Merge pull request #214 from Leeingnyo/feature/http-cache

HTTP cache for thumbnails, pages, dimensions

src/library/entry.cr

@@ -46,6 +46,18 @@ class Entry
     file.close
   end
 
+  def to_slim_json : String
+    JSON.build do |json|
+      json.object do
+        {% for str in ["zip_path", "title", "size", "id"] %}
+        json.field {{str}}, @{{str.id}}
+      {% end %}
+        json.field "title_id", @book.id
+        json.field "pages" { json.number @pages }
+      end
+    end
+  end
+
   def to_json(json : JSON::Builder)
     json.object do
       {% for str in ["zip_path", "title", "size", "id"] %}

src/library/library.cr

@@ -85,6 +85,21 @@ class Library
     titles + titles.flat_map &.deep_titles
   end
 
+  def to_slim_json : String
+    JSON.build do |json|
+      json.object do
+        json.field "dir", @dir
+        json.field "titles" do
+          json.array do
+            self.titles.each do |title|
+              json.raw title.to_slim_json
+            end
+          end
+        end
+      end
+    end
+  end
+
   def to_json(json : JSON::Builder)
     json.object do
       json.field "dir", @dir

src/library/title.cr

@@ -57,6 +57,41 @@ class Title
     end
   end
 
+  def to_slim_json : String
+    JSON.build do |json|
+      json.object do
+        {% for str in ["dir", "title", "id"] %}
+        json.field {{str}}, @{{str.id}}
+      {% end %}
+        json.field "signature" { json.number @signature }
+        json.field "titles" do
+          json.array do
+            self.titles.each do |title|
+              json.raw title.to_slim_json
+            end
+          end
+        end
+        json.field "entries" do
+          json.array do
+            @entries.each do |entry|
+              json.raw entry.to_slim_json
+            end
+          end
+        end
+        json.field "parents" do
+          json.array do
+            self.parents.each do |title|
+              json.object do
+                json.field "title", title.title
+                json.field "id", title.id
+              end
+            end
+          end
+        end
+      end
+    end
+  end
+
   def to_json(json : JSON::Builder)
     json.object do
       {% for str in ["dir", "title", "id"] %}

src/routes/api.cr

@@ -1,6 +1,7 @@
 require "../mangadex/*"
 require "../upload"
 require "koa"
+require "digest"
 
 struct APIRouter
   @@api_json : String?
@@ -75,12 +76,14 @@ struct APIRouter
     Koa.path "page", schema: Int32, desc: "The page number to return (starts from 1)"
     Koa.response 200, schema: Bytes, media_type: "image/*"
     Koa.response 500, "Page not found or not readable"
+    Koa.response 304, "Page not modified (only available when `If-None-Match` is set)"
     Koa.tag "reader"
     get "/api/page/:tid/:eid/:page" do |env|
       begin
         tid = env.params.url["tid"]
         eid = env.params.url["eid"]
         page = env.params.url["page"].to_i
+        prev_e_tag = env.request.headers["If-None-Match"]?
 
         title = Library.default.get_title tid
         raise "Title ID `#{tid}` not found" if title.nil?
@@ -90,7 +93,15 @@ struct APIRouter
         raise "Failed to load page #{page} of " \
               "`#{title.title}/#{entry.title}`" if img.nil?
 
-        send_img env, img
+        e_tag = Digest::SHA1.hexdigest img.data
+        if prev_e_tag == e_tag
+          env.response.status_code = 304
+          ""
+        else
+          env.response.headers["ETag"] = e_tag
+          env.response.headers["Cache-Control"] = "public, max-age=86400"
+          send_img env, img
+        end
       rescue e
         Logger.error e
         env.response.status_code = 500
@@ -102,12 +113,14 @@ struct APIRouter
     Koa.path "tid", desc: "Title ID"
     Koa.path "eid", desc: "Entry ID"
     Koa.response 200, schema: Bytes, media_type: "image/*"
+    Koa.response 304, "Page not modified (only available when `If-None-Match` is set)"
     Koa.response 500, "Page not found or not readable"
     Koa.tag "library"
     get "/api/cover/:tid/:eid" do |env|
       begin
         tid = env.params.url["tid"]
         eid = env.params.url["eid"]
+        prev_e_tag = env.request.headers["If-None-Match"]?
 
         title = Library.default.get_title tid
         raise "Title ID `#{tid}` not found" if title.nil?
@@ -118,7 +131,14 @@ struct APIRouter
         raise "Failed to get cover of `#{title.title}/#{entry.title}`" \
            if img.nil?
 
-        send_img env, img
+        e_tag = Digest::SHA1.hexdigest img.data
+        if prev_e_tag == e_tag
+          env.response.status_code = 304
+          ""
+        else
+          env.response.headers["ETag"] = e_tag
+          send_img env, img
+        end
       rescue e
         Logger.error e
         env.response.status_code = 500
@@ -126,8 +146,11 @@ struct APIRouter
       end
     end
 
-    Koa.describe "Returns the book with title `tid`"
+    Koa.describe "Returns the book with title `tid`", <<-MD
+    Supply the `tid` query parameter to strip away "display_name", "cover_url", and "mtime" from the returned object to speed up the loading time
+    MD
     Koa.path "tid", desc: "Title ID"
+    Koa.query "slim"
     Koa.response 200, schema: "title"
     Koa.response 404, "Title not found"
     Koa.tag "library"
@@ -137,7 +160,11 @@ struct APIRouter
         title = Library.default.get_title tid
         raise "Title ID `#{tid}` not found" if title.nil?
 
-        send_json env, title.to_json
+        if env.params.query["slim"]?
+          send_json env, title.to_slim_json
+        else
+          send_json env, title.to_json
+        end
       rescue e
         Logger.error e
         env.response.status_code = 404
@@ -145,14 +172,21 @@ struct APIRouter
       end
     end
 
-    Koa.describe "Returns the entire library with all titles and entries"
+    Koa.describe "Returns the entire library with all titles and entries", <<-MD
+    Supply the `tid` query parameter to strip away "display_name", "cover_url", and "mtime" from the returned object to speed up the loading time
+    MD
+    Koa.query "slim"
     Koa.response 200, schema: {
       "dir"    => String,
       "titles" => ["title"],
     }
     Koa.tag "library"
     get "/api/library" do |env|
-      send_json env, Library.default.to_json
+      if env.params.query["slim"]?
+        send_json env, Library.default.to_slim_json
+      else
+        send_json env, Library.default.to_json
+      end
     end
 
     Koa.describe "Triggers a library scan"
@@ -617,21 +651,32 @@ struct APIRouter
         "height" => Int32,
       }],
     }
+    Koa.response 304, "Not modified (only available when `If-None-Match` is set)"
     get "/api/dimensions/:tid/:eid" do |env|
       begin
         tid = env.params.url["tid"]
         eid = env.params.url["eid"]
+        prev_e_tag = env.request.headers["If-None-Match"]?
 
         title = Library.default.get_title tid
         raise "Title ID `#{tid}` not found" if title.nil?
         entry = title.get_entry eid
         raise "Entry ID `#{eid}` of `#{title.title}` not found" if entry.nil?
 
-        sizes = entry.page_dimensions
-        send_json env, {
-          "success"    => true,
-          "dimensions" => sizes,
-        }.to_json
+        file_hash = Digest::SHA1.hexdigest (entry.zip_path + entry.mtime.to_s)
+        e_tag = "W/#{file_hash}"
+        if e_tag == prev_e_tag
+          env.response.status_code = 304
+          ""
+        else
+          sizes = entry.page_dimensions
+          env.response.headers["ETag"] = e_tag
+          env.response.headers["Cache-Control"] = "public, max-age=86400"
+          send_json env, {
+            "success"    => true,
+            "dimensions" => sizes,
+          }.to_json
+        end
       rescue e
         Logger.error e
         send_json env, {

src/routes/main.cr

@@ -30,7 +30,8 @@ struct MainRouter
         else
           redirect env, "/"
         end
-      rescue
+      rescue e
+        Logger.error e
         redirect env, "/login"
       end
     end