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OMI - Request Header

Draft MDC Standard

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5.3.1 Request header

Each request shall contain a header that, among other things, identifies the user. Inclusion of this information permits transactions to be isolated (see 4.3.3). Without it the server would have to track users and their authorizations across transactions.

The request header is a short string <SS> so that the server can locate the field following the header regardless of the length of the header.

NOTE – The request header has fixed length, but future versions of OMI may specify different lengths. Servers and agents need to find the version numbers following the header in connect messages, regardless of the version in use (see 4.9).

The fields of the request header and their sequence shall be:

  1.  Operation class: <LI> denotes 1 of 65 536 classes of operations. The MUMPS Development Committee assigns classes to OMI versions and to specific extensions of the standard (see 4.12). The class of operations specified by ANSI/MDC X11.2 shall be 1. All other classes are reserved for assignment by the MUMPS Development Committee.
  2. Operation type: <SI> denotes a specific operation within an operation class. For example, set and kill are operation types 10 and 13.
  3. User identifier: <LI> identifies a user for security purposes. See 4.5.
  4. Group identifier: <LI> identifies a group of users for security purposes. See 4.5.
  5. Sequence number: <LI> This sequential number starts at 1 and increments by 1 to 65 535, then continues with 1. The server may use this number to verify that requests are received and processed in the correct order. The agent may choose any valid starting sequence number for a connect request, causing the server to synchronize at that sequence number.
  6. Request identifier: <LI> links responses to requests. The content of this field is left to the implementer, except that the server must return the value from each request in the corresponding response.
<SS>
<SI> <LI>
Class		 <LI>
Type		 <LI>
User		 <LI>
Group		 <LI>
Sequence		 <LI>
Req ID

Figure 5 – Form of a request header

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Copyright © Standard Documents; 1977-2024 MUMPS Development Committee;
Copyright © Examples: 1995-2024 Ed de Moel;
Copyright © Annotations: 2003-2008 Jacquard Systems Research
Copyright © Annotations: 2008-2024 Ed de Moel.

Some specifications are "approved for inclusion in a future standard". Note that the MUMPS Development Committee cannot guarantee that such future standards will indeed be published.

This page most recently updated on 13-Sep-2014, 14:16:37.

For comments, contact Ed de Moel (demoel@jacquardsystems.com)