Adds basic Python bindings to Oxigraph

.github/workflows/build.yml

@@ -41,3 +41,17 @@ jobs:
         working-directory: ./js
       - run: npm test
         working-directory: ./js
+
+  python:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - run: rustup update
+      - uses: actions/setup-python@v2
+        with:
+          python-version: 3.5
+      - run: python -m pip install --upgrade pip maturin
+      - run: maturin develop
+        working-directory: ./python
+      - run: python -m unittest
+        working-directory: ./python/tests

Cargo.toml

@@ -2,6 +2,7 @@
 members = [
     "js",
     "lib",
+    "python",
     "server",
     "testsuite",
     "wikibase"

README.md

@@ -13,6 +13,7 @@ It is written in Rust.
 
 It is split into multiple parts:
 * The `lib` directory contains the database written as a Rust library.
+* The `python` directory contains bindings to use Oxigraph in Python. See [its README](https://github.com/oxigraph/oxigraph/blob/master/python/README.md) for the Python bindings documentation.
 * The `js` directory contains bindings to use Oxigraph in JavaScript with the help of WebAssembly. See [its README](https://github.com/oxigraph/oxigraph/blob/master/js/README.md) for the JS bindings documentation.
 * The `server` directory contains a stand-alone binary of a web server implementing the [SPARQL 1.1 Protocol](https://www.w3.org/TR/sparql11-protocol/).
 * The `wikibase` directory contains a stand-alone binary of a web server able to synchronize with a [Wikibase instance](https://wikiba.se/).

js/Cargo.toml

@@ -3,7 +3,7 @@ name = "oxigraph_js"
 version = "0.0.2"
 authors = ["Tpt <thomas@pellissier-tanon.fr>"]
 license = "MIT/Apache-2.0"
-readme = "../README.md"
+readme = "README.md"
 keywords = ["RDF", "N-Triples", "Turtle", "RDF/XML", "SPARQL"]
 repository = "https://github.com/oxigraph/oxigraph/tree/master/js"
 description = "JavaScript bindings of Oxigraph"

js/README.md

@@ -23,6 +23,21 @@ npm install oxigraph
 const oxigraph = require('oxigraph');
 ```
 
+## Example
+
+Insert the triple `<http://example/> <http://schema.org/name> "example"` and log the name of `<http://example/>` in SPARQL:
+```js
+const { MemoryStore } = require('oxigraph');
+const store = new MemoryStore();
+const dataFactory = store.dataFactory;
+const ex = dataFactory.namedNode("http://example/");
+const schemaName = dataFactory.namedNode("http://schema.org/name");
+store.add(dataFactory.triple(ex, schemaName, dataFactory.literal("example")));
+for (binding of store.query("SELECT ?name WHERE { <http://example/> <http://schema.org/name> ?name }")) {
+    console.log(binding.get("name").value);
+}
+```
+
 ## API
 
 Oxigraph currently provides a simple JS API.
@@ -140,21 +155,6 @@ Example of loading a Turtle file into the named graph `<http://example.com/graph
 store.load("<http://example.com> <http://example.com> <> .", "text/turtle", "http://example.com", store.dataFactory.namedNode("http://example.com/graph"));
 ```
 
-## Example
-
-Insert the triple `<http://example/> <http://schema.org/name> "example"` and log the name of `<http://example/>` in SPARQL:
-```js
-const { MemoryStore } = require('oxigraph');
-const store = new MemoryStore();
-const dataFactory = store.dataFactory;
-const ex = dataFactory.namedNode("http://example/");
-const schemaName = dataFactory.namedNode("http://schema.org/name");
-store.add(dataFactory.triple(ex, schemaName, dataFactory.literal("example")));
-for (binding of store.query("SELECT ?name WHERE { <http://example/> <http://schema.org/name> ?name }")) {
-    console.log(binding.get("name").value);
-}
-```
-
 
 ## How to contribute
 

lib/src/sparql/json_results.rs

@@ -1,4 +1,4 @@
-//! Implementation of [SPARQL Query Results XML Format](https://www.w3.org/TR/sparql11-results-json/)
+//! Implementation of [SPARQL Query Results JSON Format](https://www.w3.org/TR/sparql11-results-json/)
 
 use crate::model::*;
 use crate::sparql::model::*;

lib/src/store/rocksdb.rs

@@ -9,8 +9,8 @@ use rocksdb::*;
 use std::io::BufRead;
 use std::mem::take;
 use std::path::Path;
-use std::str;
 use std::sync::Arc;
+use std::{fmt, str};
 
 /// Store based on the [RocksDB](https://rocksdb.org/) key-value database.
 /// It encodes a [RDF dataset](https://www.w3.org/TR/rdf11-concepts/#dfn-rdf-dataset) and allows to query and update it using SPARQL.
@@ -155,6 +155,21 @@ impl RocksDbStore {
         self.handle().contains(&quad)
     }
 
+    /// Returns the number of quads in the store
+    pub fn len(&self) -> usize {
+        self.db
+            .full_iterator_cf(self.handle().spog_cf, IteratorMode::Start)
+            .count()
+    }
+
+    /// Returns if the store is empty
+    pub fn is_empty(&self) -> bool {
+        self.db
+            .full_iterator_cf(self.handle().spog_cf, IteratorMode::Start)
+            .next()
+            .is_none()
+    }
+
     /// Executes a transaction.
     ///
     /// The transaction is executed if the given closure returns `Ok`.
@@ -235,6 +250,15 @@ impl RocksDbStore {
     }
 }
 
+impl fmt::Display for RocksDbStore {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        for t in self.quads_for_pattern(None, None, None, None) {
+            writeln!(f, "{}", t.map_err(|_| fmt::Error)?)?;
+        }
+        Ok(())
+    }
+}
+
 impl StrLookup for RocksDbStore {
     fn get_str(&self, id: StrHash) -> Result<Option<String>> {
         Ok(self

lib/src/store/sled.rs

@@ -8,7 +8,7 @@ use crate::{DatasetSyntax, GraphSyntax, Result};
 use sled::{Config, Iter, Tree};
 use std::io::BufRead;
 use std::path::Path;
-use std::str;
+use std::{fmt, str};
 
 /// Store based on the [Sled](https://sled.rs/) key-value database.
 /// It encodes a [RDF dataset](https://www.w3.org/TR/rdf11-concepts/#dfn-rdf-dataset) and allows to query and update it using SPARQL.
@@ -138,6 +138,16 @@ impl SledStore {
         self.contains_encoded(&quad)
     }
 
+    /// Returns the number of quads in the store
+    pub fn len(&self) -> usize {
+        self.spog.len()
+    }
+
+    /// Returns if the store is empty
+    pub fn is_empty(&self) -> bool {
+        self.spog.is_empty()
+    }
+
     /// Loads a graph file (i.e. triples) into the store
     ///
     /// Warning: This functions saves the triples in batch. If the parsing fails in the middle of the file,
@@ -394,6 +404,15 @@ impl SledStore {
     }
 }
 
+impl fmt::Display for SledStore {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        for t in self.quads_for_pattern(None, None, None, None) {
+            writeln!(f, "{}", t.map_err(|_| fmt::Error)?)?;
+        }
+        Ok(())
+    }
+}
+
 impl StrLookup for SledStore {
     fn get_str(&self, id: StrHash) -> Result<Option<String>> {
         Ok(self

python/Cargo.toml

@@ -0,0 +1,31 @@
+[package]
+name = "oxigraph_python"
+version = "0.1.0"
+authors = ["Tpt <thomas@pellissier-tanon.fr>"]
+license = "MIT/Apache-2.0"
+readme = "README.md"
+keywords = ["RDF", "N-Triples", "Turtle", "RDF/XML", "SPARQL"]
+repository = "https://github.com/oxigraph/oxigraph/tree/master/python"
+description = """
+Python bindings of Oxigraph
+"""
+edition = "2018"
+
+[lib]
+crate-type = ["cdylib"]
+name = "oxigraph"
+
+[dependencies]
+oxigraph = {path = "../lib", features=["sled"]}
+pyo3 = {version="0.11", features = ["extension-module"]}
+
+[package.metadata.maturin]
+classifier = [
+    "Development Status :: 2 - Pre-Alpha",
+    "Intended Audience :: Developers",
+    "License :: OSI Approved :: Apache Software License",
+    "License :: OSI Approved :: MIT License",
+    "Programming Language :: Python :: 3 :: Only",
+    "Programming Language :: Rust",
+    "Topic :: Database :: Database Engines/Servers"
+]