Response class for Precondition Failed responses (status code 412).
The server does not meet one of the preconditions specified in the request headers.
References:
Turns a “invalid block(s)” into useful context
There are three main phases in the algorithm:
Sanitize/format input source
Search for invalid blocks
Format invalid blocks into something meaningful
This class handles the third part.
The algorithm is very good at capturing all of a syntax error in a single block in number 2, however the results can contain ambiguities. Humans are good at pattern matching and filtering and can mentally remove extraneous data, but they can’t add extra data that’s not present.
In the case of known ambiguious cases, this class adds context back to the ambiguity so the programmer has full information.
Beyond handling these ambiguities, it also captures surrounding code context information:
puts block.to_s # => "def bark"
context = CaptureCodeContext.new(
blocks: block,
code_lines: code_lines
)
lines = context.call.map(&:original)
puts lines.join
# =>
class Dog
def bark
end
Represents an error communicating via HTTP.
Raised by exit to initiate the termination of the script.
SystemCallError is the base class for all low-level platform-dependent errors.
The errors available on the current platform are subclasses of SystemCallError and are defined in the Errno module.
File.open("does/not/exist")
raises the exception:
Errno::ENOENT: No such file or directory - does/not/exist
Use the Monitor class when you want to have a lock object for blocks with mutual exclusion.
require 'monitor' lock = Monitor.new lock.synchronize do # exclusive access end
In concurrent programming, a monitor is an object or module intended to be used safely by more than one thread. The defining characteristic of a monitor is that its methods are executed with mutual exclusion. That is, at each point in time, at most one thread may be executing any of its methods. This mutual exclusion greatly simplifies reasoning about the implementation of monitors compared to reasoning about parallel code that updates a data structure.
You can read more about the general principles on the Wikipedia page for Monitors.
require 'monitor.rb' buf = [] buf.extend(MonitorMixin) empty_cond = buf.new_cond # consumer Thread.start do loop do buf.synchronize do empty_cond.wait_while { buf.empty? } print buf.shift end end end # producer while line = ARGF.gets buf.synchronize do buf.push(line) empty_cond.signal end end
The consumer thread waits for the producer thread to push a line to buf while buf.empty?. The producer thread (main thread) reads a line from ARGF and pushes it into buf then calls empty_cond.signal to notify the consumer thread of new data.
Class include require 'monitor' class SynchronizedArray < Array include MonitorMixin def initialize(*args) super(*args) end alias :old_shift :shift alias :old_unshift :unshift def shift(n=1) self.synchronize do self.old_shift(n) end end def unshift(item) self.synchronize do self.old_unshift(item) end end # other methods ... end
SynchronizedArray implements an Array with synchronized access to items. This Class is implemented as subclass of Array which includes the MonitorMixin module.
This class is the base class for Net::HTTP response classes.
Method Net::HTTP.get_response returns an instance of one of the subclasses of Net::HTTPResponse:
Net::HTTP.get_response(uri) # => #<Net::HTTPOK 200 OK readbody=true> Net::HTTP.get_response(hostname, '/nosuch') # => #<Net::HTTPNotFound 404 Not Found readbody=true>
As does method Net::HTTP#request:
req = Net::HTTP::Get.new(uri) Net::HTTP.start(hostname) do |http| http.request(req) end # => #<Net::HTTPOK 200 OK readbody=true>
Class Net::HTTPResponse includes module Net::HTTPHeader, which provides access to response header values via (among others):
Hash-like method [].
Specific reader methods, such as content_type.
Examples:
res = Net::HTTP.get_response(uri) # => #<Net::HTTPOK 200 OK readbody=true> res['Content-Type'] # => "text/html; charset=UTF-8" res.content_type # => "text/html"
Class Net::HTTPResponse has a subclass for each HTTP status code. You can look up the response class for a given code:
Net::HTTPResponse::CODE_TO_OBJ['200'] # => Net::HTTPOK Net::HTTPResponse::CODE_TO_OBJ['400'] # => Net::HTTPBadRequest Net::HTTPResponse::CODE_TO_OBJ['404'] # => Net::HTTPNotFound
And you can retrieve the status code for a response object:
Net::HTTP.get_response(uri).code # => "200" Net::HTTP.get_response(hostname, '/nosuch').code # => "404"
The response subclasses (indentation shows class hierarchy):
Net::HTTPUnknownResponse (for unhandled HTTP extensions).
Net::HTTPContinue (100)
Net::HTTPSwitchProtocol (101)
Net::HTTPProcessing (102)
Net::HTTPEarlyHints (103)
Net::HTTPOK (200)
Net::HTTPCreated (201)
Net::HTTPAccepted (202)
Net::HTTPNoContent (204)
Net::HTTPResetContent (205)
Net::HTTPPartialContent (206)
Net::HTTPMultiStatus (207)
Net::HTTPAlreadyReported (208)
Net::HTTPIMUsed (226)
Net::HTTPMultipleChoices (300)
Net::HTTPFound (302)
Net::HTTPSeeOther (303)
Net::HTTPNotModified (304)
Net::HTTPUseProxy (305)
Net::HTTPBadRequest (400)
Net::HTTPUnauthorized (401)
Net::HTTPPaymentRequired (402)
Net::HTTPForbidden (403)
Net::HTTPNotFound (404)
Net::HTTPNotAcceptable (406)
Net::HTTPRequestTimeOut (408)
Net::HTTPConflict (409)
Net::HTTPGone (410)
Net::HTTPLengthRequired (411)
Net::HTTPLocked (423)
Net::HTTPUpgradeRequired (426)
Net::HTTPTooManyRequests (429)
Net::HTTPNotImplemented (501)
Net::HTTPBadGateway (502)
Net::HTTPGatewayTimeOut (504)
Net::HTTPLoopDetected (508)
Net::HTTPNotExtended (510)
There is also the Net::HTTPBadResponse exception which is raised when there is a protocol error.
Response class for Non-Authoritative Information responses (status code 203).
The Non-Authoritative Information response indicates that the server is a transforming proxy (such as a Web accelerator) that received a 200 OK response from its origin, and is returning a modified version of the origin’s response.
References:
Response class for Reset Content responses (status code 205).
The Reset Content response indicates that the server successfully processed the request, asks that the client reset its document view, and is not returning any content.
References:
Response class for URI Too Long responses (status code 414).
The URI provided was too long for the server to process.
References:
Response class for Request Header Fields Too Large responses (status code 431).
An individual header field is too large, or all the header fields collectively, are too large.
References:
Response class for Unavailable For Legal Reasons responses (status code 451).
A server operator has received a legal demand to deny access to a resource or to a set of resources that includes the requested resource.
References:
Raised to indicate that a system exit should occur with the specified exit_code
Raised by transcoding methods when a named encoding does not correspond with a known converter.
Encoding conversion class.
Mixin methods for –version and –platform Gem::Command options.