feat(config): allow configurable image target URL patterns

docs/content/configuration/parameters.ja.md

@@ -51,6 +51,11 @@ GitHub の設定です。
 - `directory`: 画像の保存先ディレクトリ
 - `filename`: 画像のファイル名
 - `url`: Markdownから参照される画像のURL
+- `targets`: Issue本文内で検出して置換するURLプレフィックス
+
+`targets` を省略した場合は、組み込みの GitHub 添付画像URL ルールが使われます。
+`targets: []` を指定した場合は、画像URLの検出も置換も行いません。
+`https://*.githubusercontent.com` のようなワイルドカード付きホスト指定も使えます。
 
 ``[:id]`` は画像の ID に置き換わります。画像の ID はそのIssue内部で一意で、連番で割り振られます。
 

docs/content/configuration/parameters.md

@@ -51,6 +51,11 @@ Output settings.
 - `directory`: Directory to save images
 - `filename`: Image filename
 - `url`: Image URL referenced from Markdown
+- `targets`: URL prefixes to detect and replace in issue bodies
+
+If `targets` is omitted, the built-in GitHub attachment URL rules are used.
+If `targets: []` is specified, no image URLs are detected or replaced.
+Wildcard host patterns such as `https://*.githubusercontent.com` are also supported.
 
 `[:id]` will be replaced with the image ID. The image ID is unique within each issue and assigned sequentially.
 

gic.config.yaml

@@ -1,15 +1,18 @@
 github:
-  username: 'rokuosan'
-  repository: 'github-issue-cms'
+  username: "rokuosan"
+  repository: "github-issue-cms"
 
 output:
   articles:
-    directory: 'content/posts'
-    filename: '%Y-%m-%d_%H%M%S.md'
+    directory: "content/posts"
+    filename: "%Y-%m-%d_%H%M%S.md"
   images:
-    directory: 'static/images/%Y-%m-%d_%H%M%S'
-    filename: '[:id].png'
-    url: '/images/%Y-%m-%d_%H%M%S'
+    directory: "static/images/%Y-%m-%d_%H%M%S"
+    filename: "[:id].png"
+    url: "/images/%Y-%m-%d_%H%M%S"
+    targets:
+      - "https://github.com/user-attachments/"
+      - "https://*.githubusercontent.com"
 
 # For page bundle
 # output:

pkg/config/config_test.go

@@ -0,0 +1,70 @@
+package config
+
+import (
+	"os"
+	"strings"
+	"testing"
+
+	"github.com/spf13/viper"
+)
+
+func TestWriteAndReload_PreservesExplicitEmptyImageTargets(t *testing.T) {
+	tempDir := t.TempDir()
+
+	originalWd, err := os.Getwd()
+	if err != nil {
+		t.Fatalf("getwd: %v", err)
+	}
+	t.Cleanup(func() {
+		if err := os.Chdir(originalWd); err != nil {
+			t.Fatalf("restore wd: %v", err)
+		}
+		config = Config{}
+		viper.Reset()
+	})
+
+	if err := os.Chdir(tempDir); err != nil {
+		t.Fatalf("chdir: %v", err)
+	}
+	config = Config{}
+	viper.Reset()
+
+	conf := Config{
+		GitHub: NewGitHubConfig(),
+		Output: &OutputConfig{
+			Articles: NewOutputArticlesConfig(),
+			Images: &OutputImagesConfig{
+				Directory: "static/images",
+				Filename:  "[:id].png",
+				BaseURL:   Ptr("/images"),
+				Targets:   []string{},
+			},
+		},
+	}
+
+	if err := Write(conf); err != nil {
+		t.Fatalf("write: %v", err)
+	}
+
+	data, err := os.ReadFile(GetConfigPath())
+	if err != nil {
+		t.Fatalf("read config: %v", err)
+	}
+	if !strings.Contains(string(data), "targets: []") {
+		t.Fatalf("expected explicit empty targets in config, got:\n%s", string(data))
+	}
+
+	reloaded, err := Reload()
+	if err != nil {
+		t.Fatalf("reload: %v", err)
+	}
+	if reloaded.Output == nil || reloaded.Output.Images == nil {
+		t.Fatalf("missing output images after reload")
+	}
+	if reloaded.Output.Images.Targets == nil {
+		t.Fatalf("targets became nil after reload")
+	}
+	if len(reloaded.Output.Images.TargetURLs()) != 0 {
+		t.Fatalf("target urls = %#v", reloaded.Output.Images.TargetURLs())
+	}
+}

pkg/config/type.go

@@ -26,9 +26,16 @@ type OutputArticlesConfig struct {
 }
 
 type OutputImagesConfig struct {
-	Directory string  `yaml:"directory" mapstructure:"directory"`
-	Filename  string  `yaml:"filename" mapstructure:"filename"`
-	BaseURL   *string `yaml:"url" mapstructure:"url"`
+	Directory string   `yaml:"directory" mapstructure:"directory"`
+	Filename  string   `yaml:"filename" mapstructure:"filename"`
+	BaseURL   *string  `yaml:"url" mapstructure:"url"`
+	Targets   []string `yaml:"targets" mapstructure:"targets"`
+}
+
+var defaultImageTargets = []string{
+	"https://github.com/user-attachments/",
+	"https://user-images.githubusercontent.com/",
+	"https://private-user-images.githubusercontent.com/",
 }
 
 type HugoConfig struct {
@@ -115,6 +122,13 @@ func (c *OutputImagesConfig) URL() string {
 	return *c.BaseURL
 }
 
+func (c *OutputImagesConfig) TargetURLs() []string {
+	if c == nil || c.Targets == nil {
+		return defaultImageTargets
+	}
+	return c.Targets
+}
+
 func (c *Config) normalize() {
 	if c.GitHub == nil {
 		c.GitHub = NewGitHubConfig()

pkg/config/type_test.go

@@ -130,3 +130,28 @@ func TestConfigNormalize_BackfillsMissingOutputImageURLFromLegacyHugo(t *testing
 		t.Fatalf("images url = %q", conf.Output.Images.URL())
 	}
 }
+
+func TestOutputImagesConfig_TargetURLs_DefaultsWhenUnset(t *testing.T) {
+	conf := &OutputImagesConfig{}
+
+	got := conf.TargetURLs()
+
+	if len(got) != 3 {
+		t.Fatalf("target count = %d", len(got))
+	}
+	if got[0] != "https://github.com/user-attachments/" {
+		t.Fatalf("first target = %q", got[0])
+	}
+}
+
+func TestOutputImagesConfig_TargetURLs_PreservesExplicitEmptyList(t *testing.T) {
+	conf := &OutputImagesConfig{
+		Targets: []string{},
+	}
+
+	got := conf.TargetURLs()
+
+	if len(got) != 0 {
+		t.Fatalf("target count = %d", len(got))
+	}
+}

pkg/core/issue_articles.go

@@ -3,6 +3,7 @@ package core
 import (
 	"fmt"
 	"net/url"
+	"path"
 	"regexp"
 	"strings"
 
@@ -14,11 +15,6 @@ import (
 
 var (
 	regexURLCandidate = regexp.MustCompile(`https://[^\s<>"')\]]+`)
-	gitHubAssetHosts  = map[string]struct{}{
-		"github.com":                                {},
-		"user-images.githubusercontent.com":         {},
-		"private-user-images.githubusercontent.com": {},
-	}
 )
 
 // ArticleService converts issues into articles.
@@ -78,7 +74,7 @@ func (s *ArticleService) ConvertIssueToArticle(issue *github.Issue) *Article {
 	content = strings.TrimLeft(content, "\n")
 
 	time := issue.GetCreatedAt().Format("2006-01-02_150405")
-	images := extractGitHubHostedImages(content, time)
+	images := extractTargetImages(content, time, s.config.Output.Images.TargetURLs())
 
 	var tags []string
 	excludedLabels := map[string]struct{}{}
@@ -110,13 +106,13 @@ func (s *ArticleService) ConvertIssueToArticle(issue *github.Issue) *Article {
 	}
 }
 
-func extractGitHubHostedImages(content string, time string) []*Image {
+func extractTargetImages(content string, time string, targetURLs []string) []*Image {
 	var images []*Image
 	seen := map[string]struct{}{}
 	matches := regexURLCandidate.FindAllString(content, -1)
 	for _, match := range matches {
 		candidate := strings.TrimRight(match, ".,:;!?`")
-		if !isGitHubHostedAssetURL(candidate) {
+		if !matchesTargetURL(candidate, targetURLs) {
 			continue
 		}
 		if _, ok := seen[candidate]; ok {
@@ -128,21 +124,87 @@ func extractGitHubHostedImages(content string, time string) []*Image {
 	return images
 }
 
-func isGitHubHostedAssetURL(raw string) bool {
-	parsed, err := url.Parse(raw)
+func matchesTargetURL(raw string, targetURLs []string) bool {
+	parsedRaw, err := url.Parse(raw)
 	if err != nil {
 		return false
 	}
-	host := strings.ToLower(parsed.Host)
-	if _, ok := gitHubAssetHosts[host]; !ok {
+
+	for _, targetURL := range targetURLs {
+		if targetURL == "" {
+			continue
+		}
+		if matchTargetPattern(parsedRaw, targetURL) {
+			return true
+		}
+	}
+	return false
+}
+
+func matchTargetPattern(parsedRaw *url.URL, targetURL string) bool {
+	parsedTarget, err := url.Parse(targetURL)
+	if err != nil {
 		return false
 	}
-	switch host {
-	case "github.com":
-		return strings.HasPrefix(parsed.Path, "/user-attachments/")
-	default:
+	if !matchesURLComponents(parsedRaw, parsedTarget) {
+		return false
+	}
+
+	if !strings.Contains(targetURL, "*") {
 		return true
 	}
+
+	if parsedTarget.Host != "" {
+		matched, err := path.Match(strings.ToLower(parsedTarget.Host), strings.ToLower(parsedRaw.Host))
+		if err != nil || !matched {
+			return false
+		}
+	}
+	if parsedTarget.Path != "" && !matchesPathPrefixPattern(parsedRaw.Path, parsedTarget.Path) {
+		return false
+	}
+
+	return true
+}
+
+func matchesURLComponents(parsedRaw *url.URL, parsedTarget *url.URL) bool {
+	if parsedTarget.Scheme != "" && !strings.EqualFold(parsedTarget.Scheme, parsedRaw.Scheme) {
+		return false
+	}
+	if parsedTarget.Host != "" && !strings.Contains(parsedTarget.Host, "*") && !strings.EqualFold(parsedTarget.Host, parsedRaw.Host) {
+		return false
+	}
+	if parsedTarget.Path != "" && !strings.Contains(parsedTarget.Path, "*") && !strings.HasPrefix(parsedRaw.Path, parsedTarget.Path) {
+		return false
+	}
+	if parsedTarget.RawQuery != "" {
+		if !strings.HasPrefix(parsedRaw.RawQuery, parsedTarget.RawQuery) {
+			return false
+		}
+	}
+	if parsedTarget.Fragment != "" && !strings.HasPrefix(parsedRaw.Fragment, parsedTarget.Fragment) {
+		return false
+	}
+
+	return true
+}
+
+func matchesPathPrefixPattern(rawPath string, targetPath string) bool {
+	if targetPath == "" {
+		return true
+	}
+	if !strings.Contains(targetPath, "*") {
+		return strings.HasPrefix(rawPath, targetPath)
+	}
+
+	for i := 1; i <= len(rawPath); i++ {
+		matched, err := path.Match(targetPath, rawPath[:i])
+		if err == nil && matched {
+			return true
+		}
+	}
+
+	return false
 }
 
 func newMetadataParser() metadataParser {