Class: Couchbase::View

Inherits:
Object
  • Object
show all
Includes:
Enumerable
Defined in:
lib/couchbase/view.rb

Instance Method Summary collapse

Constructor Details

#initialize(connection, endpoint, params = {}) ⇒ View

Set up view endpoint and optional params

stores all info about how to make requests to Couchbase views.

Couchbase::View#each

Parameters:

  • connection (Couchbase::Bucket) —

    Connection object which

  • endpoint (String) —

    Full CouchDB view URI.

  • params (Hash) (defaults to: {}) —

    Optional parameter which will be passed to



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# File 'lib/couchbase/view.rb', line 34

def initialize(connection, endpoint, params = {})
  @connection = connection
  @endpoint = endpoint
  @params = params
end

Instance Method Details

#each(params = {}) ⇒ Object

Yields each document that was fetched by view. It doesn’t instantiate all the results because of streaming JSON parser. Returns Enumerator unless block given.

:startkey, :startkey_docid, :descending.

Examples:

Use each method with block


view.each do |doc|
  # do something with doc
end

Use Enumerator version


enum = view.each  # request hasn't issued yet
enum.map{|doc| doc.title.upcase}

Pass options during view initialization


endpoint = "http://localhost:5984/default/_design/blog/_view/recent"
view = View.new(conn, endpoint, :descending => true)
view.each do |document|
  # do something with document
end

Parameters:

  • params (Hash) (defaults to: {}) —

    Params for Couchdb query. Some useful are:



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# File 'lib/couchbase/view.rb', line 66

def each(params = {})
  return enum_for(:each, params) unless block_given?
  fetch(params) {|doc| yield(doc)}
end

#fetch(params = {}) {|document| ... } ⇒ Array

Performs query to CouchDB view. This method will stream results if block given or return complete result set otherwise. In latter case it defines method total_entries returning total_rows entry from CouchDB result object.

Parameters:

Yield Parameters:

Returns:

  • (Array) —

    with documents. There will be total_entries method defined on this array if it’s possible.

Raises:

  • (Couchbase::ViewError) —

    when on_error callback is nil and error object found in the result stream.



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# File 'lib/couchbase/view.rb', line 128

def fetch(params = {})
  curl = @connection.curl_easy(@endpoint, :params => @params.merge(params))
  if block_given?
    iter = YAJI::Parser.new(curl).each(["rows/", "errors/"], :with_path => true)
    begin
      loop do
        path, obj = iter.next
        if path == "errors/"
          from, reason = obj["from"], obj["reason"]
          if @on_error
            @on_error.call(from, reason)
          else
            raise ViewError.new(from, reason)
          end
        else
          yield Document.new(self, obj)
        end
      end
    rescue StopIteration
    end
  else
    iter = YAJI::Parser.new(curl).each(["total_rows", "rows/", "errors/"], :with_path => true)
    docs = []
    begin
      path, obj = iter.next
      if path == "total_rows"
        # if total_rows key present, save it and take next object
        total_rows = obj
        path, obj = iter.next
      end
      loop do
        if path == "errors/"
          from, reason = obj["from"], obj["reason"]
          if @on_error
            @on_error.call(from, reason)
          else
            raise ViewError.new(from, reason)
          end
        else
          docs << Document.new(self, obj)
        end
        path, obj = iter.next
      end
    rescue StopIteration
    end
    docs.instance_eval("def total_entries; #{total_rows}; end")
    return docs
  end
end

#inspect ⇒ Object 



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# File 'lib/couchbase/view.rb', line 178

def inspect
  %(#<#{self.class.name}:#{self.object_id} @endpoint=#{@endpoint.inspect} @params=#{@params.inspect}>)
end

#on_error {|from, reason| ... } ⇒ Object

Registers callback function for handling error objects in view results stream.

Examples:

Using #on_error to log all errors in view result


# JSON-encoded view result
#
# {
#   "total_rows": 0,
#   "rows": [ ],
#   "errors": [
#     {
#       "from": "127.0.0.1:5984",
#       "reason": "Design document `_design/testfoobar` missing in database `test_db_b`."
#     },
#     {
#       "from": "http:// localhost:5984/_view_merge/",
#       "reason": "Design document `_design/testfoobar` missing in database `test_db_c`."
#     }
#   ]
# }

view.on_error do |from, reason|
  logger.warn("#{view.inspect} received the error '#{reason}' from #{from}")
end
docs = view.fetch

More concise example to just count errors


errcount = 0
view.on_error{|f,r| errcount += 1}.fetch

Yield Parameters:

  • from (String) —

    Location of the node where error occured

  • reason (String) —

    The reason message describing what happened.



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# File 'lib/couchbase/view.rb', line 107

def on_error(&callback)
  @on_error = callback
  self  # enable call chains
end