13.5.3.5 To Call Out to a Mapping Table from a Conversion Entry

out-parameter-* values may be stored and retrieved in an arbitrarily named mapping table. This feature is useful for renaming attachments sent by clients that send all attachments with a generic name like att.dat regardless of whether they are postscript, msword, text or whatever. This is a generic way to relabel the part so that other clients (Outlook for example) will be able to open the part by reading the extension.

The syntax for retrieving a parameter value from a mapping table is as follows:

”mapping-table-name:mapping-input[$Y, $N]’

$Y returns a parameter value. If there is no match found or the match returns $N, then that parameter in the conversions file entry is ignored or treated as a blank string. Lack of a match or a $N does not cause the conversion entry itself to be aborted.

Consider the following mapping table:

X-ATT-NAMES

   postscript       temp.PS$Y
   wordperfect5.1   temp.WPC$Y
   msword           temp.DOC$Y

The following conversion entry for the above mapping table results in substituting generic file names in place of specific file names on attachments:

out-chan=tcp_local; in-type=application; in-subtype=*; 
   in-parameter-name-0=name; in-parameter-value-0=*; 
   out-type=application; out-subtype=’INPUT-SUBTYPE’; 
   out-parameter-name-0=name; 
   out-parameter-value-0=”’X-ATT-NAMES:\\’INPUT_SUBTYPE\\''"; 
   command="cp  ”INPUT_FILE’  ”OUTPUT_FILE’"

In the example above, out-chan=tcp_local; in-type=application; in-subtype=* specifies that a message to be processed must come from the tcp_local channel with the content-type header of application/* (* specifies that any subtype would do).

in-parameter-name-0=name; in-parameter-value-0=* additionally specifies that the message must have a content-type parameter called name=* and that any value for that parameter will be accepted (again, * specifies that any parameter value would do.)

out-type=application; specifies that the MIME Content-type parameter for the post-processing message be application.

out-subtype=’INPUT-SUBTYPE’; specifies that the MIME subtype parameter for the post-processing body part be the INPUT-SUBTYPE environmental variable, which is the original value of the input subtype. Thus, if you wanted change

Content-type: application/xxxx; name=foo.doc

to

Content-type: application/msword; name=foo.doc

then you would use

out-type=application; out-subtype=msword

out-parameter-name-0=name; specifies that the output body part will have a MIME Content-type name= parameter.

out-parameter-value-0=’X-ATT-NAMES:\\’INPUT_SUBTYPE\\’’; says to take the value of the INPUT_SUBTYPE variable (that is, the original content-type header subtype value of the original body part) and search the mapping table X-ATT-NAMES. If a match is found, the content-type parameter specified by out-parameter-name-0 (that is, name) receives the new value specified in the X-ATT-NAMES mapping table. Thus, if the original subtype was msword, the value of the name parameter will be temp.DOC.