fix(fsi): Can get body even if no structure exists. Infer it.

api/fsi_test.go

@@ -151,7 +151,7 @@ func TestNoHistory(t *testing.T) {
 	}
 	// Handle temporary directory by replacing the temp part with a shorter string.
 	resultBody := strings.Replace(gotBodyString, initDir, initSubdir, -1)
-	expectBody := `{"data":{"peername":"peer","name":"test_ds","fsiPath":"fsi_init_dir","dataset":{"bodyPath":"fsi_init_dir/body.csv","meta":{"keywords":[],"qri":"md:0"},"name":"test_ds","peername":"peer","qri":"ds:0","structure":{"format":"csv","formatConfig":{"lazyQuotes":true},"qri":"st:0","schema":{"items":{"items":[{"title":"field_1","type":"boolean"},{"title":"field_2","type":"boolean"},{"title":"field_3","type":"integer"}],"type":"array"},"type":"array"}}},"published":false},"meta":{"code":200}}`
+	expectBody := `{"data":{"peername":"peer","name":"test_ds","fsiPath":"fsi_init_dir","dataset":{"bodyPath":"fsi_init_dir/body.csv","meta":{"keywords":[],"qri":"md:0"},"name":"test_ds","peername":"peer","qri":"ds:0","structure":{"format":"csv","formatConfig":{"lazyQuotes":true},"qri":"st:0","schema":{"items":{"items":[{"title":"field_1","type":"string"},{"title":"field_2","type":"string"},{"title":"field_3","type":"integer"}],"type":"array"},"type":"array"}}},"published":false},"meta":{"code":200}}`
 	if diff := cmp.Diff(expectBody, resultBody); diff != "" {
 		t.Errorf("api response (-want +got):\n%s", diff)
 	}

cmd/fsi_integration_test.go

@@ -161,6 +161,42 @@ run ` + "`qri save`" + ` to commit this dataset
 	}
 }
 
+// Test that we can get the body even if structure has been deleted.
+func TestGetBodyWithoutStructure(t *testing.T) {
+	fr := NewFSITestRunner(t, "qri_test_get_body_without_structure")
+	defer fr.Delete()
+
+	workDir := fr.CreateAndChdirToWorkDir("body_only")
+
+	// Init as a linked directory.
+	if err := fr.ExecCommand("qri init --name body_only --format csv"); err != nil {
+		t.Fatal(err)
+	}
+
+	// Verify the directory contains the files that we expect.
+	dirContents := listDirectory(workDir)
+	expectContents := []string{".qri-ref", "body.csv", "meta.json", "structure.json"}
+	if diff := cmp.Diff(expectContents, dirContents); diff != "" {
+		t.Errorf("directory contents (-want +got):\n%s", diff)
+	}
+
+	// Remove the structure.
+	if err := os.Remove(filepath.Join(workDir, "structure.json")); err != nil {
+		t.Fatal(err)
+	}
+
+	// Get the body, even though there's no structure. One will be inferred.
+	if err := fr.ExecCommand("qri get body"); err != nil {
+		t.Fatalf(err.Error())
+	}
+
+	output := fr.GetCommandOutput()
+	expectBody := "for linked dataset [test_peer/body_only]\n\none,two,3\nfour,five,6\n\n"
+	if diff := cmp.Diff(expectBody, output); diff != "" {
+		t.Errorf("directory contents (-want +got):\n%s", diff)
+	}
+}
+
 // Test that checkout, used on a simple dataset with a body.json and no meta, creates a
 // working directory with a clean status.
 func TestCheckoutSimpleStatus(t *testing.T) {

fsi/body.go

@@ -31,17 +31,27 @@ func GetBody(dirPath string, format dataset.DataFormat, fcfg dataset.FormatConfi
 	}
 	defer f.Close()
 
+	var structure *dataset.Structure
+
+	var schema map[string]interface{}
 	stComponent := components.Base().GetSubcomponent("structure")
-	stComponent.LoadAndFill(nil)
-	structure, ok := stComponent.(*component.StructureComponent)
-	if !ok {
-		return nil, fmt.Errorf("could not get structure")
+	if stComponent != nil {
+		stComponent.LoadAndFill(nil)
+		comp, ok := stComponent.(*component.StructureComponent)
+		if !ok {
+			return nil, fmt.Errorf("could not get structure")
+		}
+		structure = comp.Value
+		schema = structure.Schema
 	}
-	stValue := structure.Value
-	schema := stValue.Schema
 
 	if schema == nil {
 		bodyFormat := bodyComponent.Base().Format
+		// If there was no structure, define one using the body's file extension.
+		if structure == nil {
+			structure = &dataset.Structure{}
+			structure.Format = bodyFormat
+		}
 		// Create schema by detecting it from the body.
 		// TODO(dlong): This should move into `dsio` package.
 		entries, err := component.OpenEntryReader(f, bodyFormat)
@@ -63,7 +73,7 @@ func GetBody(dirPath string, format dataset.DataFormat, fcfg dataset.FormatConfi
 	if fcfg != nil {
 		assign.FormatConfig = fcfg.Map()
 	}
-	st.Assign(stValue, assign)
+	st.Assign(structure, assign)
 
-	return base.ConvertBodyFile(file, stValue, st, limit, offset, all)
+	return base.ConvertBodyFile(file, structure, st, limit, offset, all)
 }

fsi/init.go

@@ -37,7 +37,8 @@ func (fsi *FSI) InitDataset(p InitParams) (name string, err error) {
 		return "", fmt.Errorf("invalid path to initialize. '%s' is not a directory", p.Dir)
 	}
 
-	// TODO(dlong): This function should more closely resemble Checkout in lib/fsi.go
+	// TODO(dlong): This function should more closely resemble Checkout in lib/fsi.go. That is,
+	// do some stuff to initialize, create components, then call WriteComponents.
 
 	// Either use an existing directory, or create one at the given directory.
 	var targetPath string