Render posts completely using common rendering methods

The aim is to reduce reliance on custom logic in the handlers for every
protocol, eventually outsourcing all of it into `render.Methods`,
leaving each protocol to simply direct calls to the correct template.

5 files changed, 45 insertions, 137 deletions

diff --git a/src/gmi/gemtext.go b/src/gmi/gemtext/gemtext.go
index 884635c..5c8f594 100644
--- a/src/gmi/gemtext.go
+++ b/src/gmi/gemtext/gemtext.go
@@ -1,4 +1,6 @@
-package gmi
+// Package gemtext contains code related to processing and producing gemtext
+// documents.
+package gemtext
 
 import (
 	"bufio"
@@ -23,12 +25,12 @@ func hasImgExt(p string) bool {
 // matches `=> dstURL [optional description]`
 var linkRegexp = regexp.MustCompile(`^=>\s+(\S+)\s*(.*?)\s*$`)
 
-// GemtextToMarkdown reads a gemtext formatted body from the Reader and writes
+// ToMarkdown reads a gemtext formatted body from the Reader and writes
 // the markdown version of that body to the Writer.
 //
 // gmiGateway, if given, is used for all `gemini://` links. The `gemini://`
 // prefix will be stripped, and replaced with the given URL.
-func GemtextToMarkdown(dst io.Writer, src io.Reader, gmiGateway *url.URL) error {
+func ToMarkdown(dst io.Writer, src io.Reader, gmiGateway *url.URL) error {
 
 	bufSrc := bufio.NewReader(src)
 
diff --git a/src/gmi/gemtext_test.go b/src/gmi/gemtext/gemtext_test.go
index 75da9df..fe58a64 100644
--- a/src/gmi/gemtext_test.go
+++ b/src/gmi/gemtext/gemtext_test.go
@@ -1,4 +1,4 @@
-package gmi
+package gemtext
 
 import (
 	"bytes"
@@ -9,7 +9,7 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
-func TestGemtextToMarkdown(t *testing.T) {
+func TestToMarkdown(t *testing.T) {
 
 	gmiGateway, _ := url.Parse("https://gateway.com/x/")
 
@@ -58,7 +58,7 @@ func TestGemtextToMarkdown(t *testing.T) {
 		t.Run(strconv.Itoa(i), func(t *testing.T) {
 
 			got := new(bytes.Buffer)
-			err := GemtextToMarkdown(got, bytes.NewBufferString(test.in), gmiGateway)
+			err := ToMarkdown(got, bytes.NewBufferString(test.in), gmiGateway)
 			assert.NoError(t, err)
 			assert.Equal(t, test.exp, got.String())
 		})
diff --git a/src/gmi/gmi.go b/src/gmi/gmi.go
index 467ab5a..e37ca74 100644
--- a/src/gmi/gmi.go
+++ b/src/gmi/gmi.go
@@ -14,14 +14,14 @@ import (
 	"path/filepath"
 	"strings"
 
-	"git.sr.ht/~adnano/go-gemini"
-	"git.sr.ht/~adnano/go-gemini/certificate"
 	"dev.mediocregopher.com/mediocre-blog.git/src/cache"
 	"dev.mediocregopher.com/mediocre-blog.git/src/cfg"
 	"dev.mediocregopher.com/mediocre-blog.git/src/post"
 	"dev.mediocregopher.com/mediocre-blog.git/src/post/asset"
 	"dev.mediocregopher.com/mediocre-go-lib.git/mctx"
 	"dev.mediocregopher.com/mediocre-go-lib.git/mlog"
+	"git.sr.ht/~adnano/go-gemini"
+	"git.sr.ht/~adnano/go-gemini/certificate"
 )
 
 // Params are used to instantiate a new API instance. All fields are required
@@ -37,7 +37,8 @@ type Params struct {
 	ListenAddr       string
 	CertificatesPath string
 
-	HTTPPublicURL *url.URL
+	HTTPPublicURL        *url.URL
+	HTTPGeminiGatewayURL *url.URL
 }
 
 // SetupCfg implement the cfg.Cfger interface.
@@ -193,12 +194,7 @@ func postsMiddleware(tplHandler gemini.Handler) gemini.Handler {
 			return
 		}
 
-		query := r.URL.Query()
-		query.Set("id", id)
-		r.URL.RawQuery = query.Encode()
-
-		r.URL.Path = "/posts/post.gmi"
-
+		ctx = withTplPath(ctx, "/posts/post.gmi")
 		tplHandler.ServeGemini(ctx, rw, r)
 	})
 }
diff --git a/src/gmi/tpl.go b/src/gmi/tpl.go
index 03d9819..8ffa6bc 100644
--- a/src/gmi/tpl.go
+++ b/src/gmi/tpl.go
@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"context"
 	"embed"
+	"errors"
 	"fmt"
 	"io"
 	"io/fs"
@@ -11,126 +12,27 @@ import (
 	"net/url"
 	"path"
 	"path/filepath"
-	"strconv"
 	"strings"
 	"text/template"
 
-	"git.sr.ht/~adnano/go-gemini"
 	"dev.mediocregopher.com/mediocre-blog.git/src/post"
+	"dev.mediocregopher.com/mediocre-blog.git/src/render"
 	"dev.mediocregopher.com/mediocre-go-lib.git/mctx"
-	gmnhg "github.com/tdemin/gmnhg"
+	"git.sr.ht/~adnano/go-gemini"
 )
 
-//go:embed tpl
-var tplFS embed.FS
-
-type rendererGetPostsRes struct {
-	Posts   []post.StoredPost
-	HasMore bool
-}
-
-type rendererGetPostSeriesNextPreviousRes struct {
-	Next     *post.StoredPost
-	Previous *post.StoredPost
-}
-
-type renderer struct {
-	url             *url.URL
-	publicURL       *url.URL
-	postStore       post.Store
-	preprocessFuncs post.PreprocessFunctions
-}
-
-func (r renderer) GetPosts(page, count int) (rendererGetPostsRes, error) {
-	posts, hasMore, err := r.postStore.Get(page, count)
-	return rendererGetPostsRes{posts, hasMore}, err
-}
-
-func (r renderer) GetPostByID(id string) (post.StoredPost, error) {
-	p, err := r.postStore.GetByID(id)
-	if err != nil {
-		return post.StoredPost{}, fmt.Errorf("fetching post %q: %w", id, err)
-	}
-	return p, nil
-}
-
-func (r renderer) GetPostSeriesNextPrevious(p post.StoredPost) (rendererGetPostSeriesNextPreviousRes, error) {
-
-	seriesPosts, err := r.postStore.GetBySeries(p.Series)
-	if err != nil {
-		return rendererGetPostSeriesNextPreviousRes{}, fmt.Errorf(
-			"fetching posts for series %q: %w", p.Series, err,
-		)
-	}
-
-	var (
-		res       rendererGetPostSeriesNextPreviousRes
-		foundThis bool
-	)
-
-	for i := range seriesPosts {
-
-		seriesPost := seriesPosts[i]
-
-		if seriesPost.ID == p.ID {
-			foundThis = true
-			continue
-		}
-
-		if !foundThis {
-			res.Next = &seriesPost
-			continue
-		}
-
-		res.Previous = &seriesPost
-		break
-	}
-
-	return res, nil
-}
-
-func (r renderer) PostBody(p post.StoredPost) (string, error) {
-
-	buf := new(bytes.Buffer)
-
-	if err := p.PreprocessBody(buf, r.preprocessFuncs); err != nil {
-		return "", fmt.Errorf("preprocessing post body: %w", err)
-	}
-
-	bodyBytes := buf.Bytes()
-
-	if p.Format == post.FormatMarkdown {
-
-		gemtextBodyBytes, err := gmnhg.RenderMarkdown(bodyBytes, 0)
-		if err != nil {
-			return "", fmt.Errorf("converting from markdown: %w", err)
-		}
-
-		bodyBytes = gemtextBodyBytes
-	}
-
-	return string(bodyBytes), nil
-}
+type ctxKey string
 
-func (r renderer) GetQueryValue(key, def string) string {
-	v := r.url.Query().Get(key)
-	if v == "" {
-		v = def
-	}
-	return v
-}
-
-func (r renderer) GetQueryIntValue(key string, def int) (int, error) {
-	vStr := r.GetQueryValue(key, strconv.Itoa(def))
-	return strconv.Atoi(vStr)
-}
+const (
+	ctxKeyTplPath ctxKey = "tplPath"
+)
 
-func (r renderer) GetPath() (string, error) {
-	basePath := filepath.Join("/", r.publicURL.Path) // in case it's empty
-	return filepath.Rel(basePath, r.url.Path)
+func withTplPath(ctx context.Context, path string) context.Context {
+	return context.WithValue(ctx, ctxKeyTplPath, path)
 }
 
-func (r renderer) Add(a, b int) int { return a + b }
+//go:embed tpl
+var tplFS embed.FS
 
 func (a *api) tplHandler() (gemini.Handler, error) {
 
@@ -177,7 +79,6 @@ func (a *api) tplHandler() (gemini.Handler, error) {
 			return blogURL(a.params.HTTPPublicURL, path, true)
 		},
 		Image: func(args ...string) (string, error) {
-
 			var (
 				id    = args[0]
 				descr = "Image"
@@ -243,9 +144,13 @@ func (a *api) tplHandler() (gemini.Handler, error) {
 		rw gemini.ResponseWriter,
 		r *gemini.Request,
 	) {
+		tplPath, _ := ctx.Value(ctxKeyTplPath).(string)
+		if tplPath == "" {
+			tplPath = r.URL.Path
+		}
+		tplPath = strings.TrimPrefix(tplPath, "/")
 
-		tplPath := strings.TrimPrefix(r.URL.Path, "/")
-		mimeType := mime.TypeByExtension(path.Ext(r.URL.Path))
+		mimeType := mime.TypeByExtension(path.Ext(tplPath))
 
 		ctx = mctx.Annotate(ctx,
 			"url", r.URL,
@@ -266,14 +171,19 @@ func (a *api) tplHandler() (gemini.Handler, error) {
 
 		buf := new(bytes.Buffer)
 
-		err := tpl.Execute(buf, renderer{
-			url:             r.URL,
-			publicURL:       a.params.PublicURL,
-			postStore:       a.params.PostStore,
-			preprocessFuncs: preprocessFuncs,
-		})
-
-		if err != nil {
+		err := tpl.Execute(buf, render.NewMethods(
+			ctx,
+			r.URL,
+			a.params.PublicURL,
+			a.params.HTTPGeminiGatewayURL,
+			a.params.PostStore,
+			preprocessFuncs,
+		))
+
+		if errors.Is(err, post.ErrPostNotFound) {
+			a.params.Logger.Warn(ctx, "post not found", err)
+			rw.WriteHeader(gemini.StatusNotFound, "Post not found")
+		} else if err != nil {
 			a.params.Logger.Error(ctx, "rendering error", err)
 			rw.WriteHeader(gemini.StatusTemporaryFailure, err.Error())
 			return
diff --git a/src/gmi/tpl/posts/post.gmi b/src/gmi/tpl/posts/post.gmi
index 0234395..b568044 100644
--- a/src/gmi/tpl/posts/post.gmi
+++ b/src/gmi/tpl/posts/post.gmi
@@ -1,4 +1,4 @@
-{{ $post := .GetPostByID (.GetQueryValue "id" "") -}}
+{{ $post := .GetThisPost -}}
 
 {{ if eq $post.Format "md" -}}
 This post has been translated from it's original markdown format, if it seems busted it might appear better over HTTP:
@@ -14,7 +14,7 @@ This post has been translated from it's original markdown format, if it seems bu
 
 {{ end -}}
 
-{{ .PostBody $post }}
+{{ .PostGemtextBody $post }}
 
 ========================================