Cfhttp post to AWS S3 works in CF9 but fails in CF10

Question

I'm using the Instructure Canvas API for uploading files. After the initial API call, Canvas returns information that is used to make a POST request to Amazon Web Services's S3 service to upload a file.
Here is the request I'm using to post the file to AWS S3, populated with the data returned by the Canvas API:
<cfhttp url="#aws.upload_url#" result="result" method="post" multipart="yes">
          <cfhttpparam type="formfield" name="key" value="#aws.upload_params.key#" />
          <cfhttpparam type="formfield" name="acl" value="#aws.upload_params.acl#" />
          <cfhttpparam type="formfield" name="Filename" value="#photoName#" />
          <cfhttpparam type="formfield" name="AWSAccessKeyId" value="#aws.upload_params.AWSAccessKeyId#" />
          <cfhttpparam type="formfield" name="Policy" value="#aws.upload_params.Policy#" />
          <cfhttpparam type="formfield" name="Signature" value="#aws.upload_params.Signature#" />
          <cfhttpparam type="formfield" name="Content-Type" value="#aws.upload_params['content-type']#" />
          <cfhttpparam type="formfield" name="success_action_redirect" value="#aws.upload_params['success_action_redirect']#" />
          <cfhttpparam type="file" name="file" file="#fullPath#" />
</cfhttp>
This request works on a ColdFusion 9 server (the response returns "200 OK"), but fails on a ColdFusion 10 server (the response returns "500 Internal Server Error"). The Canvas API call works in both cases.
Any ideas or suggestions appreciated.

Answer 1

Thanks for the replies. I used cfdump to examine the results, but other than a custom 500 error page, I didn't see anything out of the ordinary.
Using CF's built-in S3 capabilities may work. I haven't used it before and so I was just following the steps provided in Canvas's documentation. I am not positive how to use the data returned from the initial Canvas API call to form the S3 request. I tried the following:
<cffile
    action="write"
    output="S3 Specifications"     file="s3://#jsonData.upload_params.AWSAccessKeyId#:#jsonData.upload_params.policy#@#Repla ce(jsonData.upload_url,'https://','','ALL')##jsonData.upload_params.key#"/>
Assuming that the returned policy value (a 545-character random string) is the secrect key and that the upload_params_key should be appended to the bucket location (it looks approximately like this: account_XXXXX/attachments/XXXXXXXX/XXXXXXXXXX.jpg). I was getting a SignatureDoesNotMatch error from that request.
Additionally, I tried sending the requests to a basic web server that should capture the request data and write them to a file. It doesn't look like it worked like I expected it to--I'm not sure why neither instance includes all the data--but here are the results in case they are relevant:
CF9:
POST / HTTP/1.1
Host: osric.com:50000
Connection: close, TE
TE: trailers, deflate, gzip, compress
User-Agent: ColdFusion
Accept-Encoding: deflate, gzip, x-gzip, compress, x-compress
Content-type: multipart/form-data; boundary=-----------------------------7d0d117230764
Content-length: 6289
CF10:
POST / HTTP/1.1
User-Agent: ColdFusion
Content-Type: multipart/form-data; boundary=-----------------------------7d0d117230764
Connection: close
Content-Length: 6289
Host: osric.com:50000
-------------------------------7d0d117230764
Content-Disposition: form-data; name="key"
Content-Type: text/plain; charset=UTF-8
account_XXXXX/attachments/XXXXXXXX/XXXXXXXXX.jpg
-------------------------------7d0d117230764
Content-Disposition: form-data; name="acl"
Content-Type: text/plain; charset=UTF-8
private
-------------------------------7d0d117230764
Content-Disposition: form-data; name="Filename"
Content-Type: text/plain; charset=UTF-8
XXXXXXXXX.jpg
-------------------------------7d0d117230764
Content-Disposition: form-data; name="AWSAccessKeyId"
Content-Type: text/plain; charset=UTF-8
XXXXXXXXXXXXXXXXXXXXXX
-------------------------------7d0d117230764
Content-Disposition: form-data; name="Policy"
Content-Type: text/plain; charset=UTF-8
XXXXXXXXXXXXXXXXXXXXX[...lots of characters...]XXXXX
-------------------------------7d0d117230764
Content-Disposition: form-data; name="Signature"
Content-Type: text/plain; charset=UTF-