New gomplate.Renderer interface

Signed-off-by: Dave Henderson <dhenderson@gmail.com>

1 files changed, 155 insertions, 0 deletions

diff --git a/render_test.go b/render_test.go
new file mode 100644
index 00000000..b40d0a10
--- /dev/null
+++ b/render_test.go
@@ -0,0 +1,155 @@
+package gomplate
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"net/url"
+	"os"
+	"strings"
+	"testing"
+	"testing/fstest"
+
+	"github.com/hairyhenderson/go-fsimpl"
+	"github.com/hairyhenderson/gomplate/v3/data"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestRenderTemplate(t *testing.T) {
+	fsys := fstest.MapFS{}
+	ctx := ContextWithFSProvider(context.Background(),
+		fsimpl.WrappedFSProvider(fsys, "mem"))
+
+	// no options - built-in function
+	tr := NewRenderer(Options{})
+	out := &bytes.Buffer{}
+	err := tr.Render(ctx, "test", "{{ `hello world` | toUpper }}", out)
+	assert.NoError(t, err)
+	assert.Equal(t, "HELLO WORLD", out.String())
+
+	// with datasource and context
+	hu, _ := url.Parse("stdin:")
+	wu, _ := url.Parse("env:WORLD")
+
+	os.Setenv("WORLD", "world")
+	defer os.Unsetenv("WORLD")
+
+	tr = NewRenderer(Options{
+		Context: map[string]Datasource{
+			"hi": {URL: hu},
+		},
+		Datasources: map[string]Datasource{
+			"world": {URL: wu},
+		},
+	})
+	ctx = data.ContextWithStdin(ctx, strings.NewReader("hello"))
+	out = &bytes.Buffer{}
+	err = tr.Render(ctx, "test", `{{ .hi | toUpper }} {{ (ds "world") | toUpper }}`, out)
+	assert.NoError(t, err)
+	assert.Equal(t, "HELLO WORLD", out.String())
+
+	// with a nested template
+	nu, _ := url.Parse("nested.tmpl")
+	fsys["nested.tmpl"] = &fstest.MapFile{Data: []byte(
+		`<< . | toUpper >>`)}
+
+	tr = NewRenderer(Options{
+		Templates: map[string]Datasource{
+			"nested": {URL: nu},
+		},
+		LDelim: "<<",
+		RDelim: ">>",
+	})
+	out = &bytes.Buffer{}
+	err = tr.Render(ctx, "test", `<< template "nested" "hello" >>`, out)
+	assert.NoError(t, err)
+	assert.Equal(t, "HELLO", out.String())
+
+	// errors contain the template name
+	tr = NewRenderer(Options{})
+	err = tr.Render(ctx, "foo", `{{ bogus }}`, &bytes.Buffer{})
+	assert.ErrorContains(t, err, "template: foo:")
+}
+
+//// examples
+
+func ExampleRenderer() {
+	ctx := context.Background()
+
+	// create a new template renderer
+	tr := NewRenderer(Options{})
+
+	// render a template to stdout
+	err := tr.Render(ctx, "mytemplate",
+		`{{ "hello, world!" | toUpper }}`,
+		os.Stdout)
+	if err != nil {
+		fmt.Println("gomplate error:", err)
+	}
+
+	// Output:
+	// HELLO, WORLD!
+}
+
+func ExampleRenderer_manyTemplates() {
+	ctx := context.Background()
+
+	// create a new template renderer
+	tr := NewRenderer(Options{})
+
+	templates := []Template{
+		{
+			Name:   "one.tmpl",
+			Text:   `contents of {{ tmpl.Path }}`,
+			Writer: &bytes.Buffer{},
+		},
+		{
+			Name:   "two.tmpl",
+			Text:   `{{ "hello world" | toUpper }}`,
+			Writer: &bytes.Buffer{},
+		},
+		{
+			Name:   "three.tmpl",
+			Text:   `1 + 1 = {{ math.Add 1 1 }}`,
+			Writer: &bytes.Buffer{},
+		},
+	}
+
+	// render the templates
+	err := tr.RenderTemplates(ctx, templates)
+	if err != nil {
+		panic(err)
+	}
+
+	for _, t := range templates {
+		fmt.Printf("%s: %s\n", t.Name, t.Writer.(*bytes.Buffer).String())
+	}
+
+	// Output:
+	// one.tmpl: contents of one.tmpl
+	// two.tmpl: HELLO WORLD
+	// three.tmpl: 1 + 1 = 2
+}
+
+func ExampleRenderer_datasources() {
+	ctx := context.Background()
+
+	// a datasource that retrieves JSON from a maritime registry dataset
+	u, _ := url.Parse("https://www.econdb.com/maritime/vessel/9437/")
+	tr := NewRenderer(Options{
+		Context: map[string]Datasource{
+			"vessel": {URL: u},
+		},
+	})
+
+	err := tr.Render(ctx, "jsontest",
+		`{{"\U0001F6A2"}} The {{ .vessel.data.Name }}'s call sign is {{ .vessel.data.Callsign }}, `+
+			`and it has a draught of {{ .vessel.data.Draught }}.`,
+		os.Stdout)
+	if err != nil {
+		panic(err)
+	}
+
+	// Output:
+	// 🚢 The MONTREAL EXPRESS's call sign is ZCET4, and it has a draught of 10.5.
+}