summaryrefslogtreecommitdiff
path: root/lib/gitlab/markdown/relative_link_filter.rb
blob: 632be4d754255bbf4803dbe3c6f2e12ace6a4b9a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
require 'gitlab/markdown'
require 'html/pipeline/filter'
require 'uri'

module Gitlab
  module Markdown
    # HTML filter that "fixes" relative links to files in a repository.
    #
    # Context options:
    #   :commit
    #   :project
    #   :project_wiki
    #   :ref
    #   :requested_path
    class RelativeLinkFilter < HTML::Pipeline::Filter
      def call
        return doc unless linkable_files?

        doc.search('a').each do |el|
          process_link_attr el.attribute('href')
        end

        doc.search('img').each do |el|
          process_link_attr el.attribute('src')
        end

        doc
      end

      protected

      def linkable_files?
        context[:project_wiki].nil? && repository.try(:exists?) && !repository.empty?
      end

      def process_link_attr(html_attr)
        return if html_attr.blank?

        uri = URI(html_attr.value)
        if uri.relative? && uri.path.present?
          html_attr.value = rebuild_relative_uri(uri).to_s
        end
      rescue URI::Error
        # noop
      end

      def rebuild_relative_uri(uri)
        file_path = relative_file_path(uri.path)

        uri.path = [
          relative_url_root,
          context[:project].path_with_namespace,
          path_type(file_path),
          ref || context[:project].default_branch,  # if no ref exists, point to the default branch
          file_path
        ].compact.join('/').squeeze('/').chomp('/')

        uri
      end

      def relative_file_path(path)
        nested_path = build_relative_path(path, context[:requested_path])
        file_exists?(nested_path) ? nested_path : path
      end

      # Convert a relative path into its correct location based on the currently
      # requested path
      #
      # path         - Relative path String
      # request_path - Currently-requested path String
      #
      # Examples:
      #
      #   # File in the same directory as the current path
      #   build_relative_path("users.md", "doc/api/README.md")
      #   # => "doc/api/users.md"
      #
      #   # File in the same directory, which is also the current path
      #   build_relative_path("users.md", "doc/api")
      #   # => "doc/api/users.md"
      #
      #   # Going up one level to a different directory
      #   build_relative_path("../update/7.14-to-8.0.md", "doc/api/README.md")
      #   # => "doc/update/7.14-to-8.0.md"
      #
      # Returns a String
      def build_relative_path(path, request_path)
        return request_path if path.empty?
        return path unless request_path

        parts = request_path.split('/')
        parts.pop if path_type(request_path) != 'tree'

        while parts.length > 1 && path.start_with?('../')
          parts.pop
          path.sub!('../', '')
        end

        parts.push(path).join('/')
      end

      def file_exists?(path)
        return false if path.nil?
        repository.blob_at(current_sha, path).present? ||
          repository.tree(current_sha, path).entries.any?
      end

      # Get the type of the given path
      #
      # path - String path to check
      #
      # Examples:
      #
      #   path_type('doc/README.md') # => 'blob'
      #   path_type('doc/logo.png')  # => 'raw'
      #   path_type('doc/api')       # => 'tree'
      #
      # Returns a String
      def path_type(path)
        unescaped_path = Addressable::URI.unescape(path)

        if tree?(unescaped_path)
          'tree'
        elsif image?(unescaped_path)
          'raw'
        else
          'blob'
        end
      end

      def tree?(path)
        repository.tree(current_sha, path).entries.any?
      end

      def image?(path)
        repository.blob_at(current_sha, path).try(:image?)
      end

      def current_sha
        context[:commit].try(:id) ||
          ref ? repository.commit(ref).try(:sha) : repository.head_commit.sha
      end

      def relative_url_root
        Gitlab.config.gitlab.relative_url_root.presence || '/'
      end

      def ref
        context[:ref]
      end

      def repository
        context[:project].try(:repository)
      end
    end
  end
end