }
 }
 
 impl<S: StoreConnection> PreparedQuery for SimplePreparedQuery<S> {
-    fn exec<'a>(&'a self, options: &'a QueryOptions<'a>) -> Result<QueryResult<'a>> {
+    fn exec(&self) -> Result<QueryResult> {
         match &self.0 {
             SimplePreparedQueryAction::Select {
                 plan,
                 variables,
                 evaluator,
-            } => evaluator.evaluate_select_plan(&plan, &variables, options),
+            } => evaluator.evaluate_select_plan(&plan, &variables),
             SimplePreparedQueryAction::Ask { plan, evaluator } => {
-                evaluator.evaluate_ask_plan(&plan, options)
+                evaluator.evaluate_ask_plan(&plan)
             }
             SimplePreparedQueryAction::Construct {
                 plan,
                 construct,
                 evaluator,
-            } => evaluator.evaluate_construct_plan(&plan, &construct, &options),
+            } => evaluator.evaluate_construct_plan(&plan, &construct),
             SimplePreparedQueryAction::Describe { plan, evaluator } => {
-                evaluator.evaluate_describe_plan(&plan, &options)
+                evaluator.evaluate_describe_plan(&plan)
             }
         }
     }
 }
 
+/// Handler for SPARQL SERVICEs.
+///
+/// Might be used to implement [SPARQL 1.1 Federated Query](https://www.w3.org/TR/sparql11-federated-query/)
 pub trait ServiceHandler {
+    /// Get the handler for a given service identified by a RDF IRI.
+    ///
+    /// A service is a function that returns an iterator of bindings from a `GraphPattern`.
+    /// Returns `None` if there is no handler for the service.
     fn handle<'a>(
         &'a self,
-        node: NamedNode,
+        node: &NamedNode,
     ) -> Option<(fn(GraphPattern) -> Result<BindingsIterator<'a>>)>;
 }
 
+#[derive(Default)]
+struct EmptyServiceHandler {}
+
+impl ServiceHandler for EmptyServiceHandler {
+    fn handle(
+        &self,
+        _node: &NamedNode,
+    ) -> Option<(fn(GraphPattern) -> Result<BindingsIterator<'static>>)> {
+        None
+    }
+}
+
 /// Options for SPARQL query parsing and evaluation like the query base IRI
 pub struct QueryOptions<'a> {
     pub(crate) base_iri: Option<&'a str>,
     pub(crate) default_graph_as_union: bool,
-    pub(crate) service_handler: Option<Box<dyn ServiceHandler>>,
+    pub(crate) service_handler: Box<dyn ServiceHandler>,
 }
 
 impl<'a> Default for QueryOptions<'a> {
@@ -184,7 +197,7 @@ impl<'a> Default for QueryOptions<'a> {
         Self {
             base_iri: None,
             default_graph_as_union: false,
-            service_handler: None as Option<Box<dyn ServiceHandler>>,
+            service_handler: Box::new(EmptyServiceHandler::default()),
         }
     }
 }
@@ -204,7 +217,7 @@ impl<'a> QueryOptions<'a> {
 
     /// Consider the union of all graphs in the repository as the default graph
     pub fn with_service_handler(mut self, service_handler: Box<dyn ServiceHandler>) -> Self {
-        self.service_handler = Some(service_handler);
+        self.service_handler = service_handler;
         self
     }
 }

lib/src/sparql/plan.rs

@@ -22,7 +22,7 @@ pub enum PlanNode {
         service_name: PatternValue,
         variables: Vec<Variable>,
         child: Box<PlanNode>,
-        graph_pattern: GraphPattern,
+        graph_pattern: Box<GraphPattern>,
         silent: bool,
     },
     QuadPatternJoin {
@@ -175,7 +175,7 @@ impl PlanNode {
             PlanNode::HashDeduplicate { child } => child.add_variables(set),
             PlanNode::Skip { child, .. } => child.add_variables(set),
             PlanNode::Limit { child, .. } => child.add_variables(set),
-            PlanNode::Project { child: _, mapping } => {
+            PlanNode::Project { mapping, .. } => {
                 for i in 0..mapping.len() {
                     set.insert(i);
                 }
@@ -473,13 +473,15 @@ pub enum TripleTemplateValue {
 pub struct DatasetView<S: StoreConnection> {
     store: S,
     extra: RefCell<MemoryStrStore>,
+    default_graph_as_union: bool,
 }
 
 impl<S: StoreConnection> DatasetView<S> {
-    pub fn new(store: S) -> Self {
+    pub fn new(store: S, default_graph_as_union: bool) -> Self {
         Self {
             store,
             extra: RefCell::new(MemoryStrStore::default()),
+            default_graph_as_union,
         }
     }
 
@@ -489,7 +491,6 @@ impl<S: StoreConnection> DatasetView<S> {
         predicate: Option<EncodedTerm>,
         object: Option<EncodedTerm>,
         graph_name: Option<EncodedTerm>,
-        default_graph_as_union: bool,
     ) -> Box<dyn Iterator<Item = Result<EncodedQuad>> + 'a> {
         if graph_name == None {
             Box::new(
@@ -500,7 +501,7 @@ impl<S: StoreConnection> DatasetView<S> {
                         Ok(quad) => quad.graph_name != ENCODED_DEFAULT_GRAPH,
                     }),
             )
-        } else if graph_name == Some(ENCODED_DEFAULT_GRAPH) && default_graph_as_union {
+        } else if graph_name == Some(ENCODED_DEFAULT_GRAPH) && self.default_graph_as_union {
             Box::new(
                 self.store
                     .quads_for_pattern(subject, predicate, object, None)

lib/src/sparql/plan_builder.rs

@@ -104,13 +104,14 @@ impl<E: Encoder> PlanBuilder<E> {
                 right: Box::new(self.build_for_graph_pattern(b, variables, graph_name)?),
             },
             GraphPattern::Service(n, p, s) => {
+                // Child building should be at the begging in order for `variables` to be filled
+                let child = self.build_for_graph_pattern(p, variables, graph_name)?;
                 let service_name = self.pattern_value_from_named_node_or_variable(n, variables)?;
-                let graph_pattern = *p.clone();
                 PlanNode::Service {
                     service_name,
                     variables: variables.clone(),
-                    child: Box::new(self.build_for_graph_pattern(p, variables, service_name)?),
+                    child: Box::new(child),
-                    graph_pattern,
+                    graph_pattern: Box::new(*p.clone()),
                     silent: *s,
                 }
             }

lib/src/store/memory.rs

@@ -29,9 +29,8 @@ use std::sync::{PoisonError, RwLock, RwLockReadGuard, RwLockWriteGuard};
 /// assert_eq!(vec![quad], results.unwrap());
 ///
 /// // SPARQL query
-/// let prepared_query = connection.prepare_query("SELECT ?s WHERE { ?s ?p ?o }", None).unwrap();
+/// let prepared_query = connection.prepare_query("SELECT ?s WHERE { ?s ?p ?o }", QueryOptions::default()).unwrap();
-/// let options = QueryOptions::default();
+/// let results = prepared_query.exec().unwrap();
-/// let results = prepared_query.exec(&options).unwrap();
 /// if let QueryResult::Bindings(results) = results {
 ///     assert_eq!(results.into_values_iter().next().unwrap().unwrap()[0], Some(ex.into()));
 /// }

lib/src/store/mod.rs

@@ -11,7 +11,7 @@ pub use crate::store::memory::MemoryRepository;
 pub use crate::store::rocksdb::RocksDbRepository;
 
 use crate::model::*;
-use crate::sparql::SimplePreparedQuery;
+use crate::sparql::{QueryOptions, SimplePreparedQuery};
 use crate::store::numeric_encoder::*;
 use crate::{DatasetSyntax, GraphSyntax, RepositoryConnection, Result};
 use rio_api::parser::{QuadsParser, TriplesParser};
@@ -72,12 +72,8 @@ impl<S: StoreConnection> From<S> for StoreRepositoryConnection<S> {
 impl<S: StoreConnection> RepositoryConnection for StoreRepositoryConnection<S> {
     type PreparedQuery = SimplePreparedQuery<S>;
 
-    fn prepare_query<'a>(
+    fn prepare_query(&self, query: &str, options: QueryOptions) -> Result<SimplePreparedQuery<S>> {
-        &self,
+        SimplePreparedQuery::new(self.inner.clone(), query, options) //TODO: avoid clone
-        query: &str,
-        base_iri: Option<&'a str>,
-    ) -> Result<SimplePreparedQuery<S>> {
-        SimplePreparedQuery::new(self.inner.clone(), query, base_iri) //TODO: avoid clone
     }
 
     fn quads_for_pattern<'a>(
@@ -101,12 +97,12 @@ impl<S: StoreConnection> RepositoryConnection for StoreRepositoryConnection<S> {
         )
     }
 
-    fn prepare_query_from_pattern<'a>(
+    fn prepare_query_from_pattern(
-        &'a self,
+        &self,
         pattern: &GraphPattern,
-        base_iri: Option<&'a str>,
+        options: QueryOptions,
     ) -> Result<Self::PreparedQuery> {
-        SimplePreparedQuery::new_from_pattern(self.inner.clone(), pattern, base_iri)
+        SimplePreparedQuery::new_from_pattern(self.inner.clone(), pattern, options)
         //TODO: avoid clone
     }
 

lib/src/store/rocksdb.rs

@@ -40,9 +40,8 @@ use std::str;
 /// assert_eq!(vec![quad], results.unwrap());
 ///
 /// // SPARQL query
-/// let options = QueryOptions::default();
+/// let prepared_query = connection.prepare_query("SELECT ?s WHERE { ?s ?p ?o }", QueryOptions::default()).unwrap();
-/// let prepared_query = connection.prepare_query("SELECT ?s WHERE { ?s ?p ?o }", None).unwrap();
+/// let results = prepared_query.exec().unwrap();
-/// let results = prepared_query.exec(&options).unwrap();
 /// if let QueryResult::Bindings(results) = results {
 ///     assert_eq!(results.into_values_iter().next().unwrap().unwrap()[0], Some(ex.into()));
 /// }

lib/tests/service_test_cases.rs

@@ -12,7 +12,7 @@ fn simple_service_test() {
     impl ServiceHandler for TestServiceHandler {
         fn handle<'a>(
             &'a self,
-            _named_node: NamedNode,
+            _named_node: &NamedNode,
         ) -> Option<(fn(GraphPattern) -> Result<BindingsIterator<'a>>)> {
             fn pattern_handler<'a>(graph_pattern: GraphPattern) -> Result<BindingsIterator<'a>> {
                 let triples =
@@ -56,13 +56,13 @@ fn two_service_test() {
     impl ServiceHandler for TwoServiceTest {
         fn handle<'a>(
             &'a self,
-            named_node: NamedNode,
+            named_node: &NamedNode,
         ) -> Option<(fn(GraphPattern) -> Result<BindingsIterator<'a>>)> {
             let service1 = NamedNode::parse("http://service1.org").unwrap();
             let service2 = NamedNode::parse("http://service2.org").unwrap();
-            if named_node == service1 {
+            if named_node == &service1 {
                 Some(TwoServiceTest::handle_service1)
-            } else if named_node == service2 {
+            } else if named_node == &service2 {
                 Some(TwoServiceTest::handle_service2)
             } else {
                 None
@@ -133,7 +133,7 @@ fn silent_service_empty_set_test() {
     impl ServiceHandler for ServiceTest {
         fn handle<'a>(
             &'a self,
-            _named_node: NamedNode,
+            _named_node: &NamedNode,
         ) -> Option<(fn(GraphPattern) -> Result<BindingsIterator<'a>>)> {
             Some(ServiceTest::handle_service)
         }
@@ -177,7 +177,7 @@ fn non_silent_service_test() {
     impl ServiceHandler for ServiceTest {
         fn handle<'a>(
             &'a self,
-            _named_node: NamedNode,
+            _named_node: &NamedNode,
         ) -> Option<(fn(GraphPattern) -> Result<BindingsIterator<'a>>)> {
             Some(ServiceTest::handle_service)
         }
@@ -242,10 +242,11 @@ fn query_repository<'a>(
     query: String,
     options: QueryOptions<'a>,
 ) -> Result<BindingsIterator<'a>> {
-    let connection = repository.connection()?;
+    match repository
-    let prepared_query = connection.prepare_query(&query, None)?;
+        .connection()?
-    let result = prepared_query.exec(&options)?;
+        .prepare_query(&query, options)?
-    match result {
+        .exec()?
+    {
         QueryResult::Bindings(iterator) => {
             let (varaibles, iter) = iterator.destruct();
             let collected = iter.collect::<Vec<_>>();
@@ -265,10 +266,11 @@ fn pattern_repository<'a>(
     pattern: GraphPattern,
     options: QueryOptions<'a>,
 ) -> Result<BindingsIterator<'a>> {
-    let connection = repository.connection()?;
+    match repository
-    let prepared_query = connection.prepare_query_from_pattern(&pattern, None)?;
+        .connection()?
-    let result = prepared_query.exec(&options)?;
+        .prepare_query_from_pattern(&pattern, options)?
-    match result {
+        .exec()?
+    {
         QueryResult::Bindings(iterator) => {
             let (varaibles, iter) = iterator.destruct();
             let collected = iter.collect::<Vec<_>>();
@@ -277,9 +279,7 @@ fn pattern_repository<'a>(
                 Box::new(collected.into_iter()),
             ))
         }
-        _ => Err(format_err!(
+        _ => Err(format_err!("Expected bindings but got another QueryResult")),
-            "Excpected bindings but got another QueryResult"
-        )),
     }
 }
 

lib/tests/sparql_test_cases.rs

@@ -158,13 +158,13 @@ fn sparql_w3c_query_evaluation_testsuite() -> Result<()> {
             }
             match repository
                 .connection()?
-                .prepare_query(&read_file_to_string(&test.query)?, Some(&test.query))
+                .prepare_query(&read_file_to_string(&test.query)?, QueryOptions::default().with_base_iri(&test.query))
             {
                 Err(error) => Err(format_err!(
                     "Failure to parse query of {} with error: {}",
                     test, error
                 )),
-                Ok(query) => match query.exec(&QueryOptions::default()) {
+                Ok(query) => match query.exec() {
                     Err(error) => Err(format_err!(
                         "Failure to execute query of {} with error: {}",
                         test, error

server/src/main.rs

@@ -148,10 +148,9 @@ fn evaluate_sparql_query<R: RepositoryConnection>(
     request: &Request,
 ) -> Response {
     //TODO: stream
-    let options = QueryOptions::default();
+    match connection.prepare_query(query, QueryOptions::default()) {
-    match connection.prepare_query(query, None) {
         Ok(query) => {
-            let results = query.exec(&options).unwrap();
+            let results = query.exec().unwrap();
             if let QueryResult::Graph(_) = results {
                 let supported_formats = [
                     GraphSyntax::NTriples.media_type(),