SP-API "Invalid Input" error for all report requests

Question

When I make requests to the 'Inventory' or 'Sales' endpoints, I get successful responses. This confirms that my signature and IAM are correct. I am manually signing the requests because I am not sure how to use boto3 to create the signature.

I am not sure why, but when making POST requests, the response will state The Canonical String for this request should have been... and provides the payload_hash below. I am copy/pasting the string provides. Once I do this, I then get the InvalidInput response. However, when using GET requests, I am able to use payload_hash = hashlib.sha256(('').encode('utf-8')).hexdigest() as seen below and it works fine.

This is the same response as with GET_SALES_AND_TRAFFIC_REPORT and other reports.

CREATING CANONICAL STRING:

t = datetime.datetime.utcnow()
amzdate = t.strftime('%Y%m%dT%H%M%SZ')
datestamp = t.strftime('%Y%m%d')

canonical_querystring = '/reports/2021-06-30/reports'
signed_headers = 'host;user-agent;x-amz-access-token;x-amz-date'
payload_hash = 'deda182f2e780e6c5e6abb9b19a087a8db6c620c39e784bf4a3384e76d742278'
# payload_hash = hashlib.sha256(('').encode('utf-8')).hexdigest()

canonical_request = method + '\n' + canonical_querystring + '\n' + '\n' +  'host:' + host + '\n' + 'user-agent:python-requests/2.27.1'  + '\n' + 'x-amz-access-token:' + access  + '\n' + 'x-amz-date:' + amzdate + '\n' + '\n' + signed_headers + '\n' +  payload_hash

REQUEST:

headers = {
    'x-amz-access-token': access,
    'x-amz-date':amzdate,
    'Authorization':authorization_header,
    'Content-Type': 'application/json'
}

data = {
    'marketplaceIds':'ATVPDKIKX0DER',
    'reportType': 'GET_SALES_AND_TRAFFIC_REPORT',
    'dataStartTime':'2022-03-10T20:11:24.000Z',
    'dataEndTime':'2022-03-20T20:11:24.000Z',
    'reportOptions':{
        'dateGranularity':'WEEK',
        'asinGranularity':'CHILD'
    }
}

r = requests.post(
    'https://sellingpartnerapi-na.amazon.com/reports/2021-06-30/reports',
    headers = headers,
    data = data
)
print(r)
print(r.text)

RESPONSE:

<Response [400]>
{
  "errors": [
    {
      "code": "InvalidInput",
      "message": "Invalid Input",
      "details": ""
    }
  ]
}

Answer 1

Took me awhile to get the signing stuff to work in postman, just looking at your request I believe MarketplaceIds needs to be an array, although you would get a specific error if that was the main problem:

"marketplaceIds": [
    "ATVPDKIKX0DER"
]

Answer 2

I was just working on this. So, I used AWS4Auth for creating a canonical string just to be sure that I'm not messing with any of it.

A way to do that: (Assuming you have already generated LWA access token, which I can see in your header as 'access')

import json
import boto3
from requests_aws4auth.aws4auth import AWS4Auth

client = boto3.client('sts')
aws_account_id = 'YOUR_ACCOUNT_ID'
iamrole = 'arn:aws:iam::'+aws_account_id+':role/YOU_ROLE_NAME'
response = client.assume_role(
    RoleArn= iamrole,
    RoleSessionName='SPAPIRoleSession'
)

# Initializing AccessKey, SecretKey and SessionToken variables to be used in signature signing.
AccessKeyId = response['Credentials']['AccessKeyId']
SecretAccessKey = response['Credentials']['SecretAccessKey']
SessionToken = response['Credentials']['SessionToken']

#add your region accordingly: my region is us-east-1
auth = AWS4Auth(AccessKeyId, SecretAccessKey, 'us-east-1', 'execute-api', session_token=SessionToken) 

# Create headers to add to SP API request. Headers should include: content_type and "x-amz-access-token"(b)
headers = {'content-type': 'application/json','Accept': 'application/json','x-amz-access-token':access}

#your params: I made a small change to 'dataEndTime', if you mentioned the granularity as a week, make sure the start and end dates are 7 days apart. Look at the AWS documentation for more details
data = {
'marketplaceIds':'ATVPDKIKX0DER',
'reportType': 'GET_SALES_AND_TRAFFIC_REPORT',
'dataStartTime':'2022-03-10T20:11:24.000Z',
'dataEndTime':'2022-03-17T20:11:24.000Z',
'reportOptions':{
    'dateGranularity':'WEEK',
    'asinGranularity':'CHILD'}
       }

# Change data to json and add auth as additional parameter
reportId = requests.post("https://sellingpartnerapi-na.amazon.com/reports/2021-06-30/reports", 
           json=(data), 
           headers=headers, 
           auth=auth)

print(reportId)    
print(reportId.json())

RESPONSE:

<Response [202]>

{'reportId': '54120019456'}  

This should result in giving you the reportId required. Let me know if this helps. Thanks