markdown: added template codes. awaiting integration and tests

middleware/markdown/metadata.go

@@ -0,0 +1,132 @@
+package markdown
+
+import (
+	"encoding/json"
+
+	"github.com/BurntSushi/toml"
+	"gopkg.in/yaml.v2"
+)
+
+var (
+	parsers = []MetadataParser{
+		&JSONMetadataParser{},
+		&TOMLMetadataParser{},
+		&YAMLMetadataParser{},
+	}
+)
+
+// Metadata stores a page's metadata
+type Metadata struct {
+	Template  string
+	Variables map[string]interface{}
+}
+
+// Load loads parsed metadata into m
+func (m *Metadata) load(parsedMap map[string]interface{}) {
+	if template, ok := parsedMap["template"]; ok {
+		m.Template, _ = template.(string)
+	}
+	if variables, ok := parsedMap["variables"]; ok {
+		m.Variables, _ = variables.(map[string]interface{})
+	}
+}
+
+// MetadataParser parses the page metadata
+// into Metadata
+type MetadataParser interface {
+	// Identifiers
+	Opening() []byte
+	Closing() []byte
+	Parse([]byte) error
+	Metadata() Metadata
+}
+
+// JSONMetadataParser is the MetdataParser for JSON
+type JSONMetadataParser struct {
+	metadata Metadata
+}
+
+// Parse parses b into metadata
+func (j *JSONMetadataParser) Parse(b []byte) error {
+	m := make(map[string]interface{})
+	if err := json.Unmarshal(b, &m); err != nil {
+		return err
+	}
+	j.metadata.load(m)
+	return nil
+}
+
+// Metadata returns the metadata parsed by this parser
+func (j *JSONMetadataParser) Metadata() Metadata {
+	return j.metadata
+}
+
+// Opening returns the opening identifier JSON metadata
+func (j *JSONMetadataParser) Opening() []byte {
+	return []byte("{")
+}
+
+// Closing returns the closing identifier JSON metadata
+func (j *JSONMetadataParser) Closing() []byte {
+	return []byte("}")
+}
+
+// TOMLMetadataParser is the MetadataParser for TOML
+type TOMLMetadataParser struct {
+	metadata Metadata
+}
+
+// Parse parses b into metadata
+func (t *TOMLMetadataParser) Parse(b []byte) error {
+	m := make(map[string]interface{})
+	if err := toml.Unmarshal(b, &m); err != nil {
+		return err
+	}
+	t.metadata.load(m)
+	return nil
+}
+
+// Metadata returns the metadata parsed by this parser
+func (t *TOMLMetadataParser) Metadata() Metadata {
+	return t.metadata
+}
+
+// Opening returns the opening identifier TOML metadata
+func (t *TOMLMetadataParser) Opening() []byte {
+	return []byte("+++")
+}
+
+// Closing returns the closing identifier TOML metadata
+func (t *TOMLMetadataParser) Closing() []byte {
+	return []byte("+++")
+}
+
+// YAMLMetadataParser is the MetdataParser for YAML
+type YAMLMetadataParser struct {
+	metadata Metadata
+}
+
+// Parse parses b into metadata
+func (y *YAMLMetadataParser) Parse(b []byte) error {
+	m := make(map[string]interface{})
+	if err := yaml.Unmarshal(b, &m); err != nil {
+		return err
+	}
+	y.metadata.load(m)
+	return nil
+}
+
+// Metadata returns the metadata parsed by this parser
+func (y *YAMLMetadataParser) Metadata() Metadata {
+	return y.metadata
+}
+
+// Opening returns the opening identifier TOML metadata
+func (y *YAMLMetadataParser) Opening() []byte {
+	return []byte("---")
+}
+
+// Closing returns the closing identifier TOML metadata
+func (y *YAMLMetadataParser) Closing() []byte {
+	return []byte("---")
+}