Module: Kernel

Defined in:
lib/goodies/lwr-simple.rb

Instance Method Summary collapse

Instance Method Details

#get(uri) ⇒ Object

get will fetch the document identified by the given URL and return it. The url argument can be either a simple string or a URI object.

You will not be able to examine the response code or response headers like (‘Content-Type’) wgen you are accessing the web using this function. If you need that information you should use the full OO interface of Net::HTTP.



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# File 'lib/goodies/lwr-simple.rb', line 39

def get(uri)
	url = LWR::Simple.normalize(uri)

	begin
		return open(url).read
	rescue
		nil
	end
end

#getprint(uri, limit = 10) ⇒ Object Also known as: getputs

Get and print a document identified by URL. If the request fails, then the status code and message are printed on $stderr. The return value is the HTTPResponse object. See also getputs.

Raises:

  • (ArgumentError) 


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# File 'lib/goodies/lwr-simple.rb', line 79

def getprint(uri, limit = 10)
	raise ArgumentError, 'HTTP redirect too deep' if limit == 0
	
	url = LWR::Simple.normalize(uri)

	begin
		res = Net::HTTP.get_response(url)
	rescue => ex
		$stderr.puts "#{ex.class}: #{ex.message}"
	else
		case res
			when Net::HTTPSuccess
				puts res.body
			when Net::HTTPRedirection
				getprint(res["location"], limit - 1)
			else
				$stderr.puts "#{res.code} #{res.message}"
		end
	ensure
		return res
	end
end

#getstore(uri, file) ⇒ Object

Gets a document identified by a URL and stores it in the file. The URL can either be a string or a URI object. File can be either a string or a File object. If a problem ocurrs while writing to a file, nil is returned. If it succeeds, the return value is the HTTPResponse object.



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# File 'lib/goodies/lwr-simple.rb', line 106

def getstore(uri, file)
	res = nil

	file = file.path if file.is_a? File

	begin
		File.open(file, "w") do |f|
			res = f.getprint(uri) # this is why Ruby is so sweet
		end
	rescue
		return nil
	end

	res
end

#head(uri) ⇒ Object

Get document headers. Returns the following 5 values if successful:

  • content_type

  • document_length

  • modified_time

  • expires

  • server

Returns an empty array if it fails.



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# File 'lib/goodies/lwr-simple.rb', line 57

def head(uri)
	url = LWR::Simple.normalize(uri)

	head = []

	begin
		Net::HTTP::start(url.host, url.port) do |c|
			res = c.request_head(url.path)
			head << res["content-type"]
			head << res["content-length"]
			head << res["last-modified"]
			head << res["expires"]
			head << res["server"]
		end
	ensure
		return head
	end
end

#mirror(uri, file) ⇒ Object 



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# File 'lib/goodies/lwr-simple.rb', line 122

def mirror(uri, file)
	url = LWR::Simple.normalize(uri)
	req = Net::HTTP::Get.new(url.path)

	case file
		when String
			if File.exists? file
				file_exists = true
			else
				file_exists = false
			end
			file = File.open(file, "w")
		when File
			if File.exists? file.path
				file_exists = true
			else
				file_exists = false
			end
		else
			raise ArgumentError, "Failed arguments"
	end

	if file_exists
		req.add_field("If-Modified-Since", file.mtime.httpdate)
	end

	res = Net::HTTP.new(url.host, url.port).start do |http|
		http.request(req)
	end

	case res
		when Net::HTTPSuccess
			tmpfile = Tempfile.new("lwr")
			tmpfile.print res.body
			
			if res["content-length"] and tmpfile.size < res["content-length"].to_i
				raise Exception, "Transfer truncated, only #{tmpfile.size} of #{res["content-length"]} bytes received"
				File.unlink(tmpfile.path)
			elsif res["content-length"] and tmpfile.size > res["content-length"].to_i
				raise Exception, "Content-length mismatch, expected #{res["content-length"]} bytes, got #{tmpfile.size}"
				File.unlink(tmpfile.path)
			else # OK
				File.unlink(file.path) if File.exists? file.path
				File.rename(tmpfile.path, file.path)

			end

		else
	end

	res

end