Atlas/examples/tutorial-resultset.lua at master · JavaDevelopRep/Atlas · GitHub

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--[[ $%BEGINLICENSE%$

This program is free software; you can redistribute it and/or

modify it under the terms of the GNU General Public License as

published by the Free Software Foundation; version 2 of the

License.

This program is distributed in the hope that it will be useful,

but WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

GNU General Public License for more details.

You should have received a copy of the GNU General Public License

along with this program; if not, write to the Free Software

Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA

02110-1301 USA

$%ENDLICENSE%$ --]]

--[[

--]]

-- init the query-counter if it isn't done yet

if not proxy.global.query_counter then

proxy.global.query_counter = 0

end

local query_counter = 0

---

-- read_query() can return a resultset

-- You can use read_query() to return a result-set.

-- @param packet the mysql-packet sent by the client

-- @return

-- * nothing to pass on the packet as is,

-- * proxy.PROXY_SEND_QUERY to send the queries from the proxy.queries queue

-- * proxy.PROXY_SEND_RESULT to send your own result-set

function read_query( packet )

-- a new query came in in this connection

proxy.global.query_counter = proxy.global.query_counter + 1

query_counter = query_counter + 1

if string.byte(packet) == proxy.COM_QUERY then

--[[

we use a simple string-match to split commands are word-boundaries

mysql> show querycounter

is split into

command = "show"

option = "querycounter"

spaces are ignored, the case has to be as is.

mysql> show myerror

returns a error-packet

--]]

-- try to match the string up to the first non-alphanum

local f_s, f_e, command = string.find(packet, "^%s*(%w+)", 2)

local option

if f_e then

-- if that match, take the next sub-string as option

f_s, f_e, option = string.find(packet, "^%s+(%w+)", f_e + 1)

end

-- we got our commands, execute it

if string.lower(command) == "show" and string.lower(option) == "querycounter" then

---

-- proxy.PROXY_SEND_RESULT requires

-- proxy.response.type to be either

-- * proxy.MYSQLD_PACKET_OK or

-- * proxy.MYSQLD_PACKET_ERR

-- for proxy.MYSQLD_PACKET_OK you need a resultset

-- * fields

-- * rows

-- for proxy.MYSQLD_PACKET_ERR

-- * errmsg

proxy.response.type = proxy.MYSQLD_PACKET_OK

proxy.response.resultset = {

fields = {

{ type = proxy.MYSQL_TYPE_LONG, name = "global_query_counter", },

{ type = proxy.MYSQL_TYPE_LONG, name = "query_counter", },

rows = {

{ proxy.global.query_counter, query_counter }

}

-- we have our result, send it back

return proxy.PROXY_SEND_RESULT

elseif string.lower(command) == "show" and string.lower(option) == "myerror" then

proxy.response.type = proxy.MYSQLD_PACKET_ERR

proxy.response.errmsg = "my first error"

return proxy.PROXY_SEND_RESULT

end

Atlas/examples/tutorial-resultset.lua at master · JavaDevelopRep/Atlas · GitHub

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