httpd_util

Module

httpd_util

Module summary

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

Description

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

Exports

convert_request_date(DateString) -> ErlDate|bad_date

Types:

DateString = string()
ErlDate = {{Year,Month,Date},{Hour,Min,Sec}}
Year = Month = Date = Hour = Min = Sec = integer()

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

Types:

FileInfo = file_info()
Etag = string()

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

Types:

NthDayOfWeek = 1-7
DayOfWeek = string()

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

Types:

HexValue = DecValue = string()

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

flatlength(NestedList) -> Size

Types:

NestedList = list()
Size = integer()

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

hexlist_to_integer(HexString) -> Number

Types:

Number = integer()
HexString = string()

hexlist_to_integer converts the hexadecimal value of HexString to an integer.

integer_to_hexlist(Number) -> HexString

Types:

Number = integer()
HexString = string()

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

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

Types:

ETSTable = ets_table()
Key = term()
Result = term() | undefined | Undefined
Undefined = term()

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)lookup_mime(ConfigDB,Suffix,Undefined) -> MimeType

Types:

ConfigDB = ets_table()
Suffix = string()
MimeType = string() | undefined | Undefined
Undefined = term()

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)lookup_mime_default(ConfigDB,Suffix,Undefined) -> MimeType

Types:

ConfigDB = ets_table()
Suffix = string()
MimeType = string() | undefined | Undefined
Undefined = term()

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

Types:

StatusCode = 301 | 400 | 403 | 404 | 500 | 501 | 504
PhraseArgs = term()
ConfigDB = ets_table
Message = string()

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

301

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.

501

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

504

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

month(NthMonth) -> Month

Types:

NthMonth = 1-12
Month = string()

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

Types:

ETSTable = ets_table()
Key = term()
Result = [term()]

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

reason_phrase(StatusCode) -> Description

Types:

StatusCode = 100| 200 | 201 | 202 | 204 | 205 | 206 | 300 | 301 | 302 | 303 | 304 | 400 | 401 | 402 | 403 | 404 | 405 | 406 | 410 411 | 412 | 413 | 414 415 | 416 | 417 | 500 | 501 | 502 | 503 | 504 | 505
Description = string()

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() -> RFC1123Daterfc1123_date({{YYYY,MM,DD},{Hour,Min,Sec}}) -> RFC1123Date

Types:

YYYY = MM = DD = Hour = Min = Sec = integer()
RFC1123Date = string()

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

Types:

String = RegExp = string()
SplitRes = {ok, FieldList} | {error, errordesc()}
Fieldlist = [string()]
N = integer

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

Types:

RequestLine = string()
Splitted = not_a_script | {Path, PathInfo, QueryString}
Path = QueryString = PathInfo = string()

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}

Types:

RequestLine = Path = QueryStringOrPathInfo = string()

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

Types:

String = Stripped = string()

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

Types:

FileName = Suffix = string()

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

See also

httpd(3)