From 7e87c09c50983a25ed7c9816e11a856903ed89d5 Mon Sep 17 00:00:00 2001
From: Brian Picciano <mediocregopher@gmail.com>
Date: Fri, 13 May 2022 13:35:54 -0600
Subject: [PATCH] Add /posts handler to api

---
 srv/src/api/api.go                | 16 ++++++++---
 srv/src/api/posts.go              | 46 +++++++++++++++++++++++++++++++
 srv/src/cmd/mediocre-blog/main.go | 11 ++++++++
 3 files changed, 69 insertions(+), 4 deletions(-)
 create mode 100644 srv/src/api/posts.go

diff --git a/srv/src/api/api.go b/srv/src/api/api.go
index 56f33b2..75147d5 100644
--- a/srv/src/api/api.go
+++ b/srv/src/api/api.go
@@ -14,6 +14,7 @@ import (
 	"github.com/mediocregopher/blog.mediocregopher.com/srv/cfg"
 	"github.com/mediocregopher/blog.mediocregopher.com/srv/chat"
 	"github.com/mediocregopher/blog.mediocregopher.com/srv/mailinglist"
+	"github.com/mediocregopher/blog.mediocregopher.com/srv/post"
 	"github.com/mediocregopher/blog.mediocregopher.com/srv/pow"
 	"github.com/mediocregopher/mediocre-go-lib/v2/mctx"
 	"github.com/mediocregopher/mediocre-go-lib/v2/mlog"
@@ -22,9 +23,14 @@ import (
 // Params are used to instantiate a new API instance. All fields are required
 // unless otherwise noted.
 type Params struct {
-	Logger           *mlog.Logger
-	PowManager       pow.Manager
-	MailingList      mailinglist.MailingList
+	Logger     *mlog.Logger
+	PowManager pow.Manager
+
+	PostStore        post.Store
+	PostHTTPRenderer post.Renderer
+
+	MailingList mailinglist.MailingList
+
 	GlobalRoom       chat.Room
 	UserIDCalculator *chat.UserIDCalculator
 
@@ -172,7 +178,7 @@ func (a *api) handler() http.Handler {
 	)))
 
 	var apiHandler http.Handler = apiMux
-	apiHandler = postOnlyMiddleware(apiHandler)
+	apiHandler = postOnlyMiddleware(apiHandler) // TODO probably should be last?
 	apiHandler = checkCSRFMiddleware(apiHandler)
 	apiHandler = logMiddleware(a.params.Logger, apiHandler)
 	apiHandler = annotateMiddleware(apiHandler)
@@ -184,5 +190,7 @@ func (a *api) handler() http.Handler {
 
 	mux.Handle("/api/", http.StripPrefix("/api", apiHandler))
 
+	mux.Handle("/posts/", a.postHandler())
+
 	return mux
 }
diff --git a/srv/src/api/posts.go b/srv/src/api/posts.go
new file mode 100644
index 0000000..995f2fb
--- /dev/null
+++ b/srv/src/api/posts.go
@@ -0,0 +1,46 @@
+package api
+
+import (
+	"errors"
+	"fmt"
+	"net/http"
+	"path/filepath"
+	"strings"
+
+	"github.com/mediocregopher/blog.mediocregopher.com/srv/api/apiutils"
+	"github.com/mediocregopher/blog.mediocregopher.com/srv/post"
+)
+
+func (a *api) postHandler() http.Handler {
+	return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
+
+		id := strings.TrimSuffix(filepath.Base(r.URL.Path), ".html")
+
+		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 {
+			apiutils.InternalServerError(
+				rw, r, fmt.Errorf("fetching post with id %q: %w", id, err),
+			)
+			return
+		}
+
+		renderablePost, err := post.NewRenderablePost(a.params.PostStore, storedPost)
+		if err != nil {
+			apiutils.InternalServerError(
+				rw, r, fmt.Errorf("constructing renderable post with id %q: %w", id, err),
+			)
+			return
+		}
+
+		if err := a.params.PostHTTPRenderer.Render(rw, renderablePost); err != nil {
+			apiutils.InternalServerError(
+				rw, r, fmt.Errorf("rendering post with id %q: %w", id, err),
+			)
+			return
+		}
+	})
+}
diff --git a/srv/src/cmd/mediocre-blog/main.go b/srv/src/cmd/mediocre-blog/main.go
index 69ee7b6..28571a3 100644
--- a/srv/src/cmd/mediocre-blog/main.go
+++ b/srv/src/cmd/mediocre-blog/main.go
@@ -11,6 +11,7 @@ import (
 	cfgpkg "github.com/mediocregopher/blog.mediocregopher.com/srv/cfg"
 	"github.com/mediocregopher/blog.mediocregopher.com/srv/chat"
 	"github.com/mediocregopher/blog.mediocregopher.com/srv/mailinglist"
+	"github.com/mediocregopher/blog.mediocregopher.com/srv/post"
 	"github.com/mediocregopher/blog.mediocregopher.com/srv/pow"
 	"github.com/mediocregopher/mediocre-go-lib/v2/mctx"
 	"github.com/mediocregopher/mediocre-go-lib/v2/mlog"
@@ -112,8 +113,18 @@ func main() {
 
 	chatUserIDCalc := chat.NewUserIDCalculator([]byte(*chatUserIDCalcSecret))
 
+	postSQLDB, err := post.NewSQLDB(dataDir)
+	if err != nil {
+		logger.Fatal(ctx, "initializing sql db for post data", err)
+	}
+	defer postSQLDB.Close()
+
+	postStore := post.NewStore(postSQLDB)
+
 	apiParams.Logger = logger.WithNamespace("api")
 	apiParams.PowManager = powMgr
+	apiParams.PostStore = postStore
+	apiParams.PostHTTPRenderer = post.NewMarkdownToHTMLRenderer()
 	apiParams.MailingList = ml
 	apiParams.GlobalRoom = chatGlobalRoom
 	apiParams.UserIDCalculator = chatUserIDCalc