Технологию SSI поддерживают
почти все сервера: Apache, Netscape, Spry Web и Microsoft Internet Information
Server. По сути это препроцессор, то есть перед выдачей страницы клиенту
производится обработка ее сервером.
SSI+ это более расширенная версия SSI.
Поддержка этой технологии связанна с
специальной конфигурацией WWW сервера
и протокола HTTP.
Директивы SSI позволяют
использовать в HTML документах такие
возможности как: выполнение других программ, получение информации о
файлах, переменных среды. SSI позволяет в отдельных случаях добиваться
довольно многого обходясь без написания CGI..
Если сервер не
воспринимает режим SSI, то есть команды SSI не обрабатываются, то они
воспринимаются как комментарий и выводятся пользователю как есть.
Какой
тип файлов обрабатывается SSI зависит от конфигурирования сервера, по
умолчанию обрабатываются файлы с расширением .shtml .sht , но можно настроить
сервер и на обработку файлов .htm .html. Для этого нужно в файле испоганить
настройки apache или для ограниченного в правах пользователя вбить в файл .htaccess: AddType text/html .htm .html .shtml
AddHandler server-parsed .htm .html .shtml
Options +Includes
URL адрес HTML документа из которого сделан запрос клиентом
HTTP_FROM
Имя (подобное имени Е-mail address) удаленного клиента
HTTP_FORWARDED
Имя Proxy Server, через который общается клиент
ACCEPT_LANGUGE
Список языков доступных для копьютера клиента
HTTP_COOKIE
Содержение ответа клиента на запрос от сервера (см. ниже)
include
Предназначена для вставки содержимого файла в текущий документ, также
может использоваться для вывода результатов работы скрипта.
Аргументы:
file - Путь к файлу, относительно текущей директории.
(То есть не может быть абсолютным путем к файлу (начинаться с / или
содержать ../).
virtual - Виртуальный (фактический) путь к документу
на сервере. Он может начинатся с /, но должен быть на том же сервере.
Пример:
fsize
Выводит размер файла, формат выдачи может быть изменен командой config
Аргументы:
file - Путь к файлу, относительно текущей директории.
(То есть не может быть абсолютным путем к файлу (начинаться с / или
содержать ../).
virtual - Виртуальный (фактический) путь к документу
на сервере. Он может начинатся с /, но должен быть на том же сервере.
Пример:
[an error occurred while processing this directive]
flastmod
Выводит дату/время последнего изменения файла, формат выдачи может быть изменен командой config
Аргументы:
file - Путь к файлу, относительно текущей директории.
(То есть не может быть абсолютным путем к файлу (начинаться с / или
содержать ../).
virtual - Виртуальный (фактический) путь к документу
на сервере. Он может начинатся с /, но должен быть на том же сервере.
Пример:
[an error occurred while processing this directive]
exec
Вызывает внешние программы, формат выдачи может быть изменен командой config.
Аргументы:
cmd - вызов исполняемых программ в UNIX shell.
cgi - вызов CGI скрипта.
Пример:
config
Модифицирует формат вывода для других команд.
Аргументы:
errmsg - формат сообщения об ошибке, которое выдается когда обработчик SSI+
обнаруживает ошибки. Для SSI+ также можно использовать onerr.
Пример:
sizefmt - формат информации об объеме файла. Допустимые значения sizefmt -
bytes или addrev. Они задают округление значения объема файла до ближайшего
килобайта.
Пример:
timefmt - формат значений даты/времени.
Пример:
Форматы представления даты и времени SSI
Код
Значение
Пример
%a
День недели в сокращенном виде
Sun
%A
День недели
Sunday
%b
Месяц в сокращенном виде (также %h)
Jan
%B
Месяц
Januar
%d
Дата
01
%D
Дата в формате %m/%d/%y
06/23/99
%e
Дата
1
%H
Время в часах в 24-часовой системе
13
%I
Время в часах в 12-часовой системе
01
%j
День года (десятичное число)
360
%m
Номер месяца
11
%M
Количество минут
08
%p
AM|PM
AM
%r
Время в формате %I:%M:%p
09:21:13 PM
%S
Количество секунд
09
%T
Время в 24-часовой системе в формате %H:%M:%S
12:22:40
%U
Порядковый номер недели года (также%W)
37
%w
Порядковый номер дня недели (начиная с Sunday=0)
2
%y
Год века
96
%Y
Год
1996
%z
Часовой пояс
EST
'cmdecho' The cmdecho
variable is used to set the output option of subsequent exec..cmd
tokens. The format is 'cmdecho'='""'where
is either 'ON' or 'OFF'. When the SSI+ parsing engine encounters
an exec..cmd token it executes the command. If the command returns
output then that output may be echoed into the HTML document or it may be
ignored. The format of the data echoed is dependent on the presence or absence
of config..cmdprefix and config..cmdpostfix tokens in the
document. In the absence of config..cmdprefix and config..cmdpostfix
tokens the output will be echoed exactly as returned with no formatting
and no special character interpretation. In the presence of config..cmdprefix
and/or config..cmdpostfix tokens the output will be formatted and
interpreted. To activate echoing set cmdecho to 'ON' otherwise set
it to 'OFF'. The default is 'OFF'.
'cmdprefix' The cmdprefix variable is used to set the
string prefixed to each line out output from subsequent exec..cmd
tokens. The format is
'cmdprefix="'"'where is any
character string and/or HTML format tags. When the SSI+ parsing
engine encounters an exec..cmdtoken it executes the command.
If the command returns output then that output may be echoed into
the HTML document or it maybe ignored. If the output is echoed (see 'cmdecho'
above),then each line output from the executable will be prefixed
with the string supplied before being echoed into the HTML document.
'cmdpostfix' The cmdpostfix variable is used to set the
string appended to the end of each line out output from subsequent exec..cmd
tokens. The format is
'cmdpostfix="'"'where is any
character string and/or HTML format tags. When the SSI+ parsing
engine encounters an exec..cmdtoken it executes the command.
If the command returns output then that output may be echoed into
the HTML document or it maybe ignored. If the output is echoed (see 'cmdecho'
above),then each line output from the executable will be appended
with the string supplied before being echoed into the HTML document.
'onerr' The onerr variable is used to set the action to be
taken when the SSI+ engine encounters an error. The format is
'onerr="'"'where is one of
the following tags.
'goto' causes a jump to a label token (see
below). The format of the goto tag is:
'goto'
'print' causes text to be printed. The format of the
print tag is:
'print "'"'
where is any HTML text or tag.
'error' causes the current config..error message
to be printed.
'break' causes termination of the HTML document
transmission to the client.
'errorbreak' causes the current config..error
message to be printed, and then causes termination of the HTML
document transmission to the client.
'printbreak' causes text to be printed, and then causes
termination of the HTML document transmission to the client. The
format of the printbreak tag is the same as the format of the
print tag.
Example. The following token on an HTML document sets the SSI+
error action to print a message and terminate the document. From this
point on down when an error occurs in the SSI+ parsing engine the
message will be inserted into the HTML document at the location of the
offending SSI+ statement, and the document will be terminated
Example. Suppose you wish to create an HTML document that
performs a 'PING' operation on address '204.96.64.171' and then echo
the results back to the client browser, with each line echoed as an
element in an unnumbered list.
Insert the following lines into your HTML document:
When the document is accessed by a remote browser the output would
look something like this:
Pinging 204.96.64.171 with 32 bytes of data:
Reply from 204.96.64.171: bytes=32 time<10ms TTL=32
Reply from 204.96.64.171: bytes=32 time<10ms TTL=32
Reply from 204.96.64.171: bytes=32 time<10ms TTL=32
Reply from 204.96.64.171: bytes=32 time<10ms TTL=32
odbc
Notice! Due to some problems with the MS ODBC drivers we are
phasing out the support of the SSI+ ODBC tags. To impliment ODBC with
WebQuest we are using CScript with our WQODBC.DLL. For more
information on CScript and ODBC, check out the Guestbook tutorial. The
SSI+ ODBC tags will not exist in WebQuest 3.0.
The odbc tag provides for querying and updating odbc
databases. Four variables are defined for the odbc token; 'debug',
'connect', 'statement', and 'format'.
'debug' variable
The debug variable is used to set the SSI+ engine into debug
mode. Debug mode provides diagnostics of a highly detailed nature from
both the SSI engine itself and the local ODBC engine. Debug messages
appear on the returned HTML document at the position at which the
errors occur. The debug variable should be used only for development
and must be removed before production. When the debug variable is
present a warning message will appear indicating it's presence, this
message is benign and will not affect any other aspect of the SSI+
engine. The format of the debug variable is :
'debug='""' where;
The connect variable is used to connect to a pre-existing odbc
data source, to allow for subsequent statement tag operations
on that data source. The format of the connect variable is
'connect="'','',''"'where
;
is the name odbc data source as defined on the
local system in the odbc configuration utility. CAUTION! the
account under which the server is run must be granted permission to
access the data source.
is the name which to log into the data source.
is the password with which to access the data source.
Example. To connect to a data source called 'odbcsht' as user
'dufus' and password 'dorkboy', one would use the following statement:
.
'statement' variable
The statement variable is used to submit a Transact SQL
statement to the odbc data source. The format of a statement variable
is as follows: 'statement="''"',where:
is any Transact SQL statement as
defined in odbc and SQL reference text and help files.
Example. Suppose one wanted to query the 'CUSTOMERS' table
from the above connected 'odbcsht' database to return all rows and
display each row on a separate line. One may use the following
sequence of statements:
Connect to the database with a connect token as described above.
Setup the output format with a statement token as described below.
Execute the query:
Each row of the database will the be inserted into the HTML page
per the format statement as demonstrated below.
The format variable is used to provide a template for the
format of data that is returned from and odbc query. Use this variable
to set up the appearance of data that will be returned from subsequent
statement tag operations that return data from a database (i.e.
the SQL statement 'SELECT'). The format of the format variable is
'format="''"'where;
is a standard C language printf format
string with the restriction of only allowing string (%s) insertions.
The user is referred to any C language text for a description of
this format. The number of instances of %s must be equal to the
number of fields selected in a the subsequent SQL SELECT statement token.
Example. Suppose one wanted to query the 'CUSTOMERS' table
from the above connected 'odbcsht' database to display the columns
'name', 'age', and 'viscosity' with each row on a separate line. One
may use the following sequence of statements:
Connect to the database with a connect token as described above.
Setup the output format: .
Execute the query with a statement token as described above.
Each row of the database will the be inserted into the HTML page
per the format statement. For example if the database has 3 rows the
HTML output would look something like this:
Customer's name is Conan, and he is 29 years old, he prefers a
motor oil with SPF 15 viscosity
Customer's name is Kevin, and he is 45 years old, he prefers a
motor oil with SPF 30 viscosity
Customer's name is Alan, and he is 43 years old, he prefers a
motor oil with SPF 50 viscosity
При отработке данного примера будет отправлено электронное письмо (e-mail),
содержание которого задано атрибутомmessage, по адресу, определенному атрибутомtoaddress, если данный адрес и host,
заданный атрибутомtohost (данный
атрибут может отсутсвовать), реально
существует.
The email tag provides for sending an Email whenever an HTML
page is accessed or an HTML form submitted. The nature of the
variables below is defined in RFC 733. The variables 'fromhost',
'tohost', 'fromaddress' and 'toaddress' are required, all others are optional.
'debug' enables advanced diagnostics. This variable should only be
used during development. The format of this variable is
'debug=" ''"' where
:= 'ON' to enable debugging
:= 'OFF' to disable debugging, this is the
default action if the debug variable is omitted.
'fromhost' defines the name of the smtp host sending the mail.
'tohost' defines the name of the smtp host the mail will be sent to.
'fromaddress' defines the email address from party.
'toaddress' defines the email address of the recipient party.
'message' defines the message body to be sent.
'subject' defines the subject field of the message to be sent.
'sender' defines the email address sending party.
'replyto' defines the email address to which replies should be sent.
'cc' defines the courtesy copy email addresses.
'inreplyto' defines the inreplyto field of the message to be sent.
'id' defines the id field of the message to be sent.
Example. The following document send an email with debugging
enabled. Supposewe have a form with datum : [First, Last, Middle
Initial, Company,Address1, Address2, City, State, Zip, Country, Phone,
Fax, Request,Urgency, ReplyMethod; Email, Subject, Message] we may
post thatform to an HTML document containing the following fragment
tosend an email.
The if tag provides for conditional execution of SSI
operations, and conditional printing of HTML text, based on logical
comparisons. The format of the if tag is :
'if' '"''"'
'"''"'
where:
is the first operand of a logical comparison
statement
is the second operand of a logical comparison
statement
is the logical comparison method ['==',
'!=','<', '>', '!<', '!>']
is the action to take if the logical comparison
evaluates to TRUE ['goto', 'print', 'error', 'break', 'errorbreak', 'printbreak']
The operands may be any string or number (integer or floating point).
In the event that both operands are numbers the comparison will be
based on the value of the numbers. In the event that one or both of
the operands and not numbers, the comparison will be based on the
alphabetic order of the operands.
The special case of the NULL operand is defined by two quotes with no
characters between them. The NULL operand may used to check for the
existence of form data from the remote client (see example below).
The operator defines what kind of comparison is performed on the operands:
'==' The equalto operator evaluates to TRUE if the operands are
equal to each other.
'!=' The notequalto operator evaluates to TRUE if the operands are
not equal to each other.
'<' The lessthan operator evaluates to TRUE if operand1 is less
than operand2.
'>' The greaterthan operator evaluates to TRUE if operand1 is
greater than operand2
'!<' The notlessthan operator evaluates to TRUE if operand1 is
not less than operand2
'!>' The notgreaterthan operator evaluates to TRUE if operand1
is not greater than operand2
'hasstring' The hasstring operator returns TRUE is the text string
in operand2 is found in the operand1 string.
In the event that the logical comparison evaluates to FALSE, nothing
happens, If the logical comparison evaluates to TRUE then one of the
following operations may be performed:
'goto' causes a jump to a label token (see below).The
format of the goto tag is:
'goto'
'print' causes text to be printed. The format of the print tag is:
'print'
where is any HTML text or tag.
'error' causes the current config..error message to be printed.
'break' causes termination of the HTML document transmission to
the client.
'errorbreak' causes the current config..error message to be
printed, and then causes termination of the HTML document
transmission to the client.
'printbreak' causes text to be printed, and then causes
termination of the HTML document transmission to the client. The
format of the printbreak tag is the same as the format of the print tag.
Example. The following document fragment compares two numbers,
if the operands are not equal then a goto will jump to a label.
This should not print
This should print
Example. The following document fragment demonstrates
conditional execution based on data delivered from an HTML form.
Suppose we have two form datum called 'formdata1' and 'formdata2' and
we wish to compare them. The following document fragment compares the
two operands, if the operands are equal then a goto will jump to a
label. Otherwise the next line will print and the document will
terminate on a break token (see below).
The operands are not equal.
operands are equal.
Example. The following document fragment prints two different
statements depending on whether or not the client agent is NCSA Mosaic.
You are not using Mosaic
You are using Mosaic
Example. Suppose we have a form with amongst other things a
field named "BOO" and we wish to make sure that the remote
client user enterted data into the "BOO" field before
submitting the form. The following document fragment checks for the
presence of data in the "BOO" field, if data exists then
nothing happens, if data does not exist then a message will be
displayed and the document will terminate.
