Results for: "Psych"

Psych::Visitors::RestrictedYAMLTree#accept

No documentation available

Psych::Streaming::ClassMethods#new

Create a new streaming emitter. Emitter will print to io. See Psych::Stream for an example.

Enumerator::Chain

Enumerator::Chain is a subclass of Enumerator, which represents a chain of enumerables that works as a single enumerator.

This type of objects can be created by Enumerable#chain and Enumerator#+.

PTY::ChildExited

Thrown when PTY::check is called for a pid that represents a process that has exited.

Socket::UDPSource

UDP/IP address information used by Socket.udp_server_loop.

DidYouMean::SpellChecker

No documentation available

DidYouMean::KeyErrorChecker

No documentation available

DidYouMean::MethodNameChecker

No documentation available

DidYouMean::ClassNameChecker

No documentation available

DidYouMean::VariableNameChecker

No documentation available

DidYouMean::NullChecker

No documentation available

DidYouMean::PatternKeyNameChecker

No documentation available

DidYouMean::RequirePathChecker

No documentation available

DidYouMean::TreeSpellChecker

spell checker for a dictionary that has a tree structure, see doc/tree_spell_checker_api.md

Net::HTTPHeaderSyntaxError

No documentation available

Net::HTTPSession

Class Net::HTTP provides a rich library that implements the client in a client-server model that uses the HTTP request-response protocol. For information about HTTP, see:

About the Examples

Strategies

The methods cited above are convenience methods that, via their few arguments, allow minimal control over the requests. For greater control, consider using request objects.

URIs

On the internet, a URI (Universal Resource Identifier) is a string that identifies a particular resource. It consists of some or all of: scheme, hostname, path, query, and fragment; see URI syntax.

A Ruby URI::Generic object represents an internet URI. It provides, among others, methods scheme, hostname, path, query, and fragment.

Schemes

An internet URI has a scheme.

The two schemes supported in Net::HTTP are 'https' and 'http':

uri.scheme                       # => "https"
URI('http://example.com').scheme # => "http"

Hostnames

A hostname identifies a server (host) to which requests may be sent:

hostname = uri.hostname # => "jsonplaceholder.typicode.com"
Net::HTTP.start(hostname) do |http|
  # Some HTTP stuff.
end

Paths

A host-specific path identifies a resource on the host:

_uri = uri.dup
_uri.path = '/todos/1'
hostname = _uri.hostname
path = _uri.path
Net::HTTP.get(hostname, path)

Queries

A host-specific query adds name/value pairs to the URI:

_uri = uri.dup
params = {userId: 1, completed: false}
_uri.query = URI.encode_www_form(params)
_uri # => #<URI::HTTPS https://jsonplaceholder.typicode.com?userId=1&completed=false>
Net::HTTP.get(_uri)

Fragments

A URI fragment has no effect in Net::HTTP; the same data is returned, regardless of whether a fragment is included.

Request Headers

Request headers may be used to pass additional information to the host, similar to arguments passed in a method call; each header is a name/value pair.

Each of the Net::HTTP methods that sends a request to the host has optional argument headers, where the headers are expressed as a hash of field-name/value pairs:

headers = {Accept: 'application/json', Connection: 'Keep-Alive'}
Net::HTTP.get(uri, headers)

See lists of both standard request fields and common request fields at Request Fields. A host may also accept other custom fields.

HTTP Sessions

A session is a connection between a server (host) and a client that:

See example sessions at Strategies.

Session Using Net::HTTP.start

If you have many requests to make to a single host (and port), consider using singleton method Net::HTTP.start with a block; the method handles the session automatically by:

In the block, you can use these instance methods, each of which that sends a single request:

Session Using Net::HTTP.start and Net::HTTP.finish

You can manage a session manually using methods start and finish:

http = Net::HTTP.new(hostname)
http.start
http.get('/todos/1')
http.get('/todos/2')
http.delete('/posts/1')
http.finish # Needed to free resources.

Single-Request Session

Certain convenience methods automatically handle a session by:

Such methods that send GET requests:

Such methods that send POST requests:

HTTP Requests and Responses

Many of the methods above are convenience methods, each of which sends a request and returns a string without directly using Net::HTTPRequest and Net::HTTPResponse objects.

You can, however, directly create a request object, send the request, and retrieve the response object; see:

Following Redirection

Each returned response is an instance of a subclass of Net::HTTPResponse. See the response class hierarchy.

In particular, class Net::HTTPRedirection is the parent of all redirection classes. This allows you to craft a case statement to handle redirections properly:

def fetch(uri, limit = 10)
  # You should choose a better exception.
  raise ArgumentError, 'Too many HTTP redirects' if limit == 0

  res = Net::HTTP.get_response(URI(uri))
  case res
  when Net::HTTPSuccess     # Any success class.
    res
  when Net::HTTPRedirection # Any redirection class.
    location = res['Location']
    warn "Redirected to #{location}"
    fetch(location, limit - 1)
  else                      # Any other class.
    res.value
  end
end

fetch(uri)

Basic Authentication

Basic authentication is performed according to RFC2617:

req = Net::HTTP::Get.new(uri)
req.basic_auth('user', 'pass')
res = Net::HTTP.start(hostname) do |http|
  http.request(req)
end

Streaming Response Bodies

By default Net::HTTP reads an entire response into memory. If you are handling large files or wish to implement a progress bar you can instead stream the body directly to an IO.

Net::HTTP.start(hostname) do |http|
  req = Net::HTTP::Get.new(uri)
  http.request(req) do |res|
    open('t.tmp', 'w') do |f|
      res.read_body do |chunk|
        f.write chunk
      end
    end
  end
end

HTTPS

HTTPS is enabled for an HTTP connection by Net::HTTP#use_ssl=:

Net::HTTP.start(hostname, :use_ssl => true) do |http|
  req = Net::HTTP::Get.new(uri)
  res = http.request(req)
end

Or if you simply want to make a GET request, you may pass in a URI object that has an HTTPS URL. Net::HTTP automatically turns on TLS verification if the URI object has a ‘https’ URI scheme:

uri # => #<URI::HTTPS https://jsonplaceholder.typicode.com/>
Net::HTTP.get(uri)

Proxy Server

An HTTP object can have a proxy server.

You can create an HTTP object with a proxy server using method Net::HTTP.new or method Net::HTTP.start.

The proxy may be defined either by argument p_addr or by environment variable 'http_proxy'.

Proxy Using Argument p_addr as a String

When argument p_addr is a string hostname, the returned http has the given host as its proxy:

http = Net::HTTP.new(hostname, nil, 'proxy.example')
http.proxy?          # => true
http.proxy_from_env? # => false
http.proxy_address   # => "proxy.example"
# These use default values.
http.proxy_port      # => 80
http.proxy_user      # => nil
http.proxy_pass      # => nil

The port, username, and password for the proxy may also be given:

http = Net::HTTP.new(hostname, nil, 'proxy.example', 8000, 'pname', 'ppass')
# => #<Net::HTTP jsonplaceholder.typicode.com:80 open=false>
http.proxy?          # => true
http.proxy_from_env? # => false
http.proxy_address   # => "proxy.example"
http.proxy_port      # => 8000
http.proxy_user      # => "pname"
http.proxy_pass      # => "ppass"

Proxy Using ‘ENV['http_proxy']’

When environment variable 'http_proxy' is set to a URI string, the returned http will have the server at that URI as its proxy; note that the URI string must have a protocol such as 'http' or 'https':

ENV['http_proxy'] = 'http://example.com'
http = Net::HTTP.new(hostname)
http.proxy?          # => true
http.proxy_from_env? # => true
http.proxy_address   # => "example.com"
# These use default values.
http.proxy_port      # => 80
http.proxy_user      # => nil
http.proxy_pass      # => nil

The URI string may include proxy username, password, and port number:

ENV['http_proxy'] = 'http://pname:ppass@example.com:8000'
http = Net::HTTP.new(hostname)
http.proxy?          # => true
http.proxy_from_env? # => true
http.proxy_address   # => "example.com"
http.proxy_port      # => 8000
http.proxy_user      # => "pname"
http.proxy_pass      # => "ppass"

Filtering Proxies

With method Net::HTTP.new (but not Net::HTTP.start), you can use argument p_no_proxy to filter proxies:

Compression and Decompression

Net::HTTP does not compress the body of a request before sending.

By default, Net::HTTP adds header 'Accept-Encoding' to a new request object:

Net::HTTP::Get.new(uri)['Accept-Encoding']
# => "gzip;q=1.0,deflate;q=0.6,identity;q=0.3"

This requests the server to zip-encode the response body if there is one; the server is not required to do so.

Net::HTTP does not automatically decompress a response body if the response has header 'Content-Range'.

Otherwise decompression (or not) depends on the value of header Content-Encoding:

What’s Here

First, what’s elsewhere. Class Net::HTTP:

This is a categorized summary of methods and attributes.

Net::HTTP Objects

Sessions

Connections

Requests

Responses

Proxies

Security

Addresses and Ports

HTTP Version

Debugging

Net::HTTPSuccess

Parent class for success (2xx) HTTP response classes.

A success response indicates the action requested by the client was received, understood, and accepted.

References:

Net::HTTPServerError

Parent class for server error (5xx) HTTP response classes.

A server error response indicates that the server failed to fulfill a request.

References:

Net::HTTPMultipleChoices

Response class for Multiple Choices responses (status code 300).

The Multiple Choices response indicates that the server offers multiple options for the resource from which the client may choose.

References:

Net::HTTPMultipleChoice

Response class for Multiple Choices responses (status code 300).

The Multiple Choices response indicates that the server offers multiple options for the resource from which the client may choose.

References:

Net::HTTPSeeOther

Response class for See Other responses (status code 303).

The response to the request can be found under another URI using the GET method.

References:

Net::HTTPServiceUnavailable

Response class for Service Unavailable responses (status code 503).

The server cannot handle the request (because it is overloaded or down for maintenance).

References:

Net::ProtoSyntaxError

No documentation available

OptionParser::Switch

Individual switch class. Not important to the user.

Defined within Switch are several Switch-derived classes: NoArgument, RequiredArgument, etc.

Prism::Dispatcher

The dispatcher class fires events for nodes that are found while walking an AST to all registered listeners. It’s useful for performing different types of analysis on the AST while only having to walk the tree once.

To use the dispatcher, you would first instantiate it and register listeners for the events you’re interested in:

class OctalListener
  def on_integer_node_enter(node)
    if node.octal? && !node.slice.start_with?("0o")
      warn("Octal integers should be written with the 0o prefix")
    end
  end
end

listener = OctalListener.new
dispatcher = Prism::Dispatcher.new
dispatcher.register(listener, :on_integer_node_enter)

Then, you can walk any number of trees and dispatch events to the listeners:

result = Prism.parse("001 + 002 + 003")
dispatcher.dispatch(result.value)

Optionally, you can also use ‘#dispatch_once` to dispatch enter and leave events for a single node without recursing further down the tree. This can be useful in circumstances where you want to reuse the listeners you already have registers but want to stop walking the tree at a certain point.

integer = result.value.statements.body.first.receiver.receiver
dispatcher.dispatch_once(integer)
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