httpd - An implementation of an HTTP 1.1 compliant Web server, as defined in RFC 2616.

start()

start(ConfigFile) -> ServerRet

start_link()

start_link(ConfigFile) -> ServerRet

Types

ConfigFile = string()

ServerRet = {ok, Pid} | ignore | {error, EReason} | {stop, SReason}

Pid = pid()

EReason = {already_started, Pid} | term()

SReason = string()

start/1 and start_link/1 starts a server as specified in the given ConfigFile. The ConfigFile supports a number of config directives specified below.

start/0 and start/0 starts a server as specified in a hard-wired config file, that is start("/var/tmp/server_root/conf/8888.conf"). Before utilizing start/0 or start_link/0, copy the example server root($INETS_ROOT/examples/server_root/) to a specific installation directory(/var/tmp/) and you have a server running in no time.

If you copy the example server root to the specific installation directory it is furthermore easy to start an SSL enabled server, that is start("/var/tmp/server_root/conf/ssl.conf").

restart()

restart(Port) -> ok | {error,Reason}

restart(ConfigFile) -> ok | {error,Reason}

restart(Address,Port) -> ok | {error,Reason}

Types

Port = integer()

Address = {A, B, C, D} | string() | undefined

ConfigFile = string()

Reason = term()

restart restarts the server and reloads its config file.

The follwing directives cannot be changed: BindAddress, Port and SocketType. If these should be changed, then a new server should be started instead.

Note:

Module:do(Info)-> {proceed, OldData} | {proceed, NewData} | {break, NewData} | done

Types

Info = mod()

OldData = list()

NewData = [{response, {StatusCode, Body}}] | [{response, {response, Head, Body2}}] | [{response, {already_sent, Statuscode, Size}]

StausCode = integer()

Body = String

Head = [HeaderOption]

HeaderOption = {Key, Value} | {code, StatusCode}

Key = allow | cache_control | content_MD5 | content_encoding | content_encoding | content_language, Value | content_length | content_location | content_range | content_type | date | etag | expires | last_modified | location | pragma | retry_after | server | trailer | transfer_encoding

Value = string()

Body2 = {Fun, Arg} | Body | nobody

Fun = fun( Arg )->sent| close | Body

Arg = [term()]

Info is a record of type mod, this record is defined in httpd.hrl see EWSAPI Module programming in the Inets Users Guide for more information.

When a valid request reaches httpd it calls do/1 in each module defined by the Modules configuration directive. The function may generate data for other modules or a response that can be sent back to the client.

The field data in Info is a list. This list will be the list returned from the from the last call to do/1.

Body is the body of the http-response that will be sent back to the client an appropriate header will be appended to the message. StatusCode will be the status code of the response see RFC2616 for the appropriate values.

Head is a key value list of HTTP header fields. the server will construct a HTTP header from this data. See RFC 2616 for the appropriate value for each header field. If the client is a HTTP/1.0 client then the server will filter the list so that only HTTP/1.0 header fields will be sent back to the client.

If Body2 is returned and equal to {Fun, Arg} The Web server will try apply/2. on Fun with Arg as argument and excpect that the fun either returns a list (Body) that is a HTTP-repsonse or the atom sent if the HTTP-response is sent back to the client. If close is returned from the fun something has gone wrong and the server will signal this to the client by closing the connection.

Module:load(Line, Context)-> eof | ok | {ok, NewContext} | {ok, NewContext, Directive} | {ok, NewContext, DirectiveList} | {error, Reason}

Types

Line = string()

Context = NewContext = DirectiveList = [Directive]

Directive = {DirectiveKey , DirectiveValue}

DirectiveKey = DirectiveValue = term()

Reason = term()

load/2 takes a row Line from the configuration file and tries to convert it to a key value tuple. If a directive is dependent on other directives, the directive may create a context. If the directive is not dependent on other directives return {ok, [], Directive}, otherwise return a new context, that is {ok, NewContext} or {ok, Context Directive}. If {error, Reason} is returned the configuration directive is assumed to be invalid.

Module:store({DirectiveKey, DirectiveValue}, DirectiveList)-> {ok, {DirectiveKey, NewDirectiveValue}} | {ok, [{ok, {DirectiveKey, NewDirectiveValue}} | {error, Reason}

Types

DirectiveList = [{DirectiveKey, DirectiveValue}]

DirectiveKey = DirecitveValue = term()

Context = NewContext = DirectiveList = [Directive]

Directive = {Key , Value}

Reason = term()

When all rows in the configuration file is read the function store/2 is called for each configuration directive. This makes it possible for a directive to alter other configuration directives. DirectiveList is a list of all configuration directives read in from load. If a directive may update other configuration directives then use this function.

Module:remove(ConfigDB)-> ok | {error, Reason}

Types

ConfigDB = ets_table()

Reason = term()

When httpd shutdown it will try to execute remove/1 in each ewsapi module. The ewsapi programmer may use this to close ets tables, save data, or close down background processes.

httpd_core(3), httpd_conf(3), httpd_socket(3), httpd_util(3),

Joakim Grebenö - support@erlang.ericsson.se
Torbjörn Törnkvist - support@erlang.ericsson.se
Joe Armstrong  - support@erlang.ericsson.se