(Ruby) Download Binary File to In-Memory Bytes

This example demonstrates how to download the binary content of a file from Google Drive directly into local memory.

Chilkat Ruby Downloads install from rubygems.org gem install chilkat or download... Ruby Library for Windows, MacOS, Linux, Alpine Linux

require 'chilkat'

success = true

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

# This example uses a previously obtained access token having permission for the 
# Google Drive scope.

gAuth = Chilkat::CkAuthGoogle.new()
gAuth.put_AccessToken("GOOGLE-DRIVE-ACCESS-TOKEN")

rest = Chilkat::CkRest.new()

# Connect using TLS.
# A single REST object, once connected, can be used for many Google Drive REST API calls.
# The auto-reconnect indicates that if the already-established HTTPS connection is closed,
# then it will be automatically re-established as needed.
bAutoReconnect = true
success = rest.Connect("www.googleapis.com",443,true,bAutoReconnect)

# Provide the authentication credentials (i.e. the access token)
rest.SetAuthGoogle(gAuth)

# ------------------------------------------------------------------------------
# To download a file, we must know the file ID.
# In a previous example (see Build Local Metadata Cache
# we built a local cache to make it easy to lookup file IDs given a file path.
# Let's say we want to download "testFolder/abc/123/penguins.jpg".
# First we lookup the fileId in the cache.  With the fileId, we can download the file.
gdCache = Chilkat::CkCache.new()
gdCache.put_Level(0)
gdCache.AddRoot("C:/ckCache/googleDrive")

fileId = gdCache.fetchText("testFolder/abc/123/penguins.jpg")
if (gdCache.get_LastMethodSuccess() != true)
    print "Filepath not found in cache." + "\n";
    exit
end

# We need to send a GET request like this:
# GET https://www.googleapis.com/drive/v3/files/fileId?alt=media
# The fileId is part of the path.
sbPath = Chilkat::CkStringBuilder.new()
sbPath.Append("/drive/v3/files/")
sbPath.Append(fileId)
rest.AddQueryParam("alt","media")

# To download to memory, we'll send the request in one call, then receive
# the response header, and then the response body.
# If the response header indicates failure or an unexpected response, then the
# body is not the data we desire.

# First send the HTTP request.
success = rest.SendReqNoBody("GET",sbPath.getAsString())
if (success != true)
    print rest.lastErrorText() + "\n";
    exit
end

# Get the response header.
statusCode = rest.ReadResponseHeader()
if (statusCode != 200)
    print "response status code = " + rest.get_ResponseStatusCode().to_s() + "\n";
    print "response status text = " + rest.responseStatusText() + "\n";
    print "response header: " + rest.responseHeader() + "\n";

    # Read the response body (which should be error text or HTML)
    errResponseBody = rest.readRespBodyString()
    if (rest.get_LastMethodSuccess() == true)
        print "response body: " + errResponseBody + "\n";
    end

    exit
end

# Read the response body, which should contain the file data.
jpgBytes = Chilkat::CkByteData.new()
success = rest.ReadRespBodyBinary(jpgBytes)
if (rest.get_LastMethodSuccess() != true)
    print rest.lastErrorText() + "\n";
    exit
end

# Save jpgBytes to a file so we can examine the file to verify that it worked.
fac = Chilkat::CkFileAccess.new()
fac.WriteEntireFile("qa_output/penguins_out.jpg",jpgBytes)

print "File downloaded." + "\n";