Migrating Existing Archives
Use
When a component is stored, the MIME type is transferred by means of the field Content Type in the request header (see RFCs 2045 and 2046). The content server then contains the MIME type, but does not evaluate it. The MIME type is used as the response Content Type (for the get function, for example).
In older archives, only document classes such as ALF, FAX, and DOC were recognized. Therefore, a MIME type must be derived from these old document classes, so that previously stored documents can be accessed via the new interface. The MIME type is derived from the document class.
Document Structure
There are many documents in the former ArchiveLink interface that consist of several components. This is particularly true of documents in the document classes FAX, OTF, and ALF. As well as one or more (FAX) data files, these documents sometimes also contain a description file (ALF) and a note file.
When existing archives are being migrated, a component ID ( compId) must be assigned to each component. The procedure is as follows:
-
The compId data is assigned to the data file. If several data files exist (for document class FAX, for example, if there are several pages and each page is saved separately as a TIFF file), they are assigned to the components "data1", "data2", and so on. In this case there is no component "data".
-
A description file (ALF only) is assigned to the component "descr".
-
Finally, the note file is assigned to the component "note".
Deriving MIME Types from Document Classes
When an archive is migrated, the MIME type of the component "data" (or "data1", "data2", and so on) is derived from the document class.
Conversion rules are shown in the following table. The order of the entries is important. The first appropriate entry from the top is used for conversion.
|
Document type |
MIME Type |
|
FAX |
image/tiff |
|
BIN |
application/octet-stream |
|
DOC |
application/msword |
|
Portable Document Format (PDF) |
application/pdf |
|
PS |
application/postscript |
|
RTF |
application/rtf |
|
XLS |
application/vnd.ms-excel |
|
MPP |
application/vnd.ms-project |
|
PPT |
application/vnd.ms-powerpoint |
|
ALF |
application/x-alf |
|
OTF |
application/x-otf |
|
RAW |
application/x-raw |
|
REO |
application/octet-stream |
|
SCR |
application/x-scr |
|
BMP |
image/bmp |
|
GIF |
image/gif |
|
JPG |
image/jpeg |
|
PCX |
image/pcx |
|
TIFF |
image/tiff |
|
TIF |
image/tiff |
|
HTM |
text/html |
|
TXT |
text/plain |
The components "descr" (ALF only) and "note" contain the MIME-Type as follows:
|
compId |
MIME Type |
|
note |
application/x-note |
|
descr |
application/x-alf-descr |