438 lines
10 KiB
Go
438 lines
10 KiB
Go
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// Copyright 2013 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Package blog implements a web server for articles written in present format.
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package blog // import "golang.org/x/tools/blog"
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import (
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"bytes"
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"encoding/json"
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"encoding/xml"
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"fmt"
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"html/template"
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"log"
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"net/http"
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"os"
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"path/filepath"
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"regexp"
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"sort"
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"strings"
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"time"
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"golang.org/x/tools/blog/atom"
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"golang.org/x/tools/present"
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)
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var validJSONPFunc = regexp.MustCompile(`(?i)^[a-z_][a-z0-9_.]*$`)
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// Config specifies Server configuration values.
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type Config struct {
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ContentPath string // Relative or absolute location of article files and related content.
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TemplatePath string // Relative or absolute location of template files.
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BaseURL string // Absolute base URL (for permalinks; no trailing slash).
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BasePath string // Base URL path relative to server root (no trailing slash).
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GodocURL string // The base URL of godoc (for menu bar; no trailing slash).
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Hostname string // Server host name, used for rendering ATOM feeds.
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HomeArticles int // Articles to display on the home page.
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FeedArticles int // Articles to include in Atom and JSON feeds.
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FeedTitle string // The title of the Atom XML feed
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PlayEnabled bool
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}
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// Doc represents an article adorned with presentation data.
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type Doc struct {
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*present.Doc
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Permalink string // Canonical URL for this document.
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Path string // Path relative to server root (including base).
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HTML template.HTML // rendered article
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Related []*Doc
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Newer, Older *Doc
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}
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// Server implements an http.Handler that serves blog articles.
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type Server struct {
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cfg Config
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docs []*Doc
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tags []string
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docPaths map[string]*Doc // key is path without BasePath.
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docTags map[string][]*Doc
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template struct {
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home, index, article, doc *template.Template
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}
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atomFeed []byte // pre-rendered Atom feed
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jsonFeed []byte // pre-rendered JSON feed
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content http.Handler
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}
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// NewServer constructs a new Server using the specified config.
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func NewServer(cfg Config) (*Server, error) {
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present.PlayEnabled = cfg.PlayEnabled
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if notExist(cfg.TemplatePath) {
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return nil, fmt.Errorf("template directory not found: %s", cfg.TemplatePath)
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}
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root := filepath.Join(cfg.TemplatePath, "root.tmpl")
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parse := func(name string) (*template.Template, error) {
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path := filepath.Join(cfg.TemplatePath, name)
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if notExist(path) {
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return nil, fmt.Errorf("template %s was not found in %s", name, cfg.TemplatePath)
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}
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t := template.New("").Funcs(funcMap)
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return t.ParseFiles(root, path)
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}
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s := &Server{cfg: cfg}
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// Parse templates.
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var err error
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s.template.home, err = parse("home.tmpl")
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if err != nil {
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return nil, err
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}
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s.template.index, err = parse("index.tmpl")
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if err != nil {
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return nil, err
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}
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s.template.article, err = parse("article.tmpl")
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if err != nil {
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return nil, err
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}
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p := present.Template().Funcs(funcMap)
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s.template.doc, err = p.ParseFiles(filepath.Join(cfg.TemplatePath, "doc.tmpl"))
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if err != nil {
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return nil, err
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}
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// Load content.
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err = s.loadDocs(filepath.Clean(cfg.ContentPath))
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if err != nil {
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return nil, err
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}
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err = s.renderAtomFeed()
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if err != nil {
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return nil, err
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}
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err = s.renderJSONFeed()
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if err != nil {
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return nil, err
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}
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// Set up content file server.
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s.content = http.StripPrefix(s.cfg.BasePath, http.FileServer(http.Dir(cfg.ContentPath)))
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return s, nil
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}
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var funcMap = template.FuncMap{
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"sectioned": sectioned,
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"authors": authors,
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}
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// sectioned returns true if the provided Doc contains more than one section.
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// This is used to control whether to display the table of contents and headings.
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func sectioned(d *present.Doc) bool {
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return len(d.Sections) > 1
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}
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// authors returns a comma-separated list of author names.
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func authors(authors []present.Author) string {
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var b bytes.Buffer
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last := len(authors) - 1
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for i, a := range authors {
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if i > 0 {
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if i == last {
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b.WriteString(" and ")
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} else {
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b.WriteString(", ")
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}
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}
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b.WriteString(authorName(a))
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}
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return b.String()
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}
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// authorName returns the first line of the Author text: the author's name.
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func authorName(a present.Author) string {
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el := a.TextElem()
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if len(el) == 0 {
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return ""
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}
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text, ok := el[0].(present.Text)
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if !ok || len(text.Lines) == 0 {
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return ""
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}
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return text.Lines[0]
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}
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// loadDocs reads all content from the provided file system root, renders all
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// the articles it finds, adds them to the Server's docs field, computes the
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// denormalized docPaths, docTags, and tags fields, and populates the various
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// helper fields (Next, Previous, Related) for each Doc.
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func (s *Server) loadDocs(root string) error {
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// Read content into docs field.
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const ext = ".article"
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fn := func(p string, info os.FileInfo, err error) error {
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if filepath.Ext(p) != ext {
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return nil
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}
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f, err := os.Open(p)
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if err != nil {
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return err
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}
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defer f.Close()
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d, err := present.Parse(f, p, 0)
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if err != nil {
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return err
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}
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html := new(bytes.Buffer)
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err = d.Render(html, s.template.doc)
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if err != nil {
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return err
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}
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p = p[len(root) : len(p)-len(ext)] // trim root and extension
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p = filepath.ToSlash(p)
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s.docs = append(s.docs, &Doc{
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Doc: d,
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Path: s.cfg.BasePath + p,
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Permalink: s.cfg.BaseURL + p,
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HTML: template.HTML(html.String()),
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})
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return nil
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}
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err := filepath.Walk(root, fn)
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if err != nil {
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return err
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}
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sort.Sort(docsByTime(s.docs))
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// Pull out doc paths and tags and put in reverse-associating maps.
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s.docPaths = make(map[string]*Doc)
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s.docTags = make(map[string][]*Doc)
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for _, d := range s.docs {
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s.docPaths[strings.TrimPrefix(d.Path, s.cfg.BasePath)] = d
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for _, t := range d.Tags {
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s.docTags[t] = append(s.docTags[t], d)
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}
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}
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// Pull out unique sorted list of tags.
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for t := range s.docTags {
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s.tags = append(s.tags, t)
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}
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sort.Strings(s.tags)
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// Set up presentation-related fields, Newer, Older, and Related.
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for _, doc := range s.docs {
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// Newer, Older: docs adjacent to doc
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for i := range s.docs {
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if s.docs[i] != doc {
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continue
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}
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if i > 0 {
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doc.Newer = s.docs[i-1]
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}
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if i+1 < len(s.docs) {
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doc.Older = s.docs[i+1]
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}
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break
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}
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// Related: all docs that share tags with doc.
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related := make(map[*Doc]bool)
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for _, t := range doc.Tags {
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for _, d := range s.docTags[t] {
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if d != doc {
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related[d] = true
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}
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}
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}
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for d := range related {
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doc.Related = append(doc.Related, d)
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}
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sort.Sort(docsByTime(doc.Related))
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}
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return nil
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}
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// renderAtomFeed generates an XML Atom feed and stores it in the Server's
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// atomFeed field.
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func (s *Server) renderAtomFeed() error {
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var updated time.Time
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if len(s.docs) > 0 {
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updated = s.docs[0].Time
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}
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feed := atom.Feed{
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Title: s.cfg.FeedTitle,
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ID: "tag:" + s.cfg.Hostname + ",2013:" + s.cfg.Hostname,
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Updated: atom.Time(updated),
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Link: []atom.Link{{
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Rel: "self",
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Href: s.cfg.BaseURL + "/feed.atom",
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}},
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}
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for i, doc := range s.docs {
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if i >= s.cfg.FeedArticles {
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break
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}
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e := &atom.Entry{
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Title: doc.Title,
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ID: feed.ID + doc.Path,
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Link: []atom.Link{{
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Rel: "alternate",
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Href: doc.Permalink,
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}},
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Published: atom.Time(doc.Time),
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Updated: atom.Time(doc.Time),
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Summary: &atom.Text{
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Type: "html",
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Body: summary(doc),
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},
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Content: &atom.Text{
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Type: "html",
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Body: string(doc.HTML),
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},
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Author: &atom.Person{
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Name: authors(doc.Authors),
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},
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}
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feed.Entry = append(feed.Entry, e)
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}
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data, err := xml.Marshal(&feed)
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if err != nil {
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return err
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}
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s.atomFeed = data
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return nil
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}
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type jsonItem struct {
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Title string
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Link string
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Time time.Time
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Summary string
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Content string
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Author string
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}
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// renderJSONFeed generates a JSON feed and stores it in the Server's jsonFeed
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// field.
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func (s *Server) renderJSONFeed() error {
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var feed []jsonItem
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for i, doc := range s.docs {
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if i >= s.cfg.FeedArticles {
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break
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}
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item := jsonItem{
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Title: doc.Title,
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Link: doc.Permalink,
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Time: doc.Time,
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Summary: summary(doc),
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Content: string(doc.HTML),
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Author: authors(doc.Authors),
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}
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feed = append(feed, item)
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}
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data, err := json.Marshal(feed)
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if err != nil {
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return err
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}
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s.jsonFeed = data
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return nil
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}
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// summary returns the first paragraph of text from the provided Doc.
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func summary(d *Doc) string {
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if len(d.Sections) == 0 {
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return ""
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}
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for _, elem := range d.Sections[0].Elem {
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text, ok := elem.(present.Text)
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if !ok || text.Pre {
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// skip everything but non-text elements
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continue
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}
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var buf bytes.Buffer
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for _, s := range text.Lines {
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buf.WriteString(string(present.Style(s)))
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buf.WriteByte('\n')
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}
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return buf.String()
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}
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return ""
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}
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// rootData encapsulates data destined for the root template.
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type rootData struct {
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Doc *Doc
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BasePath string
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GodocURL string
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Data interface{}
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}
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// ServeHTTP serves the front, index, and article pages
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// as well as the ATOM and JSON feeds.
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func (s *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
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var (
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d = rootData{BasePath: s.cfg.BasePath, GodocURL: s.cfg.GodocURL}
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t *template.Template
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)
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switch p := strings.TrimPrefix(r.URL.Path, s.cfg.BasePath); p {
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case "/":
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d.Data = s.docs
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if len(s.docs) > s.cfg.HomeArticles {
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d.Data = s.docs[:s.cfg.HomeArticles]
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}
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t = s.template.home
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case "/index":
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d.Data = s.docs
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t = s.template.index
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case "/feed.atom", "/feeds/posts/default":
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w.Header().Set("Content-type", "application/atom+xml; charset=utf-8")
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|
|
w.Write(s.atomFeed)
|
||
|
|
return
|
||
|
|
case "/.json":
|
||
|
|
if p := r.FormValue("jsonp"); validJSONPFunc.MatchString(p) {
|
||
|
|
w.Header().Set("Content-type", "application/javascript; charset=utf-8")
|
||
|
|
fmt.Fprintf(w, "%v(%s)", p, s.jsonFeed)
|
||
|
|
return
|
||
|
|
}
|
||
|
|
w.Header().Set("Content-type", "application/json; charset=utf-8")
|
||
|
|
w.Write(s.jsonFeed)
|
||
|
|
return
|
||
|
|
default:
|
||
|
|
doc, ok := s.docPaths[p]
|
||
|
|
if !ok {
|
||
|
|
// Not a doc; try to just serve static content.
|
||
|
|
s.content.ServeHTTP(w, r)
|
||
|
|
return
|
||
|
|
}
|
||
|
|
d.Doc = doc
|
||
|
|
t = s.template.article
|
||
|
|
}
|
||
|
|
err := t.ExecuteTemplate(w, "root", d)
|
||
|
|
if err != nil {
|
||
|
|
log.Println(err)
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// docsByTime implements sort.Interface, sorting Docs by their Time field.
|
||
|
|
type docsByTime []*Doc
|
||
|
|
|
||
|
|
func (s docsByTime) Len() int { return len(s) }
|
||
|
|
func (s docsByTime) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
|
||
|
|
func (s docsByTime) Less(i, j int) bool { return s[i].Time.After(s[j].Time) }
|
||
|
|
|
||
|
|
// notExist reports whether the path exists or not.
|
||
|
|
func notExist(path string) bool {
|
||
|
|
_, err := os.Stat(path)
|
||
|
|
return os.IsNotExist(err)
|
||
|
|
}
|