/Erlang 21




Module Summary

Miscellaneous utility functions to be used when implementing Erlang web server API modules.


This module provides the Erlang web server API module programmer with miscellaneous utility functions.


convert_request_date(DateString) -> ErlDate|bad_date


convert_request_date/1 converts DateString to the Erlang date format. DateString must be in one of the three date formats defined in RFC 2616.

create_etag(FileInfo) -> Etag


create_etag/1 calculates the Etag for a file from its size and time for last modification. FileInfo is a record defined in kernel/include/file.hrl.

day(NthDayOfWeek) -> DayOfWeek


day/1 converts the day of the week (NthDayOfWeek) from an integer (1-7) to an abbreviated string, that is:

1 = "Mon", 2 = "Tue", ..., 7 = "Sat".

decode_hex(HexValue) -> DecValue


Converts the hexadecimal value HexValue into its decimal equivalent (DecValue).

flatlength(NestedList) -> Size


flatlength/1 computes the size of the possibly nested list NestedList, which can contain binaries.

hexlist_to_integer(HexString) -> Number


hexlist_to_integer converts the hexadecimal value of HexString to an integer.

integer_to_hexlist(Number) -> HexString


integer_to_hexlist/1 returns a string representing Number in a hexadecimal form.

lookup(ETSTable,Key) -> Result
lookup(ETSTable,Key,Undefined) -> Result


lookup extracts {Key,Value} tuples from ETSTable and returns the Value associated with Key. If ETSTable is of type bag, only the first Value associated with Key is returned. lookup/2 returns undefined and lookup/3 returns Undefined if no Value is found.

lookup_mime(ConfigDB,Suffix,Undefined) -> MimeType


lookup_mime returns the MIME type associated with a specific file suffix as specified in the file mime.types (located in the config directory).

lookup_mime_default(ConfigDB,Suffix,Undefined) -> MimeType


lookup_mime_default returns the MIME type associated with a specific file suffix as specified in the mime.types file (located in the config directory). If no appropriate association is found, the value of DefaultType is returned.

message(StatusCode,PhraseArgs,ConfigDB) -> Message


message/3 returns an informative HTTP 1.1 status string in HTML. Each StatusCode requires a specific PhraseArgs:


string(): A URL pointing at the new document position.

400 | 401 | 500

none (no PhraseArgs).

403 | 404

string(): A Request-URI as described in RFC 2616.


{Method,RequestURI,HTTPVersion}: The HTTP Method, Request-URI, and HTTP-Version as defined in RFC 2616.


string(): A string describing why the service was unavailable.

month(NthMonth) -> Month


month/1 converts the month NthMonth as an integer (1-12) to an abbreviated string, that is:

1 = "Jan", 2 = "Feb", ..., 12 = "Dec".

multi_lookup(ETSTable,Key) -> Result


multi_lookup extracts all {Key,Value} tuples from an ETSTable and returns all Values associated with Key in a list.

reason_phrase(StatusCode) -> Description


reason_phrase returns Description of an HTTP 1.1 StatusCode, for example, 200 is "OK" and 201 is "Created". For more information, see RFC 2616.

rfc1123_date() -> RFC1123Date
rfc1123_date({{YYYY,MM,DD},{Hour,Min,Sec}}) -> RFC1123Date


rfc1123_date/0 returns the current date in RFC 1123 format. rfc_date/1 converts the date in the Erlang format to the RFC 1123 date format.

split(String,RegExp,N) -> SplitRes


split/3 splits String in N chunks using RegExp. split/3 is equivalent to regexp:split/2 with the exception that N defines the maximum number of fields in FieldList.

split_script_path(RequestLine) -> Splitted


split_script_path/1 is equivalent to split_path/1 with one exception. If the longest possible path is not a regular, accessible, and executable file, then not_a_script is returned.

split_path(RequestLine) -> {Path,QueryStringOrPathInfo}


split_path/1 splits RequestLine in a file reference (Path), and a QueryString or a PathInfo string as specified in RFC 2616. A QueryString is isolated from Path with a question mark (?) and PathInfo with a slash (/). In the case of a QueryString, everything before ? is a Path and everything after ? is a QueryString. In the case of a PathInfo, RequestLine is scanned from left-to-right on the hunt for longest possible Path being a file or a directory. Everything after the longest possible Path, isolated with a /, is regarded as PathInfo. The resulting Path is decoded using decode_hex/1 before delivery.

strip(String) -> Stripped


strip/1 removes any leading or trailing linear white space from the string. Linear white space is to be read as horizontal tab or space.

suffix(FileName) -> Suffix


suffix/1 is equivalent to filename:extension/1 with the exception that Suffix is returned without a leading dot (.).

See also


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Licensed under the Apache License, Version 2.0.