NAME

       write-hash -  (hash)

PURPOSE

       Store key/value pair into a hash.

SYNTAX

           write-hash <hash> \
               key <key> \
               value <value> \
               [ status <status> ] \
               [ old-value <old value> ]

DESCRIPTION

       write-hash  will  store string <key> (in "key" clause) and <value> (in "value" clause) into <hash>, which
       must be created with new-hash.

       <key> and <value> are collectively called an "element".

       If <key> already exists in the hash, then the old value associated with it is  returned  in  string  <old
       value>  (in "old-value" clause) and <value> will replace the old value - in this case <status> number (in
       "status" clause) has a value of GG_INFO_EXIST.

       If <key> did not exist, <status> will be GG_OKAY and <old value> is unchanged.

       If a <hash> was created with "process-scope" clause (see new-hash), then the element (including <key> and
       <value>) will not be freed when the current request ends, rather it will persist while the process  runs,
       unless deleted (see read-hash with delete clause).

EXAMPLES

       Writing data to a hash:

           new-hash h
           write-hash h key "mykey" value "some data"

       Writing new value with the same key and obtaining the previous value (which is "some data"):

           write-hash h key "mykey" value "new data" status st old-value od
           if-true st equal GG_INFO_EXIST
               @Previous value for this key is <<print-out od>>
           end-if

       The  following  is  a  key/value  service, where a process-scoped hash is created. It provides inserting,
       deleting and querying key/value  pairs.  Such  a  service  process  can  run  indefinitely.  Create  file
       keysrv.golf:

           %% /keysrv public
               do-once
               new-hash h hash-size 1024 process-scope
               end-do-once

               // Get input parameters
               get-param op
               get-param key
               get-param data

               if-true op equal "add" // Add data to hash
                   write-hash h key key value data old-value old_data status st
                   if-true st equal GG_INFO_EXIST
                       delete-string old_data
                   end-if
                   @Added [<<print-out key>>]
               else-if op equal "delete" // Delete data and obtain the value deleted
                   read-hash h key (key) value val delete status st
                   if-true st equal GG_ERR_EXIST
                       @Not found [<<print-out key>>]
                   else-if
                       // If found, then delete key and value
                       @Deleted [<<print-out val>>]
                       delete-string val
                   end-if
               else-if op equal "query" // Query hash based on key value
                   read-hash h key (key) value val status st
                   if-true st equal GG_ERR_EXIST
                       @Not found, queried [<<print-out key>>]
                   else-if
                       @Value [<<print-out val>>]
                   end-if
               end-if
           %%

       Create and make the application, then run it as service:

           // Create application
           gg -k hash
           // Make application
           gg -q
           // Start application (single process key service)
           mgrg -w 1 hash

       Try it from a command line client (see gg):

           // Add data
           gg -r --req="/keysrv/op=add/key=15/data=15" --service --app="/hash" --exec
           // Query data
           gg -r --req="/keysrv/op=query/key=15" --service --app="/hash" --exec
           // Delete data
           gg -r --req="/keysrv/op=delete/key=15" --service --app="/hash" --exec

       See read-hash for more examples.

SEE ALSO

        Hash

       get-hash new-hash purge-hash read-hash resize-hash write-hash See all documentation

$DATE                                               $VERSION                                           GOLF(2gg)