Symbolic variables

A symbolic variable represents a transfer data item whose value is not known at the time Transfer CFT parameters are set, but only at the time the transfer is executed.

For example, prior to a transfer the transfer identifier IDT is not known, so the symbolic variable &IDT can be used to reference the value. For more information see Symbolic variable syntax.

Symbolic variables may be used in defining the values of certain parameters of the commands and procedure files associated with transfers. This avoids having to repeat the same basic descriptions a considerable number of times: a single CFTSEND command can hence be applied to several files by using the symbolic variables in the FNAME parameter. This also makes it possible to only have to describe one transfer-related procedure applicable to several transfers. The real value of the parameter is substituted for the symbolic variable, at the time the Transfer CFT command or the procedure is executed.

Symbolic variable syntax

The symbolic variable syntax is as follows:

• A special character in the first position (leftmost)
• Optionally followed by the character(s):

• Optionally followed by a character string to be used as a prefix (-string_prefix) and/or a character string to be used as a suffix (+string_suffix) and/or a character string to be used as a substitute/alternate value (=string_alternate)
• Optionally followed by a numeric formula with a syntax ‘n’ or ‘p.’ or ‘p.n’
• And then a character string representing the identifier of the variable to be substituted

Refer to the Transfer CFT Operations Guide that corresponds to your OS, in order to determine the special character <char_symb> used on your system.

The special character which is used in the rest of this document, as well as in the Transfer CFT Operations Guide corresponding to your OS, is the ‘&’ character.

The identifiers, recognized by Transfer CFT, which can be used in the syntax of a symbolic variable are indicated in the List of symbolic variables. In this section, the ‘VAR’ notation is used to generically designate such an identifier.

The substitution mechanism, which is used to assign a value to the symbolic variable using the effective value of the ‘VAR’ identifier, depends on the numeric formula indicated after the & character.

According to the syntax used:

• &VAR syntax (numeric formula not used)

  The value substituted for the symbolic variable equals the effective value of the ‘VAR’ identifier, truncated of the blank characters on the right.

• &+VAR syntax:

  The value substituted for the symbolic variable is shifted to upper case.

• &nVAR syntax:
  • The value substituted for the symbolic variable corresponds to a fixed length string of n characters, equal to the string corresponding to the effective value of ‘VAR’, truncated as required, or with blank characters added to the right.
  • The first character in this string corresponds to the first character, from the left, of the string corresponding to the value of the ‘VAR’ identifier.
• &p.VAR syntax:

  The value substituted for the symbolic variable corresponds to the character substring formed from the effective value of ‘VAR’ such that:

  • The first character of this substring corresponds to the p th character (from the left) of the string corresponding to the value of ‘VAR’
  • The length corresponds exactly to the length of the effective value of ‘VAR’, the character in the i position being equal to the character in the p+i position of the value of ‘VAR’. If the length of the value of ‘VAR’ is m characters, the length of the substring will consequently be m-p+1 characters

• &p.nVAR syntax:
  • The value substituted for the symbolic variable corresponds to the character sub-string formed from the effective value of ‘VAR’ such that:

    The first character of this substring corresponds to the p th character (from the left) of the string corresponding to the value of ‘VAR’

    This substring is n characters long (fixed length), the character in the i position being equal to the character in the p+i position of the value of ‘VAR’. If the length of the effective value of VAR is less than p+n characters, the characters completing the substring are blank characters

• &(-string_prefix) (+string_suffix) (=string_alternate)p.nVAR syntax:

After the &p.nVAR symbolic variable has been substituted:

• The <str_prefix>character string is added before the variable, if the substituted variable is not empty
• The <str_suffix> character string is added after the variable, if the substituted variable is not empty
• The <str_alternate> character string is used if the substituted variable is empty
• The character strings <str_prefix>, <str_suffix> and <str_alternate> can contain a symbolic variable

Example symbolic variable usage

If PART=PART1 and IDF=TEST, then FNAME=&IDF&PART.tst is substituted by FNAME=TESTPART1.tst

In formats in which "n" or "p" are used, the following remarks are valid:

• A value of "n" equal to 0 is non significant
• A value of "p" equal to 0 is non significant
• A position "p" greater than the length of the "effective" value of ‘VAR’ gives, after substitution, a string of zero length

This allows identifiers of length less than p to be selected, for example.

Example of possible formats

Given the generic identifier ‘VAR’ of effective value, the character string: ‘F2345’.

Depending on the format of the associated symbolic variable, the substituted values are:

Example using optional characters

Given the generic identifier ‘VAR’ of an effective value, and the character string: ‘SEND'.

Depending on the associated symbolic variable format, the substituted values are:

Example of rebuilding filenames using symbolic variables

Given the syntax FNAME=&FROOT&(-.)FSUF:

• If &FSUF is empty, FNAME gets the value &FROOT
• If &FSUF is not empty, FNAME gets the value &FROOT.&FSUF

For example, if you have a file readme.txt on two different platforms:

• Given the syntax FNAME=&(+(1234&))PARM
  • If &PARM is not empty, FNAME gets the value &PARM(1234)

Example of breaking down files names

Break down the name of the file to send using the symbolic variables &FUNIT , &FUNITC , &FPATH , &FROOT , &FSUF (applied to

the SFNAME).

Break down the name of the received file using the symbolic variables &UNIT, &UNITC, &PATH , &ROOT, &SUF (applied to the FNAME).

List of symbolic variables

The table below indicates all the symbolic variables available, using the syntax &VAR. The substituted value, corresponding to the effective value of the identifier ‘VAR’ (truncated of the blank characters on the right), is also indicated.

List of symbolic variables

(1): These variables are linked to SSL use.

(2): EXEC in SEND, EXECSF, EXECSM, EXEC in RECV, EXECRF, EXECRM, EXECE, EXECSE, EXECRE, EXECA, EXECSFA, EXECSMA, PREEXEC, EXITEOT, EXECSUB, EXECSUBA, EXECSUBPRE

• Time: HHMMSSCC  
• Complete date: YYYYMMDD
• Year: YY
• Month: MM
• Day: DD

Sender

The symbolic variables are substituted by the values of the local parameters of the commands.

Receiver

The symbolic variables are substituted:

• By the sender parameter values when these values are conveyed by the protocol
• By default, by the corresponding local parameter values

Using symbolic variables

Symbolic variables can be used:

• To assign a value to certain parameters of the parameter setting or transfer commands
• In the processing operations defined by the user in the procedures associated with the transfers

Example

A file name can consist of the day’s date and the partner’s name:  the description command for the PAY file in reception.

When a file of this type is received from the ALPHSITE partner on July 14 13:

Transfer CFT creates and writes to a file: PAYALPH.14

See the end-of-transfer examples in Transfer-related procedure examples.

Defining symbolic variable blacklists for processing scripts

UNIX and Windows only

You can use blacklist characters as a POSIX Regular Extended expression to define forbidden characters in a processing script. To prevent unauthorized actions, do not use these characters in symbolic variables.

Defining the blacklist

Use the uconf cft.server.processing_scripts_variables_blacklist parameter to define the character sequence to forbid. We recommend setting this parameter to "`|\$(|;|&&||" for UNIX, and "&" for Windows.

UNIX

Windows

DIAGI 158

This DIAGI indicates that there was an error while replacing the Transfer CFT variables.

Log messages

• CFTS67E: Error replacing variable <var> <error message>
• CFTS68E: PART=&part [IDF=&idf | IDM=&idm]IDT=&idt _ &fname not executed

Transport security symbolic variables

This section describes additional symbolic variables relating to transport security. These symbolic variables can be used in end-of-transfer procedures EXECRF, EXECSF, EXECRM, and so on. These variables indicate whether transport security is used, and if so, the session parameters such as the authentication mode, suite negotiated and certificates used.