393 lines
8.8 KiB
Plaintext
393 lines
8.8 KiB
Plaintext
\documentclass{book}
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\title{JET Extension Tags}
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\author{Bradford Matthew Arant Sr.}
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\date{\today}
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\begin{document}
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\maketitle
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\tableofcontents
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\chapter{Introduction}
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JET will pass through the untagged areas to the output without any
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modifications. Data contained within the tags may modify their
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containers before placing any output. The space taken by the tag
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itself is not passed to the output and will not appear in the output.
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Skip Blank Lines options on containers will skip passing any blank
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lines or line containing only whitespace to the output.
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\chapter{Tags and Attributes}
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XML style tagging is used to insert functions and other behaviors into
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the script. As the document contents are output a tag may be inserted
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to perform the desired function and affect the output.
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Tag attributes are used to pass parameters into the operations and
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functionality for each tag.
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Outputting a database from mysql may be performed using the <mysql> tag
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in combination with the <ifrow>, <whilerow> and <sql> tags.
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\section{User Defined Tags and Tag Liraries}
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You can define your own tag definitions and use them within your JET
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scripts.
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Keywords are not defined as part of the tag definition and any
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attribute added to the implementation of the tag is passed into the
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tag process as a local variable for that container.
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A <container /> tag can be inserted into the container and will take
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the contents of the container at runtime and insert it into the output
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when processing the user defined tag definition. The container tag of
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the the <container /> is processed before the container containing the
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<container /> so that local variabls can be set and processed that
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will affect the tags overall output.
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Tags are many times nested with tags running within the container of a
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higher tag.
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\chapter{Variables and Variable Types}
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Variables are used to contain dynamic content values and can be
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sourced from several locations and limited in scope depending on use.
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Some variable types can be set to reflect script state or are read
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only from other outside sources of data. The following is a list of
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variable types and a brief description of their source:
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\begin{itemize}
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\item Global - values can be initiaized using the set tag and
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specifying the scope of global.
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\item Local -
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\end{itemize}
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\section{Global Variables}
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Global is the default if the scope is
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not specified for any function that writes to a variable.
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\section{Local Variables}
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\section{Environment Variables}
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\section{CGI Variables}
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\chapter{Expressions}
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Expressions are used to perform complicated calculations (arithmetic), perform
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comparisons between values (boolean), manipulate strings (string) or
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perform operations on dates (date).
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\section{Operators}
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Operators are used to perform arithmetic or boolean operations on
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arguments to derive a particular result. There are two types of
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operators, as follows:
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\begin{itemize}
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\item Arithmetic -
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\item Boolean -
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\end{itemize}
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\subsection{Arithmentic Operators}
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\subsection{Boolean Operators}
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\section{Function Reference}
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\subsection{concat}
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\subsection{integer}
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\subsection{left}
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\subsection{random}
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Use the random function to return a random number between 0 and 1.
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\subsection{round}
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Use the round function to round a numeric value to the specified
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number of digits after the decimal point.
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\subsection{substring}
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Use the substring operation to extract a portion of a string and return
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the value as a string.
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\chapter{Common Gateway Interface Features}
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JET extension tags provides options for enabling the processing of
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data using the Common Gateway Interface (CGI) specification used by
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Apache and NGINX as well as other HTTP server applications. This makes
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JET a powerful tool for creating web interfaces and API handler
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environments for various javascript frameworks as well as just native
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HTML style interaction.
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To enable the CGI features within a requested document you can specify
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the cgi="true" attribute on a <jet> tag containing the document or
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<jet /> tag contained within the document.
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When you enable the CGI interface the script will look for specific
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environment variables used to retrieve the input data from the browser
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interface and automatically provide these values to the JET scripting
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using the variables interface. There are currently three supported
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data formats or content types through this interface. These content
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types are:
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formdata/urlencoded
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mutipart/formdata
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text/json
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\chapter{Tag Reference}
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This chapter will cover all the tags and parameters required to
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perform the operations that JET provides.
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\section{call}
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Use the call tag to evoke an executable file from a jet script.
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The atrributes are:
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pgm
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argn
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name
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input
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error
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\begin{verbatim}
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<call pgm="ls" arg1="-al" name="listing" />
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\end{verbatim}
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will call the ls command with parameter -al and place the output into
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a variable named 'listing'.
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\section{comment}
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Use the comment tag to create a section in the jet script that can be
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used for making comments and is ignored by the jet reader.
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The comments tag has no attributes.
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\section{for}
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Use the for tag to iterate a tag container for a logical number of
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times.
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The attributes are:
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start
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end
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step
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name
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\section{header}
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Use the header tag to output a header prior to outputting the process
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buffer to the requester.
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The attributes are:
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name
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expr
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value
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container
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\section{if/else}
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Use the if tag to perform a conditional output on the tag container.
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An optional else container provides alternate output in the event the
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condition is not met.
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The attributes are:
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value1
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value2
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type
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expr
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\section{ifrow/else}
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Use the ifrow tag to output the tag container if a row exists in the
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mysql tag. An optional else container provides alternate output in the
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event that there is no row for the sql result.
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The attributes are:
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sessionid
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\section{include}
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Use the include tag to include another content file at the location of
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the include tag.
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The attributes are:
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file
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\section{jet}
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Use the jet tag to specify parameters for the jet parsing session and
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to control the output options.
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\section{mysql}
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Use the mysql tag to specify parameters for connecting to a mysql
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server. The container of the tag is where you can specify the sql
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statement and method of processing the result output of the executed
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sql statement. The mysql session created is valid only withon the
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container of this tag.
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The attributes are:
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host
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database
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user
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password
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sessionid
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\section{read}
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Use the read tag to read the contents of a file contained on the local
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file system into a variable for further output or processing.
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The attributes are:
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file
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name
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\section{set}
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Use the set tag to store initialize a variable to a value contained in
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a value attribute, the result of an expression (expr) attribute or the
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contents of the set tag container.
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The attributes are:
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name
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expr
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value
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container
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scope
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\section{sql}
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Use the sql tag to specify an sql statement to run on the sql server
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specified in the mysql tag.
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As long as sql statements are executed within the same mysql
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containing tag then the same mysql session is used for each sql
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statement.
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The attributes are:
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sessionid
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container
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\section{stream}
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Use stream tag to output data from the server without waiting for the
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standard output buffering and processing of the JET script. This is
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useful for outputting images and streams for audio and video without
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the server having to load the whole thing into RAM first.
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The attributes are:
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file
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\section{system}
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Use the system tag to execute a bash shell command within the JET
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script.
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\section{tag}
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Use the tag tag to define a new tag definition for use within the
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script.
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Tags are normally defined globally and can be used anywhere within the
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script.
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Tags can also be defined within other tags and the scope of those tags
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is only within the defining tag's container. The enclosed tag
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definition will not be available globally.
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\section{until}
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Use the until tag to process a container at least once and
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continue to process the container until the specified condition is met.
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Note that this tag always processes the container at least once.
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Be careful not to create a never ending loop by not modifying any of
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the condition parameters specified in the condition clause.
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\section{while}
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Use the while tag to process a container if the specified condition is
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true.
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Note that the container may not be processed if the condition is never
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met.
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Be careful not to create a never ending loop by not modifying any of
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the condition parameters specified in the condition clause.
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\section{whiledir}
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Use the whiledir tag to loop a directory path to the container for
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processing.
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\section{whilerow}
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Use the whilerow tag in combination with mysql and sql tags to provide
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a container to process for each row retrieved by the sql statement.
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\section{write}
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Use the write tag to write data to the local file system.
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\end{document} |