%%{ machine http_parser_common; #### HTTP PROTOCOL GRAMMAR # line endings CRLF = "\r\n"; # character types CTL = (cntrl | 127); safe = ("$" | "-" | "_" | "."); extra = ("!" | "*" | "'" | "(" | ")" | ","); reserved = (";" | "/" | "?" | ":" | "@" | "&" | "=" | "+"); sorta_safe = ("\"" | "<" | ">"); unsafe = (CTL | " " | "#" | "%" | sorta_safe); national = any -- (alpha | digit | reserved | extra | safe | unsafe); unreserved = (alpha | digit | safe | extra | national); escape = ("%" xdigit xdigit); uchar = (unreserved | escape | sorta_safe); pchar = (uchar | ":" | "@" | "&" | "=" | "+"); tspecials = ("(" | ")" | "<" | ">" | "@" | "," | ";" | ":" | "\\" | "\"" | "/" | "[" | "]" | "?" | "=" | "{" | "}" | " " | "\t"); # elements token = (ascii -- (CTL | tspecials)); # URI schemes and absolute paths scheme = ( alpha | digit | "+" | "-" | "." )* ; absolute_uri = (scheme ":" (uchar | reserved )*); path = ( pchar+ ( "/" pchar* )* ) ; query = ( uchar | reserved )* %query_string ; param = ( pchar | "/" )* ; params = ( param ( ";" param )* ) ; rel_path = ( path? %request_path (";" params)? ) ("?" %start_query query)?; absolute_path = ( "/"+ rel_path ); Request_URI = ( "*" | absolute_uri | absolute_path ) >mark %request_uri; Fragment = ( uchar | reserved )* >mark %fragment; Method = ( upper | digit | safe ){1,20} >mark %request_method; http_number = ( digit+ "." digit+ ) ; HTTP_Version = ( "HTTP/" http_number ) >mark %http_version ; Request_Line = ( Method " " Request_URI ("#" Fragment){0,1} " " HTTP_Version CRLF ) ; field_name = ( token -- ":" )+ >start_field $snake_upcase_field %write_field; field_value = any* >start_value %write_value; message_header = field_name ":" " "* field_value :> CRLF; Request = Request_Line ( message_header )* ( CRLF @done ); main := Request; }%%