ryanray · October 4, 2015 01:24 · Oct 4, 2015
diff --git a/aws-api-gateway-form-to-json.ftl b/aws-api-gateway-form-to-json.ftl
@@ -0,0 +1,51 @@
+## convert HTML POST data or HTTP GET query string to JSON
+ 
+## get the raw post data from the AWS built-in variable and give it a nicer name
+#if ($context.httpMethod == "POST")
+ #set($rawAPIData = $input.path('$'))
+#elseif ($context.httpMethod == "GET")
+ #set($rawAPIData = $input.params().querystring)
+ #set($rawAPIData = $rawAPIData.toString())
+ #set($rawAPIDataLength = $rawAPIData.length() - 1)
+ #set($rawAPIData = $rawAPIData.substring(1, $rawAPIDataLength))
+ #set($rawAPIData = $rawAPIData.replace(", ", "&"))
+#else
+ #set($rawAPIData = "")
+#end
+ 
+## first we get the number of "&" in the string, this tells us if there is more than one key value pair
+#set($countAmpersands = $rawAPIData.length() - $rawAPIData.replace("&", "").length())
+ 
+## if there are no "&" at all then we have only one key value pair.
+## we append an ampersand to the string so that we can tokenise it the same way as multiple kv pairs.
+## the "empty" kv pair to the right of the ampersand will be ignored anyway.
+#if ($countAmpersands == 0)
+ #set($rawPostData = $rawAPIData + "&")
+#end
+ 
+## now we tokenise using the ampersand(s)
+#set($tokenisedAmpersand = $rawAPIData.split("&"))
+ 
+## we set up a variable to hold the valid key value pairs
+#set($tokenisedEquals = [])
+ 
+## now we set up a loop to find the valid key value pairs, which must contain only one "="
+#foreach( $kvPair in $tokenisedAmpersand )
+ #set($countEquals = $kvPair.length() - $kvPair.replace("=", "").length())
+ #if ($countEquals == 1)
+  #set($kvTokenised = $kvPair.split("="))
+  #if ($kvTokenised[0].length() > 0)
+   ## we found a valid key value pair. add it to the list.
+   #set($devNull = $tokenisedEquals.add($kvPair))
+  #end
+ #end
+#end
+ 
+## next we set up our loop inside the output structure "{" and "}"
+{
+#foreach( $kvPair in $tokenisedEquals )
+  ## finally we output the JSON for this pair and append a comma if this isn't the last pair
+  #set($kvTokenised = $kvPair.split("="))
+ "$util.urlDecode($kvTokenised[0])" : #if($kvTokenised[1].length() > 0)"$util.urlDecode($kvTokenised[1])"#{else}""#end#if( $foreach.hasNext ),#end
+#end
+}