Forum Discussion

abhinay's avatar
abhinay
Icon for Nimbostratus rankNimbostratus
Dec 27, 2022

iRule for HTTP Post Method to match form data in the body

Please let me know how to match formdata "key" and "value" using HTTP Method "POST" from its Body.  From below I would like to match key "func" its value that contains "qds."   "body": { "mod...
application delivery
security
xuwen's avatar
xuwen
Icon for Cumulonimbus rankCumulonimbus
Dec 30, 2022

It would be pretty impractical to use iRules TCL to perform the translation POST JSON data. However, this task is trivial for iRules LX because of the power of Node.js

rules>>json_post

when HTTP_REQUEST {
    # Collect POST data
    if { [HTTP::method] eq "POST" }{
        set cl [HTTP::header "Content-Length"]
        HTTP::collect $cl
    }
}
when HTTP_REQUEST_DATA {
    # Send data to Node.js
    set handle [ILX::init "ilxlab2_plugin" "ilxlab2_ext"]
    if {[catch {ILX::call $handle jsonPost [HTTP::payload]} result]} {
      # Error handling
      log local0.error  "Client - [IP::client_addr], ILX failure: $result"
      HTTP::respond 400 content "<html>There has been an error.</html>"
      return
    }
    log local0. "result is $result"
    # Replace Content-Type header and POST payload
    # HTTP::header replace "Content-Type" "application/json"
    # HTTP::payload replace 0 $cl $result
    if { [lindex $result 0] > 0 } {
        HTTP::respond 400 content "<html>The following error occured: Invalid JSON</html>"
    } else {
        if { [lindex $result 1] contains "qds" } {
            HTTP::respond 403 content "Forbidden Access!"
        } else {
            HTTP::respond 400 content "value is [lindex $result 1]"
        }
    }
}

ilxlab2_ext>>index.js

'use strict' // Just for best practices
// Import modules here
var f5 = require('f5-nodejs');
// var qs = require('querystring'); // Used for parsing the POST data querystring

// Create an ILX server instance
var ilx = new f5.ILXServer();

// This method will transform POST data into JSON
ilx.addMethod('jsonPost', function (req, res) {
  // Get POST data from TCL and parse to JS object
  //var postData = qs.parse(req.params()[0]);
  var postData = req.params()[0];
  try {
    var jsonData = JSON.parse(postData);
  } catch (err) {
      console.log('Error with JSON.parse: ' + err.message);
      return res.reply(1);
  }
  if ( jsonData.formdata[0].key == "func" ) {
      console.log(jsonData.formdata[0].value);
      var qds_value = jsonData.formdata[0].value;
      return res.reply([0, qds_value])
  } else {
      return res.reply([0, "no"])
  }
  

  // Turn postData object into JSON and return to TCL
  // res.reply(JSON.stringify(postData));
});

//Start the ILX server
ilx.listen();

 curl test command is:

curl -kv http://10.10.10.177 -X POST -H "Content-Type: application/json" -d '{"mode":"formdata","formdata":[{"key":"func","value":"qds.ObjAction","type":"default"}]}'

result is:

[root@f5:LICENSE EXPIRES IN 4 DAYS:Active:Standalone] config # curl -kv http://10.10.10.177 -X POST -H "Content-Type: application/json" -d '{"mode":"formdata","formdata":[{"key":"func","value":"qds.ObjAction","type":"default"}]}'
Note: Unnecessary use of -X or --request, POST is already inferred.
* Rebuilt URL to: http://10.10.10.177/
*   Trying 10.10.10.177...
* Connected to 10.10.10.177 (10.10.10.177) port 80 (#0)
> POST / HTTP/1.1
> Host: 10.10.10.177
> User-Agent: curl/7.47.1
> Accept: */*
> Content-Type: application/json
> Content-Length: 88
> 
* upload completely sent off: 88 out of 88 bytes
* HTTP 1.0, assume close after body
< HTTP/1.0 403 Forbidden
< Server: BigIP
* HTTP/1.0 connection set to keep alive!
< Connection: Keep-Alive
< Content-Length: 17
< 
* Connection #0 to host 10.10.10.177 left intact
Forbidden Access![root@f5:LICENSE EXPIRES IN 4 DAYS:Active:Standalone] config #

tail -f /var/log/ltm

Dec 30 15:20:48 f5 info tmm[10644]: Rule /Common/ilxlab2_plugin/json_post <HTTP_REQUEST_DATA>: result is 0 qds.ObjAction
Dec 30 15:20:48 f5.bigip-gtm110.com info sdmd[5171]: 018e0017:6: pid[20389]  plugin[/Common/ilxlab2_plugin.ilxlab2_ext] qds.ObjAction