MSM-Workstation
The Macbeth Example -- Using MSM-PDQweb
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Which entry does MSM-PDQweb call?
One parameter value that was not described on the previous page
is the one that is specified as the "action" in the HTML-command
that starts the form
(<form action="macbeth.web" method="POST">).
The value of this variable is the name of a file with a special
"extension". When a browser processes a URL (Uniform
Resource Locator), this extension decides what
software the browser calls to process the resource. Extensions
like .HTM and .HTML typically cause a web-page to be presented,
extensions like .GIF and .JPS cause a picture to be displayed.
The special extension .WEB causes the web-browser to invoke the
main processor of MSM-PDQweb. This program interpretes the
information in the specified file, and takes further action,
depending on the parameters being passed.
In this case, the file name is macbeth.web and the
contents of this file is:
[MAPPINGS]
;
FIRST=FIRST^demopdq
;
[DATASOURCES]
;
; IP Address (or name) : Port : Password : connection count : timeout
127.0.0.1:2001:PASSWORD:1:20
;
[CGI]
;
HTTP_COOKIE
HTTP_USER_AGENT
REMOTE_ADDR
REMOTE_HOST
REMOTE_USER
;
[DEBUG]
;
; TRACEFILE=C:\edm\msmws\TRACE.LOG
The lines enclosed in square brackets identify the starts of the
various sections of the file, each section is described
separately below.
Mappings
This section describes the mapping of the various "aliases" for
names of entry points to the actual locations in programs that
are to be called. The value to the left of the equal sign is the
value that is expected in web-variable EP, the variable
on the right-hand side of the equal sign is the entry point that
is called when the alias specified on the left is transmitted.
Judicious use of this list of entry points in application
programs that can be called "from the web" is an important
security feature: only those entry points that are advertised in
this section of a .WEB file can be called.
Hint: this limitation on the number of entry points that
can be called is one security feature. It remains up to the
application software to validate further access privileges before
any sensitive operations are executed.
Datasources
This section identifies how the browser can access the MSM
Server on which the web-request is to be processed.
The parameters specified in this section identify:
- the IP address (or node name) of the CPU on which the MSM
Server is running. A special value of 127.0.0.1 means that the
server is running on the same CPU as the web-server that receives
the request.
- the port number on which the MSM Server is listening for
web-requests
- a password to protect the server against unauthorized access
- a number that specifies the maximum number of requests that
may be processed simultaneous for requests through this
particular .WEB file
- a number that specifies the maximum number of seconds that
may elapse before a message is sent to the browser that no server
could process the request. If no data is transmitted from the
server before this "time-out" period has passed, the end-user
will receive a message indicating that no result will be
forthcoming.
CGI
This section identifies the "further" web-variables that are to
be passed to the application software. Form-specific variables
will be available in the array %("MSMWEB_QUERY",name),
these "further" variables will be available in the same array,
but using only one subscript: %(cginame).
Debug
Use of the debug-section is not generally recommended.
If there are problems that need thorough investigation, removing
the semicolon preceding the specification TRACEFILE=...
will activate the debug facility.
Note: the filename specified on the right-hand side of the
equal sign must be valid in order for the debug facility to work
properly.
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