CkPython

Wasabi File Streaming Upload

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Demonstrates how to do a streaming upload from a file to the Wasabi storage service. The AWS authorization presents some difficulties when the REST request body is to be streamed from a file (or from some other source). The issue is that the SHA-256 hash of the file data must be calculated. There are only two possible ways to do this: (1) stream the file into memory in its entirety and calculate the SHA-256 hash prior to uploading, or (2) pre-calculate the SHA-256 in a streaming fashion, and then provide it to the AWS authentication object.

If the application does NOT pre-compute the SHA-256, then Chilkat (internally) is forced to stream into memory, calculate the SHA-256, and then upload from the in-memory copy of the file.

CkPython

import sys
import chilkat

success = False

# This example requires the Chilkat API to have been previously unlocked.
# See Global Unlock Sample for sample code.

# This first part is optional.  AWS authentication requires
# the SHA-256 hash of the request body (i.e. the contents of the file
# to be uploaded).  We can choose to pre-calculate the SHA-256 in a streaming fashion
# and then provide it to the authenticator object.  This way, if the file is
# extremely large, it never needs to completely reside in memory.
crypt = chilkat.CkCrypt2()
# ----------------------------------------------------
# Important: Wasabi requires a lowercase hex format.
# ----------------------------------------------------
crypt.put_EncodingMode("hex-lower")
crypt.put_HashAlgorithm("sha-256")
fileToUploadPath = "qa_data/xml/hamlet.xml"
hashStr = crypt.hashFileENC(fileToUploadPath)

rest = chilkat.CkRest()

# Connect to the Amazon AWS REST server.
bTls = True
port = 443
bAutoReconnect = True
# This example will demonstrate uploading to a bucket in the eu-west-2 region
success = rest.Connect("s3.eu-west-2.wasabisys.com",port,bTls,bAutoReconnect)

# Provide AWS credentials for the REST call.
authAws = chilkat.CkAuthAws()
authAws.put_AccessKey("access-key")
authAws.put_SecretKey("secret-key")
authAws.put_ServiceName("s3")
# Provide the pre-computed SHA-256 here:
authAws.put_PrecomputedSha256(hashStr)

success = rest.SetAuthAws(authAws)

rest.AddHeader("Expect","100-continue")
rest.AddHeader("Content-Type","application/xml")

# Set the bucket name via the HOST header.
# In this case, the bucket name is "chilkat100".
rest.put_Host("chilkat100.s3.eu-west-2.wasabisys.com")

fileStream = chilkat.CkStream()
fileStream.put_SourceFile(fileToUploadPath)

# Upload to the Wasabi Storage service.
# If the application provided the SHA-256 hash of the file contents (as shown above)
# then file is streamed and never has to completely reside in memory.
# If the application did NOT provide the SHA-256, then Chilkat will (internally) 
# load the entire file into memory, calculate the SHA-256, and then upload.
responseStr = rest.fullRequestStream("PUT","/hamlet.xml",fileStream)
if (rest.get_LastMethodSuccess() != True):
    print(rest.lastErrorText())
    sys.exit()

# When successful, the Wasabi Storage service will respond with a 200 response code,
# with an XML body.  
if (rest.get_ResponseStatusCode() == 200):
    print(responseStr)
    print("File uploaded.")
else:
    # Examine the request/response to see what happened.
    print("response status code = " + str(rest.get_ResponseStatusCode()))
    print("response status text = " + rest.responseStatusText())
    print("response header: " + rest.responseHeader())
    print("response body: " + responseStr)
    print("---")
    print("LastRequestStartLine: " + rest.lastRequestStartLine())
    print("LastRequestHeader: " + rest.lastRequestHeader())