FIX: Follow the canonical URL when importing a remote topic. (#14489)

FinalDestination now supports the `follow_canonical` option, which will perform an initial GET request, parse the canonical link if present, and perform a HEAD request to it.

We use this mode during embeds to avoid treating URLs with different query parameters as different topics.
This commit is contained in:
Roman Rizzi 2021-10-01 12:48:21 -03:00 committed by GitHub
parent 0359adc0b8
commit 4c2d5158c5
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4 changed files with 122 additions and 53 deletions

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@ -113,7 +113,8 @@ class TopicEmbed < ActiveRecord::Base
fd = FinalDestination.new(
url,
validate_uri: true,
max_redirects: 5
max_redirects: 5,
follow_canonical: true,
)
url = fd.resolve

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@ -63,7 +63,8 @@ class FinalDestination
end
@status = :ready
@http_verb = @force_get_hosts.any? { |host| hostname_matches?(host) } ? :get : :head
@follow_canonical = @opts[:follow_canonical]
@http_verb = http_verb(@force_get_hosts, @follow_canonical)
@cookie = nil
@limited_ips = []
@verbose = @opts[:verbose] || false
@ -77,6 +78,14 @@ class FinalDestination
20
end
def http_verb(force_get_hosts, follow_canonical)
if follow_canonical || force_get_hosts.any? { |host| hostname_matches?(host) }
:get
else
:head
end
end
def timeout
@timeout || FinalDestination.connection_timeout
end
@ -215,6 +224,18 @@ class FinalDestination
end
end
if @follow_canonical
next_url = uri(fetch_canonical_url(response.body))
if next_url.to_s.present? && next_url != @uri
@follow_canonical = false
@uri = next_url
@http_verb = http_verb(@force_get_hosts, @follow_canonical)
return resolve
end
end
@content_type = response.headers['Content-Type'] if response.headers.has_key?('Content-Type')
@status = :resolved
return @uri
@ -458,4 +479,12 @@ class FinalDestination
end
end
def fetch_canonical_url(body)
return if body.blank?
canonical_link = Nokogiri::HTML5(body).at("link[rel='canonical']")
return if canonical_link.nil?
canonical_link['href']
end
end

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@ -49,6 +49,13 @@ describe FinalDestination do
}
end
def canonical_follow(from, dest)
stub_request(:get, from).to_return(
status: 200,
body: "<head><link rel=\"canonical\" href=\"#{dest}\"></head>"
)
end
def redirect_response(from, dest)
stub_request(:head, from).to_return(
status: 302,
@ -175,6 +182,39 @@ describe FinalDestination do
end
end
context 'follows canonical links' do
it 'resolves the canonical link as the final destination' do
canonical_follow("https://eviltrout.com", "https://codinghorror.com/blog")
stub_request(:head, "https://codinghorror.com/blog").to_return(doc_response)
final = FinalDestination.new('https://eviltrout.com', opts.merge(follow_canonical: true))
expect(final.resolve.to_s).to eq("https://codinghorror.com/blog")
expect(final.redirected?).to eq(false)
expect(final.status).to eq(:resolved)
end
it "does not follow the canonical link if it's the same as the current URL" do
canonical_follow("https://eviltrout.com", "https://eviltrout.com")
final = FinalDestination.new('https://eviltrout.com', opts.merge(follow_canonical: true))
expect(final.resolve.to_s).to eq("https://eviltrout.com")
expect(final.redirected?).to eq(false)
expect(final.status).to eq(:resolved)
end
it "does not follow the canonical link if it's invalid" do
canonical_follow("https://eviltrout.com", "")
final = FinalDestination.new('https://eviltrout.com', opts.merge(follow_canonical: true))
expect(final.resolve.to_s).to eq("https://eviltrout.com")
expect(final.redirected?).to eq(false)
expect(final.status).to eq(:resolved)
end
end
context "GET can be forced" do
before do
stub_request(:head, 'https://force.get.com/posts?page=4')

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@ -190,18 +190,20 @@ describe TopicEmbed do
end
describe '.find_remote' do
fab!(:embeddable_host) { Fabricate(:embeddable_host) }
let(:file) { StringIO.new }
before do
TopicEmbed.stubs(:open).returns file
end
context ".title_scrub" do
let(:url) { 'http://eviltrout.com/123' }
let(:contents) { "<title>Through the Looking Glass - Classic Books</title><body>some content here</body>" }
fab!(:embeddable_host) { Fabricate(:embeddable_host) }
let!(:file) { StringIO.new }
before do
file.stubs(:read).returns contents
TopicEmbed.stubs(:open).returns file
stub_request(:head, url)
stub_request(:get, url)
end
it "doesn't scrub the title by default" do
@ -214,44 +216,38 @@ describe TopicEmbed do
response = TopicEmbed.find_remote(url)
expect(response.title).to eq("Through the Looking Glass")
end
end
context 'post with allowed classes "foo" and "emoji"' do
fab!(:user) { Fabricate(:user) }
let(:url) { 'http://eviltrout.com/123' }
let(:contents) { "my normal size emoji <p class='foo'>Hi</p> <img class='emoji other foo' src='/images/smiley.jpg'>" }
fab!(:embeddable_host) { Fabricate(:embeddable_host) }
let!(:file) { StringIO.new }
response = nil
before do
SiteSetting.allowed_embed_classnames = 'emoji, foo'
file.stubs(:read).returns contents
TopicEmbed.stubs(:open).returns file
stub_request(:head, url)
response = TopicEmbed.find_remote(url)
stub_request(:get, url)
@response = TopicEmbed.find_remote(url)
end
it "has no author tag" do
expect(response.author).to be_blank
expect(@response.author).to be_blank
end
it 'img node has emoji class' do
expect(response.body).to have_tag('img', with: { class: 'emoji' })
expect(@response.body).to have_tag('img', with: { class: 'emoji' })
end
it 'img node has foo class' do
expect(response.body).to have_tag('img', with: { class: 'foo' })
expect(@response.body).to have_tag('img', with: { class: 'foo' })
end
it 'p node has foo class' do
expect(response.body).to have_tag('p', with: { class: 'foo' })
expect(@response.body).to have_tag('p', with: { class: 'foo' })
end
it 'nodes removes classes other than emoji' do
expect(response.body).to have_tag('img', without: { class: 'other' })
expect(@response.body).to have_tag('img', without: { class: 'other' })
end
end
@ -259,67 +255,56 @@ describe TopicEmbed do
fab!(:user) { Fabricate(:user, username: 'eviltrout') }
let(:url) { 'http://eviltrout.com/321' }
let(:contents) { '<html><head><meta name="author" content="eviltrout"></head><body>rich and morty</body></html>' }
fab!(:embeddable_host) { Fabricate(:embeddable_host) }
let!(:file) { StringIO.new }
response = nil
before(:each) do
file.stubs(:read).returns contents
TopicEmbed.stubs(:open).returns file
stub_request(:head, url)
response = TopicEmbed.find_remote(url)
stub_request(:get, url)
end
it "has no author tag" do
response = TopicEmbed.find_remote(url)
expect(response.author).to eq(user)
end
end
context 'post with no allowed classes' do
fab!(:user) { Fabricate(:user) }
let(:url) { 'http://eviltrout.com/123' }
let(:contents) { "my normal size emoji <p class='foo'>Hi</p> <img class='emoji other foo' src='/images/smiley.jpg'>" }
fab!(:embeddable_host) { Fabricate(:embeddable_host) }
let!(:file) { StringIO.new }
response = nil
before(:each) do
SiteSetting.allowed_embed_classnames = ''
file.stubs(:read).returns contents
TopicEmbed.stubs(:open).returns file
stub_request(:head, url)
response = TopicEmbed.find_remote(url)
stub_request(:get, url)
@response = TopicEmbed.find_remote(url)
end
it 'img node doesn\'t have emoji class' do
expect(response.body).to have_tag('img', without: { class: 'emoji' })
expect(@response.body).to have_tag('img', without: { class: 'emoji' })
end
it 'img node doesn\'t have foo class' do
expect(response.body).to have_tag('img', without: { class: 'foo' })
expect(@response.body).to have_tag('img', without: { class: 'foo' })
end
it 'p node doesn\'t foo class' do
expect(response.body).to have_tag('p', without: { class: 'foo' })
expect(@response.body).to have_tag('p', without: { class: 'foo' })
end
it 'img node doesn\'t have other class' do
expect(response.body).to have_tag('img', without: { class: 'other' })
expect(@response.body).to have_tag('img', without: { class: 'other' })
end
end
context "non-ascii URL" do
let(:url) { 'http://eviltrout.com/test/ماهی' }
let(:contents) { "<title>سلام</title><body>این یک پاراگراف آزمون است.</body>" }
fab!(:embeddable_host) { Fabricate(:embeddable_host) }
let!(:file) { StringIO.new }
before do
stub_request(:head, url)
stub_request(:get, url).to_return(body: contents).then.to_raise
stub_request(:get, url)
file.stubs(:read).returns contents
end
it "doesn't throw an error" do
@ -331,12 +316,10 @@ describe TopicEmbed do
context "encoded URL" do
let(:url) { 'http://example.com/hello%20world' }
let(:contents) { "<title>Hello World!</title><body></body>" }
fab!(:embeddable_host) { Fabricate(:embeddable_host) }
let!(:file) { StringIO.new }
before do
stub_request(:head, url)
stub_request(:get, url).to_return(body: contents).then.to_raise
stub_request(:get, url)
file.stubs(:read).returns contents
end
it "doesn't throw an error" do
@ -356,17 +339,15 @@ describe TopicEmbed do
context "emails" do
let(:url) { 'http://example.com/foo' }
let(:contents) { '<p><a href="mailto:foo%40example.com">URL encoded @ symbol</a></p><p><a href="mailto:bar@example.com">normal mailto link</a></p>' }
fab!(:embeddable_host) { Fabricate(:embeddable_host) }
let!(:file) { StringIO.new }
before do
file.stubs(:read).returns contents
TopicEmbed.stubs(:open).returns file
stub_request(:get, url)
end
it "handles mailto links" do
stub_request(:head, url)
response = TopicEmbed.find_remote(url)
expect(response.body).to have_tag('a', with: { href: 'mailto:foo%40example.com' })
expect(response.body).to have_tag('a', with: { href: 'mailto:bar@example.com' })
end
@ -375,18 +356,36 @@ describe TopicEmbed do
context "malformed href" do
let(:url) { 'http://example.com/foo' }
let(:contents) { '<p><a href="(http://foo.bar)">Baz</a></p>' }
let!(:file) { StringIO.new }
before do
file.stubs(:read).returns contents
TopicEmbed.stubs(:open).returns file
stub_request(:get, url)
end
it "doesnt raise an exception" do
stub_request(:head, url)
expect { TopicEmbed.find_remote(url) }.not_to raise_error
end
end
context 'canonical links' do
let(:url) { 'http://eviltrout.com/123?asd' }
let(:canonical_url) { 'http://eviltrout.com/123' }
let(:content) { "<head><link rel=\"canonical\" href=\"#{canonical_url}\"></head>" }
let(:canonical_content) { "<title>Canonical</title><body></body>" }
before do
file.stubs(:read).returns canonical_content
stub_request(:get, url)
stub_request(:head, canonical_url)
end
it 'a' do
response = TopicEmbed.find_remote(url)
expect(response.title).to eq("Canonical")
end
end
end
describe '.absolutize_urls' do