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A pure Ruby HTTP parser using Parslet.
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require 'parslet' | |
require 'pp' | |
class HTTPParser < Parslet::Parser | |
# | |
# Character Classes | |
# | |
rule(:digit) { match('[0-9]') } | |
rule(:digits) { digit.repeat(1) } | |
rule(:xdigit) { digit | match('[a-fA-F]') } | |
rule(:upper) { match('[A-Z]') } | |
rule(:lower) { match('[a-z]') } | |
rule(:alpha) { upper | lower } | |
rule(:alnum) { alpha | digit } | |
rule(:cntrl) { match('[\x00-\x1f]') } | |
rule(:ascii) { match('[\x00-\x7f]') } | |
rule(:sp) { str(' ') } | |
rule(:lws) { sp | str("\t") } | |
rule(:crlf) { str("\r\n") } | |
rule(:ctl) { cntrl | str("\x7f") } | |
rule(:text) { lws | ctl.absnt? >> ascii } | |
rule(:safe) { str('$') | str('-') | str('_') | str('.') } | |
rule(:extra) { | |
str('!') | str('*') | str("'") | str('(') | str(')') | str(',') | |
} | |
rule(:reserved) { | |
str(';') | str('/') | str('?') | str(':') | str('@') | |
str('&') | str('=') | str('+') | |
} | |
rule(:sorta_safe) { str('"') | str('<') | str('>') } | |
rule(:unsafe) { ctl | sp | str('#') | str('%') | sorta_safe } | |
rule(:national) { | |
(alpha | digit | reserved | extra | safe | unsafe).absnt? >> any | |
} | |
rule(:unreserved) { alpha | digit | safe | extra | national } | |
rule(:escape) { str("%u").maybe >> xdigit >> xdigit } | |
rule(:uchar) { unreserved | escape | sorta_safe } | |
rule(:pchar) { | |
uchar | str(':') | str('@') | str('&') | str('=') | str('+') | |
} | |
rule(:separators) { | |
str('(') | str(')') | str('<') | str('>') | str('@') | str(',') | | |
str(';') | str(':') | str("\\") | str('"') | str('/') | str('[') | | |
str(']') | str('?') | str('=') | str('{') | str('}') | sp | | |
str("\t") | |
} | |
# | |
# Elements | |
# | |
rule(:token) { (ctl | separators).absnt? >> ascii } | |
rule(:comment_text) { (str('(') | str(')')).absnt? >> text } | |
rule(:comment) { str('(') >> comment_text.repeat >> str(')') } | |
rule(:quoted_pair) { str("\\") >> ascii } | |
rule(:quoted_text) { quoted_pair | str('"').absnt? >> text } | |
rule(:quoted_string) { str('"') >> quoted_text >> str('"') } | |
# | |
# URI Elements | |
# | |
rule(:scheme) { | |
(alpha | digit | str('+') | str('-') | str('.')).repeat | |
} | |
rule(:absolute_uri) { scheme >> str(':') >> (uchar | reserved).repeat } | |
rule(:path) { pchar.repeat(1) >> (str('/') >> pchar.repeat).repeat } | |
rule(:query_string) { (uchar | reserved).repeat } | |
rule(:param) { (pchar | str('/')).repeat } | |
rule(:params) { param >> (str(';') >> param).repeat } | |
rule(:frag) { (uchar | reserved).repeat } | |
rule(:relative_path) { | |
path.maybe.as(:path) >> | |
(str(';') >> params.as(:params)).maybe >> | |
(str('?') >> query_string.as(:query)).maybe >> | |
(str('#') >> frag.as(:fragment)).maybe | |
} | |
rule(:absolute_path) { str('/').repeat(1) >> relative_path } | |
rule(:request_uri) { str('*') | absolute_uri | absolute_path } | |
# | |
# HTTP Elements | |
# | |
rule(:request_method) { | |
str('OPTIONS') | | |
str('GET') | | |
str('HEAD') | | |
str('POST') | | |
str('PUT') | | |
str('DELETE') | | |
str('TRACE') | | |
str('CONNECT') | | |
token.repeat(1) | |
} | |
rule(:version_number) { digits >> str('.') >> digits } | |
rule(:http_version) { str('HTTP/') >> version_number.as(:version) } | |
rule(:request_line) { | |
request_method.as(:method) >> | |
sp >> request_uri.as(:uri) >> | |
sp >> http_version | |
} | |
rule(:header_name) { (str(':').absnt? >> token).repeat(1) } | |
rule(:header_value) { (text | token | separators | quoted_string).repeat(1) } | |
rule(:header) { | |
header_name.as(:name) >> str(':') >> lws.repeat(1) >> | |
header_value.as(:value) >> crlf | |
} | |
rule(:request) { | |
request_line >> crlf >> header.repeat.as(:headers) >> crlf | |
} | |
root :request | |
end | |
parser = HTTPParser.new | |
begin | |
pp parser.parse(STDIN.read) | |
rescue Parslet::ParseFailed => error | |
STDERR.puts error | |
STDERR.puts parser.root.error_tree | |
end |
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