/
main.go
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/
main.go
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// This file is part of gmnhg.
// gmnhg is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// gmnhg is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License
// along with gmnhg. If not, see <https://www.gnu.org/licenses/>.
// gmnhg converts Hugo content files to a Gemini site. This program is
// to be started in the top level directory of a Hugo site (the one
// containing config.toml, config.json, or config.yaml).
//
// gmnhg will read layout template files (with .gotmpl extension) and
// then apply them to content files ending with .md by the following
// algorithm (layout file names are relative to gmnhg/):
//
// 1. If the .md file specifies its own layout, the relevant layout file
// is applied. If not, the default template is applied (single). If the
// layout file does not exist, the file is skipped. Draft posts are not
// rendered.
//
// 2. For every top-level content directory an index.gmi is generated,
// the corresponding template is taken from top/{directory_name}.gotmpl.
// Its content is taken from either _index.gmi.md or _index.md (.gmi.md
// preferred) in that dir. If there's no matching template or no
// _index.gmi.md / _index.md, the index won't be rendered.
//
// Templates for subdirectories are placed in subfolders under top/. For
// example, a template for an index at series/first/_index.gmi.md should
// be placed at top/series/first.gotmpl.
//
// 3. The very top index.gmi is generated from index.gotmpl and
// top-level _index.gmi.
//
// The program will then copy static files from static/ directory to the
// output dir. Page resources (non-Markdown files) will also be copied
// from the content/ directory as-is, without further modification.
//
// Templates are passed the following data:
//
// 1. Single pages are given .Post, which contains the entire post
// rendered, .Metadata, which contains the metadata crawled from it (see
// Metadata in internal/gmnhg/post.go), and .Link, which contains the
// filename relative to content dir (with .md replaced with .gmi).
//
// 2. Directory index pages, including the top-level index, are passed
// .Posts, which is a slice over post metadata crawled (see Metadata in
// internal/gmnhg/post.go), .Dirname, which is the directory name
// relative to the content dir, .Link, which contains the index filename
// relative to the content dir (with .md replaced with .gmi), .Content,
// which is rendered from directory's _index.gmi.md / _index.md,
// .Metadata, which contains metadata crawled from _index.gmi.md /
// _index.md, and .Site, which contains site-level configuration data
// loaded from the Hugo site's config.toml, config.yaml, or config.json.
//
// The following keys are available in the .Site map, listed with their
// associated Hugo configuration key: .BaseURL (baseUrl), .GmnhgBaseURL,
// (gmnhg.baseUrl), .Title (title), .GmnhgTitle (gmnhg.title),
// .Copyright (copyright), and .LanguageCode (languageCode).
//
// Directory indices are passed all posts from subdirectories (branch
// and leaf bundles), with the exception of leaf resource pages. This
// allows for roll-up indices.
//
// 3. RSS templates receive the same data as directory index pages
// (except for .Metadata), but the filename provided by .Link is rss.xml
// instead of index.gmi.
//
// This program provides some extra template functions on top of sort:
//
// * sort, which sorts slices of int, float64, strings, and anything
// implementing sort.Interface (which includes slices of posts),
// returning a new, sorted slice.
//
// * sortRev, which works like sort, but sorts in reverse order.
//
// * sortPosts, which is an alias to sortRev preserved for backwards
// compatilibity.
//
// Template functions from sprig are also available
// (https://github.com/Masterminds/sprig); see the sprig documentation
// for more details.
//
// RSS will be generated as rss.xml for the root directory and all
// branch directories. Site title and other RSS metadata will be loaded
// from the Hugo configuration file (config.toml, config.yaml, or
// config.json).
//
// gmnhg provides a way to override these attributes by defining a
// "gmnhg" section in the configuration file and nesting the attributes
// to override underneath this section. Presently you can override both
// "baseUrl" and "title" in this manner. It is recommended to override
// at least "baseUrl" unless your site uses a protocol-relative base URL
// (beginning with a double slash instead of https://).
//
// RSS templates can be overriden by defining a template in one of
// several places:
//
// * Site-wide: gmnhg/_default/rss.gotmpl
//
// * Site root: gmnhg/rss.gotmpl
//
// * Directories: gmnhg/rss/dirname.gotmpl for a directory "/dirname" or
// gmnhg/rss/dirname/subdir.gotmpl for "/dirname/subdir"
//
// One might want to ignore _index.gmi.md files with the following Hugo
// config option in config.toml:
//
// ignoreFiles = [ "_index\\.gmi\\.md$" ]
package main
import (
"bytes"
"encoding/json"
"flag"
"fmt"
"io"
"io/ioutil"
"os"
"path"
"path/filepath"
"regexp"
"strings"
"text/template"
"github.com/BurntSushi/toml"
"gopkg.in/yaml.v2"
gemini "github.com/tdemin/gmnhg"
"github.com/tdemin/gmnhg/internal/gmnhg"
)
const (
defaultPageTemplate = "single"
hugoIndexMdFilename = "_index.md"
geminiIndexMdFilename = "_index.gmi.md"
indexFilename = "index.gmi"
rssFilename = "rss.xml"
)
const (
contentBase = "content/"
templateBase = "gmnhg/"
staticBase = "static/"
outputBase = "output/"
)
var (
tmplNameRegex = regexp.MustCompile("^" + templateBase + `([\pL\d\-_ /]+)\.gotmpl$`)
leafIndexRegex = regexp.MustCompile("^" + contentBase + `([\pL\d\-_ /]+)/index\.[\pL\d_]+$`)
pagePathRegex = regexp.MustCompile("^" + contentBase + `([\pL\d\-_ /]+)/([\pL\d\-_ ]+)\.md$`)
)
var hugoConfigFiles = []string{"config.toml", "config.yaml", "config.json"}
type SiteConfig struct {
BaseURL string `yaml:"baseURL"`
Title string `yaml:"title"`
Copyright string `yaml:"copyright"`
LanguageCode string `yaml:"languageCode"`
Gmnhg GmnhgConfig `yaml:"gmnhg"`
}
type GmnhgConfig struct {
BaseURL string `yaml:"baseURL"`
Title string `yaml:"title"`
}
func findIndexMd(basepath string) string {
for _, filename := range []string{geminiIndexMdFilename, hugoIndexMdFilename} {
path := path.Join(basepath, filename)
if info, err := os.Stat(path); err == nil && !info.IsDir() {
return path
}
}
return ""
}
func copyFile(dst, src string) error {
input, err := os.Open(src)
if err != nil {
return err
}
defer input.Close()
if p := path.Dir(dst); p != "" {
if err := os.MkdirAll(p, 0755); err != nil {
return err
}
}
output, err := os.Create(dst)
if err != nil {
return err
}
defer output.Close()
if _, err := io.Copy(output, input); err != nil {
return err
}
return nil
}
func writeFile(dst string, contents []byte) error {
if p := path.Dir(dst); p != "" {
if err := os.MkdirAll(p, 0755); err != nil {
return err
}
}
output, err := os.Create(dst)
if err != nil {
return err
}
defer output.Close()
if _, err := output.Write(contents); err != nil {
return err
}
return nil
}
func hasSubPath(paths []string, path string) bool {
for _, p := range paths {
if strings.HasPrefix(path, p+"/") {
return true
}
}
return false
}
var version = "v0+HEAD"
func main() {
var (
outputDir, workingDir string
isVersionCmd bool
)
flag.StringVar(&outputDir, "output", outputBase, "output directory (will be created if missing)")
flag.StringVar(&workingDir, "working", "", "working directory (defaults to current directory)")
flag.BoolVar(&isVersionCmd, "version", false, "display version")
flag.Parse()
if isVersionCmd {
println("gmnhg", version)
return
}
if workingDir != "" {
if err := os.Chdir(workingDir); err != nil {
panic(err)
}
}
configFound := false
var siteConf SiteConfig
for _, filename := range hugoConfigFiles {
if fileInfo, err := os.Stat(filename); !(os.IsNotExist(err) || fileInfo.IsDir()) {
configFound = true
buf, err := ioutil.ReadFile(filename)
if err != nil {
panic(err)
}
switch ext := filepath.Ext(filename); ext {
case ".toml":
if err := toml.Unmarshal(buf, &siteConf); err != nil {
panic(err)
}
case ".yaml":
if err := yaml.Unmarshal(buf, &siteConf); err != nil {
panic(err)
}
case ".json":
if err := json.Unmarshal(buf, &siteConf); err != nil {
panic(err)
}
}
break
}
}
if !configFound {
panic(fmt.Errorf("no Hugo config in %v found; not in a Hugo site dir?", hugoConfigFiles))
}
// build templates
templates := make(map[string]*template.Template)
if _, err := os.Stat(templateBase); !os.IsNotExist(err) {
if err := filepath.Walk(templateBase, func(path string, info os.FileInfo, err error) error {
if err != nil {
return err
}
if info.IsDir() {
return nil
}
name := tmplNameRegex.FindStringSubmatch(path)
if name == nil || len(name) != 2 {
return nil
}
tmplName := name[1]
contents, err := ioutil.ReadFile(path)
if err != nil {
return err
}
tmpl, err := template.New(tmplName).Funcs(defineFuncMap()).Parse(string(contents))
if err != nil {
return err
}
templates[tmplName] = tmpl
return nil
}); err != nil {
panic(err)
}
}
// collect leaf node paths (directories containing an index.* file)
leafIndexPaths := []string{}
if err := filepath.Walk(contentBase, func(path string, info os.FileInfo, err error) error {
if err != nil {
return err
}
if info.IsDir() {
return nil
}
if matches := leafIndexRegex.FindStringSubmatch(path); matches != nil {
leafIndexPaths = append(leafIndexPaths, contentBase+matches[1])
}
return nil
}); err != nil {
panic(err)
}
// render posts to Gemtext and collect top level posts data
posts := make(map[string]gmnhg.Post)
topLevelPosts := make(map[string]gmnhg.Posts)
if err := filepath.Walk(contentBase, func(path string, info os.FileInfo, err error) error {
if err != nil {
return err
}
if n := info.Name(); info.IsDir() || !strings.HasSuffix(n, ".md") || n == hugoIndexMdFilename || n == geminiIndexMdFilename {
return nil
}
fileContent, err := ioutil.ReadFile(path)
if err != nil {
return err
}
content, metadata := gmnhg.ParseMetadata(fileContent)
// skip drafts from rendering
if metadata.IsDraft {
return nil
}
gemText, err := gemini.RenderMarkdown(content, gemini.Defaults)
if err != nil {
return err
}
// skip headless leaves from rendering
isLeafIndex := info.Name() == "index.md"
if isLeafIndex && metadata.IsHeadless {
return nil
}
key := strings.TrimPrefix(strings.TrimSuffix(path, ".md"), contentBase) + ".gmi"
p := gmnhg.Post{
Post: gemText,
Link: key,
Metadata: metadata,
}
posts[key] = p
if matches := pagePathRegex.FindStringSubmatch(path); matches != nil {
dirs := strings.Split(matches[1], "/")
// only include leaf resources pages in leaf index
if !isLeafIndex && hasSubPath(leafIndexPaths, path) {
topLevelPosts["/"+matches[1]] = append(topLevelPosts["/"+matches[1]], p)
} else {
// include normal pages in all subdirectory indices
for i, dir := range dirs {
if i > 0 {
dirs[i] = dirs[i-1] + "/" + dir
}
}
for _, dir := range dirs {
topLevelPosts["/"+dir] = append(topLevelPosts["/"+dir], p)
}
topLevelPosts["/"] = append(topLevelPosts["/"], p)
}
}
return nil
}); err != nil {
panic(err)
}
// clean up output dir beforehand
if _, err := os.Stat(outputDir); os.IsNotExist(err) {
if err := os.MkdirAll(outputDir, 0755); err != nil {
panic(err)
}
} else {
dir, err := ioutil.ReadDir(outputDir)
if err != nil {
panic(err)
}
for _, d := range dir {
os.RemoveAll(path.Join(outputDir, d.Name()))
}
}
var singleTemplate = defaultSingleTemplate
if tmpl, hasTmpl := templates[defaultPageTemplate]; hasTmpl {
singleTemplate = tmpl
}
// render posts to files
for fileName, post := range posts {
var tmpl = singleTemplate
if pl := post.Metadata.Layout; pl != "" {
t, ok := templates[pl]
if !ok {
// no point trying to render pages with no layout
continue
}
tmpl = t
}
buf := bytes.Buffer{}
if err := tmpl.Execute(&buf, &post); err != nil {
panic(err)
}
if err := writeFile(path.Join(outputDir, fileName), buf.Bytes()); err != nil {
panic(err)
}
}
// render indexes for top-level dirs
for dirname, posts := range topLevelPosts {
// skip the main index
if dirname == "/" {
continue
}
tmpl, hasTmpl := templates["top"+dirname]
if !hasTmpl {
continue
}
fileContent, err := ioutil.ReadFile(findIndexMd(path.Join(contentBase, dirname)))
if err != nil {
// skip unreadable index files
continue
}
content, metadata := gmnhg.ParseMetadata(fileContent)
if metadata.IsDraft {
continue
}
gemtext, err := gemini.RenderMarkdown(content, gemini.Defaults)
if err != nil {
panic(err)
}
sc := map[string]interface{}{
"BaseURL": siteConf.BaseURL,
"GmnhgBaseURL": siteConf.Gmnhg.BaseURL,
"Title": siteConf.Title,
"GmnhgTitle": siteConf.Gmnhg.Title,
"Copyright": siteConf.Copyright,
"LanguageCode": siteConf.LanguageCode,
}
cnt := map[string]interface{}{
"Posts": posts,
"Dirname": dirname,
"Link": path.Join(dirname, indexFilename),
"Content": gemtext,
"Site": sc,
"Metadata": metadata,
}
buf := bytes.Buffer{}
if err := tmpl.Execute(&buf, cnt); err != nil {
panic(err)
}
if err := writeFile(path.Join(outputDir, dirname, indexFilename), buf.Bytes()); err != nil {
panic(err)
}
}
// render index page
var indexTmpl = defaultIndexTemplate
if t, hasIndexTmpl := templates["index"]; hasIndexTmpl {
indexTmpl = t
}
indexContent, err := ioutil.ReadFile(findIndexMd(contentBase))
if err != nil {
panic(err)
}
content, metadata := gmnhg.ParseMetadata(indexContent)
gemtext, err := gemini.RenderMarkdown(content, gemini.Defaults)
if err != nil {
panic(err)
}
sc := map[string]interface{}{
"BaseURL": siteConf.BaseURL,
"GmnhgBaseURL": siteConf.Gmnhg.BaseURL,
"Title": siteConf.Title,
"GmnhgTitle": siteConf.Gmnhg.Title,
"Copyright": siteConf.Copyright,
"LanguageCode": siteConf.LanguageCode,
}
cnt := map[string]interface{}{
"Posts": topLevelPosts,
"Dirname": "/",
"Link": path.Join("/", indexFilename),
"Content": gemtext,
"Site": sc,
"Metadata": metadata,
}
buf := bytes.Buffer{}
if err := indexTmpl.Execute(&buf, cnt); err != nil {
panic(err)
}
if err := writeFile(path.Join(outputDir, indexFilename), buf.Bytes()); err != nil {
panic(err)
}
// render RSS/Atom feeds
if tmpl, hasTmpl := templates["_default/rss"]; hasTmpl {
defaultRssTemplate = tmpl
}
for dirname, posts := range topLevelPosts {
// do not render RSS for leaf paths
if hasSubPath(leafIndexPaths, path.Join(contentBase, dirname)+"/") {
continue
}
tmpl, hasTmpl := templates["rss"+dirname]
if !hasTmpl {
if rootTmpl, hasTmpl := templates["rss"]; dirname == "/" && hasTmpl {
tmpl = rootTmpl
} else {
tmpl = defaultRssTemplate
}
}
sc := map[string]interface{}{
"BaseURL": siteConf.BaseURL,
"GmnhgBaseURL": siteConf.Gmnhg.BaseURL,
"Title": siteConf.Title,
"GmnhgTitle": siteConf.Gmnhg.Title,
"Copyright": siteConf.Copyright,
"LanguageCode": siteConf.LanguageCode,
}
cnt := map[string]interface{}{
"Posts": posts,
"Dirname": dirname,
"Link": path.Join(dirname, rssFilename),
"Site": sc,
}
buf := bytes.Buffer{}
if err := tmpl.Execute(&buf, cnt); err != nil {
panic(err)
}
if err := writeFile(path.Join(outputDir, dirname, rssFilename), buf.Bytes()); err != nil {
panic(err)
}
}
// copy page resources to output dir
if err := filepath.Walk(contentBase, func(p string, info os.FileInfo, err error) error {
if err != nil {
return err
}
if info.IsDir() || strings.HasSuffix(info.Name(), ".md") {
return nil
}
return copyFile(path.Join(outputDir, strings.TrimPrefix(p, contentBase)), p)
}); err != nil {
panic(err)
}
// copy static files to output dir unmodified
if err := filepath.Walk(staticBase, func(p string, info os.FileInfo, err error) error {
if os.IsNotExist(err) {
return nil
}
if err != nil {
return err
}
if info.IsDir() {
return nil
}
return copyFile(path.Join(outputDir, strings.TrimPrefix(p, staticBase)), p)
}); err != nil {
panic(err)
}
}