Server: refactor bulk load code

server/src/main.rs

@@ -1,4 +1,4 @@
-use anyhow::{anyhow, bail};
+use anyhow::bail;
 use clap::{Parser, Subcommand};
 use flate2::read::MultiGzDecoder;
 use oxhttp::model::{Body, HeaderName, HeaderValue, Request, Response, Status};
@@ -116,10 +116,17 @@ pub fn main() -> anyhow::Result<()> {
                                     bulk_load(
                                         loader,
                                         MultiGzDecoder::new(fp),
-                                        &file.with_extension(""),
+                                        GraphOrDatasetFormat::from_path(&file.with_extension(""))
+                                            .unwrap(),
+                                        None,
                                     )
                                 } else {
-                                    bulk_load(loader, fp, &file)
+                                    bulk_load(
+                                        loader,
+                                        fp,
+                                        GraphOrDatasetFormat::from_path(&file).unwrap(),
+                                        None,
+                                    )
                                 }
                             } {
                                 eprintln!("Error while loading file {}: {}", file.display(), error)
@@ -142,29 +149,72 @@ pub fn main() -> anyhow::Result<()> {
     }
 }
 
-fn bulk_load(loader: BulkLoader, reader: impl Read, file: &Path) -> anyhow::Result<()> {
-    let extension = file
-        .extension()
-        .and_then(|extension| extension.to_str())
-        .ok_or_else(|| {
-            anyhow!(
-                "Not able to guess the file format of {} because the file name as no extension",
-                file.display()
-            )
-        })?;
+fn bulk_load(
+    loader: BulkLoader,
+    reader: impl Read,
+    format: GraphOrDatasetFormat,
+    base_iri: Option<&str>,
+) -> anyhow::Result<()> {
     let reader = BufReader::new(reader);
-    if let Some(format) = DatasetFormat::from_extension(extension) {
-        loader.load_dataset(reader, format, None)?;
-        Ok(())
-    } else if let Some(format) = GraphFormat::from_extension(extension) {
-        loader.load_graph(reader, format, GraphNameRef::DefaultGraph, None)?;
+    match format {
+        GraphOrDatasetFormat::Graph(format) => {
+            loader.load_graph(reader, format, GraphNameRef::DefaultGraph, base_iri)
+        }
+        GraphOrDatasetFormat::Dataset(format) => loader.load_dataset(reader, format, base_iri),
+    }?;
     Ok(())
+}
+
+#[derive(Copy, Clone)]
+enum GraphOrDatasetFormat {
+    Graph(GraphFormat),
+    Dataset(DatasetFormat),
+}
+
+impl GraphOrDatasetFormat {
+    fn from_path(path: &Path) -> anyhow::Result<Self> {
+        if let Some(ext) = path.extension().and_then(|ext| ext.to_str()) {
+            Self::from_name(ext).map_err(|e| {
+                e.context(format!(
+                    "Not able to guess the file format from file name extension '{}'",
+                    ext
+                ))
+            })
         } else {
             bail!(
-            "Not able to guess the file format from the extension {}",
-            extension
+                "The path {} has no extension to guess a file format from",
+                path.display()
             )
         }
+    }
+
+    fn from_name(name: &str) -> anyhow::Result<Self> {
+        let mut candidates = Vec::with_capacity(4);
+        if let Some(f) = GraphFormat::from_extension(name) {
+            candidates.push(GraphOrDatasetFormat::Graph(f));
+        }
+        if let Some(f) = DatasetFormat::from_extension(name) {
+            candidates.push(GraphOrDatasetFormat::Dataset(f));
+        }
+        if let Some(f) = GraphFormat::from_media_type(name) {
+            candidates.push(GraphOrDatasetFormat::Graph(f));
+        }
+        if let Some(f) = DatasetFormat::from_media_type(name) {
+            candidates.push(GraphOrDatasetFormat::Dataset(f));
+        }
+        if candidates.is_empty() {
+            bail!("The format '{}' is unknown", name)
+        } else if candidates.len() == 1 {
+            Ok(candidates[0])
+        } else {
+            bail!("The format '{}' can be resolved to multiple known formats, not sure what to pick ({})", name, candidates.iter().fold(String::new(), |a, f| {
+                a + " " + match f {
+                    GraphOrDatasetFormat::Graph(f) => f.file_extension(),
+                    GraphOrDatasetFormat::Dataset(f) => f.file_extension(),
+                }
+            }).trim())
+        }
+    }
 }
 
 fn handle_request(request: &mut Request, store: Store) -> Response {
@@ -1093,6 +1143,8 @@ mod tests {
     use anyhow::Result;
     use assert_cmd::Command;
     use assert_fs::prelude::*;
+    use flate2::write::GzEncoder;
+    use flate2::Compression;
     use oxhttp::model::Method;
     use predicates::prelude::*;
 
@@ -1146,6 +1198,24 @@ mod tests {
         Ok(())
     }
 
+    #[test]
+    fn cli_load_gzip_dataset() -> Result<()> {
+        let file = assert_fs::NamedTempFile::new("sample.nq.gz")?;
+        let mut encoder = GzEncoder::new(Vec::new(), Compression::default());
+        encoder
+            .write_all(b"<http://example.com/s> <http://example.com/p> <http://example.com/o> .")?;
+        file.write_binary(&encoder.finish()?)?;
+        cli_command()?
+            .arg("load")
+            .arg("-f")
+            .arg(file.path())
+            .assert()
+            .success()
+            .stdout("")
+            .stderr(predicate::str::starts_with("1 triples loaded"));
+        Ok(())
+    }
+
     #[test]
     fn get_ui() {
         ServerTest::new().test_status(