Class: Ldp::Resource

Inherits:
Object
  • Object
show all
Defined in:
lib/ldp/resource.rb

Direct Known Subclasses

BinarySource, RdfSource

Defined Under Namespace

Classes: BinarySource, RdfSource

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(client, subject, response = nil, base_path = '') ⇒ Resource

Returns a new instance of Resource.



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# File 'lib/ldp/resource.rb', line 20

def initialize client, subject, response = nil, base_path = ''
  @client = client
  @subject = subject
  @get = response if response.is_a? Faraday::Response and current? response
  @base_path = base_path
end

Instance Attribute Details

#client ⇒ Object (readonly)

Returns the value of attribute client.



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# File 'lib/ldp/resource.rb', line 6

def client
  @client
end

#content ⇒ Object

Returns the value of attribute content.



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# File 'lib/ldp/resource.rb', line 7

def content
  @content
end

#subject ⇒ Object (readonly)

Returns the value of attribute subject.



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# File 'lib/ldp/resource.rb', line 6

def subject
  @subject
end

Class Method Details

.for(client, subject, response) ⇒ Object 



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# File 'lib/ldp/resource.rb', line 9

def self.for(client, subject, response)
  case
  when response.container?
    Ldp::Container.for client, subject, response
  when response.rdf_source?
    Resource::RdfSource.new client, subject, response
  else
    Resource::BinarySource.new client, subject, response
  end
end

Instance Method Details

#create(&block) ⇒ RdfSource

Create a new resource at the URI

Returns:

Raises:

  • (Ldp::Conflict) —

    if you attempt to call create on an existing resource



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# File 'lib/ldp/resource.rb', line 81

def create &block
  raise Ldp::Conflict, "Can't call create on an existing resource (#{subject})" unless new?
  verb = subject.nil? ? :post : :put
  resp = client.send(verb, (subject || @base_path), content) do |req|
    req.headers["Link"] = "<#{interaction_model}>;rel=\"type\"" if interaction_model
    yield req if block_given?
  end

  @subject = resp.headers['Location']
  @subject_uri = nil
  reload
end

#current?(response = nil) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/ldp/resource.rb', line 106

def current? response = nil
  response ||= @get
  return true if new? and subject.nil?

  new_response = client.head(subject)

  response.headers['ETag'] &&
    response.headers['Last-Modified'] &&
    new_response.headers['ETag'] == response.headers['ETag'] &&
    new_response.headers['Last-Modified'] == response.headers['Last-Modified']
end

#delete ⇒ Object

Delete the resource



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# File 'lib/ldp/resource.rb', line 67

def delete
  client.delete subject do |req|
    req.headers['If-Unmodified-Since'] = get.last_modified if retrieved_content?
  end
end

#get ⇒ Object

Get the resource



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# File 'lib/ldp/resource.rb', line 53

def get
  @get ||= client.get(subject)
end

#head ⇒ Object 



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# File 'lib/ldp/resource.rb', line 57

def head
  @head ||= begin
    @get || client.head(subject)
            rescue Ldp::NotFound
              None
  end
end

#new? ⇒ Boolean

Is the resource new, or does it exist in the LDP server?

Returns:

  • (Boolean) 


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# File 'lib/ldp/resource.rb', line 41

def new?
  subject.nil? || head == None
end

#reload ⇒ Object

Reload the LDP resource



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# File 'lib/ldp/resource.rb', line 35

def reload
  self.class.new client, subject, @get
end

#retrieved_content? ⇒ Boolean

Have we retrieved the content already?

Returns:

  • (Boolean) 


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# File 'lib/ldp/resource.rb', line 47

def retrieved_content?
  @get
end

#save ⇒ Object 



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# File 'lib/ldp/resource.rb', line 73

def save
  new? ? create : update
end

#subject_uri ⇒ Object

Get the graph subject as a URI



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# File 'lib/ldp/resource.rb', line 29

def subject_uri
  @subject_uri ||= RDF::URI(subject)
end

#update(new_content = nil) ⇒ Object

Update the stored graph



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# File 'lib/ldp/resource.rb', line 96

def update new_content = nil
  new_content ||= content
  resp = client.put subject, new_content do |req|
    req.headers['If-Unmodified-Since'] = get.last_modified if retrieved_content?
    yield req if block_given?
  end
  update_cached_get(resp) if retrieved_content?
  resp
end

#update_cached_get(response) ⇒ Object 



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# File 'lib/ldp/resource.rb', line 118

def update_cached_get(response)
  response = Response.new(response)

  if response.etag.nil? || response.last_modified.nil?
    response = client.head(subject)
  end
  @get.etag = response.etag
  @get.last_modified = response.last_modified
end