$Web Done: Difference between revisions

Revision as of 20:39, 12 April 2013

Send Web response

$Web_Done signals completion of a request. This callable $function accepts two optional arguments and returns a numeric result code.

Syntax

%rc = $Web_Done([ status_code], [message] )

Syntax terms

%rc

A numeric variable to contain either of these return codes:

0	Completed successfully
-1	Not a web thread

status_code

Used in many cases for automatic browser error or exception handling, these codes are summarized below.

message

Further elucidation of the error. In some cases, displayed verbatim to the browser's user.

Status codes

Status codes and their associated messages are standardized for most Web Servers. The standards are available for browsing in Chapter 9 of the HTTP working draft.

The standard codes are:

200	OK
201	Created
202	Accepted
204	No Content
301	Moved Permanently
302	Moved Temporarily
304	Not Modified
400	Bad Request
401	Not Authorized (logon required)
403	Forbidden
404	Not Found
500	Internal Server Error
501	Not Implemented
502	Bad Gateway
503	Service Unavailable

Usage notes

Invoking $Web_Done closes the client connection, optionally sending the status code and message text to the user. Once $Web_Done is invoked, the thread may continue processing but no more calls to $Web* functions are allowed, and nothing further may be sent to the client. The connection to the client is also broken by a Model 204 LOGOFF or any return to command level. These are perfectly valid ways of terminating requests. The function of $Web_Done is to send the status code and error message and terminate the connection; hence no further information will be sent to the client.
Of potential value when monitoring your application, the Sirius statistic JWEBERRS reports the number of times that Janus Web Server returned one of the 4xx status codes. Also, the JSCREENS statistic counts the number of times Janus Web Server incremented the SCREENS statistic. These statistics are available as of Sirius Mods version 7.6, and they are retrievable or viewable with $SyStat or SirMon.

Examples

Use $Web_Done in error routines and to sever client connections with custom messages. For example:

SECURE: In AUTHS Fd UID = %user End Find CT_SEC: Count Records In SECURE If Not Count In CT_SEC Then %x = $Web_Done('403','Forbidden') Stop End If

@@ Line 6: / Line 6: @@
 ==Syntax==
-<p class="syntax"><span class="term">%rc</span> = <span class="literal">$Web_Done</span>(<span class="term"> status_code</span>, <span class="term">message</span> )
+<p class="syntax"><span class="term">%rc</span> = <span class="literal">$Web_Done</span>([<span class="term"> status_code</span>], [<span class="term">message</span>] )
 </p>
@@ Line 33: / Line 33: @@
 <tr><th>200</th>
 <td>OK</td></tr>
 <tr><th>201</th>
 <td>Created</td></tr>
 <tr><th>202</th>
 <td>Accepted</td></tr>
 <tr><th>204</th>
 <td>No Content</td></tr>
 <tr><th>301</th>
 <td>Moved Permanently</td></tr>
 <tr><th>302</th>
 <td>Moved Temporarily</td></tr>
 <tr><th>304</th>
 <td>Not Modified</td></tr>
 <tr><th>400</th>
 <td>Bad Request</td></tr>
 <tr><th>401</th>
 <td>Not Authorized (logon required)</td></tr>
 <tr><th>403</th>
 <td>Forbidden</td></tr>
 <tr><th>404</th>
 <td>Not Found</td></tr>
 <tr><th>500</th>
 <td>Internal Server Error</td></tr>
 <tr><th>501</th>
 <td>Not Implemented</td></tr>
 <tr><th>502</th>
 <td>Bad Gateway</td></tr>
 <tr><th>503</th>
 <td>Service Unavailable
-</td></tr></table>
+</td></tr>
+</table>
 ==Usage notes==