Discover Web App Manifest in HTML

... and return a hash of the JSON data.

lib/manifique/web_client.rb

@@ -13,8 +13,25 @@ module Manifique
     end
 
     def fetch_web_manifest
-      do_get_request @url
+      res = do_get_request @url
-      # binding.pry
+      links = parse_http_link_header(res)
+      doc = Nokogiri::HTML(res.body)
+      manifest_url = discover_web_manifest_url(links, doc)
+
+      unless manifest_url.match(/^https?\:\/\//)
+        # Link is just the manifest path, not an absolute URL
+        manifest_url = @url + manifest_url
+      end
+
+      res = do_get_request manifest_url
+
+      begin
+        manifest_data = JSON.parse(res.body)
+      rescue
+        manifest_data = false
+      end
+
+      manifest_data
     end
 
     private
@@ -31,5 +48,20 @@ module Manifique
         res
       end
     end
+
+    def parse_http_link_header(response)
+      link_parser = Nitlink::Parser.new
+      link_parser.parse(response)
+    end
+
+    def discover_web_manifest_url(links, doc)
+      # TODO implement/test link header discovery
+      # if url = links.by_rel('manifest').target.to_s or
+      if url = doc.at_css("link[rel=manifest]").attributes["href"].value
+        return url
+      else
+        raise "No Web App Manifest found on #{@url}"
+      end
+    end
   end
 end

manifest.json

@@ -0,0 +1 @@
+{"name":"kosmos.social","short_name":"kosmos.social","description":"A friendly place for tooting. Run by the Kosmos peeps.","icons":[{"src":"/android-chrome-192x192.png","sizes":"192x192","type":"image/png"}],"theme_color":"#282c37","background_color":"#191b22","display":"standalone","start_url":"/web/timelines/home","scope":"https://kosmos.social/","share_target":{"url_template":"share?title={title}\u0026text={text}\u0026url={url}"}}

spec/fixtures/mastodon-web-app-manifest.json

@@ -0,0 +1,20 @@
+{
+  "name": "kosmos.social",
+  "short_name": "kosmos.social",
+  "description": "A friendly place for tooting. Run by the Kosmos peeps.",
+  "icons": [
+    {
+      "src": "/android-chrome-192x192.png",
+      "sizes": "192x192",
+      "type": "image/png"
+    }
+  ],
+  "theme_color": "#282c37",
+  "background_color": "#191b22",
+  "display": "standalone",
+  "start_url": "/web/timelines/home",
+  "scope": "https://kosmos.social/",
+  "share_target": {
+    "url_template": "share?title={title}&text={text}&url={url}"
+  }
+}

spec/manifique/agent_spec.rb

@@ -5,8 +5,8 @@ RSpec.describe Manifique::Agent do
     describe "URL validation" do
       context "with invalid URL" do
         it "raises an exception" do
-          expect { Manifique::Agent.new }.to raise_error
+          expect { Manifique::Agent.new }.to raise_error(RuntimeError)
-          expect { Manifique::Agent.new(url: "htp://example.com") }.to raise_error
+          expect { Manifique::Agent.new(url: "htp://example.com") }.to raise_error(RuntimeError)
         end
       end
 

spec/manifique/web_client_spec.rb

@@ -2,18 +2,18 @@ require "spec_helper"
 require "manifique/web_client"
 
 RSpec.describe Manifique::WebClient do
+  describe "#do_get_request" do
     before do
-    stub_request(:get, "http://example.com/200_empty").
-      to_return(body: "", status: 200, headers: {})
-
       stub_request(:get, "http://example.com/404").
         to_return(body: "", status: 404, headers: {})
 
       stub_request(:get, "http://example.com/500").
         to_return(body: "", status: 500, headers: {})
+
+      stub_request(:get, "http://example.com/200_empty").
+        to_return(body: "", status: 200, headers: {})
     end
 
-  describe "#do_get_request" do
     context "unsuccessful requests" do
       describe "404" do
         let(:client) { Manifique::WebClient.new }
@@ -48,4 +48,30 @@ RSpec.describe Manifique::WebClient do
       end
     end
   end
+
+  describe "#fetch_web_manifest" do
+    context "link[rel=manifest] present" do
+      before do
+        index_html = File.read(File.join(__dir__, "..", "fixtures", "mastodon.html"));
+        stub_request(:get, "https://kosmos.social/").
+          to_return(body: index_html, status: 200, headers: {
+            "Content-Type": "text/html; charset=utf-8"
+          })
+        manifest = File.read(File.join(__dir__, "..", "fixtures", "mastodon-web-app-manifest.json"));
+        stub_request(:get, "https://kosmos.social/mastodon-web-app-manifest.json").
+          to_return(body: manifest, status: 200, headers: {
+            "Content-Type": "application/json; charset=utf-8"
+          })
+      end
+
+      let(:agent) { Manifique::WebClient.new(url: "https://kosmos.social") }
+
+      subject { agent.fetch_web_manifest }
+
+      it "fetches and returns the manifest" do
+        expect(subject).to be_kind_of(Hash)
+        expect(subject["name"]).to eq("kosmos.social")
+      end
+    end
+  end
 end