Unable to serialize map types for rest-xml

[jamesls]

I don't believe there's a pre-existing issue filed for botocore against this.

This has been reported in the AWS CLI repo here: aws/aws-cli#356

The fix will have to happen in botocore.

From looking into this, it looks like the Map parameter is missing a build_parameter_rest. It has a build_parameter_query/build_parameter_json method, but the build_parameter_rest is inherited from the base class. This means that the final serialization of the metadata param is:

{'headers': {u'x-amz-meta-': {'mykey2': 'myvalue2', 'mykey': 'myvalue'}, ...,
 'uri_params': {u'Bucket': 'test', u'Key': 'copied.txt'},
 'payload': <botocore.payload.XMLPayload object at 0x1034a2ed0>}

And because x-amz-meta- is a dictionary, this will raise an error later on in the auth module which expects the header to be a string. The expected serialization is:

{'headers': {'x-amz-meta-mykey': 'myvalue', 'x-amz-meta-mykey2': 'myvalue2'}}

From what I can tell, s3 is the only rest-xml service that uses map types, so we can put in a specific case for rest-xml:

$ fgrep "rest-xml" *.json
cloudfront.json:  "type": "rest-xml",
route53.json:  "type": "rest-xml",
s3.json:  "type": "rest-xml",

$ fgrep '"type": "map"' s3.json cloudfront.json route53.json
s3.json:            "type": "map",
s3.json:            "type": "map",
s3.json:            "type": "map",
s3.json:            "type": "map",
s3.json:            "type": "map",

[jamesls]

I might be missing something here, but it looks like we also don't properly parse HeadObject calls that return metadata:

>>> op.call(endpoint, bucket='bucket', key='copied.txt')[1]
...
2014-04-21 13:24:36,781 - botocore.response - DEBUG - Response Headers:
content-length: 0
accept-ranges: bytes
server: AmazonS3
last-modified: Mon, 21 Apr 2014 20:22:37 GMT
etag: "d41d8cd98f00b204e9800998ecf8427e"
date: Mon, 21 Apr 2014 20:24:37 GMT
x-amz-meta-mykey1: value1      <-------- this is not being returned.
content-type: application/json
...
{u'LastModified': 'Mon, 21 Apr 2014 20:22:37 GMT', u'AcceptRanges': 'bytes', u'ETag': '"d41d8cd98f00b204e9800998ecf8427e"', u'ContentType': 'application/json', u'ContentLength': '0'}