POST url encoded form to Amazon API Gateway

Question

I'm creating a webhook to receive notifications from a 3rd-party service, they sent the data in the body of a POST with content type application/x-www-form-urlencoded.

But it generates the same error:

{"message": "Could not parse request body into json: Unrecognized token \'name\': was expecting \'null\', \'true\', \'false\' or NaN\n at [Source: [B@456fe137; line: 1, column: 6]"}

I could reproduce the error with the following curl call:

% curl -v -X POST -d 'name=Ignacio&city=Tehuixtla' https://rl9b6lh8gk.execute-api.us-east-1.amazonaws.com/prod/mandrillListener
*   Trying 54.230.227.63...
* Connected to rl9b6lh8gk.execute-api.us-east-1.amazonaws.com (54.230.227.63) port 443 (#0)
* TLS 1.2 connection using TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
* Server certificate: *.execute-api.us-east-1.amazonaws.com
* Server certificate: Symantec Class 3 Secure Server CA - G4
* Server certificate: VeriSign Class 3 Public Primary Certification Authority - G5
> POST /prod/mandrillListener HTTP/1.1
> Host: rl9b6lh8gk.execute-api.us-east-1.amazonaws.com
> User-Agent: curl/7.43.0
> Accept: */*
> Content-Length: 27
> Content-Type: application/x-www-form-urlencoded
>
* upload completely sent off: 27 out of 27 bytes
< HTTP/1.1 400 Bad Request
< Content-Type: application/json
< Content-Length: 180
< Connection: keep-alive
< Date: Thu, 28 Jan 2016 12:29:40 GMT
< x-amzn-RequestId: cd4d9232-c5ba-11e5-a158-b9b39f0b0599
< X-Cache: Error from cloudfront
< Via: 1.1 1915b8b49d2fbff532431a79650103eb.cloudfront.net (CloudFront)
< X-Amz-Cf-Id: cxU2_b5DzIw4M_n3hJBFXTu9AVRBL3GpbQqUId9IxgS004DfLYqYmg==
<
* Connection #0 to host rl9b6lh8gk.execute-api.us-east-1.amazonaws.com left intact
{"message": "Could not parse request body into json: Unrecognized token \'name\': was expecting \'null\', \'true\', \'false\' or NaN\n at [Source: [B@d92973b; line: 1, column: 6]"}

If I wrap the body with double-quotes it works fine:

% curl -v -X POST -d '"name=Ignacio&city=Tehuixtla"' https://rl9b6lh8gk.execute-api.us-east-1.amazonaws.com/prod/mandrillListener
*   Trying 54.230.227.19...
* Connected to rl9b6lh8gk.execute-api.us-east-1.amazonaws.com (54.230.227.19) port 443 (#0)
* TLS 1.2 connection using TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
* Server certificate: *.execute-api.us-east-1.amazonaws.com
* Server certificate: Symantec Class 3 Secure Server CA - G4
* Server certificate: VeriSign Class 3 Public Primary Certification Authority - G5
> POST /prod/mandrillListener HTTP/1.1
> Host: rl9b6lh8gk.execute-api.us-east-1.amazonaws.com
> User-Agent: curl/7.43.0
> Accept: */*
> Content-Length: 29
> Content-Type: application/x-www-form-urlencoded
>
* upload completely sent off: 29 out of 29 bytes
< HTTP/1.1 200 OK
< Content-Type: application/json
< Content-Length: 6
< Connection: keep-alive
< Date: Thu, 28 Jan 2016 12:33:20 GMT
< x-amzn-RequestId: 50610606-c5bb-11e5-b140-5d837ffe26ed
< X-Cache: Miss from cloudfront
< Via: 1.1 a670cda0e28541e40881b95b60c672b7.cloudfront.net (CloudFront)
< X-Amz-Cf-Id: mCLKL4eOnpUMd15IXQZw0RStJHw9Vdf3ivdCl37dcmno2JFOfxw0Vg==
<
* Connection #0 to host rl9b6lh8gk.execute-api.us-east-1.amazonaws.com left intact
"true"%

The lamba has only one line:

context.succeed('true');

How can I make the api gateway do not treat the body as json?

I tried the documentation about template mapping with no success, I even tried to convert it to a static template, with no variables at all! In all cases the error happens before getting to my code.

Answer 1

The mapping template to make form data work is pretty complicated. Here is a gist: https://gist.github.com/ryanray/668022ad2432e38493df

Also, you can see this post I wrote that has an example of how to integrate with Slack(their hooks send a POST as form data to API Gateway): http://www.ryanray.me/serverless-slack-integrations