--- name: "httpd_util" section: "3erl" platform: "linux" package: "erlang-manpages" version: "1:25.2.3+dfsg-1+deb12u4" release: "Debian 12 (Bookworm)" platforms: ["linux"] url: "https://new.carta.tech/httpd_util" --- # httpd\_util(3erl) Miscellaneous utility functions to be used when implementing Erlang web server API modules. ## NAME httpd\_util - 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. **Note:** Note the module is only recommended for using with httpd - for other cases it should be considered as deprecated. ## EXPORTS **convert\_request\_date(DateString) -\> ErlDate\|bad\_date**\ Types: 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. **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) -\> Result**\ **lookup(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 \| 308 \| 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() -\> RFC1123Date**\ **rfc1123\_date(Date) -\> RFC1123Date**\ Types: Date = calendar:datetime()\ 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) -\> Split**\ Types: RequestLine = string()\ Split = 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(3erl)](/httpd/3erl.md)