Module: Lightstreamer::PostRequest

Defined in:
lib/lightstreamer/post_request.rb

Overview

This module contains helper methods for sending single and multiple POST requests to a Lightstreamer server and handling the possible error responses.

Class Method Summary collapse

Class Method Details

.execute(url, query) ⇒ Object

Sends a POST request to the specified Lightstreamer URL with the given query params. If an error occurs then a LightstreamerError subclass will be raised.

Parameters:

  • url (String) —

    The URL to send the POST request to.

  • query (Hash) —

    The POST request’s query params.



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# File 'lib/lightstreamer/post_request.rb', line 14

def execute(url, query)
  errors = execute_multiple url, [request_body(query)]
  raise errors.first if errors.first
end

.execute_multiple(url, bodies) ⇒ Array<LightstreamerError, nil>

Sends a POST request to the specified Lightstreamer URL that concatenates multiple individual POST request bodies into one to avoid sending lots of individual requests. The return value is an array with one entry per body and indicates the error state returned by the server for that body’s request, or ‘nil` if no error occurred.

Parameters:

  • url (String) —

    The URL to send the POST request to.

  • bodies (Array<String>) —

    The individual POST request bodies that are to be sent together in one request. These should be created with #request_body.

Returns:

  • (Array<LightstreamerError, nil>) —

    The execution result of each of the passed bodies. If an entry is ‘nil` then no error occurred when executing that body.



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# File 'lib/lightstreamer/post_request.rb', line 29

def execute_multiple(url, bodies)
  response = Excon.post url, body: bodies.join("\r\n"), expects: 200, connect_timeout: 15

  response_lines = response.body.split("\n").map(&:strip)

  errors = []
  errors << parse_error(response_lines) until response_lines.empty?

  raise LightstreamerError if errors.size != bodies.size

  errors
rescue Excon::Error => e
  raise Errors::ConnectionError, e.message
end

.parse_error(response_lines) ⇒ LightstreamerError?

Parses the next error from the given lines that were returned by a POST request. The consumed lines are removed from the passed array.

Parameters:

  • response_lines (Array<String>)

Returns:



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# File 'lib/lightstreamer/post_request.rb', line 68

def parse_error(response_lines)
  first_line = response_lines.shift

  return nil if first_line == 'OK'
  return Errors::SyncError.new if first_line == 'SYNC ERROR'

  if first_line == 'ERROR'
    error_code = response_lines.shift
    LightstreamerError.build response_lines.shift, error_code
  else
    LightstreamerError.new first_line
  end
end

.request_body(query) ⇒ String

Returns the request body to send for a POST request with the given options.

Parameters:

  • query (Hash) —

    The POST request’s query params.

Returns:

  • (String) —

    The request body for the given query params.



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# File 'lib/lightstreamer/post_request.rb', line 49

def request_body(query)
  params = {}

  query.each do |key, value|
    next if value.nil?

    value = value.map(&:to_s).join(' ') if value.is_a? Array
    params[key] = value
  end

  URI.encode_www_form params
end