RpSequel : rfc sql crud with wordpress

juust | 23/10/2009

I set out to use MsAccess with xhr/ajax to maintain tables I added to my wordpress database, from my desktop. (Because I suck at html forms backends and consider them a waste of time.)

I used a similar technique ten years ago, setting up msaccess as reporting tool for SAP R/3 with RFC dll’s and ActiveX. That remained stable for eight years without maintenance. Hey, I might get lucky with Wordpress xml-rpc and xhr/ajax.

I called the example RpSequel.

adding sql rpc functions

To sync the data sets, I will duplicate a list with sequel operations from my desktop database as rfc call to my blog’s xmlrpc-endpoint. To handle that list, I plug a sql crud method into the xml-rpc method array in Wordpress :

  1. add_filter( 'xmlrpc_methods', 'rpsequel_methods' );
  2.  
  3. function rpsequel_methods( $methods ) {
  4.     $methods['rpsequel.rpsequelInsert'] = 'rpsequelInsert';
  5.     return $methods;
  6. }
  7.  
  8. function rpsequelInsert($args) {
  9. }

The basic INSERT method itself can be simple:

  1. function rpsequelInsert($args) {
  2.         global $wpdb;
  3.  
  4. //the first parameters
  5.         $blog_id = (int) $args[0];
  6.         $username = $args[1];
  7.         $password = $args[2];
  8.         $tablename      = $args[3];
  9.  
  10. //get the structs
  11.         $structs        = $args[4];
  12.  
  13. //pick the first
  14.         $struct = $structs[0];
  15.  
  16. //compose the mysql insert statement    
  17.         foreach($struct as $key => $value){
  18.             $SqlFields .= " `".$key . "`,";
  19.             $SqlValues .= " '".$value . "',";
  20.         }
  21.  
  22.         $SqlFields=substr($SqlFields, 0, strlen($SqlFields)-1);
  23.         $SqlValues=substr($SqlValues, 0, strlen($SqlValues)-1);
  24.    
  25.         $SqlStatement .= "INSERT INTO ".$wpdb->prefix.$tablename. " (". $SqlFields .  ") VALUES (".$SqlValues . ")";
  26.        
  27. //execute the query        
  28.         $wpdb->query($wpdb->prepare($SqlStatement));
  29.  
  30. //return the record id
  31.        return $wpdb->insert_id;
  32. }

That in itself is not very exciting, it stuffs records in the host’s database. Which is fine, however, I want the blog to respond to individual operations.

I can write rpc-functions for every single function I want the blog to perform, that means truckloads of rpc-functions, on both client and server end. I am incredibly lazy, so I ain’t gonna go there.

adding hooks to sql rpc functions

Lucky for me, Wordpress has hooks, hooks are cool.

Adding action hooks (before_insert and after_insert) to the crud method makes it more powerful. Two hooks are enough to separate the business logic of the desktop database from the blogs reporting logic.

  1. function rpsequelInsert($args) {
  2.         global $wpdb;
  3.  
  4. //the first parameters
  5.         $blog_id = (int) $args[0];
  6.         $username = $args[1];
  7.         $password = $args[2];
  8.         $tablename      = $args[3];
  9.  
  10. //get the structs
  11.         $structs        = $args[4];
  12.  
  13. //here is the first action hook,
  14. //it hands the tablename and the records over to any
  15. //function that 'listens' on the action hook
  16.  
  17. do_action('rpsequel_before_insert',  $tablename, $structs);
  18.  
  19. //the rest of the rather dull method
  20.  
  21.         $struct = $structs[0];
  22. //….
  23. //execute the query        
  24.         $wpdb->query($wpdb->prepare($SqlStatement));
  25.  
  26. //here is the second action hook,
  27. //it hands the table name with the new record id
  28. //to any function that 'listens' on the action hook
  29.  
  30. do_action('rpsequel_after_insert',  $tablename, $wpdb->insert_id);
  31.  
  32. //return the record id
  33.        return $wpdb->insert_id;
  34. }

Now it is more exciting.

  • I can send a list of records and a rfc insert-method to the blogs xmlrpc endpoint
  • the rfc crud-plugin can process the records one by one
  • Before and after each insert operation, the method triggers an action.
  • Before inserting, it exposes the record data.
  • After inserting, it exposes the record id.

And the last two, was exactly what I wanted.

adding functionality with plugins

Now I can add tiny plugins, that ‘listen’ on the action hooks in the rfc-methods. If there is an INSERT into the database, my plugins read which table it affects. They can perform actions, either before the insert, with the new record data, or after the insert, with the new record id.

  1. add_action ( 'rpsequel_before_insert', 'before_insert_logic', 10, 2);
  2. add_action ( 'rpsequel_after_insert', 'after_insert_logic', 10, 2);
  3.  
  4. function before_insert_logic($rpc_tablename, $rpc_array) {
  5.    if($rpc_tablename=="ships") {
  6. //do some stuff before inserting incoming records
  7.    }
  8. }
  9.  
  10. function after_insert_logic($rpc_tablename, $rpc_insert_id) {
  11.    if($rpc_tablename=="ships") {
  12. //do some stuff after inserting incoming records
  13.    }
  14. }

That’s basically all it takes. As technique, it has it’s limitations, but it can come in handy sometimes.

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integrating ms office and wordpress with vba and xml-rpc

juust | 20/10/2009

Okay.

Yesterday I made some basic stuff to grab my Wordpress blog data with visual basic for applicationsn cos I don’t feel like programming php admin pages for tables.

So let’s make a basic xml-rpc crud plugin and put my agenda on vba remote control.

The basic xml-rpc plugin is simple, plug extra methods into the xml-rpc method array, and write a function per crud-method.

  1.  
  2. add_filter( 'xmlrpc_methods', 'add_agenda_xmlrpc_methods' );
  3.  
  4. function add_agenda_xmlrpc_methods( $methods ) {
  5.     $methods['agenda.addAgendaItem'] = 'addAgendaItem';
  6.     $methods['agenda.updateAgendaItem'] = 'updateAgendaItem';
  7.     $methods['agenda.deleteAgendaItem'] = 'deleteAgendaItem';
  8.     $methods['agenda.reportAgendaItem'] = 'reportAgendaItem';
  9.     return $methods;
  10. }
  11.  
  12. function addAgendaItem($args) { }
  13.  
  14. function updateAgendaItem($args) { }
  15.  
  16. function deleteAgendaItem($args) { }
  17.  
  18. function reportAgendaItem($args) { }
  19.  
  20. //basic login helper function
  21. function CheckLogin($user, $pwd) {}

There now, if I call on the xmlrpc.php file, the extra methods are added to the callback array and I can use the table CRUD functions from my vba desktop.

  1. function addAgendaItem($args) {
  2.  
  3.         $blog_id = (int) $args[0];
  4.         $username = $args[1];
  5.         $password = $args[2];
  6.         $AgendaItem     = $args[3];
  7.  
  8. //remember : add a login check
  9. //(for the example it is irrelevant)
  10.  
  11.         global $wpdb;
  12.         $sql = "INSERT INTO ".$wpdb->prefix."Agenda (
  13.                `userid`, `tags`, `description`, `firstdate`, `enddate`, `link`, `price`, `location`
  14.                ) VALUES (
  15.                '".$AgendaItem[0]['userid']."',
  16.                '".$AgendaItem[0]['tags']."',
  17.                '".$AgendaItem[0]['description']."',
  18.                '".$AgendaItem[0]['firstdate']."',
  19.                '".$AgendaItem[0]['enddate']."',
  20.                '".$AgendaItem[0]['link']."',
  21.                '".$AgendaItem[0]['price']."',
  22.                '".$AgendaItem[0]['location']."'                
  23.                )";
  24.         $wpdb->query($wpdb->prepare($sql));
  25.  
  26.         return $wpdb->insert_id;
  27. }

note : the agendaitem is a struct in an array (see below), I use [0] to get the first struct (which is the actual array with field-value pairs, my record with agenda info).

Activate the plugin, and write a simple test

  1.  
  2. 'Type to hold an agenda info record
  3. Type AgendaItem
  4.     userid As String
  5.     tags As String
  6.     Description As String
  7.     firstdate As String
  8.     enddate As String
  9.     link As String
  10.     price As String
  11.     location As String
  12. End Type
  13.  
  14.  
  15. Function AddAgendaItem()
  16.  
  17. txtURL = "http://wwwblog.com/xmlrpc.php"
  18. txtUserName = "MyUsername"
  19. txtPassword = "MyPassword"
  20.  
  21.   Dim objSvrHTTP As ServerXMLHTTP
  22.   Dim strT As String
  23.   Set objSvrHTTP = New ServerXMLHTTP
  24.  
  25.   objSvrHTTP.Open "POST", txtURL, False, CStr(txtUserName), _
  26.    CStr(txtPassword)
  27.  
  28.   objSvrHTTP.setRequestHeader "Accept", "application/xml"
  29.   objSvrHTTP.setRequestHeader "Content-Type", "application/xml"
  30.  
  31.     strT = ""
  32.     strT = strT & "<methodcall>"
  33.     strT = strT & "<methodname>agenda.addAgendaItem</methodname>"
  34.    
  35.     strT = strT & "<params>"
  36.     strT = strT & "<param><value><string>" & txtBlogId & "</string></value></param>"
  37.     strT = strT & "<param><value><string>" & txtUserName & "</string></value></param>"
  38.     strT = strT & "<param><value><string>" & txtPassword & "</string></value></param>"
  39.  
  40. 'now we go make the struct, I use a Type (stdobject), normally
  41. 'you'd use a recordset
  42.  
  43. Dim a As AgendaItem
  44.  
  45. With a
  46.     .userid = 1
  47.     .Description = "rpc testing"
  48.     .firstdate = "2009/10/14"
  49.     .enddate = "2009/10/14"
  50.     .link = "http://www.juust.org/"
  51.     .price = "rpc testing"
  52.     .location = "limmen"
  53.     .tags = "php, xml-rpc"
  54. End With
  55.  
  56.     strT = strT & "<param><value><array>"
  57.     strT = strT & "<data>"
  58.    
  59.     strT = strT & "<value><struct>"
  60.  
  61.     strT = strT & "<member><name>userid</name><value><string>" & a.userid & "</string></value></member>"
  62.     strT = strT & "<member><name>tags</name><value><string>" & a.tags & "</string></value></member>"
  63.     strT = strT & "<member><name>description</name><value><string>" & a.Description & "</string></value></member>"
  64.     strT = strT & "<member><name>firstdate</name><value><string>" & a.firstdate & "</string></value></member>"
  65.     strT = strT & "<member><name>enddate</name><value><string>" & a.enddate & "</string></value></member>"
  66.     strT = strT & "<member><name>link</name><value><string>" & a.link & "</string></value></member>"
  67.     strT = strT & "<member><name>price</name><value><string>" & a.price & "</string></value></member>"
  68.     strT = strT & "<member><name>location</name><value><string>" & a.location & "</string></value></member>"
  69.  
  70. 'close the struct    
  71.     strT = strT & "</struct></value>"
  72.     strT = strT & "</data>"
  73.  
  74. 'close the struct array
  75.     strT = strT & "</array></value></param>"
  76.  
  77. 'end parameters
  78.     strT = strT & "</params>"
  79.  
  80. 'end method
  81.     strT = strT & "</methodcall>"
  82.  
  83. 'send the lot to the blog  
  84.   objSvrHTTP.send strT
  85.  
  86. 'print the response to debug
  87.   Debug.Print  objSvrHTTP.responseText
  88.  
  89. End function

Et voila :

agenda rpc

That’s yer basic Office-Wordpress XML-RPC integration.

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more vba and wordpress xml rpc

juust | 19/10/2009

Basic Example II, vba wordpress remote control, demo.ayHello is fun but quite useless, so let’s proceed to wp.getUsersBlogs.

I make a table in access (id, isAdmin, blogid, url, blogName, xmlrpc) and then query wordpress, parse the xml response in store it in the database.

So here we go query Wordpress :

  1.     methodname = "wp.getUsersBlogs"
  2.  
  3. 'xmlrpc url
  4.     txtURL = "http://www.blog.com/xmlrpc.php"
  5.  
  6. 'authorization
  7.     txtUserName = "user"
  8.     txtPassword = "pass"
  9.  
  10. 'XML http request  
  11.     Dim objSvrHTTP As ServerXMLHTTP
  12.     Dim strT As String
  13.     Set objSvrHTTP = New ServerXMLHTTP
  14.    
  15.     objSvrHTTP.Open "POST", txtURL, False, CStr(txtUserName), _
  16.      CStr(txtPassword)
  17.    
  18.     objSvrHTTP.setRequestHeader "Accept", "application/xml"
  19.     objSvrHTTP.setRequestHeader "Content-Type", "application/xml"
  20.  
  21. 'here is the bit with the wp.getUserBlogs methodname,
  22. 'and the username and password    
  23.     strT = ""
  24.     strT = strT & "<methodcall>"
  25.     strT = strT & "<methodname>" & methodname & "</methodname>"
  26.     strT = strT & "<params>"
  27.     strT = strT & "<param><value><string>" & txtUserName & "</string></value></param>"
  28.     strT = strT & "<param><value><string>" & txtPassword & "</string></value></param>"
  29.     strT = strT & "</params>"
  30.     strT = strT & "</methodcall>"
  31.    
  32.     objSvrHTTP.send strT

that’s pretty straight forward.

I get an xml message back with the data stored in an array of STRUCT types.

  1. 'Create the DomDocument Object
  2. Dim oDoc As MSXML2.DOMDocument
  3. Set oDoc = CreateObject("MSXML2.DOMDocument")
  4. oDoc.async = False
  5. oDoc.validateOnParse = False
  6.  
  7. 'Load the response in the DomDocument Object
  8. Dim fSuccess As Boolean
  9. fSuccess = oDoc.loadXML(objSvrHTTP.responseText)
  10. If Not fSuccess Then
  11.     MsgBox "failed"
  12.     Exit Function
  13. End If
  14.        
  15. 'counters
  16. ct = 1
  17. cs = 1
  18.  
  19. 'array to story the field values
  20. Dim SArray(1 To 5) As String
  21.  
  22. 'open the table as recordset
  23. Dim d As DAO.Recordset
  24. Set d = CurrentDb.OpenRecordset("blogs", dbOpenTable)
  25.  
  26. 'lets get the structs
  27. Set oChildren = oDoc.selectNodes("//struct")
  28. For Each oStruct In oChildren
  29.  
  30. 'the struct has members,
  31.  
  32.    Set Members = oStruct.childNodes
  33.    For Each Member In Members
  34.  
  35. 'each member has a param pair (field, value)
  36. 'skip the first param, and store the field value
  37. 'in an array
  38.  
  39.        Set Params = Member.childNodes
  40.        For Each Param In Params
  41.             ct = ct + 1
  42.             If ct / 2 <> Int(ct / 2) Then
  43.                 SArray(ct / 2) = Param.Text
  44.                 cs = cs + 1
  45.             End If
  46.        Next
  47.  
  48.     Next
  49.  
  50.     'we got the struct data,
  51.     'now add the array to the database
  52.    
  53.      With d
  54.         .AddNew
  55.         !isAdmin = SArray(1)
  56.         !url = SArray(2)
  57.         !blogid = SArray(3)
  58.         !blogName = SArray(4)
  59.         !xmlrpc = SArray(5)
  60.         .Update
  61.     End With
  62.  
  63. Next
  64.  
  65. 'close up shop
  66. d.Close
  67. Set d = Nothing
  68.  
  69. End Function

The other worpdress api calls work quite the same.

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