fix: meta extraction at transformer

Author: barelyhuman

go.mod

@@ -11,6 +11,7 @@ require (
 	github.com/yuin/goldmark v1.7.1
 	github.com/yuin/goldmark-highlighting v0.0.0-20220208100518-594be1970594
 	github.com/yuin/gopher-lua v1.1.0
+	gopkg.in/yaml.v3 v3.0.1
 	layeh.com/gopher-json v0.0.0-20201124131017-552bb3c4c3bf
 )
 

go.sum

@@ -191,5 +191,6 @@ gopkg.in/yaml.v2 v2.3.0 h1:clyUAQHOM3G0M3f5vQj7LuJrETvjVot3Z5el9nffUtU=
 gopkg.in/yaml.v2 v2.3.0/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 layeh.com/gopher-json v0.0.0-20201124131017-552bb3c4c3bf h1:rRz0YsF7VXj9fXRF6yQgFI7DzST+hsI3TeFSGupntu0=
 layeh.com/gopher-json v0.0.0-20201124131017-552bb3c4c3bf/go.mod h1:ivKkcY8Zxw5ba0jldhZCYYQfGdb2K6u9tbYK1AwMIBc=

pkg/alvu/alvu.go

@@ -299,23 +299,33 @@ func runTransfomers(filesToProcess []string, ac *AlvuConfig) ([]transformers.Tra
 		}
 
 		originalContent, err := os.ReadFile(fileToNormalize)
+		mutableContent := originalContent
 		if err != nil {
 			return nil, fmt.Errorf("failed to read file %v with error %v", fileToNormalize, err)
 		}
 
+		var meta map[string]interface{}
 		for _, transformer := range ac.Transformers[extension] {
-			nextContent, err := transformer.TransformContent(originalContent)
+			nextContent, err := transformer.TransformContent(mutableContent)
 			if err != nil {
 				return nil, fmt.Errorf("failed to transform file: %v, with error: %v", fileToNormalize, err)
 			}
-			originalContent = nextContent
+			newMeta, _, _ := transformer.ExtractMeta(originalContent)
+			if err != nil {
+				return nil, fmt.Errorf("failed to extract meta from file: %v, with error: %v", fileToNormalize, err)
+			}
+			if hasKeys(newMeta) {
+				meta = newMeta
+			}
+			mutableContent = nextContent
 		}
 
-		transformedFile, err := ac.createTransformedFile(fileToNormalize, string(originalContent))
+		transformedFile, err := ac.createTransformedFile(fileToNormalize, string(mutableContent))
 		if err != nil {
 			return nil, fmt.Errorf("failed to transform file: %v, with error: %v", fileToNormalize, err)
 		}
 
+		transformedFile.Meta = meta
 		normalizedFiles = append(normalizedFiles, transformedFile)
 	}
 	return normalizedFiles, nil
@@ -493,3 +503,11 @@ func injectInLegacySlot(htmlString string, replacement string) string {
 	}
 	return strings.Replace(htmlString, contentTag, replacement, contentTagPos)
 }
+
+func hasKeys(i map[string]interface{}) bool {
+	keys := make([]string, 0, len(i))
+	for k := range i {
+		keys = append(keys, k)
+	}
+	return len(keys) > 0
+}

pkg/alvu/hooks.go

@@ -169,17 +169,19 @@ func (h *Hooks) ProcessFile(file transformers.TransformedFile) (hookedFile Hooke
 	)
 	fileTargetName = filepath.Clean(strings.TrimPrefix(fileTargetName, "/"))
 	fileTargetName = strings.Replace(fileTargetName, filepath.Ext(fileTargetName), ".html", 1)
+	fileTargetName = strings.TrimSpace(fileTargetName)
 
 	hookInput := struct {
 		Name       string `json:"name"`
 		SourcePath string `json:"source_path"`
 		// DestPath         string                 `json:"dest_path"`
-		// Meta             map[string]interface{} `json:"meta"`
-		WriteableContent string `json:"content"`
+		Meta             map[string]interface{} `json:"meta"`
+		WriteableContent string                 `json:"content"`
 		// HTMLContent      string                 `json:"html"`
 	}{
 		Name:       fileTargetName,
 		SourcePath: file.SourcePath,
+		Meta:       file.Meta,
 	}
 
 	localCollection := []*HookSource{}

transformers/html/html.go

@@ -7,4 +7,9 @@ func (mt *HTMLTransformer) TransformContent(input []byte) (result []byte, err er
 	return
 }
 
+func (mt *HTMLTransformer) ExtractMeta(input []byte) (result map[string]interface{}, content []byte, err error) {
+	result = map[string]interface{}{}
+	return
+}
+
 func (mt *HTMLTransformer) Init() {}

transformers/markdown/markdown.go

@@ -16,6 +16,7 @@ import (
 	"github.com/yuin/goldmark/renderer/html"
 	"github.com/yuin/goldmark/text"
 	"github.com/yuin/goldmark/util"
+	"gopkg.in/yaml.v3"
 )
 
 type MarkdownTransformer struct {
@@ -30,7 +31,13 @@ func (mt *MarkdownTransformer) TransformContent(input []byte) (result []byte, er
 	mt.EnsureProcessor()
 
 	var buffer bytes.Buffer
-	err = mt.processor.Convert(input, &buffer)
+	_, content, err := mt.ExtractMeta(input)
+
+	if err != nil {
+		return
+	}
+
+	err = mt.processor.Convert(content, &buffer)
 	if err != nil {
 		return
 	}
@@ -39,6 +46,28 @@ func (mt *MarkdownTransformer) TransformContent(input []byte) (result []byte, er
 	return
 }
 
+func (mt *MarkdownTransformer) ExtractMeta(input []byte) (result map[string]interface{}, content []byte, err error) {
+	result = map[string]interface{}{}
+	sep := []byte("---")
+
+	content = input
+
+	if !bytes.HasPrefix(input, sep) {
+		return
+	}
+
+	metaParts := bytes.SplitN(content, sep, 3)
+	if len(metaParts) > 2 {
+		fmt.Printf("metaParts: %v\n", metaParts)
+		err = yaml.Unmarshal([]byte(metaParts[1]), &result)
+		if err != nil {
+			return
+		}
+		content = metaParts[2]
+	}
+	return
+}
+
 func (mt *MarkdownTransformer) EnsureProcessor() {
 	if mt.processor != nil {
 		return

transformers/transformers.go

@@ -4,8 +4,10 @@ type TransformedFile struct {
 	SourcePath      string
 	TransformedFile string
 	Extension       string
+	Meta            map[string]interface{}
 }
 
 type Transfomer interface {
 	TransformContent(data []byte) ([]byte, error)
+	ExtractMeta(data []byte) (map[string]interface{}, []byte, error)
 }