A collection of LPEG patterns

Use cases

• Strict validation of user input
• Searching free-form input

Modules

core

A small module implementing commonly used rules from RFC-5234 appendix B.1

• ALPHA (pattern)
• BIT (pattern)
• CHAR (pattern)
• CR (pattern)
• CRLF (pattern)
• CTL (pattern)
• DIGIT (pattern)
• DQUOTE (pattern)
• HEXDIG (pattern)
• HTAB (pattern)
• LF (pattern)
• LWSP (pattern)
• OCTET (pattern)
• SP (pattern)
• VCHAR (pattern)
• WSP (pattern)

IPv4

• IPv4address (pattern): parses an IPv4 address in dotted decimal notation. on success, returns addresses as an IPv4 object
• IPv4_methods (table):
  • unpack (function): the IPv4 address as a series of 4 8 bit numbers
  • binary (function): the IPv4 address as a 4 byte binary string
• IPv4_mt (table): metatable given to IPv4 objects
  • __index (table): IPv4_methods
  • __tostring (function): returns the IPv4 address in dotted decimal notation

IPv4 "dotted decimal notation" in this document refers to "strict" form (see RFC-6943 section 3.1.1) unless otherwise noted.

IPv6

• IPv6address (pattern): parses an IPv6 address
• IPv6addrz (pattern): parses an IPv6 address with optional "ZoneID" (see RFC-6874)
• IPv6_methods (table): methods available on IPv6 objects
  • unpack (function): the IPv6 address as a series of 8 16bit numbers, optionally followed by zoneid
  • binary (function): the IPv6 address as a 16 byte binary string
  • setzoneid (function): set the zoneid of this IPv6 address
• IPv6_mt (table): metatable given to IPv6 objects
  • __tostring (function): will return the IPv6 address as a valid IPv6 string

uri

Parses URIs as described in RFC-3986.

• uri (pattern): on success, returns a table with fields: (similar to luasocket)
  • scheme
  • userinfo
  • host
  • port
  • path
  • query
  • fragment
• absolute_uri (pattern): similar to uri, but does not permit fragments
• uri_reference (pattern): similar to uri, but permits relative URIs
• relative_part (pattern): matches a relative uri not including query and fragment; data is held in named group captures "userinfo", "host", "port", "path"
• scheme (pattern): matches the scheme portion of a URI
• userinfo (pattern): matches the userinfo portion of a URI
• host (pattern): matches the host portion of a URI
• IP_literal (pattern): matches an IP based host portion of a URI. Capture is an IPv4, IPv6 or IPvFuture object
• port (pattern): matches the port portion of a URI
• authority (pattern): matches the authority portion of a URI; data is held in named group captures of "userinfo", "host", "port"
• path (pattern): matches the path portion of a URI. Captures nil for the empty path.
• segment (pattern): matches a path segment (a piece of a path without a /)
• query (pattern): matches the query portion of a URI
• fragment (pattern): matches the fragment portion of a URI
• sane_uri (pattern): a variant that shouldn't match things that people would not normally consider URIs. e.g. uris without a hostname
• sane_host (pattern): a variant that shouldn't match things that people would not normally consider valid hosts.
• sane_authority (pattern): a variant that shouldn't match things that people would not normally consider valid hosts.
• pct_encoded (pattern): matches a percent encoded octet, produces a capture of the normalised form.
• sub_delims (pattern): the set of subcomponent delimeters

email

• mailbox (pattern): the mailbox format: matches either name_addr or an addr-spec.
• name_addr (pattern): the name and address format i.e. Display Name<email@example.com> Has captures of the local_part and the domain. Captures the display name in the named capture "display"
• email (pattern): also known as an "addr-spec"; follows RFC-5322 section 3.4.1 Has captures of the local_part and the domain Be careful trying to reconstruct the email address from the captures; you may need escaping
• local_part (pattern): the bit before the @ in an email address
• domain (pattern): the bit after the @ in an email address
• email_nocfws (pattern): a variant that doesn't allow for comments or folding whitespace
• local_part_nocfws (pattern): the bit before the @ in an email address; no comments or folding whitespace allowed.
• domain_nocfws (pattern): the bit after the @ in an email address; no comments or folding whitespace allowed.

http

These patterns should be considered to have non stable APIs.

RFC 4918

• DAV (pattern)
• Depth (pattern)
• Destination (pattern)
• If (pattern)
• Lock_Token (pattern)
• Overwrite (pattern)
• TimeOut (pattern)

RFC 5023

• SLUG (pattern)

RFC 5323

• DASL (pattern)

RFC 5789

• Accept_Patch (pattern)

RFC 5988

• Link (pattern)

RFC 6265

• Set_Cookie (pattern)
• Cookie (pattern)

RFC 6266

• Content_Disposition (pattern)

RFC 6454

• Origin (pattern)

RFC 6455

• Sec_WebSocket_Accept (pattern)
• Sec_WebSocket_Key (pattern)
• Sec_WebSocket_Extensions (pattern)
• Sec_WebSocket_Protocol_Client (pattern)
• Sec_WebSocket_Protocol_Server (pattern)
• Sec_WebSocket_Version_Client (pattern)
• Sec_WebSocket_Version_Server (pattern)

RFC 6638

• Schedule_Reply (pattern)
• Schedule_Tag (pattern)
• If_Schedule_Tag_Match (pattern)

RFC 6797

• Strict_Transport_Security (pattern)

RFC 7034

• X_Frame_Options (pattern)

RFC 7089

• Accept_Datetime (pattern)
• Memento_Datetime (pattern)

RFC 7230

• request_line (pattern)
• field_name (pattern)
• field_value (pattern)
• header_field (pattern)
• OWS (pattern)
• RWS (pattern)
• BWS (pattern)
• token (pattern)
• qdtext (pattern)
• quoted_string (pattern)
• comment (pattern)
• Content_Length (pattern)
• Transfer_Encoding (pattern)
• chunk_ext (pattern)
• TE (pattern)
• Trailer (pattern)
• request_target (pattern)
• Host (pattern)
• Via (pattern): captures are a list of tables with fields .protocol, .by and .comment
• Connection (pattern)
• Upgrade (pattern): captures are a list of strings containing protocol or protocol/version

RFC 7231

• IMF_fixdate (pattern)
• Content_Encoding (pattern)
• Content_Type (pattern)
• Content_Language (pattern)
• Content_Location (pattern)
• Expect (pattern)
• Max_Forwards (pattern)
• Accept (pattern)
• Accept_Charset (pattern)
• Accept_Encoding (pattern)
• Accept_Language (pattern)
• From (pattern)
• Referer (pattern)
• User_Agent (pattern)
• Date (pattern): capture is a table in the same format as used by os.time
• Location (pattern)
• Retry_After (pattern): capture is either a table describing an absolute time in the same format as used by os.time, or a relative time as a number of seconds
• Vary (pattern)
• Allow (pattern)
• Server (pattern)

RFC 7232

• Last_Modified (pattern): capture is a table in the same format as used by os.time
• ETag (pattern)
• If_Match (pattern)
• If_None_Match (pattern)
• If_Modified_Since (pattern): capture is a table in the same format as used by os.time
• If_Unmodified_Since (pattern): capture is a table in the same format as used by os.time

RFC 7233

• Accept_Ranges (pattern)
• Range (pattern)
• If_Range (pattern): capture is either an entity_tag or a table in the same format as used by os.time
• Content_Range (pattern)

RFC 7234

• Age (pattern)
• Cache_Control (pattern): captures are grouped into key/value pairs (where a directive with no value has a value of true)
• Expires (pattern): capture is a table in the same format as used by os.time
• Pragma (pattern)
• Warning (pattern)

RFC 7235

• WWW_Authenticate (pattern)
• Authorization (pattern)
• Proxy_Authenticate (pattern)
• Proxy_Authorization (pattern)

RFC 7239

• Forwarded (pattern)

RFC 7469

• Public_Key_Pins (pattern)
• Public_Key_Pins_Report_Only (pattern)

RFC 7486

• Hobareg (pattern)

RFC 7615

• Authentication_Info (pattern)
• Proxy_Authentication_Info (pattern)

RFC 7639

• ALPN (pattern)

RFC 7809

• CalDAV_Timezones (pattern)

RFC 7838

• Alt_Svc (pattern)
• Alt_Used (pattern)

Expect-CT Extension for HTTP

• Expect_CT (pattern)

Referrer-Policy header

• Referrer_Policy (pattern)

phone

• phone (pattern): includes detailed checking for:
  • USA phone numbers using the NANP

language

Patterns for definitions from RFC-4646 Section 2.1

• langtag (pattern): Capture is a table with the language tag decomposed into components:
  • language
  • extlang (optional)
  • script (optional)
  • region (optional)
  • variant (optional): an array
  • extension (optional): a dictionary from singleton to value
  • privateuse (optional): an array
• privateuse (pattern): captures an array
• Language_Tag (pattern): captures the whole language tag