View Source httpd_util (inets v9.3)

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.

Note

Note the module is only recommended for using with httpd - for other cases it should be considered as deprecated.

See also

httpd

Summary

Functions

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

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

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

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

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

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

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.

Functions

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convert_request_date(DateString)

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-spec convert_request_date(DateString) -> ErlDate | bad_date
                              when DateString :: string(), ErlDate :: calendar:datetime().

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.

-spec create_etag(FileInfo) -> Etag when FileInfo :: file: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.

-spec day(NthDayOfWeek) -> DayOfWeek when 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".

-spec lookup(EtsTable, Key) -> Result
                when EtsTable :: ets:table(), Key :: term(), Result :: term() | undefined.

Equivalent to lookup/3.

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lookup(EtsTable, Key, Undefined)

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-spec lookup(EtsTable, Key, Undefined) -> Result
                when
                    EtsTable :: ets:table(),
                    Key :: term(),
                    Undefined :: term(),
                    Result :: term() | Undefined.

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.

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lookup_mime(ConfigDB, Suffix)

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-spec lookup_mime(ConfigDB, Suffix) -> MimeType
                     when ConfigDB :: ets:tid(), Suffix :: string(), MimeType :: string() | undefined.

Equivalent to lookup_mime/3.

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lookup_mime(ConfigDB, Suffix, Undefined)

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-spec lookup_mime(ConfigDB, Suffix, Undefined) -> MimeType
                     when
                         ConfigDB :: ets:tid(),
                         Suffix :: string(),
                         Undefined :: term(),
                         MimeType :: string() | Undefined.

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

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lookup_mime_default(ConfigDB, Suffix)

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-spec lookup_mime_default(ConfigDB, Suffix) -> MimeType
                             when
                                 ConfigDB :: ets:tid(),
                                 Suffix :: string(),
                                 MimeType :: string() | undefined.

Equivalent to lookup_mime_default/3.

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lookup_mime_default(ConfigDB, Suffix, Undefined)

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-spec lookup_mime_default(ConfigDB, Suffix, Undefined) -> MimeType
                             when
                                 ConfigDB :: ets:tid(),
                                 Suffix :: string(),
                                 Undefined :: term(),
                                 MimeType :: string() | Undefined.

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.

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message(StatusCode, PhraseArgs, ConfigDB)

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-spec message(StatusCode, PhraseArgs, ConfigDB) -> Message
                 when
                     StatusCode ::
                         301 | 304 | 400 | 401 | 403 | 404 | 408 | 412 | 413 | 414 | 500 | 501 | 503 |
                         504,
                     PhraseArgs :: term(),
                     ConfigDB :: ets:tid(),
                     Message :: string().

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

  • 301 - string/0: A URL pointing at the new document position.

  • 400 | 401 | 500 - none (no PhraseArgs).

  • 403 | 404 - string/0: 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/0: A string describing why the service was unavailable.

-spec month(NthMonth) -> Month when 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".

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multi_lookup(EtsTable, Key)

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-spec multi_lookup(EtsTable, Key) -> Result
                      when EtsTable :: ets:tid(), Key :: term(), Result :: list() | [term()].

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

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reason_phrase(StatusCode)

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-spec reason_phrase(StatusCode) -> Description
                       when
                           StatusCode ::
                               100 | 101 | 102 | 200 | 201 | 202 | 203 | 204 | 205 | 206 | 207 | 226 |
                               300 | 301 | 302 | 303 | 304 | 305 | 306 | 307 | 308 | 400 | 401 | 402 |
                               403 | 404 | 405 | 406 | 407 | 408 | 409 | 410 | 411 | 412 | 413 | 414 |
                               415 | 416 | 417 | 422 | 423 | 424 | 425 | 426 | 500 | 501 | 502 | 503 |
                               504 | 505 | 507,
                           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.

-spec rfc1123_date() -> RFC1123Date when RFC1123Date :: string().

Equivalent to rfc1123_date/1.

-spec rfc1123_date(LocalTime) -> RFC1123Date
                      when
                          LocalTime :: calendar:datetime() | undefined,
                          RFC1123Date :: string() | undefined.

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.

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split(String, RegExp, N)

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-spec split(String, RegExp, N) -> SplitRes
               when
                   String :: string(),
                   RegExp :: string(),
                   N :: non_neg_integer(),
                   SplitRes :: {ok, FieldList} | {error, term()},
                   FieldList :: [string()].

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

-spec split_path(URIString) -> {Path, QueryStringOrPathInfo}
                    when URIString :: string(), Path :: string(), 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

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split_script_path(URIString)

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-spec split_script_path(URIString) -> Split
                           when
                               URIString :: string(),
                               Split :: not_a_script | {Path, {PathInfo, QueryString}} | {Path, []},
                               Path :: string(),
                               QueryString :: string(),
                               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.