S3 generate_presigned_url is not working with md5 hash

The pre-signed url is not working with md5 hash. Normally when put

params = {'Bucket': bucket_name, 'Key': key}
url = s3_client.generate_presigned_url('put_object',
                                               Params=params,
                                               ExpiresIn=3600)

it works.

But when put any other put_object parameter like ACL md5 etc it throws

params = {'Bucket': bucket_name, 'Key': key, 
                  'ACL': 'public-read', 'ContentMD5': '1cx12....'}
url = s3_client.generate_presigned_url('put_object',
                                               Params=params,
                                               ExpiresIn=3600)

Error><Code>SignatureDoesNotMatch</Code><Message>
The request signature we calculated does not match the 
signature you provided. Check your key and signing method

If trying put header like Content-MD5 in put request it throws Headers not signed. My S3 client is like

s3 = boto3.client('s3',
                      region_name=app.config['AWS_REGION'],
                      aws_access_key_id=app.config['AWS_ACCESS_KEY_ID'],
                      config=Config(signature_version='s3v4'),
                      aws_secret_access_key=app.config['AWS_SECRET_ACCESS_KEY']
                      )

I am using boto3==1.4.1

[subhankarb]

@JordonPhillips thanks a lot, it is working. I am posting the working example for future reference.

import boto3
import requests

parts = s3_client.generate_presigned_post(Bucket=bucket_name,
                                              Key=key,
                                              Fields={
                                                'acl': 'public-read',
                                                'Content-MD5': str(md5),
                                                'Content-Type': 'binary/octet-stream'
                                                },
                                              Conditions=[
                                                  {"acl": "public-read"},
                                                  ["starts-with", "$Content-Type", ""],
                                                  ["starts-with", "$Content-MD5", ""]
                                              ]
                                          )

url = parts['url']
data = parts['fields']
files = {'file': open(local_path, 'rb')} # the key supposed to be file may be
response = requests.post(url, data=data, files=files)

Closing the issue

[duhaime]

Examples of both POST and PUT methods:

import boto3
import requests

access_key_id = 'AKIA....'
secret_access_key = 'LfNHsQ....'
bucket = 'images-dev'
filename = 'beautiful.png'

s3_client = boto3.client(
  's3',
  aws_access_key_id=access_key_id,
  aws_secret_access_key=secret_access_key
)

PUT:

response = s3_client.generate_presigned_url(
  ClientMethod = 'put_object',
  Params = {
    'Bucket': bucket,
    'Key': filename,
  }
)

# put
r = requests.put(response, data=open(filename, 'rb'))
print(r.status_code)

POST:

# sign url
response = s3_client.generate_presigned_post(
  Bucket = bucket,
  Key = filename,
)

# post
r = requests.post(response['url'], data=response['fields'], files={
  'file': open(filename, 'rb')
})
print(r.status_code)