Refs #11076. Add doc to websocket

Documentation/Report.rst

@@ -494,9 +494,15 @@ Columns of the upper / outer level result can be accessed via variables in two w
 
 The STORE_RECORD will always be merged with previous content. The Level Keys are unique.
 
+.. important::
+
 Multiple columns, with the same column name, can't be accessed individually. Only the last column is available.
 
-Retrieving the *final* value of :ref:`special-column-names` is possible via '{{&<column>:R}}. Example::
+.. important::
+
+Retrieving the *final* value of :ref:`special-column-names` is possible via '{{&<column>:R}} (there is an '&' direct behind '{{')
+
+Example::
 
   10.sql = SELECT 'p:home&form=Person|s|b:success|t:Edit' AS _link
   10.20.sql = SELECT '{{link:R}}', '{{&link:R}}'
@@ -599,12 +605,12 @@ One exception are columns, whose name starts with '_'.  E.g.::
   content will be hidden.
 * The fourth column (alias name 'link') uses a QFQ special column name. Here, only in this example, it has no
   further meaning.
-* All columns in a row with the same special column name  (e.g. ``... AS _page``) will have the same column name: 'page'.
-  To access individual columns a uniq column title can be added::
+* All columns in a row, with the same special column name  (e.g. ``... AS _page``) will have the same column name: 'page'.
+  To access individual columns a uniq column title is necessary and can be added ``|_column1``::
 
       10.sql = SELECT '..1..' AS '_page|column1', '..2..' AS '_page|column2'
 
-  Those columns can be accessed via ``{{10.column1}}`` ,  ``{{10.column2}}`` or ``{{column1:R}}`` ,  ``{{column2:R}}``
+  Those columns can be accessed via ``{{10.column1}}`` ,  ``{{10.column2}}`` or (recommended) ``{{column1:R}}`` ,  ``{{column2:R}}``
 * To skip wrapping via ``fbeg``, ``fsep``, ``fend`` for dedicated columns, add the keyword ``|_noWrap`` to the column alias.
   Example::
 
@@ -612,6 +618,7 @@ One exception are columns, whose name starts with '_'.  E.g.::
 
 Summary:
 
+
 * Special column names always start with '_'.
 * Columns starting with a '_' but not defined as as QFQ special column name are hidden(!) - in other words: they are
   not **printed** as output.
@@ -2185,6 +2192,44 @@ Line 6: A PDF download.
 
 Line 7: A disabled menu entry.
 
+.. _websocket:
+
+WebSocket
+---------
+
+Sending messages via WebSocket and receiving the answer is done via: ::
+
+  SELECT 'w:ws://<host>:<port>/<path>|t:<message>' AS _websocket
+
+Instead of '... AS _websocket' it's also possible to use '... AS _link'.
+
+The answer is written to output and stored in the given column (in this case 'websocket' or 'link').
+
+.. tip::
+
+To suppress the direct output, add '_hide' to the column name::
+
+  SELECT 'w:ws://<host>:<port>/<path>|t:<message>' AS '_websocket|_hide'
+
+.. tip::
+
+To define a uniq column name (to access it later via STORE_RECORD)::
+
+  SELECT 'w:ws://<host>:<port>/<path>|t:<message>' AS '_websocket|myName'
+
+.. tip::
+
+Get the answer from STORE_RECORD by using '{{&...'. Check `access-column-values`_.
+
+Example::
+
+  SELECT 'w:ws://<host>:<port>/<path>|t:<message>' AS '_websocket|myName'
+
+  Results:
+
+    '{{myName:R}}'  >> 'w:ws://<host>:<port>/<path>|t:<message>'
+    '{{&myName:R}}'  >> '<received socket answer>'
+
 
 .. _drag_and_drop: