package http import ( "bytes" "context" "errors" "fmt" "html/template" "net/http" "path/filepath" "strings" txttpl "text/template" "time" "github.com/gomarkdown/markdown" "github.com/gomarkdown/markdown/html" "github.com/gomarkdown/markdown/parser" "github.com/mediocregopher/blog.mediocregopher.com/srv/http/apiutil" "github.com/mediocregopher/blog.mediocregopher.com/srv/post" "github.com/mediocregopher/mediocre-go-lib/v2/mctx" ) func (a *api) parsePostBody(post post.Post) (*txttpl.Template, error) { tpl := txttpl.New("root") tpl = tpl.Funcs(txttpl.FuncMap(a.tplFuncs())) tpl = txttpl.Must(tpl.New("image.html").Parse(mustReadTplFile("image.html"))) tpl = tpl.Funcs(txttpl.FuncMap{ "Image": func(id string) (string, error) { tplPayload := struct { ID string Resizable bool }{ ID: id, Resizable: isImgResizable(id), } buf := new(bytes.Buffer) if err := tpl.ExecuteTemplate(buf, "image.html", tplPayload); err != nil { return "", err } return buf.String(), nil }, }) tpl, err := tpl.New(post.ID + "-body.html").Parse(post.Body) if err != nil { return nil, err } return tpl, nil } type postTplPayload struct { post.StoredPost SeriesPrevious, SeriesNext *post.StoredPost Body template.HTML } func (a *api) postToPostTplPayload(storedPost post.StoredPost) (postTplPayload, error) { bodyTpl, err := a.parsePostBody(storedPost.Post) if err != nil { return postTplPayload{}, fmt.Errorf("parsing post body as template: %w", err) } bodyBuf := new(bytes.Buffer) if err := bodyTpl.Execute(bodyBuf, nil); err != nil { return postTplPayload{}, fmt.Errorf("executing post body as template: %w", err) } // this helps the markdown renderer properly parse pages which end in a // `` tag... I don't know why. _, _ = bodyBuf.WriteString("\n") parserExt := parser.CommonExtensions | parser.AutoHeadingIDs parser := parser.NewWithExtensions(parserExt) htmlFlags := html.HrefTargetBlank htmlRenderer := html.NewRenderer(html.RendererOptions{Flags: htmlFlags}) renderedBody := markdown.ToHTML(bodyBuf.Bytes(), parser, htmlRenderer) tplPayload := postTplPayload{ StoredPost: storedPost, Body: template.HTML(renderedBody), } if series := storedPost.Series; series != "" { seriesPosts, err := a.params.PostStore.GetBySeries(series) if err != nil { return postTplPayload{}, fmt.Errorf( "fetching posts for series %q: %w", series, err, ) } var foundThis bool for i := range seriesPosts { seriesPost := seriesPosts[i] if seriesPost.ID == storedPost.ID { foundThis = true continue } if !foundThis { tplPayload.SeriesNext = &seriesPost continue } tplPayload.SeriesPrevious = &seriesPost break } } return tplPayload, nil } func (a *api) renderPostHandler() http.Handler { tpl := a.mustParseBasedTpl("post.html") renderPostsIndexHandler := a.renderPostsIndexHandler() renderEditPostHandler := a.renderEditPostHandler(false) return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) { id := strings.TrimSuffix(filepath.Base(r.URL.Path), ".html") if id == "/" { renderPostsIndexHandler.ServeHTTP(rw, r) return } if _, ok := r.URL.Query()["edit"]; ok { renderEditPostHandler.ServeHTTP(rw, r) return } storedPost, err := a.params.PostStore.GetByID(id) if errors.Is(err, post.ErrPostNotFound) { http.Error(rw, "Post not found", 404) return } else if err != nil { apiutil.InternalServerError( rw, r, fmt.Errorf("fetching post with id %q: %w", id, err), ) return } tplPayload, err := a.postToPostTplPayload(storedPost) if err != nil { apiutil.InternalServerError( rw, r, fmt.Errorf( "generating template payload for post with id %q: %w", id, err, ), ) return } executeTemplate(rw, r, tpl, tplPayload) }) } func (a *api) renderPostsIndexHandler() http.Handler { renderEditPostHandler := a.renderEditPostHandler(false) tpl := a.mustParseBasedTpl("posts.html") const pageCount = 20 return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) { if _, ok := r.URL.Query()["edit"]; ok { renderEditPostHandler.ServeHTTP(rw, r) return } page, err := apiutil.StrToInt(r.FormValue("p"), 0) if err != nil { apiutil.BadRequest( rw, r, fmt.Errorf("invalid page number: %w", err), ) return } posts, hasMore, err := a.params.PostStore.Get(page, pageCount) if err != nil { apiutil.InternalServerError( rw, r, fmt.Errorf("fetching page %d of posts: %w", page, err), ) return } tplPayload := struct { Posts []post.StoredPost PrevPage, NextPage int }{ Posts: posts, PrevPage: -1, NextPage: -1, } if page > 0 { tplPayload.PrevPage = page - 1 } if hasMore { tplPayload.NextPage = page + 1 } executeTemplate(rw, r, tpl, tplPayload) }) } func (a *api) renderEditPostHandler(isDraft bool) http.Handler { tpl := a.mustParseBasedTpl("edit-post.html") return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) { id := filepath.Base(r.URL.Path) var storedPost post.StoredPost if id != "/" { var err error if isDraft { storedPost.Post, err = a.params.PostDraftStore.GetByID(id) } else { storedPost, err = a.params.PostStore.GetByID(id) } if errors.Is(err, post.ErrPostNotFound) { http.Error(rw, "Post not found", 404) return } else if err != nil { apiutil.InternalServerError( rw, r, fmt.Errorf("fetching post with id %q: %w", id, err), ) return } } else if !isDraft { http.Error(rw, "Post ID required in URL", 400) return } tags, err := a.params.PostStore.GetTags() if err != nil { apiutil.InternalServerError(rw, r, fmt.Errorf("fetching tags: %w", err)) return } tplPayload := struct { Post post.StoredPost Tags []string IsDraft bool }{ Post: storedPost, Tags: tags, IsDraft: isDraft, } executeTemplate(rw, r, tpl, tplPayload) }) } func postFromPostReq(r *http.Request) (post.Post, error) { p := post.Post{ ID: r.PostFormValue("id"), Title: r.PostFormValue("title"), Description: r.PostFormValue("description"), Tags: strings.Fields(r.PostFormValue("tags")), Series: r.PostFormValue("series"), } // textareas encode newlines as CRLF for historical reasons p.Body = r.PostFormValue("body") p.Body = strings.ReplaceAll(p.Body, "\r\n", "\n") p.Body = strings.TrimSpace(p.Body) if p.ID == "" || p.Title == "" || p.Body == "" || len(p.Tags) == 0 { return post.Post{}, errors.New("ID, Title, Tags, and Body are all required") } return p, nil } func (a *api) storeAndPublishPost(ctx context.Context, p post.Post) error { first, err := a.params.PostStore.Set(p, time.Now()) if err != nil { return fmt.Errorf("storing post with id %q: %w", p.ID, err) } if !first { return nil } a.params.Logger.Info(ctx, "publishing blog post to mailing list") urlStr := a.postURL(p.ID, true) if err := a.params.MailingList.Publish(p.Title, urlStr); err != nil { return fmt.Errorf("publishing post to mailing list: %w", err) } if err := a.params.PostDraftStore.Delete(p.ID); err != nil { return fmt.Errorf("deleting draft: %w", err) } return nil } func (a *api) postPostHandler() http.Handler { return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) { ctx := r.Context() p, err := postFromPostReq(r) if err != nil { apiutil.BadRequest(rw, r, err) return } ctx = mctx.Annotate(ctx, "postID", p.ID) if err := a.storeAndPublishPost(ctx, p); err != nil { apiutil.InternalServerError( rw, r, fmt.Errorf("storing/publishing post with id %q: %w", p.ID, err), ) return } a.executeRedirectTpl(rw, r, a.postURL(p.ID, false)) }) } func (a *api) deletePostHandler(isDraft bool) http.Handler { return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) { id := filepath.Base(r.URL.Path) if id == "/" { apiutil.BadRequest(rw, r, errors.New("id is required")) return } var err error if isDraft { err = a.params.PostDraftStore.Delete(id) } else { err = a.params.PostStore.Delete(id) } if errors.Is(err, post.ErrPostNotFound) { http.Error(rw, "Post not found", 404) return } else if err != nil { apiutil.InternalServerError( rw, r, fmt.Errorf("deleting post with id %q: %w", id, err), ) return } if isDraft { a.executeRedirectTpl(rw, r, a.draftsURL(false)) } else { a.executeRedirectTpl(rw, r, a.postsURL(false)) } }) } func (a *api) previewPostHandler() http.Handler { tpl := a.mustParseBasedTpl("post.html") return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) { p, err := postFromPostReq(r) if err != nil { apiutil.BadRequest(rw, r, err) return } storedPost := post.StoredPost{ Post: p, PublishedAt: time.Now(), } tplPayload, err := a.postToPostTplPayload(storedPost) if err != nil { apiutil.InternalServerError( rw, r, fmt.Errorf("generating template payload: %w", err), ) return } executeTemplate(rw, r, tpl, tplPayload) }) }