Setting up a webpage to receive an HTTP Post

[imjoken]

We use Mandrill and want to use their Webhooks. Their webhook will send an HTTP Post to a web page when designated transactions occur (such as a bounce). Does anyone know how to set up a web page in Alpha to accept these HTTP posts?

[Davidk]

Re: Setting up a webpage to receive an HTTP Post

I wanted to know the same thing but for a different purpose.

Have you tried creating an a5w page and then point Mandrill at it? I wonder if the a5w page can read the body of the Post, just like it can read passed parameters?

[Lenny Forziati]

Re: Setting up a webpage to receive an HTTP Post

David is on the right track. The A5W page will see the POSTed data just like it sees query string parameters. You'll need to review the API documentation for the specific service to see exactly how they are sending the data. If the are sending name-value pairs in the body with either application/x-www-form-urlencoded or multipart/form-data format, the Application Server will create page variables for each. If they are sending in any other way (e.g. application/json), you can access the entire body as Request.Body and then handle it as needed.

[imjoken]

Re: Setting up a webpage to receive an HTTP Post

Thanks Lenny. I'll give it a try.

[Steve Wood]

Re: Setting up a webpage to receive an HTTP Post

Be sure to not include any HTML in your Post-listening page, just xbasic. My first four lines below will abort the page if not a POST transaction:

IF request.body=="" .OR. upper(request.request_method)<>"POST" THEN
?"Sorry, you cannot run this page"
end
END IF
'==your code to abort if NOT a Post from Mandrill
cc = request.body
'==your code to parse the response.
'==your code to do something with the response

[imjoken]

Re: Setting up a webpage to receive an HTTP Post

Thanks Steve. Mandrill posts using JSON. Do you know what form the request.body returns. Is it a dot variable. I can't find anything on request.body either in the wiki or help menu.

[Davidk]

Re: Setting up a webpage to receive an HTTP Post

Thanks Steve.

[Steve Wood]

Re: Setting up a webpage to receive an HTTP Post

request.body contains exactly whatever text the page received. That's why you do not want any HTML on that page, it will "receive" that as well.

So if the page is sent JSON, that's exactly what request.body will contain. Because it is JSON it is NOT going to contain any additional request variables, or at least not one-per-variable like Lenny was suggesting. That only works if the POST has named-pairs like &name=Steve.

So you have to parse the JSON text. Search the documentation for "json" for some examples, its not something I have done much of at this point.

[Steve Workings]

Re: Setting up a webpage to receive an HTTP Post

Jay - it's still just text. I've done this with a few different services. My starting point is to just capture the complete block of text and maybe save it to a file Save_To_File() to get an idea what you're dealing with. It also gives you a sample block of text to use to write any parsing code you want.

Mandrill should have some documentation about what they send, but I see examples out there too, such as this:

https://gist.github.com/ramonsmits/7563502

[imjoken]

Re: Setting up a webpage to receive an HTTP Post

Thanks guys. This gives me enough to get going.

Also, just found the A5 Function below. Seems to me that I can use this function, along with request.body, to populate an array of the messages that Mandrill will send and then step through the array to submit to my Sql table.

a5_JSON_PopulateArray()

[Steve Workings]

Re: Setting up a webpage to receive an HTTP Post

A5_json_ExtractValues(), json_parse(), and extract_string() all possibly useful, in case you haven't found 'em. I do a fair amount of XML work and find the extract_string() to be darned convenient.

[Davidk]

Re: Setting up a webpage to receive an HTTP Post

So glad you asked this question Jay. I've been meaning to try this for a long time... just thinking about it...

So... here's the code in my a5w page... named... mandrilltest.a5w

<%A5

	DIM cn as SQL::Connection
	dim flagResult as l 
	flagResult = cn.open("::Name::myConnection")
	if flagResult = .f. then 
		'dim errorMsg as c
		'errorMsg = "document.getElementById('errorMsg').innerHTML='Error: " + js_escape(cn.CallResult.text) + "';"
		'?"<script>" + errorMsg + "</script>"
		''ui_msg_box("Error","Could not connect to database. Error reported was: " + crlf() + cn.CallResult.text)
		end 
	end if

	dim currData as c
	currData = mandrill_events
	'currData = "Testing"

	'Specify if you are using Portable SQL syntax, or not
	'cn.PortableSQLEnabled = .t. 

	dim args as SQL::Arguments

	args.set("currData",currData)
	
	dim sqlStatement as c 
	sqlStatement = "INSERT INTO tblMandrillTest (TestData) VALUES (:currData)"
	flagResult = cn.Execute(sqlStatement,args)

	if flagResult = .f. then 
		'dim errorMsg as c
		'errorMsg = "document.getElementById('errorMsg').innerHTML='Error: " + js_escape(cn.CallResult.text) + "';"
		'?"<script>" + errorMsg + "</script>"
		''ui_msg_box("Error",cn.CallResult.text)
		'cn.close()
		'end 
	end if 

	cn.close()

%>

My Mandrill Webhook looks like this...

http://www.mywebsite.com/mandrilltest.a5w

That's it. It actually works. 'Cause this stuff is pure voodoo... it's great.

You'll see for currData above I put in a static value at first... just to test the page. I just wanted to write a value to a table. So... do that and just run your page from a browser and check your table. If the static value is there your code is good.

Next, Mandrill sends off it's HTTP Post JSON in 1 Parameter named mandrill_events.

The JSON looks like this...

[
   {
      "event":"send",
      "_id":"123b50e7219d476f123351f628a76123",
      "msg":{
         "ts":1231231231,
         "subject":"Test",
         "email":"[email protected]",
         "tags":[

         ],
         "opens":[

         ],
         "clicks":[

         ],
         "state":"sent",
         "smtp_events":[

         ],
         "subaccount":null,
         "resends":[

         ],
         "reject":null,
         "_id":"123b50e7219d476f123351f628a76123"",
         "sender":"[email protected]",
         "template":null
      },
      "ts":1231231231
   }
]

You can do something like this...

dim mandrillInfo as p
mandrillInfo = json_parse(currData)

And that will shove the JSON into a dot variable and then the world is yours.

This is very cool stuff.

No idea how you'd error check the XBasic for connections etc. But Mandrill has stuff in place in case the webhook fails... so... cool.

[Lenny Forziati]

Re: Setting up a webpage to receive an HTTP Post

David, one minor tweak you may want to consider... Instead of exiting without doing anything if you cannot open the database connection, you may want to instead save Request.Body away as a text file in a known location. You can then process those files later in the event of a database issue instead of losing the information that was POSTed to your page.

[Davidk]

Re: Setting up a webpage to receive an HTTP Post

Thanks Lenny... yes... I was trying to think of something to do if it everything fell down. That would work nicely.

[Steve Workings]

Re: Setting up a webpage to receive an HTTP Post

Ah, thinking about "Disconnected" possibilities are we?