Add support for HTTP compression using gzip

.circleci/config.yml

@@ -0,0 +1,35 @@
+version: 2
+
+jobs:
+
+  test:
+    working_directory: /root/project/Dash
+
+    docker:
+      - image: julia:latest
+
+    steps:
+      - checkout
+
+      - run:
+          name: ℹ️  CI Context
+          command: |
+            echo "TRIGGERER: ${CIRCLE_USERNAME}"
+            echo "BUILD_NUMBER: ${CIRCLE_BUILD_NUM}"
+            echo "BUILD_URL: ${CIRCLE_BUILD_URL}"
+            echo "BRANCH: ${CIRCLE_BRANCH}"
+            echo "RUNNING JOB: ${CIRCLE_JOB}"
+            echo "JOB PARALLELISM: ${CIRCLE_NODE_TOTAL}"
+            echo "CIRCLE_REPOSITORY_URL: ${CIRCLE_REPOSITORY_URL}"
+            echo $CIRCLE_JOB > circlejob.txt
+
+      - run:
+          name: 🔎 Unit tests
+          command: |
+              julia -e 'using Pkg; Pkg.update(); Pkg.add(PackageSpec(path=pwd())); Pkg.build("Dash"); Pkg.test("Dash", coverage=true);'
+
+workflows:
+  version: 2
+  build:
+    jobs:
+      - "test"

Project.toml

@@ -8,6 +8,7 @@ DataStructures = "864edb3b-99cc-5e75-8d2d-829cb0a9cfe8"
 HTTP = "cd3eb016-35fb-5094-929b-558a96fad6f3"
 JSON = "682c06a0-de6a-54ab-a142-c8b1cf79cde6"
 JSON2 = "2535ab7d-5cd8-5a07-80ac-9b1792aadce3"
+CodecZlib = "944b1d66-785c-5afd-91f1-9de20f533193"
 LibGit2 = "76f85450-5226-5b5a-8eaa-529ad045b433"
 MacroTools = "1914dd2f-81c6-5fcd-8719-6d5c9610ff09"
 PlotlyBase = "a03496cd-edff-5a9b-9e67-9cda94a718b5"

src/Dash.jl

@@ -1,5 +1,5 @@
 module Dash
-import HTTP, JSON2
+import HTTP, JSON2, CodecZlib
 using MacroTools
 include("ComponentPackages.jl")
 include("ComponentMetas.jl")

src/app.jl

@@ -73,6 +73,7 @@ struct DashConfig
     assets_external_path ::Union{String, Nothing}
     include_assets_files ::Bool
     show_undo_redo ::Bool
+    compress ::Bool
 end
 
 """
@@ -87,7 +88,7 @@ struct DashApp
     config ::DashConfig
     layout ::Layout
     callbacks ::Dict{Symbol, Callback}
-    callable_components ::Dict{Symbol, Component}    
+    callable_components ::Dict{Symbol, Component}
 
     DashApp(name::String, config::DashConfig) = new(name, config, Layout(nothing), Dict{Symbol, Callback}(), Dict{Symbol, Component}())
 
@@ -129,7 +130,8 @@ end
             index_string, 
             assets_external_path, 
             include_assets_files, 
-            show_undo_redo     
+            show_undo_redo,
+            compress
         )
 
 Construct a dash app 
@@ -209,7 +211,10 @@ Construct a dash app
 
 - `show_undo_redo::Bool`: Default ``false``, set to ``true`` to enable undo
         and redo buttons for stepping through the history of the app state.
-
+
+- `compress::Bool`: Default ``true``, controls whether gzip is used to compress 
+        files and data served by HTTP.jl when supported by the client. Set to
+        ``false`` to disable compression completely.
 """
 function dash(name::String;
         external_stylesheets = ExternalSrcType[],
@@ -227,7 +232,8 @@ function dash(name::String;
         index_string = default_index, 
         assets_external_path = nothing, 
         include_assets_files = true, 
-        show_undo_redo = false
+        show_undo_redo = false,
+        compress = true
 
     )
 
@@ -250,7 +256,8 @@ function dash(name::String;
             index_string, 
             assets_external_path, 
             include_assets_files, 
-            show_undo_redo
+            show_undo_redo,
+            compress
         )
 
         result = DashApp(name, config)
@@ -273,7 +280,8 @@ function dash(layout_maker ::Function, name;
         index_string = default_index, 
         assets_external_path = nothing, 
         include_assets_files = true, 
-        show_undo_redo = false
+        show_undo_redo = false,
+        compress = true
       )
     result = dash(name,
         external_stylesheets=external_stylesheets,
@@ -291,7 +299,8 @@ function dash(layout_maker ::Function, name;
         index_string = index_string,
         assets_external_path = assets_external_path,
         include_assets_files = include_assets_files,
-        show_undo_redo = show_undo_redo
+        show_undo_redo = show_undo_redo,
+        compress = compress
         )
     layout!(result, layout_maker())
     return result

src/handlers.jl

@@ -62,35 +62,63 @@ function process_callback(app::DashApp, body::String)
 
 end
 
-function process_assets(app::DashApp, path)
+function make_response(status, headers, body, compress::Bool)
+    message_headers = headers
+
+    if compress
+        push!(message_headers, "Content-Encoding" => "gzip")
+        body = transcode(CodecZlib.GzipCompressor, body)
+    end
+
+    response = HTTP.Response(status, body)
+    for header in message_headers
+        HTTP.Messages.setheader(response, header)
+    end
+    return response
+end
+
+function process_assets(app::DashApp, path, compress::Bool)
     assets_path = "$(app.config.routes_pathname_prefix)" * strip(app.config.assets_url_path, '/') * "/"
-
-    filename = joinpath(app.config.assets_folder, replace(path, assets_path=>""))    
+    filename = joinpath(app.config.assets_folder, replace(path, assets_path=>""))
+
     try
-        return HTTP.Response(200, [], body = read(filename))
+        file_contents = read(filename)
+        mimetype = HTTP.sniff(file_contents)
+        use_gzip = compress && occursin(r"text|javascript", mimetype)
+        headers = ["Content-Type" => mimetype]
+        return make_response(200, headers, file_contents, use_gzip)
     catch
         return HTTP.Response(404)
     end
 end
 
-
 function make_handler(app::DashApp; debug::Bool = false)
     index_string::String = index_page(app, debug = debug)
 
     return function (req::HTTP.Request)
         uri = HTTP.URI(req.target)
+
+        # verify that the client accepts compression
+        accepts_gz = occursin("gzip", HTTP.header(req, "Accept-Encoding"))
+        # verify that the server was not launched with compress=false
+        with_gzip = accepts_gz && app.config.compress
+
+        headers = []
+
         ComponentPackages.@register_js_sources(uri.path, app.config.routes_pathname_prefix)
         if uri.path == "$(app.config.routes_pathname_prefix)"
-            return HTTP.Response(200, index_string) 
+            body = index_page(app, debug = debug)
         end
         if uri.path == "$(app.config.routes_pathname_prefix)_dash-layout"
-            return HTTP.Response(200, ["Content-Type" => "application/json"], body = JSON2.write(app.layout)) 
+            body = JSON2.write(app.layout)
+            push!(headers, "Content-Type" => "application/json")
         end
         if uri.path == "$(app.config.routes_pathname_prefix)_dash-dependencies"
-            return HTTP.Response(200, ["Content-Type" => "application/json"], body = dependencies_json(app)) 
+            body = dependencies_json(app)
+            push!(headers, "Content-Type" => "application/json")
         end
         if startswith(uri.path, "$(app.config.routes_pathname_prefix)assets/")
-            return process_assets(app, uri.path)
+            return process_assets(app, uri.path, with_gzip)
         end
         if uri.path == "$(app.config.routes_pathname_prefix)_dash-update-component" && req.method == "POST"            
             try
@@ -107,7 +135,9 @@ function make_handler(app::DashApp; debug::Bool = false)
                 end
             end 
         end
+        if @isdefined body
+            return make_response(200, headers, body, with_gzip)
+        end
         return HTTP.Response(404)
-    end
-
+    end 
 end

test/Project.toml

@@ -0,0 +1,11 @@
+[deps]
+CodecZlib = "944b1d66-785c-5afd-91f1-9de20f533193"
+DataStructures = "864edb3b-99cc-5e75-8d2d-829cb0a9cfe8"
+HTTP = "cd3eb016-35fb-5094-929b-558a96fad6f3"
+Inflate = "d25df0c9-e2be-5dd7-82c8-3ad0b3e990b9"
+JSON = "682c06a0-de6a-54ab-a142-c8b1cf79cde6"
+JSON2 = "2535ab7d-5cd8-5a07-80ac-9b1792aadce3"
+LibGit2 = "76f85450-5226-5b5a-8eaa-529ad045b433"
+MacroTools = "1914dd2f-81c6-5fcd-8719-6d5c9610ff09"
+PlotlyBase = "a03496cd-edff-5a9b-9e67-9cda94a718b5"
+Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"

test/assets/test.css

@@ -0,0 +1 @@
+/* Test */

test/config_functional.jl

@@ -67,37 +67,37 @@ end
 
 @testset "assets paths" begin
     app = dash("test app")
-    res = Dash.process_assets(app, "/assets/test.png")
+    res = Dash.process_assets(app, "/assets/test.png", false)
     @test res.status == 200
-    res = Dash.process_assets(app, "/assets/test3.png")
+    res = Dash.process_assets(app, "/assets/test3.png", false)
     @test res.status == 404
-    res = Dash.process_assets(app, "/images/test.png")
+    res = Dash.process_assets(app, "/images/test.png", false)
     @test res.status == 404
 
     app = dash("test app", url_base_pathname = "/test/")
-    res = Dash.process_assets(app, "/assets/test.png")
+    res = Dash.process_assets(app, "/assets/test.png", false)
     @test res.status == 404
-    res = Dash.process_assets(app, "/test/assets/test.png")
+    res = Dash.process_assets(app, "/test/assets/test.png", false)
     @test res.status == 200
-    res = Dash.process_assets(app, "/images/test.png")
+    res = Dash.process_assets(app, "/images/test.png", false)
     @test res.status == 404
 
     app = dash("test app", assets_url_path = "ass")
-    res = Dash.process_assets(app, "/ass/test.png")
+    res = Dash.process_assets(app, "/ass/test.png", false)
     @test res.status == 200
-    res = Dash.process_assets(app, "/ass/test3.png")
+    res = Dash.process_assets(app, "/ass/test3.png", false)
     @test res.status == 404
-    res = Dash.process_assets(app, "/assets/test3.png")
+    res = Dash.process_assets(app, "/assets/test3.png", false)
     @test res.status == 404
-    res = Dash.process_assets(app, "/images/test.png")
+    res = Dash.process_assets(app, "/images/test.png", false)
     @test res.status == 404
 
     app = dash("test app", assets_folder = "images")
-    res = Dash.process_assets(app, "/assets/test.png")
+    res = Dash.process_assets(app, "/assets/test.png", false)
     @test res.status == 404
-    res = Dash.process_assets(app, "/assets/test_images.png")
+    res = Dash.process_assets(app, "/assets/test_images.png", false)
     @test res.status == 200
-    res = Dash.process_assets(app, "/images/test.png")
+    res = Dash.process_assets(app, "/images/test.png", false)
     @test res.status == 404
 end
 
@@ -204,4 +204,4 @@ end
 
     index_page = Dash.index_page(app)
     @test !isnothing(findfirst("\"show_undo_redo\":true", index_page))
-end
+end

test/core.jl

@@ -1,6 +1,7 @@
 import HTTP, JSON2
 using Test
 using Dash
+using Inflate
 @testset "Components" begin
 
     a_comp = html_a("test", id = "test-a")
@@ -354,4 +355,72 @@ end
 
     @test result[:response][:props][:children] == 10
 
-end
+end
+
+@testset "HTTP Compression" begin
+    # test compression of assets
+    app = dash("Test app", assets_folder = "assets") do
+        html_div() do
+            html_div("test")
+        end
+    end
+
+    # verify that JSON is not compressed when compress = true
+    # and Accept-Encoding = "gzip" is not present within request headers
+    handler = Dash.make_handler(app)
+    request = HTTP.Request("GET", "/_dash-dependencies")
+    response = handler(request)
+    @test app.config.compress == true
+    @test String(response.body) == "[]"
+    @test !in("Content-Encoding"=>"gzip", response.headers)
+
+    # verify that JSON is compressed when compress = true
+    # and Accept-Encoding = "gzip" is present within request headers
+    request = HTTP.Request("GET", "/_dash-dependencies", ["Accept-Encoding"=>"gzip"])
+    response = handler(request)
+    @test String(inflate_gzip(response.body)) == "[]"
+    @test String(response.body) != "[]"
+    @test in("Content-Encoding"=>"gzip", response.headers)
+
+    # ensure no compression of assets when Accept-Encoding not passed
+    request = HTTP.Request("GET", "/assets/test.css")
+    response = handler(request)
+    @test String(response.body) == "/* Test */\n"
+    @test !in("Content-Encoding"=>"gzip", response.headers)
+
+    # ensure compression when Accept-Encoding = "gzip"
+    request = HTTP.Request("GET", "/assets/test.css", ["Accept-Encoding"=>"gzip"])
+    response = handler(request)
+    @test String(inflate_gzip(response.body)) == "/* Test */\n"
+    @test String(response.body) != "/* Test */\n"
+    @test in("Content-Encoding"=>"gzip", response.headers)
+
+    # test cases for compress = false
+    app = dash("Test app", assets_folder = "assets", compress=false) do
+        html_div() do
+            html_div("test")
+        end
+    end
+
+    # verify that JSON is not compressed when compress = false
+    # and Accept-Encoding = "gzip" is not present within request headers
+    handler = Dash.make_handler(app)
+    request = HTTP.Request("GET", "/_dash-dependencies")
+    response = handler(request)
+    @test app.config.compress == false
+    @test String(response.body) == "[]"
+    @test !in("Content-Encoding"=>"gzip", response.headers)
+
+    # verify that JSON is NOT compressed when compress = false
+    # and Accept-Encoding = "gzip" is present within request headers
+    request = HTTP.Request("GET", "/_dash-dependencies", ["Accept-Encoding"=>"gzip"])
+    response = handler(request)
+    @test String(response.body) == "[]"
+    @test !in("Content-Encoding"=>"gzip", response.headers)
+
+    # ensure NO compression when Accept-Encoding = "gzip" and compress = false
+    request = HTTP.Request("GET", "/assets/test.css", ["Accept-Encoding"=>"gzip"])
+    response = handler(request)
+    @test String(response.body) == "/* Test */\n"
+    @test !in("Content-Encoding"=>"gzip", response.headers)
+end