(CkPython) REST Read Response with Stream API

Demonstrates how to make a REST call that returns a binary body, and to receive the body through a stream API.

Chilkat Python Downloads install with pip pip3 install chilkat or download... Python Module for Windows, MacOS, Linux, Alpine Linux, Solaris

import sys
import chilkat

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

rest = chilkat.CkRest()

# Connect to the Amazon AWS REST server.
bTls = True
port = 443
bAutoReconnect = True
success = rest.Connect("s3.amazonaws.com",port,bTls,bAutoReconnect)

# ----------------------------------------------------------------------------
# Important: For buckets created in regions outside us-east-1,
# there are three important changes that need to be made.
# See Working with S3 Buckets in Non-us-east-1 Regions for the details.
# ----------------------------------------------------------------------------

# Provide AWS credentials for the REST call.
authAws = chilkat.CkAuthAws()
authAws.put_AccessKey("AWS_ACCESS_KEY")
authAws.put_SecretKey("AWS_SECRET_KEY")
authAws.put_ServiceName("s3")
success = rest.SetAuthAws(authAws)

# Set the bucket name via the HOST header.
# In this case, the bucket name is "chilkat100".
rest.put_Host("chilkat100.s3.amazonaws.com")

# Send the request to download the JPG.
success = rest.SendReqNoBody("GET","/starfish.jpg")
if (success != True):
    print(rest.lastErrorText())
    sys.exit()

# Read the response header.
responseStatusCode = rest.ReadResponseHeader()
if (responseStatusCode < 0):
    print(rest.lastErrorText())
    sys.exit()

print("Response status code = " + str(responseStatusCode))

# We expect a 200 response status if the JPG data is coming.
# Otherwise, we'll get a string response body with an error message(or no response body).
if (responseStatusCode != 200):
    errResponse = rest.readRespBodyString()
    if (rest.get_LastMethodSuccess() != True):
        print(rest.lastErrorText())
    else:
        print(errResponse)

    sys.exit()

bodyStream = chilkat.CkStream()
# Set a 10 second read timeout for the stream. 
# (Give up if no data arrives within 10 seconds after calling a read method.)
bodyStream.put_ReadTimeoutMs(10000)

# Create a background thread task to read the response body (which feeds
# it to the bodyStream object.)
# readResponseBodyTask is a CkTask
readResponseBodyTask = rest.ReadRespBodyStreamAsync(bodyStream,True)

# Start the task. 
success = readResponseBodyTask.Run()

# The application can now read the bodyStream...
nextChunk = chilkat.CkByteData()
while (bodyStream.get_EndOfStream() != True) :

    # Read the next chunk of bytes (whatever is immediately available,
    # or wait for more data (up to 10 seconds because we set the stream's ReadTimeoutMs property)
    success = bodyStream.ReadBytes(nextChunk)
    if (success != True):
        print("Failed to receive more response data.")
        # Make sure the background task is aborted/cancelled.
        success = readResponseBodyTask.Cancel()

        sys.exit()

    # OK.. the app has the next chunk of the body, and may do whatever it wishes with it...
    # See the CkByteData online reference documentation for 
    # information about accessing and manipulating the byte data.

print("Successfully received the entire response body.")